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  Subjects -> AGRICULTURE (Total: 821 journals)
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Showing 1 - 48 of 48 Journals sorted alphabetically
Acta Agriculturae Scandinavica, Section A - Animal Sciences     Hybrid Journal   (Followers: 9)
Acta Scientiarum. Animal Sciences     Open Access   (Followers: 3)
Advances in Animal Biosciences     Full-text available via subscription   (Followers: 9)
African Journal of Livestock Extension     Full-text available via subscription   (Followers: 1)
Animal Biotechnology     Hybrid Journal   (Followers: 10)
Animal Cells and Systems     Hybrid Journal   (Followers: 4)
Animal Nutrition     Open Access   (Followers: 17)
Animal Production     Open Access   (Followers: 3)
Animal Production Science     Hybrid Journal   (Followers: 2)
Animal Reproduction     Open Access   (Followers: 3)
Animal Reproduction Science     Hybrid Journal   (Followers: 6)
Animal Research International     Full-text available via subscription   (Followers: 6)
Animal Science Journal     Hybrid Journal   (Followers: 6)
Archives Animal Breeding     Open Access   (Followers: 3)
Archives of Animal Nutrition     Hybrid Journal   (Followers: 7)
Asian-Australasian Journal of Animal Sciences     Open Access  
Bangladesh Journal of Animal Science     Open Access   (Followers: 2)
Boletim de Indústria Animal     Open Access  
Bulletin of Animal Health and Production in Africa     Full-text available via subscription   (Followers: 2)
Canadian Journal of Animal Science     Hybrid Journal   (Followers: 5)
Indian Journal of Animal Sciences     Open Access   (Followers: 7)
International Journal of Health, Animal Science and Food Safety     Open Access   (Followers: 3)
International Journal of Livestock Production     Open Access   (Followers: 1)
Journal of Animal Breeding and Genetics     Hybrid Journal   (Followers: 4)
Journal of Animal Science     Full-text available via subscription   (Followers: 13)
Journal of Animal Science and Biotechnology     Open Access   (Followers: 6)
Journal of Animal Science and Technology     Open Access   (Followers: 2)
Journal of Applied Animal Nutrition     Hybrid Journal   (Followers: 3)
Journal of Applied Animal Welfare Science     Hybrid Journal   (Followers: 14)
Journal of Applied Poultry Research     Hybrid Journal   (Followers: 5)
Journal of World's Poultry Research     Open Access   (Followers: 2)
Jurnal Agripet     Open Access   (Followers: 1)
Jurnal Ilmu Produksi dan Teknologi Hasil Peternakan     Open Access  
La Chèvre     Full-text available via subscription  
Nigerian Journal of Animal Science     Full-text available via subscription   (Followers: 1)
Nutrición Animal Tropical     Open Access   (Followers: 2)
Online Journal of Animal and Feed Research     Open Access   (Followers: 4)
Open Journal of Animal Sciences     Open Access   (Followers: 5)
Porcine Health Management     Open Access  
Poultry Science     Hybrid Journal   (Followers: 4)
Poultry Science Journal     Open Access   (Followers: 2)
Research in Agriculture, Livestock and Fisheries     Open Access  
Revista Brasileira de Saúde e Produção Animal     Open Access  
Revista Mexicana de Ciencias Pecuarias     Open Access   (Followers: 1)
The Professional Animal Scientist     Hybrid Journal  
Tropical Animal Health and Production     Hybrid Journal  
Veeplaas     Full-text available via subscription  
World Rabbit Science     Open Access  
Journal Cover Journal of Animal Science
  [SJR: 1.377]   [H-I: 114]   [13 followers]  Follow
   Full-text available via subscription Subscription journal
   ISSN (Print) 0021-8812 - ISSN (Online) 1525-3163
   Published by American Society of Animal Science Homepage  [1 journal]
  • Effects of rotating antibiotic and ionophore feed additives on volatile
           fatty acid production, potential for methane production, and microbial
           populations of steers consuming a moderate-forage diet
    • Authors: W. L. Crossland; L. O. Tedeschi, T. R. Callaway, M. D. Miller, W. B. Smith M. Cravey
      Abstract: Ionophores and antibiotics have been shown to decrease ruminal methanogenesis both in vitro and in vivo but have shown little evidence toward a sustainable means of mitigation. Feed additive rotation was proposed and investigated for methane, VFA, and microbial population response. In the present study, cannulated steers (n = 12) were fed a moderate-forage basal diet in a Calan gate facility for 13 wk. In addition to the basal diet, steers were randomly assigned to 1 of 6 treatments: 1) control, no additive; 2) bambermycin, 20 mg bambermycin/d; 3) monensin, 200 mg monensin/d; 4) the basal diet + weekly rotation of bambermycin and monensin treatments (B7M); 5) the basal diet + rotation of bambermycin and monensin treatments every 14 d (B14M); and 6) the basal diet + rotation of bambermycin and monensin treatments every 21 d (B21M). Steers were blocked by weight in a randomized complete block design where the week was the repeated measure. Rumen fluid was collected weekly for analysis (n = 13), and results were normalized according to individual OM intake (OMI; kg/d). Potential activity of methane production was not significantly different among treatments (P> 0.05). However, treatment tended to affect the CH4–to-propionate ratio (P = 0.0565), which was highest in the control and lowest in the monensin, B21M, and B14M treatments (0.42 vs. 0.36, 0.36, and 0.33, respectively). The CH4:propionate ratio was lowest in wk 2 and 3 (P < 0.05) but the ratio in wk 4 to 12 was not different from the ratio in wk 0. Week also affected total VFA, with total VFA peaking at wk 3 and plummeting at wk 4 (4.02 vs. 2.86 mM/kg OMI; P < 0.05). A significant treatment × week interaction was observed for the acetate-to-propionate (A:P) ratio, where bambermycin- and rotationally fed steers did not have a reduced A:P ratio compared with monensin-fed steers throughout the feeding period (P < 0.0001). Microbial analysis revealed significant shifts, but several predominant classes showed adaptation between 4 and 6 wk after additive initiation. There was no significant evidence to suggest that rotations of monensin and bambermycin provided additional benefits to steers consuming a moderate-forage diet at the microbial/animal and environmental level versus those continuously fed.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1665
      Issue No: Vol. 0, No. 0 (2017)
  • Rapid Communication: Period2 gene silencing increases the synthesis of
           αs–casein protein in bovine mammary epithelial cells1
    • Authors: L.Y. Hu; M.Z. Wang, J.L. Ouyang, P.F. Li J. J. Loor
      Abstract: Period2 (PER2), a core clock gene, encodes a circadian rhythm protein which has been shown to control mammary metabolism in rodents. Whether PER2 regulates milk component synthesis such as αs–casein protein in bovine mammary cells is unknown. Thus, we used gene silencing technology to determine if PER2 silencing could affect αs–casein synthesis and cell growth in cultured primary bovine mammary epithelial cells (BMEC). The BMEC were established by enzymatic digestion of mammary tissue from mid-lactation cows. A transient-transfection technique was used to insert a small interfering RNA (siRNA) oligonucleotide specific for PER2 to inhibit transcription. Control and siRNA-transfected cells were cultured for 48 h. qRT-PCR and ELISA analysis showed that PER2 silencing enhanced the synthesis of 2 kinds of αs–casein (P < 0.05) through upregulating the mRNA level of CSN1S1 and CSN1S2 (P < 0.01). Furthermore, the 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) results demonstrated that cell proliferation was not affected (P> 0.05). These data led us to hypothesize that PER2 protein may potentially play an important role in the control of milk protein synthesis and, hence, represents a target that can be used to regulate protein synthesis rate during lactation.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1938
      Issue No: Vol. 0, No. 0 (2017)
  • Effect of band and knife castration of beef calves on welfare indicators
           of pain at three relevant industry ages: II. Chronic pain1
    • Authors: S. Marti; D. M. Meléndez, E. A. Pajor, D. Moya, C. E. M. Heuston, D. Gellatly, E. D. Janzen K. S. Schwartzkopf-Genswein
      Abstract: Three experiments were conducted to evaluate the effects of band and knife castration on behavioral and physiological indicators of chronic pain in beef calves at 3 different ages (36 calves/age group): 1 wk of age (Exp. 1, 4 ± 1.1 d of age, 43 ± 1.1 kg BW), 2 mo of age (Exp. 2, 63 ± 2.3 d of age, 92 ± 1.7 kg BW), and 4 mo of age (Exp. 3, 125 ± 4.6 d of age, 160 ± 3.4 kg BW). In each experiment calves were randomly assigned to either sham (CT), band (BA) or knife (KN) castration. Experiments 1, 2, and 3 ended when the testicles of banded calves had sloughed off (68, 49, and 42 d, respectively). Animal BW and rectal temperature were recorded weekly over the experimental period. Salivary cortisol, substance P, haptoglobin, scrotal area temperature using infrared thermography, visual evaluation of swelling (5-point scale), and gait stride length were collected on d −1 and immediately before castration and weekly thereafter until the end of the study. Hair samples were collected 1 d prior to and 28 d after castration and at the end of the study for cortisol concentration. Standing and lying behaviors were recorded over a 28-d period immediately after castration. No differences (P> 0.10) were observed in salivary cortisol, substance P, haptoglobin, or hair cortisol among castration methods for any of the 3 ages. No changes in behavior were observed in calves castrated at 1 wk or 2 mo of age. In 4 mo-old-calves, BA spent less time lying (P < 0.01) than CT and KN calves. Also, the average duration of lying time for BA calves was greater (P < 0.05) than for CT calves. Both, 1-wk- and 2-mo-old calves had inflammation in the scrotal area lasting 7 d after KN castration, whereas inflammation was observed for up to 14 d in 4-mo-old calves. Swelling in BA calves lasted for 21 to 28 d in the 2 younger groups of calves, whereas in 4-mo-old calves swelling was observed until d 35 postcastration. Knife- and band-castrated calves did not exhibit indicators of chronic pain or distress when the procedures were performed in calves younger than 2 mo of age. Therefore, pain mitigation should be used when castrating to improve animal welfare, especially when castrations are performed in calves older than 2 mo of age independent of the method of castration.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1763
      Issue No: Vol. 0, No. 0 (2017)
  • Prepartum daylight exposure increases serum calcium concentrations in
           dairy cows at the onset of lactation1
    • Authors: R. Özçelik; R. M. Bruckmaier L. E. Hernández-Castellano
      Abstract: In dairy cows, hypocalcemia is caused by the sudden calcium demand by the mammary gland at the onset of lactation. Calcitriol (1,25-dihydroxy vitamin D; 1,25-VitD) increases the intestinal calcium absorption and the renal calcium reabsorption. Daylight contributes to the formation of 1,25-VitD, as it transforms 7-dehydrocholesterol into cholecalciferol, a 1,25-VitD precursor. Calving pens are usually set in quiet places where cows can stay calm and relaxed before parturition. However, those pens often have poor lighting conditions and therefore cows may become vitamin D deficient because of inadequate daylight exposure. Therefore, we have tested the hypothesis that direct daylight exposure supports the synthesis of 1,25-VitD and consequently attenuates the decline of calcium concentrations at parturition. Twenty Holstein dairy cows were randomly assigned to 2 experimental groups (daylight group, DL; and control group). Beginning on d -10 before expected parturition, both groups were placed in a standard indoor calving pen from 1700 h to 800 h. From 800 h to 1700 h cows from the DL group were moved into a contiguous open pen with direct access to daylight whereas controls remained at the standard indoor calving pen. After parturition both groups were permanently placed in an indoor calving pen until the end of the experimental period (d 30 postpartum). Blood samples were collected daily from d -10 prior to expected parturition through d 7 postpartum with an additional sample on d 30 postpartum. Milk yield was recorded at each milking during the whole experimental period. In the DL group, 25-hydroxyvitamin D (25-VitD), 1,25-VitD and total calcium concentrations around parturition were higher than in the controls. Higher parathyroid hormone concentrations were observed in the control group compared to the DL group at parturition. Pyridinoline concentrations did not differ between groups on d 1, and therefore it is assumed that the intensity of calcium transfer from the bones to the bloodstream was not affected by the increased daylight exposure. The measured plasma metabolites (β-hydroxybutyrate, fatty acids and glucose) as well as milk yield were not affected by the increased daylight exposure. In conclusion, the increased daylight exposure before parturition increased 25-VitD and 1,25-VitD concentrations, preventing a considerable decline of total calcium concentrations around parturition.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1834
      Issue No: Vol. 0, No. 0 (2017)
  • The effects of maternal nutrition on the messenger ribonucleic acid
           expression of neutral and acidic amino acid transporters in bovine
           uteroplacental tissues from day sixteen to fifty of gestation1
    • Authors: N. P. Greseth; M. S. Crouse, K. J. McLean, M. R. Crosswhite, N. Negrin Pereira, C. R. Dahlen, P. P. Borowicz, L. P. Reynolds, A. K. Ward, B. W. Neville J. S. Caton
      Abstract: We hypothesized that both day of gestation and maternal nutrition would alter the relative mRNA expression of neutral and acid AA transporters SLC1A1, SLC1A5, SLC7A5, SLC38A2, and SLC38A7. Crossbred Angus heifers (n = 49) were synchronized, bred via AI, assigned to nutritional treatment (100% of NRC requirements for 0.45 kg/d gain [control heifers {CON}] and 60% of CON [restricted heifers {RES}]), and ovariohysterectomized on d 16, 34, or 50 of gestation (n = 6 to 9/d). Nonbred, nonpregnant (NB-NP) controls were ovariohysterectomized on d 16 of the estrous cycle (n = 6) after synchronization. The resulting arrangement was a 2 × 3 factorial + 1 (CON vs. RES × d 16, 34, or 50 + NB-NP controls). Tissues collected included caruncular endometrium (CAR), intercaruncular endometrium (ICAR), fetal membranes (FM; chorioallantois; d 16 and 34), cotyledonary placenta (COT; d 50 only), intercotyledonary placenta (ICOT; d 50 only), and amnion (AMN; d 50 only]). Relative expression of SLC1A1, SLC1A5, SLC7A5, SLC38A2, and SLC38A7 was determined for each tissue using NB-NP CAR and NB-NP ICAR tissues for the baseline; for FM, endometrium from NB-NP controls served as the baseline. In CAR, no day × treatment interaction was observed (P> 0.05). However, day of gestation affected relative expression of SLC1A1, where expression on d 16 was greater (P < 0.01) than expression on d 34 and 50. Additionally, relative expression of SLC38A2 and SLC38A7 was greater (P ≤ 0.05) in pregnant heifers compared with NB-NP heifers. For ICAR, SLC38A7 was influenced by a day × treatment interaction (P < 0.01), where expression in d 16 RES was greater (P ≤ 0.05) than that of any other day or nutritional treatment. Furthermore, expression in d 16 CON was greater (P ≤ 0.05) than that in d 50 RES, with those in d 34 CON and RES and d 50 CON being intermediate. In addition, SLC1A1 was affected by day of gestation, where expression on d 16 was greater (P < 0.01) than that on d 34 and 50. A day × treatment interaction was not observed (P> 0.05) in FM; however, SLC1A5 expression on d 34 was greater (P = 0.02) than on d 50, with that on d 16 being intermediate. Day of gestation also affected expression of SLC38A2, where expression on d 34 and 50 was greater (P < 0.01) than that on d 16. These data support our hypothesis in that both day of gestation and maternal nutrition affected the relative mRNA expression of AA transporter SLC38A7 in ICAR, whereas day of gestation has a greater effect on the relative mRNA expression of other neutral and acidic AA transporters in the various tissues studied.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1713
      Issue No: Vol. 0, No. 0 (2017)
  • Grazing management of mixed alfalfa bermudagrass pastures1
    • Authors: P. A. Beck; M. B. Sims, E. B. Kegley, D. Hubbell, T. Hess, W. Galyen, T. J. Butler, J. K. Rogers J. Jennings
      Abstract: Rotational grazing management is commonly recommended to improve persistence of legumes interseeded into bermudagrass, but impacts on animal performance are poorly understood. Steers (n = 365, BW = 249 ± 22.9 kg) grazed mixed alfalfa (Medicago sativa L.)/bermudagrass (Cynodon dactylon [L.] Pers.) pastures (n = 10; 1.6-ha) with either continuous grazing (CONT) or rotational grazing (ROT) management over 3 yr. Initial stocking rate was set at 6.25 steers/ha. When forage allowance of CONT became limiting in mid-July each year, 2 randomly selected steers were removed from all pastures to maintain equal stocking rates in CONT and ROT. Rotational grazing pastures were divided into 8 paddocks with 3-d grazing and 21-d rest between grazing events. Initial, final, and interim (28-d) BW were collected following a 16-h removal from feed and water. Data were analyzed as a repeated measures experiment with completely random design using the mixed procedure of SAS (SAS Inst. Inc., Cary, NC) using pasture within treatment by year in the random statement. Across years, steer BW did not differ (P ≥ 0.47) at the midpoint or end of the grazing season. Daily BW gains during the early summer period tended (P = 0.10) to be 0.11 kg greater for CONT than ROT in yr 1, but did not differ (P ≥ 0.24) in yr 2 and 3. In the late summer, ADG was 0.15 kg less (P < 0.01) for CONT than ROT in yr 1, were not different (P = 0.23) in yr 2, and were 0.29 kg less (P < 0.01) for CONT than ROT in yr 3. Over the entire experimental period, ADG did not differ (P ≥ 0.67) in yr 1 or 2, but tended (P = 0.09) to be 0.10 kg greater for ROT than CONT in yr 3. Forage mass of ROT was greater (P < 0.01) than CONT throughout the grazing season. Because stocking rates were maintained at the same level, ROT pastures provided greater (P < 0.01) forage allowance during the grazing season than CONT explaining differences in ADG between treatments. Alfalfa stand percentage did not differ (P = 0.79) at the beginning of the experiment, but was less (P ≤ 0.03) for CONT than ROT at all other sampling dates. These data indicate that at equal stocking rates, ROT can maintain greater alfalfa persistence, forage nutritive quality, and forage allowance compared with continuous grazing and provided increased animal performance during the late summer when the alfalfa stand was reduced in CONT pastures.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1856
      Issue No: Vol. 0, No. 0 (2017)
  • Dietary sources of phosphorus affect postileal phosphorus digestion in
           growing pigs1
    • Authors: J. B. Liu; X. Y. Shen, H. X. Zhai, L. Chen H. F. Zhang
      Abstract: The present study was conducted to investigate the postileal P digestion response of growing pigs to dietary P concentrations and sources. Twenty-four pigs (57.3 ± 1.9 kg initial BW) fitted with T-cannulas at the distal ileum were assigned to a duplicated 12 × 4 incomplete Latin square design with 12 diets and 4 periods. The 12 experimental diets consisted of 9 cornstarch-based diets using soybean meal (SBM), corn distiller’s dried grains with solubles (DDGS), and canola meal (CM) as assay ingredients at 3 levels and 3 corn–SBM–based practical diets with 3 levels of dicalcium phosphate (DCP). Chromic oxide was included as an indigestible marker to calculate apparent ileal digestibility (AID), apparent total tract digestibility (ATTD), and apparent postileal digestibility (APID) of P. Each period consisted of 5 d of adaption period, 2 d of fecal samples collection, and 2 d of ileal digesta collection. The results showed that ileal P output, fecal P output, ileal digested P, total tract digested P, and the AID and ATTD of P were affected by the interaction of P concentrations and sources (P < 0.01). When pigs were fed the semipurified diets containing SBM and corn–SBM–based practical diets, the AID and ATTD of P increased with increasing dietary P level (linear, P < 0.01). However, there were no linear or quadratic responses in the AID and ATTD of P for pigs fed diets containing increasing levels of CM and corn DDGS. Postileal digested P, the proportion of ileal digested P to total tract digested P, the proportion of postileal digested P to total tract digested P, APID of P, and hindgut disappearance of P were affected by dietary sources of P (P < 0.01). When pigs were fed the semipurified diets containing SBM and CM, there were no differences between the AID and ATTD of P. In contrast, the ATTD of P were greater than the AID of P for pigs fed diets containing corn DDGS and corn–SBM–based practical diets with DCP supplementation. In summary, postileal P digestion response of growing pigs was affected by dietary P sources.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1426
      Issue No: Vol. 0, No. 0 (2017)
  • Consequences of exposure of embryos produced in vitro in a
           serum-containing medium to dickkopf-related protein 1 and colony
           stimulating factor 2 on blastocyst yield, pregnancy rate, and birth
    • Authors: P. Tríbulo; B. H. Bernal Ballesteros, A. Ruiz, A. Tríbulo, R. J. Tríbulo, H. E. Tríbulo, G. A. Bo P. J. Hansen
      Abstract: Embryokines are molecules secreted by the mother that regulate embryonic development. Among these molecules in cattle are colony stimulating factor 2 (CSF2) and dickkopf-related protein 1 (DKK1). Here, we evaluated actions of CSF2 and DKK1 alone or in combination on characteristics of embryos produced in vitro in the presence of serum. A total of 70 beef cows from 4 farms were subjected to oocyte retrieval on 1 to 4 occasions. Within each farm, donors were randomly allocated to 1 of 4 treatment groups (vehicle, CSF2, DKK1, CSF2 + DKK1). Embryos from a given donor were always exposed to the same treatment. Treatments were added to the culture medium on d 5 after insemination, and blastocyst stage embryos were transferred to recipient females 2 d later. Treatment did not affect the percent of oocytes or cleaved embryos that developed to the blastocyst stage or the percent of recipients that became pregnant after embryo transfer. However, calves derived from embryos treated with DKK1 were smaller at birth, regardless of CSF2 treatment. Results indicate no effects of addition of CSF2 or DKK1 to culture of embryos produced in vitro with serum-containing medium on development to the blastocyst stage or competence to establish pregnancy after transfer to recipients. The fact that embryos cultured with DKK1 resulted in calves with reduced birth weight illustrates the potential ability of this embryokine to program postnatal phenotype. Results support the concept that properties of the offspring can be programmed as early as the preimplantation period.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1927
      Issue No: Vol. 0, No. 0 (2017)
  • Detoxification, metabolism, and glutathione pathway activity of aflatoxin
           B1 by dietary lactic acid bacteria in broiler chickens
    • Authors: N. Liu; K. Ding, J. Q. Wang, S. C. Jia, J. P. Wang T. S. Xu
      Abstract: Lactic acid bacteria (LAB) and the glutathione (GSH) pathway are protective against aflatoxin, but information on the effect of LAB on aflatoxin metabolism and GSH activity in farm animals is scarce. This study aimed to investigate the effects of LAB and aflatoxin B1 (AFB1) on growth performance, aflatoxin metabolism, and GSH pathway activity using 480 male Arbor Acres broiler chickens from d 1 to 35 of age. Diets were arranged in a 2 × 2 factorial design, including AFB1 at 0 or 40 µg/kg of feed and LAB at 0 or 3 × 1010 cfu/kg of feed, and the LAB was a mixture of equal amounts of Lactobacillus acidophilus, Lactobacillus plantarum, and Enterococcus faecium. The results showed that there were highly significant (P < 0.01) effects of AFB1 toxicity, LAB protection, and their interaction on ADFI, ADG, and G:F of broilers during d 1 to 35. Compared with the AFB1 diet, the LAB diet reduced (P < 0.05) the residues of AFB1 in the liver, kidney, serum, ileal digesta, and excreta on d 14 by 121.5, 80.6, 43.7, 47.0, and 26.5%, respectively, and on d 35 by 40.6, 60.2, 131.7, 37.9, and 32.9%, respectively, whereas the LAB diet increased (P < 0.05) the contents of aflatoxin M1, a metabolite of AFB1, in the liver, kidney, serum, and ileal digesta on d 14 by 98.2, 154.2, 168.6, 19.1, and 34.1%, respectively, and in the kidney and serum on d 35 by 32.6 and 142.2%, respectively. For the activity of the GSH pathway in the liver and duodenal mucosa, there were significant (P ≤ 0.01) effects of LAB and AFB1 on reduced GSH, glutathione S-transferases (GST), and glutathione reductase (GR) on d 14 and 35; compared with the control diet, the LAB diet increased (P < 0.05) GSH, GST, and GR by a range of 11.6 to 86.1%, and compared with the AFB1 diet, the LAB diet increased (P < 0.05) GSH, GST, and GR by a range of 24.1 to 146.9%. In the liver, there were interactions (P < 0.05) on GSH and GST on d 14 and on GSH on d 35; in the mucosa, interactions were significant (P ≤ 0.01) on GSH and GR on d 14 and on GST on d 35. It can be concluded that LAB is effective in the detoxification of AFB1 by modulating toxin metabolism and activating the GSH pathway in animals.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1644
      Issue No: Vol. 0, No. 0 (2017)
  • Estimates of genetic parameters, genetic trends, and inbreeding in a
           crossbred dairy sheep research flock in the United States1
    • Authors: T. W. Murphy; Y. M. Berger, P. W. Holman, M. Baldin, R. L. Burgett D. L. Thomas
      Abstract: For the past 2 decades, the Spooner Agriculture Research Station (ARS) of the University of Wisconsin-Madison operated the only dairy sheep research flock in North America. The objectives of the present study were to 1) obtain estimates of genetic parameters for lactation and reproductive traits in dairy ewes, 2) estimate the amount of genetic change in these traits over time, and 3) quantify the level of inbreeding in this flock over the last 20 yr. Multiple-trait repeatability models (MTRM) were used to analyze ewe traits through their first 6 parities. The first MTRM jointly analyzed milk (180-d-adjusted milk yield [180d MY]), fat (180-d-adjusted fat yield [180d FY]), and protein (180-d-adjusted protein yield [180d PY]) yields adjusted to 180 d of lactation; number of lambs born per ewe lambing (NLB); and lactation average test-day somatic cell score (LSCS). A second MTRM analyzed 180d MY, NLB, LSCS, and percentage milk fat (%F) and percentage milk protein (%P). The 3 yield traits were moderately heritable (0.26 to 0.32) and strongly genetically correlated (0.91 to 0.96). Percentage milk fat and %P were highly heritable (0.53 and 0.61, respectively) and moderately genetically correlated (0.61). Milk yield adjusted to 180 d was negatively genetically correlated with %F and %P (−0.31 and −0.34, respectively). Ewe prolificacy was not significantly (P> 0.67) genetically correlated with yield traits, %P, or LSCS but lowly negatively correlated with %F (−0.26). Lactation somatic cell score was unfavorably genetically correlated with yield traits (0.28 to 0.39) but not significantly (P> 0.09) correlated with %F, %P, and NLB. Within-trait multiple-trait models through the first 4 parities revealed that 180d MY, 180d FY, 180d PY, %F, and %P were strongly genetically correlated across parity (0.67 to 1.00). However, the genetic correlations across parity for NLB and LSCS were somewhat lower (0.51 to 0.96). Regressing predicted breeding values for 180d MY, without and with the addition of breed effects, on ewe year of birth revealed a positive genetic gain of 2.30 and 6.24 kg/yr, respectively, over the past 20 yr in this flock. Inbreeding coefficients of ewes with an extended pedigree ranged from 0.0 to 0.29, with an average of 0.07. To optimize genetic gains and avoid excessive inbreeding, the development of a national genetic improvement program should be a top priority for the growing dairy sheep industry.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1844
      Issue No: Vol. 0, No. 0 (2017)
  • Milk yield and genomewide expression profiling in the mammary gland of
           beef primiparous cows in response to the dietary management during the
           pre- and postweaning periods 1
    • Authors: E. Dervishi; M. Blanco, J. A. Rodríguez-Sánchez, A. Sanz, J. H. Calvo I. Casasús
      Abstract: Accelerated growth programs during prepubertal periods have been promoted to advance the first calving of beef heifers. The objectives of the present study were to evaluate nutrition-induced changes on first lactation milk yield and composition and on gene expression of the mammary gland in Parda de Montaña primiparous cows. Female calves (n = 16) were involved in a 2 × 2 factorial experiment. In the preweaning period (PRE-W; 0–6 mo), female calves were either fed a creep feed supplement (Creep) or fed only their dam’s milk (Control). In the postweaning period (POST-W; 6–15 mo), heifers received either a high-energy diet (91.7 MJ/d) or a moderate-energy diet (79.3 MJ/d). All the heifers were managed together from breeding (15 mo) to the end of their first lactation (32 mo). Animal performance; milk production and quantity during the first lactation; plasma glucose, IGF-I, and leptin concentrations; and RNA samples from the mammary gland at the end of the first lactation of the primiparous cows (32 mo) were analyzed. The BW and ADG of the primiparous cow during its first lactation were not different among treatments; however, creep feeding during PRE-W reduced milk production (P < 0.01), milk CP, crude fat, lactose, nonfat solids, and casein content throughout lactation and increased somatic cell count in the third (P < 0.05) and fourth month of lactation (P < 0.10). The energy level during the POST-W had no effect on milk production and quality. Gene expression in the mammary gland was affected by the diet in the PRE-W and POST-W, with the PRE-W diet having the greatest impact. During the PRE-W, creep feeding resulted in upregulation of genes related to immune response and chemokine activity, suggesting that these animals might be in a compromised immune status. Therefore, this strategy would not be recommendable; meanwhile, increasing the energy level in the diet during the POST-W would be recommendable, because it had no deleterious effects on milk yield and composition.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1736
      Issue No: Vol. 0, No. 0 (2017)
  • Genetic correlations between wool traits and meat quality traits in Merino
    • Authors: S. I. Mortimer; S. Hatcher, N. M. Fogarty, J. H. J. van der Werf, D. J. Brown, A. A. Swan, R. H. Jacob, G. H. Geesink, D. L. Hopkins, J. E. Hocking Edwards, E. N. Ponnampalam, R. D. Warner, K. L. Pearce D. W. Pethick
      Abstract: Genetic correlations between 29 wool production and quality traits and 25 meat quality and nutritional value traits were estimated for Merino sheep from an Information Nucleus (IN). Genetic correlations among the meat quality and nutritional value traits are also reported. The IN comprised 8 flocks linked genetically and managed across a range of sheep production environments in Australia. The wool traits included over 5,000 yearling and 3,700 adult records for fleece weight, fiber diameter, staple length, staple strength, fiber diameter variation, scoured wool color, and visual scores for breech and body wrinkle. The meat quality traits were measured on samples from the M. longissimus thoracis et lumborum and included over 1,200 records from progeny of over 170 sires for intramuscular fat (IMF), shear force of meat aged for 5 d (SF5), 24 h postmortem pH (pH24LL; also measured in the semitendinosus muscle, pH24ST), fresh and retail meat color and meat nutritional value traits such as iron and zinc levels, and long-chain omega-3 and omega-6 polyunsaturated fatty acid levels. Estimated heritabilities for IMF, SF5, pH24LL, pH24ST, retail meat color lightness (L*), myoglobin, iron, zinc and across the range of long-chain fatty acids were 0.58 ± 0.11, 0.10 ± 0.09, 0.15 ± 0.07, 0.20 ± 0.10, 0.59 ± 0.15, 0.31 ± 0.09, 0.20 ± 0.09, 0.11 ± 0.09, and range of 0.00 (eicosapentaenoic, docosapentaenoic, and arachidonic acids) to 0.14 ± 0.07 (linoleic acid), respectively. The genetic correlations between the wool production and meat quality traits were low to negligible and indicate that wool breeding programs will have little or no effect on meat quality. There were moderately favorable genetic correlations between important yearling wool production traits and the omega-3 fatty acids that were reduced for corresponding adult wool production traits, but these correlations are unlikely to be important in wool/meat breeding programs because they have high SE, and the omega-3 traits have little or no genetic variance. Significant genetic correlations among the meat quality traits included IMF with SF5 (-0.76 ± 0.24), fresh meat color L* (0.50 ± 0.18), and zinc (0.41 ± 0.19). Selection to increase IMF will improve meat tenderness and color which may address some of the issues with Merino meat quality. These estimated parameters allow Merino breeders to combine wool and meat objectives without compromising meat quality.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1628
      Issue No: Vol. 0, No. 0 (2017)
  • Effects of clay on toxin binding capacity, ruminal fermentation, diet
           digestibility, and growth of steers fed high-concentrate diets12
    • Authors: D. S. Antonelo; N. A. Lancaster, S. Melnichenko, C. R. Muegge J. P. Schoonmaker
      Abstract: Three experiments were conducted to determine the effect of increasing concentrations of a smectite clay on toxin binding capacity, ruminal fermentation, diet digestibility, and growth of feedlot cattle. In Exp. 1, 72 Angus × Simmental steers were blocked by BW (395 ± 9.9 kg) and randomly allotted to 3 treatments (4 pens/treatment and 6 steers/pen) to determine the effects of increasing amounts of clay (0, 1, or 2%) on performance. The clay was top-dressed on an 80% concentrate diet at a rate of 0, 113, or 226 g/steer daily to achieve the 0, 1, and 2% treatments, respectively. Steers were slaughtered at a target BW of 606 kg. In Exp. 2, 6 steers (596 ± 22.2 kg initial BW) were randomly allotted to the same 3 treatments in a replicated 3 × 3 Latin square design (21-d periods) to determine the effects of increasing amounts of clay on ruminal pH, VFA, and nutrient digestibility. In Exp. 3, 150 mg of clay was incubated in 10 mL of rumen fluid with 3 incremental concentrations (6 replicates per concentration) of aflatoxin B1 (AFB1) or ergotamine tartate (ET) to determine binding capacity. During the first 33-d period, there was a quadratic effect of clay on ADG (P < 0.01) and G:F (P < 0.01), increasing from 0 to 1% clay and then decreasing from 1 to 2% clay. However, during the second 30-d period, clay linearly decreased ADG and G:F (P ≤ 0.03) and overall ADG, DMI, and G:F were not impacted (P ≥ 0.46). Clay linearly decreased marbling score (P = 0.05). Hepatic enzyme activity did not differ among treatments on d 0 or at slaughter (P ≥ 0.15). Clay linearly decreased ruminal lactate and propionate, linearly increased formate and the acetate:propionate ratio (P ≤ 0.04), and tended (P = 0.07) to linearly increase butyrate. Clay tended to linearly increase (P = 0.06) OM and CP apparent digestibility. Ruminal pH, urine pH, and other digestibility measures did not differ among treatments (P ≥ 0.15). Clay was able to effectively bind AFB1 and ET at concentrations above the normal physiological range (52 and 520 μg/mL), but proportional adsorption was decreased to 35.5 and 91.1% at 5,200 μg/mL (P < 0.01) for AFB1 and ET, respectively. In conclusion, clay effectively binds ruminal toxins, decreases ruminal lactate, and improves performance only during adaptation to a high-concentrate feedlot diet.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1473
      Issue No: Vol. 0, No. 0 (2017)
  • Effect of the inoculation of sugarcane silage with Lactobacillus hilgardii
           and Lactobacillus buchneri on feeding behavior and milk yield of dairy
    • Authors: W. P. Santos; C. L. S. Ávila, M. N. Pereira, R. F. Schwan, N. M. Lopes J. C. Pinto
      Abstract: Despite its low NDF digestibility, sugarcane is an option for feeding dairy cattle in tropical regions. We evaluated the effect of sugarcane silages inoculated with Lactobacillus hilgardii CCMA 0170 (LH; an epiphytic bacteria isolated from sugarcane) or with L. buchneri NCIMB 40788 (LB; a commercial strain isolated from temperate grasses) on dairy cow performance and feeding behavior. The microbial inoculums were previously grown in the laboratory to obtain 5 log cfu/g of fresh forage. Nine tons of each inoculated silage and a noninoculated control silage (CON) were harvested from the same field and stored for at least 35 d in experimental 20 × 2.1 × 0.4 m bunker silos. Fifteen Holstein cows in late lactation (336 ± 175 days in milk at the start of the experiment) received the treatments in five 3 × 3 Latin squares with 21-d periods. The diets contained 20% of DM of sugarcane silage and 41% of DM of corn silage. Milk yield was increased from 18.0 kg/d for CON to18.8 kg/d for LH, but LB did not elicit a detectable increase in milk yield (18.1 kg/d). The daily yields of fat, protein, lactose, and total solids were increased by LH. Daily DMI and total tract apparent digestibility of nutrients did not differ among treatments. Both inoculated silages reduced acetate and increased butyrate proportions in ruminal VFA, but only LH silage reduced the acetate to propionate ratio (3.0 vs. 3.3). First meal duration was shorter for CON compared to LH and LB. The proportion of daily intake between 0700 and 1300 h tended to be increased, and the proportion between 1900 and 0700 h was reduced by LH. The inoculation of sugarcane silage with Lactobacillus hilgardii affected rumen fermentation profile and feeding behavior of late lactation dairy cows, increasing the yield of milk solids.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1526
      Issue No: Vol. 0, No. 0 (2017)
  • Comparison of nitrogen utilization and urea kinetics between yaks (Bos
           grunniens) and indigenous cattle (Bos taurus)1
    • Authors: J. W. Zhou; C. L. Zhong, H. Liu, A. A. Degen, E. C. Titgemeyer, L. M. Ding, Z. H. Shang, X. S. Guo, Q. Qiu, Z. P. Li, G. Yang R. J. Long
      Abstract: Under traditional management on the Qinghai–Tibetan Plateau, yaks (Bos grunniens) graze only on natural pasture without supplements and are forced to cope with sparse forage of low N content, especially in winter. In contrast, indigenous Tibetan yellow cattle (Bos taurus) require supplements during the cold season. We hypothesized that, in response to harsh conditions, yaks cope with low N intakes better than cattle. To test this hypothesis, a study of whole-body N retention and urea kinetics was conducted in 2 concurrent 4 × 4 Latin squares, with 1 square using yaks and 1 square using cattle. Four isocaloric forage–concentrate diets differing in N concentrations (10.3, 19.5, 28.5, and 37.6 g N/kg DM) were formulated, and by design, DMI were similar between species and across diets. Urea kinetics were determined with continuous intravenous infusion of 15N15N urea for 104 h, and total urine and feces were concomitantly collected. Urea production, urea recycling to the gut, and ruminal microbial protein synthesis all linearly increased (P < 0.001) with increasing dietary N in both yaks and cattle. Urinary N excretion was less (P = 0.04) and N retention was greater (P = 0.01) in yaks than in cattle. Urea production was greater in yaks than in cattle at the 3 lowest N diets but greater in cattle than in yaks at the highest N diet (species × diet, P < 0.02). Urea N recycled to the gut (P < 0.001), recycled urea N captured by ruminal bacteria (P < 0.001), and ruminal microbial protein production (P = 0.05) were greater in yaks than in cattle. No more than 12% of urea recycling was through saliva, with no difference between species (P = 0.61). Glomerular filtration rate was lower (P = 0.05) in yaks than in cattle. The higher urea recycling and greater capture of recycled urea by ruminal microbes in yaks than in cattle suggest that yaks use mechanisms to utilize dietary N more efficiently than cattle, which may partially explain the better survival of yaks than cattle when fed low-N diets.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1428
      Issue No: Vol. 0, No. 0 (2017)
  • Estimation of the effects of selection on French Large White sow and
           piglet performance during the suckling period1
    • Authors: P. Silalahi; T. Tribout, Y. Billon, J. Gogué J. P. Bidanel
      Abstract: The effects of 21 yr of selection were estimated for sow and piglet performance during the suckling period in a French Large White (LW) pig population using frozen semen. Two experimental groups (EXP = L77 and L98) were produced by inseminating LW sows with either stored frozen semen from 17 LW boars born in 1977 (EXP = L77) or with fresh semen from 23 LW boars born in 1998 (EXP = L98). Seventy-four L77 and 89 L98 randomly chosen females were mated to 15 L77 and 15 L98, respectively, randomly chosen boars for 6 successive parities. They produced 2,796 L77 progeny (G77) and 3,529 L98 progeny (G98) piglets including stillbirths. To disentangle direct and maternal effects on piglet growth, a 2 × 2 factorial design was set by cross-fostering half-litters across genetic groups the day after farrowing, resulting in mixed G77/G98 litters nursed by either L77 or L98 sows. Piglet traits investigated included individual weight at birth (IWB), at 21 d of age (IW21d), and at weaning at 4 wk of age (IWW) and ADG from birth to 21 d of age (ADG21d) and from birth to weaning (ADGBW) as well as probability of stillbirth, probability of mortality on the first day after farrowing and from d 2 to weaning. Sow traits analyzed included weight before farrowing and at weaning, feed intake, milk production, colostrum, and milk composition. The variability of performance across genetic groups and litters was also investigated. The data were analyzed using generalized (piglet mortality) or linear mixed models (other traits). Results showed an increase in IWB (+240 ± 72 g in 21 yr for IWB adjusted for total number born), and a negative maternal genetic trend was observed on piglet growth during the suckling period (e.g., +33 ± 13 g/d in 21 yr for ADG21d, that is, 14% of the mean), whereas direct genetic effects remained unchanged. Piglets from L98 litters also had a 40% larger probability of being stillborn and a 28% larger probability of dying on d 1 and had a more heterogeneous IWB (358 vs. 336 g; P < 0.001) and growth during the suckling period (60 vs. 56 g/d; P < 0.001). Sows from L77 and L98 experimental groups did not differ in weight, feed intake, colostrum, and milk composition. These results give evidence of negative correlated effects of selection for piglet traits related to robustness. These adverse effects are at least partly of maternal origin.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1485
      Issue No: Vol. 0, No. 0 (2017)
  • A heuristic method to identify runs of homozygosity associated with
           reduced performance in livestock
    • Authors: J. T. Howard; F. Tiezzi, Y. Huang, K. A. Gray C. Maltecca
      Abstract: Although, for the most part, genome-wide metrics are currently used in managing livestock inbreeding, genomic data offer, in principle, the ability to identify functional inbreeding. Here, we present a heuristic method to identify haplotypes contained within a run of homozygosity (ROH) associated with reduced performance. Results are presented for simulated and swine data. The algorithm comprises 3 steps. Step 1 scans the genome based on marker windows of decreasing size and identifies ROH genotypes associated with an unfavorable phenotype. Within this stage, multiple aggregation steps reduce the haplotype to the smallest possible length. In step 2, the resulting regions are formally tested for significance with the use of a linear mixed model. Lastly, step 3 removes nested windows. The effect of the unfavorable haplotypes identified and their associated haplotype probabilities for a progeny of a given mating pair or an individual can be used to generate an inbreeding load matrix (ILM). Diagonals of ILM characterize the functional individual inbreeding load (IIL). We estimated the accuracy of predicting the phenotype based on IIL. We further compared the significance of the regression coefficient for IIL on phenotypes with genome-wide inbreeding metrics. We tested the algorithm using simulated scenarios (12 scenarios), combining different levels of linkage disequilibrium (LD) and number of loci impacting a quantitative trait. Additionally, we investigated 9 traits from 2 maternal purebred swine lines. In simulated data, as the LD in the population increased, the algorithm identified a greater proportion of the true unfavorable ROH effects. For example, the proportion of highly unfavorable true ROH effects identified rose from 32 to 41% for the low- to the high-LD scenario. In both simulated and real data, the haplotypes identified were contained within a much larger ROH (9.12–12.1 Mb). The IIL prediction accuracy was greater than 0 across all scenarios for simulated data (mean of 0.49 [95% confidence interval 0.47–0.52] for the high-LD scenario) and for nearly all swine traits (mean of 0.17 [SD 0.10]). On average, across simulated and swine data sets, the IIL regression coefficient was more closely related to progeny performance than any genome-wide inbreeding metric. A heuristic method was developed that identified ROH genotypes with reduced performance and characterized the combined effects of ROH genotypes within and across individuals.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1664
      Issue No: Vol. 0, No. 0 (2017)
  • Sex effects on macromineral requirements for growth in Saanen goats: A
    • Authors: J. A. C. Vargas; A. K. Almeida, A. P. Souza, M. H. M. R. Fernandes, K. T. Resende I. A. M. A. Teixeira
      Abstract: The aim of this study was to investigate the effects of sex on the net requirements of growth for Ca (NCag), P (NPg), Na (NNag), K (NKg), and Mg (NMgg) in Saanen goats from 5 to 45 kg BW, with or without consideration of the degree of maturity. A database containing 209 individual records for Saanen goats (69 castrated males, 71 intact males, and 69 females) was generated from 6 comparative slaughter studies. Total amounts of Ca, P, Na, K, and Mg in the body were fitted to logarithmized allometric equations using empty BW (EBW) or degree of maturity (EBW/mature EBW) as regressors. The equations were fitted using a mixed model, where sex was considered a fixed effect and study was considered a random effect. Net requirements were estimated by the first derivative of the logarithmized allometric equations. Then, a Monte Carlo simulation was used to assess the uncertainty of calculated net requirement values. Without considering the degree of maturity, sex did not affect NCag, NPg, and NNag (P> 0.10). Conversely, considering the degree of maturity, NCag and NPg of intact males were 5% and 2%, respectively, greater than those of castrated males and females (P < 0.01), and NNag of males (castrated and intact) was 6% greater than that of females (P < 0.01). Regardless of approach used, NCag and NPg remained constant, whereas NNag decreased by 32% as BW ranged from 5 to 45 kg. Without considering the degree of maturity, NMgg of castrated and intact males were 8% and 18% greater than that of female goats (P = 0.054), respectively. Hereof NMgg of castrated and intact males increased by 8% and 15%, respectively, whereas that of females decreased by 8% as BW ranged from 5 to 45 kg. Considering the degree of maturity, NMgg of castrated and intact males were 7% and 17% greater than that of female goats (P = 0.054), respectively. In this regard, NMgg of castrated and intact males increased 8% and 16%, respectively, whereas that of females decreased by 7% from 5 to 45 kg BW. Both approaches showed that, regardless of sex (P> 0.10), NKg decreased by 26% (i.e., without considering the maturity degree) or 27% (i.e., considering the degree of maturity) from 5 to 45 kg BW. Therefore, the consideration of maturity stage highlights differences across sexes in the net macromineral requirements for growth in goats. Elucidation of sex effects on macromineral requirements for growth may be useful for improving the accuracy of recommendations for mineral requirements for dairy goats.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1825
      Issue No: Vol. 0, No. 0 (2017)
  • Stockpiled Tifton 85 bermudagrass for backgrounding stocker cattle1
    • Authors: K. R. Bivens; M. K. Mullenix, J. J. Tucker, B. E. Gamble R. B. Muntifering
      Abstract: A 2-yr grazing trial was conducted to evaluate the use of conserved forage type, stockpiled Tifton 85 bermudagrass (Cynodon dactylon L.; T85) or T85 hay, and supplement type for stocker cattle during the fall forage deficit in the southeastern United States. The study site consisted of six 0.75-ha paddocks of stockpiled T85 for grazing and six 0.20-ha drylot paddocks for feeding T85 hay. Steers (n = 5 per paddock; mean initial BW for both yr, 263 ± 30 kg) were randomly assigned to paddocks on November 11, 2014 and October 28, 2015 in yr 1 and yr 2, respectively. Treatments included T85 hay or stockpile (control), T85 hay or stockpile plus 0.2 kg cottonseed meal and 0.7 kg soybean hulls∙steer-1∙d-1 (SUPPL1), or 0.45 kg cottonseed meal and 0.45 kg soybean hulls∙steer-1∙d-1 (SUPPL2). Polytape fencing was used for frontal grazing stockpiled T85 paddocks to allocate a 3- to 4-d allotment of forage DM for the animals based on available forage mass and steer DMI requirements. There were no differences among treatments (P> 0.10) in mean pregrazing forage mass across sampling dates (5,099 kg DM/ha and 7,998 kg DM/ha in yr 1 and yr 2, respectively), forage allowance (1.9 kg DM/kg steer BW and 3.0 kg DM/kg steer BW in yr 1 and yr 2, respectively) and forage utilization (84% and 88% in yr 1 and yr 2, respectively). No differences (P> 0.10) were detected for nutritive value parameters CP, ADF, NDF, and TDN among stockpiled T85 treatments in both yr. However, there were differences across sampling dates (P < 0.0001) for stockpiled T85 such that forage quality generally declined as the grazing season progressed in both yr. Steers fed T85 hay had greater final BW and ADG (P = 0.018) than those grazing stockpiled T85. Mean final BW and ADG of steers grazing T85 stockpile or fed hay with no supplementation was less (P = 0.020) than those receiving supplementation. Steers grazing stockpiled T85 had decreased ADG in the second half of the grazing season in both yr of the study, which is a result of declining forage nutritive value as the stockpiling season progressed. Results indicate that stockpiled T85 supplemented with CP and energy can support stocker cattle at a maintenance level, but to achieve a target gain of 0.9 kg/day would require a greater level of supplementation to overcome decreasing forage nutritive value dynamics.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1579
      Issue No: Vol. 0, No. 0 (2017)
  • Phenotypic relationships among methane production traits assessed under ad
           libitum feeding of beef cattle12
    • Authors: T. Bird-Gardiner; P. F. Arthur, I. M. Barchia, K. A. Donoghue R. M. Herd
      Abstract: Angus cattle from 2 beef cattle projects in which daily methane production (MPR) was measured were used in this study to examine the nature of the relationships among BW, DMI, and methane traits of beef cattle fed ad libitum on a roughage diet or a grain-based feedlot diet. In both projects methane was measured using the GreenFeed Emission Monitoring system, which provides multiple short-term breath measures of methane production. The data used for this study were from 119 Angus heifers over 15 d on a roughage diet and 326 Angus steers over 70 d on a feedlot diet. Mean (±SD) age, BW, and DMI were 372 ± 28 d, 355 ± 37 kg, and 8.1 ± 1.3 kg/d for the heifers and 554 ± 86 d, 577 ± 69 kg, and 13.3 ± 2.0 kg/d for the steers, respectively. The corresponding mean MPR was 212 g/d for heifers and 203 g/d for steers. Additional traits studied included methane yield (MY; MPR/DMI), methane intensity (MPR/BW), and 3 forms of residual methane production (RMP), which is a measure of actual minus predicted MPR. For RMPB, RMPD, and RMPDB predicted MPR were obtained by regression of MPR on BW, on DMI, and on both DMI and BW, respectively. The 2 data sets were analyzed separately using the same statistical procedures. For both feed types the relationships between MPR and DMI and between MPR and BW were both positive and linear. The correlation between MPR and DMI was similar to that between MPR and BW, although the correlations were stronger for the roughage diet (r = 0.75 for MPR vs. DMI; r = 0.74 for MPR vs. BW) than the grain-based diet (r = 0.62 for MPR vs. DMI; r = 0.66 for MPR vs. BW). The correlation between MY and DMI was negative and moderate for the roughage (r = −0.68) and grain-based (r = −0.59) diets, a finding that is different from the nonsignificant correlations reported in studies of cattle on a restricted roughage diet. The 3 RMP traits were strongly correlated (r values from 0.76 to 0.99) with each other for both the roughage and the grain-based diets, which indicates that using RMPB to lower MPR could provide a result similar to using RMPD in cattle. As feed intake (DMI) is more difficult to measure than BW, this result implies that under ad libitum feeding situations in which DMI cannot be measured, RMPB can be used to identify higher- or lower-RMP animals with similar levels of effectiveness as RMPD.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1477
      Issue No: Vol. 0, No. 0 (2017)
  • Effect of dried distiller’s grains plus solubles in postpartum diets of
           beef cows on reproductive performance of dam and heifer progeny
    • Authors: E. G. Taylor; R. P. Lemenager, V. Fellner K. R. Stewart
      Abstract: Forty-eight primiparous and multiparous cows were fed a silage-based total mixed ration (TMR; CON), a TMR with 2.5 kg/d DM dried distiller’s grains plus solubles (DDGS; MID), or a TMR with 4.7 kg/d DM DDGS (HIGH) from 8.5 ± 4 to 116 ± 4 d postpartum (DPP). All diets were formulated to be isocaloric for a postpartum ADG targeted at 0.22 kg, whereas CP exceeded requirements in both diets containing DDGS. Blood samples were collected from dams at 7- and 21-d intervals for progesterone concentration (resumption of cyclicity) and plasma urea nitrogen, respectively. A weigh–suckle–weigh procedure was used to measure milk production, and samples were collected for milk composition and fatty acid profile. A 5-d Co-Synch + controlled internal drug release (CIDR) protocol was used, and cows were bred (97 ± 4 DPP) by timed AI (TAI). Ultrasonography was used for measurement of the largest antral follicle at TAI and pregnancy diagnosis. Nineteen days after TAI, cow and calf pairs were managed as a single group until weaning and exposed to natural mating for a total of a 60-d breeding season. Starting at weaning, blood samples were collected from heifer offspring at 7-d intervals for progesterone concentration used as an indicator of puberty. A 5-d Co-Synch + CIDR protocol was used, and heifers were bred by TAI. Transrectal ultrasonography was used for measurement of the largest antral follicle at TAI and antral follicle count (AFC) at CIDR device insertion as well as pregnancy diagnosis. There were no differences in dam ADG (P = 0.364); however, DMI decreased with increasing DDGS (P < 0.0001), resulting in an increased feed efficiency (P = 0.042). Milk fat and lactose tended to increase with the addition of DDGS in the diet (P ≤ 0.055), and milk urea nitrogen increased (P < 0.001). There were no differences in resumption of cyclicity (P = 1.00) or diameter of the largest antral follicle (P ≥ 0.372). Timed AI pregnancy rates were not different with the addition of DDGS in the diet (P ≥ 0.174). Heifer ADG was reduced with DDGS during late lactation (P = 0.031). Heifer AFC had a tendency to increase with increasing DDGS (P = 0.081), with no impacts on dominant follicle diameter at TAI (P = 0.161). Heifer TAI pregnancy rate also was not different among treatments (P = 0.508). Overall, feeding 4.7 kg/d DM of DDGS to dams during early lactation increases feed efficiency of the dam, with minor statistically significant effects on dam or heifer offspring reproduction.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1637
      Issue No: Vol. 0, No. 0 (2017)
  • Ground Juniperus pinchotii and urea in supplements fed to Rambouillet ewe
           lambs Part 2: Ewe lamb rumen microbial communities1
    • Authors: S. L. Ishaq; C. J. Yeoman T. R. Whitney
      Abstract: This study evaluated effects of ground redberry juniper (Juniperus pinchotii) and urea in dried distillers grains with solubles-based supplements fed to Rambouillet ewe lambs (n = 48) on rumen physiological parameters and bacterial diversity. In a randomized study (40 d), individually-penned lambs were fed ad libitum ground sorghum-sudangrass hay and of 1 of 8 supplements (6 lambs/treatment; 533 g/d; as-fed basis) in a 4 × 2 factorial design with 4 concentrations of ground juniper (15%, 30%, 45%, or 60% of DM) and 2 levels of urea (1% or 3% of DM). Increasing juniper resulted in minor changes in microbial β-diversity (PERMANOVA, pseudo F = 1.33, P = 0.04); however, concentrations of urea did not show detectable broad-scale differences at phylum, family, or genus levels according to ANOSIM (P> 0.05), AMOVA (P> 0.10), and PERMANOVA (P> 0.05). Linear discriminant analysis indicated some genera were specific to certain dietary treatments (P < 0.05), though none of these genera were present in high abundance; high concentrations of juniper were associated with Moraxella and Streptococcus, low concentrations of urea were associated with Fretibacterium, and high concentrations of urea were associated with Oribacterium and Pyramidobacter. Prevotella were decreased by juniper and urea. Ruminococcus, Butyrivibrio, and Succiniclasticum increased with juniper and were positively correlated (Spearman’s, P < 0.05) with each other but not to rumen factors, suggesting a symbiotic interaction. Overall, there was not a juniper × urea interaction for total VFA, VFA by concentration or percent total, pH, or ammonia (P> 0.29). When considering only percent inclusion of juniper, ruminal pH and proportion of acetic acid linearly increased (P < 0.001) and percentage of butyric acid linearly decreased (P = 0.009). Lamb ADG and G:F were positively correlated with Prevotella (Spearman’s, P < 0.05) and negatively correlated with Synergistaceae, the BS5 group, and Lentisphaerae. Firmicutes were negatively correlated with serum urea nitrogen, ammonia, total VFA, total acetate, and total propionate. Overall, modest differences in bacterial diversity among treatments occurred in the abundance or evenness of several OTUs, but there was not a significant difference in OTU richness. As diversity was largely unchanged, the reduction in ADG and lower-end BW was likely due t* reduced DMI rather than a reduction in microbial fermentative ability.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1731
      Issue No: Vol. 0, No. 0 (2017)
  • Responses of fresh cows to three feeding strategies that reduce starch
           levels by feeding beet pulp1
    • Authors: N. Eslamian Farsuni; H. Amanlou, N. Silva-del-Río E. Mahjoubi
      Abstract: The study objective was to evaluate the effects of reducing dietary starch content in fresh cow diets while maintaining NDF levels by substituting barley grain (BG), corn silage (CS), or both with beet pulp (BP) on nutrient digestion, ruminal fermentation, DMI, lactation performance, meal patterns, chewing activity, and sorting behavior. Thirty-six multiparous cows were randomly assigned to 1 of 4 experimental diets from calving to 21 d in lactation. Experimental diets were a high-starch diet with ground BG (CO; 24.9% starch; 0% BP) and 3 low-starch diets: the CO with BP substituted for ground BG (BB; 19.6% starch; 7% BP), the CO with BP substituted for CS (BC; 20.6% starch; 12% BP), or the CO with BP substituted for CS and ground BG (BCB; 20.3% starch; 12% BP). The CO, BB, BC, and BCB contained 33.4, 34.4, 32.9, and 33.7% NDF, respectively, and 23.1, 22.0, 18.2, and 19.2% forage NDF, respectively. There was no effect of diet on total tract nutrient digestibility (P> 0.20), ruminal pH (P = 0.49), or total VFA (P = 0.39). However, diets affected molar proportions of propionate and acetate (P ≤ 0.01). Relative to CO cows, the molar propionate percentage was less in BB cows (P < 0.01) and tended to be greater in BC cows (P = 0.10), whereas the molar percentage of acetate was less in BC cows than in BB (P < 0.01) and CO cows (P = 0.02). Relative to CO cows (16.50 kg/d), DMI was greater for BC (17.70 kg/d; P < 0.01) and BCB cows (17.50 kg/d; P = 0.01), but it was less in BB cows (15.60 kg/d; P = 0.02). Similar to DMI results, milk yields tended to be greater for BC (37.89 kg/d; P = 0.08) and BCB cows (37.81 kg/d; P = 0.09) compared with CO cows (35.41 kg/d), but BB cows (33.05 kg/d) tended to produce less milk than CO cows (P = 0.1). Milk fat content tended to be less in BC (P = 0.08) and BCB cows (P = 0.10) than in CO cows. There was no effect of diet on eating and rumination patterns (P ≥ 0.18), except shortened meal intervals for BC and BCB cows compared with CO cows (P = 0.02). Dietary treatments did not affect chewing activities per day or bout (P = 0.50), but BC and BCB cows spent less time on chewing activities per kilogram DM (P < 0.01) and NDF intake (P < 0.01) compared with CO cows. Cows fed the BC and BCB sorted for long particles (>19 mm; P < 0.01) but against particles < 1.18 mm (P < 0.01). In the present study, propionate did not seem to play a central role in feed intake regulation of fresh cows, because BB cows had depressed DMI and the lowest molar proportion of propionate. However, reducing starch levels in fresh cow diets by replacing CS and both CS and BG with BP positively affected DMI and milk yield.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.1712
      Issue No: Vol. 0, No. 0 (2017)
  • Rapid Communication: Large exploitable genetic variability exists to
           shorten age at slaughter in cattle1
    • Authors: D. P. Berry; A. R. Cromie M. M. Judge
      Abstract: Apprehension among consumers is mounting on the efficiency by which cattle convert feedstuffs into human edible protein and energy as well as the consequential effects on the environment. Most (genetic) studies that attempt to address these issues have generally focused on efficiency metrics defined over a certain time period of an animal’s life cycle, predominantly the period representing the linear phase of growth. The age at which an animal reaches the carcass specifications for slaughter, however, is also known to vary between breeds; less is known on the extent of the within-breed variability in age at slaughter. Therefore, the objective of the present study was to quantify the phenotypic and genetic variability in the age at which cattle reach a predefined carcass weight and subcutaneous fat cover. A novel trait, labeled here as the deviation in age at slaughter (DAGE), was represented by the unexplained variability from a statistical model, with age at slaughter as the dependent variable and with the fixed effects, among others, of carcass weight and fat score (scale 1 to 15 scored by video image analysis of the carcass at slaughter). Variance components for DAGE were estimated using either a 2-step approach (i.e., the DAGE phenotype derived first and then variance components estimated) or a 1-step approach (i.e., variance components for age at slaughter estimated directly in a mixed model that included the fixed effects of, among others, carcass weight and carcass fat score as well as a random direct additive genetic effect). The raw phenotypic SD in DAGE was 44.2 d. The genetic SD and heritability for DAGE estimated using the 1-step or 2-step models varied from 14.2 to 15.1 d and from 0.23 to 0.26 (SE 0.02), respectively. Assuming the (genetic) variability in the number of days from birth to reaching a desired carcass specifications can be exploited without any associated unfavorable repercussions, considerable potential exists to improve not only the (feed) efficiency of the animal and farm system but also the environmental footprint of the system. The beauty of the approach proposed, relative to strategies that select directly for the feed intake complex and enteric methane emissions, is that data on age at slaughter are generally readily available. Of course, faster gains may potentially be achieved if a dual objective of improving animal efficiency per day coupled with reduced days to slaughter was embarked on.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas2017.2016
      Issue No: Vol. 0, No. 0 (2017)
  • Replacing dietary nonessential amino acids with ammonia nitrogen does not
           alter amino acid profile of deposited protein in the carcass of growing
           pigs fed a diet deficient in nonessential amino acid nitrogen1
    • Authors: W. D. Mansilla; J. K. Htoo C. F. M. de Lange
      Abstract: Amino acid usage for protein retention, and, consequently, the AA profile of retained protein, is the main factor for determining AA requirements in growing animals. The objective of the present study was to determine the effect of supplementing ammonia N on whole-body N retention and the AA profile of retained protein in growing pigs fed a diet deficient in nonessential AA (NEAA) N. In total, 48 barrows with a mean initial BW of 13.6 kg (SD 0.7) were used. At the beginning of the study, 8 pigs were euthanized for determination of initial protein mass. The remaining animals were individually housed and fed 1 of 5 dietary treatments. A common basal diet (95% of experimental diets) was formulated to meet the requirements for all essential AA (EAA) but to be deficient in NEAA N (CP = 8.01%). The basal diet was supplemented (5%) with cornstarch (negative control) or 2 N sources (ammonia or NEAA) at 2 levels each to supply 1.35 or 2.70% extra CP. The final standardized ileal digestible (SID) NEAA content in the high-NEAA-supplemented diet (positive control) was based on the NEAA profile of whole-body protein of 20-kg pigs, and it was expected to reduce the endogenous synthesis of NEAA. Pigs were fed at 3.0 times maintenance energy requirements for ME in 3 equal meals daily. At the end of a 3-wk period, pigs were euthanized and the carcass and visceral organs were weighed, frozen, and ground for determination of protein mass. From pigs in the initial, negative control, high-ammonia, and high-NEAA groups, AA contents in the carcass and pooled visceral organs were analyzed to determine the total and deposited protein AA profile, dietary EAA efficiencies, and minimal de novo synthesis of NEAA. Carcass weight and whole-body N retention linearly increased (P < 0.05) with N supplementation. The AA profile of protein and deposited protein in the carcass was not different (P> 0.10) between N sources, but Cys content increased (P < 0.05) with NEAA compared with ammonia in visceral organ protein and deposited protein. The dietary SID EAA efficiency for increasing EAA deposition in whole-body protein increased (P < 0.05) with N supplementation, but it was not different (P> 0.10) between N sources. The de novo synthesis of NEAA increased (P < 0.05) for ammonia compared with NEAA supplementation. In conclusion, adding ammonia as a N source to diets deficient in NEAA N increases whole-body N retention without affecting the carcass AA profile.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1631
      Issue No: Vol. 0, No. 0 (2017)
  • Polyunsaturated fatty acids are less effective to reduce methanogenesis in
           rumen inoculum from calves exposed to a similar treatment early in life1
    • Authors: A. Ruiz-González; S. Debruyne, J. Jeyanathan, L. Vandaele, S. De Campeneere V. Fievez
      Abstract: The aim of this study was to evaluate the dose response on in vitro methane (CH4) production of PUFA to which the inoculum donor animals had been exposed early in life. Sixteen Holstein calves (160 ± 3 and 365 ± 2 kg BW) at 6 and 12 mo of age were used as inoculum donors. Half of the calves were given increasing amounts of extruded linseed from birth (22 g/d) until 4 mo of age (578 g/d) first mixed with milk and then included in their concentrate. Linseed oil (LSO) was supplemented in vitro at 5 different doses (0, 0.6, 1.2, 2.4, and 4.8 mg/mL). Supplementation of LSO in the rumen inocula at both ages linearly decreased (P < 0.05) the in vitro CH4 production. Total in vitro VFA production was not affected by LSO supplementation. Inhibition of CH4 was smaller when using the rumen inoculum from calves that had received a similar treatment early in life (P < 0.05). Differences in response to in vitro supplementation of a type of fatty acids similar to those applied during early life suggest some “changes” in the functioning of the rumen microbial community.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1558
      Issue No: Vol. 0, No. 0 (2017)
  • Endocannabinoid concentrations in plasma during the finishing period are
           associated with feed efficiency and carcass composition of beef cattle1
    • Authors: V. M. Artegoitia; A. P. Foote, R. G. Tait, L. A. Kuehn, R. M. Lewis, T. L. Wheeler H. C. Freetly
      Abstract: We previously have shown that plasma concentrations of endocannabinoids (EC) are positively correlated with feed efficiency and leaner carcasses in finishing steers. However, whether the animal growth during the finishing period affects the concentration of EC is unknown. The objective of this study was to quantify anandamide (AEA) and 2-arachidonyl glycerol (2-AG) in plasma during different stages of the finishing period and identify possible associations with production traits and carcass composition in beef calves. Individual DMI and BW gain were measured on 236 calves (n = 127 steers and n = 109 heifers) for 84 d on a finishing ration. Blood samples were collected on d 0 (early), 42 (mid), and 83 (late) of days on study (DOS). Cattle were slaughtered 44 d after the feeding study. Plasma concentration of AEA at 0 DOS was indirectly associated with the G:F (P < 0.01) and directly associated with residual feed intake (RFI; P < 0.05) in steers. In contrast, plasma concentration of AEA at 83 DOS was directly associated with the G:F and indirectly associated RFI in heifers and steers (P < 0.01). In addition, AEA concentration at 42 and 83 DOS was positively associated with ADG and DMI (P < 0.01) in heifers and steers. Furthermore, 2-AG concentration at 42 DOS was positively associated with ADG in steers (P < 0.01) and heifers (P < 0.10). Plasma concentration of AEA was positively associated (P < 0.05) with HCW, USDA-calculated yield grade, and 12th-rib fat thickness in heifers, whereas no associations were found in steers. In contrast, 2-AG concentration was not associated with any carcass traits. These results provide evidence that circulating EC change during animal growth and that AEA concentration may be a useful predictor of growth and feed efficiency and, in females, of carcass attributes.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1629
      Issue No: Vol. 0, No. 0 (2017)
  • Imposed running exercise does not alter cell proliferation in the
           neurogenic niches of young lambs
    • Authors: M. E. V. Swanson; H. C. Murray, M. H. Oliver, H. J. Waldvogel, E. C. Firth M. A. Curtis
      Abstract: Neurogenesis, the process by which neurons are generated in the brain from progenitor cells, occurs in the subventricular zone (SVZ) and the subgranular zone (SGZ) in the adult human brain. Recently, rodent studies have demonstrated that exercise can increase neurogenesis in the SGZ; however, it is unclear if exercise also has this effect in more complex mammalian brains. The overarching aim of this study was to explore whether exercised-induced neurogenesis occurs in larger mammalian brains more representative of human brains and to explore the use of a model for exercising large animals such as sheep. For these studies, 6 male twin lambs had a structured exercise regime for 4 wk and 6 other twin male lambs were kept in an open field pen. All lambs were injected with bromodeoxyuridine (BrdU), a thymidine analog that is incorporated into the DNA of proliferating cells. Immunoperoxidase was used to visualize and quantify BrdU-positive cells in the SVZ and SGZ. Overall, no significant change in the number or distribution of BrdU-positive cells was observed in the lamb SVZ and SGZ with exercise or colabeling of BrdU with mature neuronal or glial markers in the exercised and nonexercised lamb SVZ and SGZ. Overall, this study provides a novel methodology to investigate the effects of imposed exercise on large animals and exercise-induced neurogenesis in animals with gyrencephalic brains.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1710
      Issue No: Vol. 0, No. 0 (2017)
  • Body fat of stock-type horses predicted by rump fat thickness and
           deuterium oxide dilution and validated by near-infrared spectroscopy of
           dissected tissues1
    • Authors: E. N. Ferjak; C. A. Cavinder, D. D. Burnett, C. Mc. Argo T. T. N. Dinh
      Abstract: Body condition score and percent body fat (BF; %) of horses are positively correlated with reproductive efficiency and are indicative of metabolic issues. However, BF in horses may be poorly predicted because current procedures are either subjective or dependent on one anatomical location. Therefore, the objectives of the current study were to compare 2 methods of predicting BF using rump fat thickness (RFT) and deuterium oxide (D2O) dilution with actual tissue fat analysis by near-infrared spectroscopy (NIRS) in stock-type horses and to identify the relationship between BF and BCS. Twenty-four stock-type horses were selected to be humanely euthanized based on 3 primary criteria: geriatric, crippled, and/or unsafe. Approximately 20 h before slaughter, horses were weighed and BCS assessed to be 1 (n = 1; 433 kg), 2 (n = 1; 415 kg), 3 (n = 1; 376 kg), 4 (n = 7; 468 ± 13 kg), 5 (n = 10; 455 ± 11 kg), and 6 (n = 4; 493 ± 12 kg) and RFT was measured using ultrasonography. Blood samples were collected immediately before and 4 h after D2O infusion (0.12 g/kg BW). Deuterium oxide concentration of plasma was determined by gas isotope ratio mass spectrometry. Horses were housed in a dry lot overnight before being individually sedated (1.1 mg xylazine/kg BW) and anesthetized using a jugular venipuncture (2.2 mg ketamine/kg BW), and potassium chloride (KCl) solution was administered to cease cardiac function before exsanguination. After euthanasia, horse carcasses were processed and dissected and tissues were collected for NIRS analysis. Body fat predicted by D2O dilution was correlated with BF measured by NIRS analysis on various weight bases (r = 0.76 to 0.81, P < 0.001), whereas no correlation was observed for BF predicted by RFT. A paired t-test indicated that both D2O dilution and RFT overestimated BF by 2.48 to 3.26% (P < 0.001) and 5.81 to 6.59% (P < 0.001), respectively, compared with NIRS analysis. Body condition scores affected BF measured by NIRS analysis (P ≤ 0.038) and predicted by D2O dilution (P < 0.001) and RFT (P = 0.042). The current study provided evidence that D2O dilution was a better prediction method for BF than RFT and that BCS may serve as a BF predictor in stock-type horses.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1676
      Issue No: Vol. 0, No. 0 (2017)
  • Chromium, CLA, and ractopamine for finishing pigs1
    • Authors: C. S. Marcolla; D. M. Holanda, S. V. Ferreira, G. C. Rocha, N. V. L. Serão, M. S. Duarte, M. L. T. Abreu A. Saraiva
      Abstract: This study aimed to evaluate the effects of dietary chromium, CLA, and ractopamine on performance, carcass traits, and pork quality of finishing pigs slaughtered at 115 kg BW. Ninety-six crossbred barrows (initial BW = 70.21 ± 1.98 kg) were randomly assigned to 1 of 6 dietary treatments. There were 8 replicates per treatment (48 pens; 2 pigs/pen). A diet formulated according to the nutritional requirements was used as the control (CON). The other 5 diets were based on the CON and supplemented as follows: 0.4 mg/kg Cr yeast (CrY); 0.5% CLA; 0.4 mg/kg CrY and 0.5% CLA (CrY + CLA); 20 mg/kg ractopamine (RAC); 0.4 mg/kg CrY and 20 mg/kg RAC (CrY + RAC). Lysine levels on diets containing ractopamine were raised by 20% compared to CON to meet the greater requirements of pigs fed ractopamine. Pigs fed RAC and CrY + RAC were fed CON for the first 17 d, and then the respective diets for the last 28 d on trial. Data were analyzed in a model including the fixed effect of treatment (6 levels) and initial BW as a covariate for all characteristics, with the exception of carcass traits, in which final BW was used as a covariate. Least-squares means were separated using Tukey-Kramer’s method. Differences were considered when probability values were lower than 0.05. Pigs fed RAC and CrY + RAC had the greatest (P < 0.001) final BW and ADG. Pigs fed CrY + RAC had greater (P < 0.001) G:F than pigs within the other groups, except for those fed RAC. Pigs fed CrY + RAC and RAC had similar G:F, both greater (P < 0.001) than pigs fed CON. Average daily feed intake was similar (P = 0.83) for all diets. Pigs fed CrY + RAC had greater LM area (P = 0.01) and carcass yield (P < 0.02) than pigs fed CON, CrY, CLA, and CrY + CLA. Loin muscle area and carcass yield of pigs fed RAC were not different from pigs fed the others diets. Pigs fed CON diets had greater BF (P = 0.02) than pigs fed CLA diet. Additives did not affect (P> 0.05) pork quality, except for color. No differences (P> 0.05) were observed for carcasses pH and temperature. The L* values for pigs fed RAC were greater (P = 0.01) than pigs fed other diets. Pigs fed RAC had lower (P < 0.01) a* values compared to pigs fed other experimental diets. Serum urea nitrogen concentration (SUN) was lower (P = 0.02) in pigs fed CrY + RAC than in pigs fed CON and RAC and similar to pigs fed the other feeding additives. In summary, it was demonstrated that, when combined, CrY and RAC increase LM area and carcass yield, and reduce SUN, suggesting that chromium could improve nutrient utilization by muscle cells in RAC-fed pigs. Additionally, the additives have no major effects on pork quality.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1753
      Issue No: Vol. 0, No. 0 (2017)
  • LncRNA profiling of skeletal muscles in Large White pigs and Mashen pigs
           during development12
    • Authors: P. F. Gao; X. H. Guo, M. Du, G. Q. Cao, Q. C. Yang, Z. D. Pu, Z. Y. Wang, Q. Zhang, M. Li, Y. S. Jin, X. J. Wang, H. Liu B. G. Li
      Abstract: Long noncoding RNA (lncRNA) has been increasingly implicated in the regulation of muscle development. Large White pigs have a higher muscle growth rate than do Mashen pigs. In the present study, the lncRNA expression profiles in skeletal muscle of these 2 pig breeds were compared at 1, 90, and 180 d of age using RNA sequencing. We obtained 2,718 million clean reads and identified a total of 5,153 novel lncRNA. We found 1,407 differentially expressed lncRNA that showed consistent expression patterns between the 2 breeds at all the 3 sampling points. Ten lncRNA were randomly selected, and their expression was validated using Real-time Quantitative PCR. In summary, this study identifies a number of lncRNA that correlate with muscle growth. The regulation and function of these lncRNA in muscle growth and development need to be further explored.
      PubDate: 2017-09-01T00:00:00-05:00
      DOI: 10.2527/jas.2016.1297
      Issue No: Vol. 0, No. 0 (2017)
  • A deterministic, dynamic systems model of cow–calf production: The
           effects of breeding replacement heifers before mature cows over a 10-year
    • Authors: D. D. Shane; R. L. Larson, M. W. Sanderson, M. Miesner B. J. White
      Abstract: Some cattle production experts believe that cow–calf producers should breed replacement heifers (nulliparous cows) before cows (primiparous and multiparous cows), sometimes referred to as providing a heifer lead time (tHL). Our objective was to model the effects different durations of tHL may have on measures of herd productivity, including the percent of the herd cycling before the end of the first 21 d of the breeding season (%C21), the percent of the herd pregnant at pregnancy diagnosis (%PPD), the distribution of pregnancy by 21-d breeding intervals, the kilograms of calf weaned per cow exposed (KPC), and the replacement percentage (%RH), using a deterministic, dynamic systems model of cow–calf production over a 10-yr horizon. We also wished to examine differences in the effect of tHL related to the primiparous duration of postpartum anestrus (dPPAp). The study model examined 6 different dPPAp for primiparous cows (60, 70, 80, 90, 100, or 110 d). The multiparous cow duration of postpartum anestrus was set to 60 d. The breeding season length for nulliparous cows was 63 d, as was the breeding season length for primiparous and multiparous cows. Nulliparous cows were modeled with a tHL of 0, 7, 14, 21, 28, 35, or 42 d. Results are reported for the final breeding season of the 10-yr horizon. Increasing tHL resulted in a greater %C21 for the herd and for primiparous cows. Length of tHL had minimal impact on the %PPD unless the dPPAp was 80 d or greater. For a dPPAp of 110 d, a 0 d tHL resulted in the herd having 88.1 %PPD. When tHL was 21 d, the %PPD increased to 93.0%. The KPC was 161.2 kg when the dPPAd was 110 d and tHL was 0 d and improved to 183.2 kg when tHL was increased to 42 d. The %RH did not vary much unless the dPPAp was 90 d or greater, but increasing tHL resulted in decreased %RH. Based on the model results, increasing tHL improves the production outcomes included in the analysis, but herds with dPPAp of 90 d or greater had the greatest degree of improvement. For these herds, approximately two-thirds of the improvement in outcomes by increasing tHL from 0 d to 42 d was realized when tHL was 21 d. Costs are likely incurred when implementing tHL in a breeding management program, and an ideal tHL likely depends on the dPPAp of the herd, the expected improvement in productivity, and the costs associated with increasing tHL. Determining the dPPAp of a herd could help veterinarians and producers develop optimal herd management strategies.
      PubDate: 2017-08-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1653
      Issue No: Vol. 0, No. 0 (2017)
  • Genetic evaluation for birth and conformation traits in dual-purpose
           Belgian Blue cattle using a mixed inheritance model1
    • Authors: R. R. Mota; P. Mayeres, C. Bastin, G. Glorieux, C. Bertozzi, S. Vanderick, H. Hammami, F. G. Colinet N. Gengler
      Abstract: The segregation of the causal mutation (mh) in the muscular hypertrophy gene in dual-purpose Belgian Blue (dpBB) cattle is considered to result in greater calving difficulty (dystocia). Establishing adapted genetic evaluations might overcome this situation through efficient selection. However, the heterogeneity of dpBB populations at the mh locus implies separating the major gene and other polygenic effects in complex modeling. The use of mixed inheritance models may be an interesting option because they simultaneously assume both influences. A genetic evaluation in dpBB based on a mixed inheritance model was developed for birth and conformation traits: gestation length (GL), calving difficulty (CD), birth weight (BiW), and body conformation score (BC). A total of 27,362 animals having records were used for analyses. The total number of animals in the pedigree used to build the numerator relationship matrix was 62,617. Genotypes at the mh locus were available for 2,671 animals. Missing records at this locus were replaced with genotype probabilities. A total of 13,221 (48.3%) were registered as dpBB, 1,287 (4.7%) as beef Belgian Blue, and 12,854 (47.0%) were unknown. From those 13,221 dpBB animals, 650, 849, and 534 had double or single copies or no copy, respectively, of the causal mutation (mh) in the muscular hypertrophy gene, whereas 11,188 had missing genotypes. This heterogeneity at the mh locus may be the reason for high variability in the studied traits, that is, high heritability estimates of 0.33, 0.30, 0.38, and 0.43 for GL, CD, BiW, and BC, respectively. In general, additive (P < 0.05) and dominance (P < 0.001) allele substitution for calves and dams had significant impact for all traits. The moderate coefficient of genetic variation (27.80%) and high direct heritability (0.28) for CD suggested genetic variability in dpBB and possible genetic improvement through selection. This variability has allowed dpBB breeders to successfully apply mass selection in the past. Genetic trend means from 1988 to 2016 showed that sire selection for CD within genotype was progressively applied by breeders. The selection intensity was more important for CD in double-muscled lines than in segregated lines. Our study illustrated the possible confusion caused by the use of major genes in selection and the importance of fitting appropriate models such as mixed inheritance models that combine polygenic and gene content information.
      PubDate: 2017-08-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1748
      Issue No: Vol. 0, No. 0 (2017)
  • Beef steers with average dry matter intake and divergent average daily
           gain have altered gene expression in the jejunum
    • Authors: A. P. Foote; B. N. Keel, C. M. Zarek A. K. Lindholm-Perry
      Abstract: The objective of this study was to determine the association of differentially expressed genes (DEG) in the jejunum of steers with average DMI and high or low ADG. Feed intake and growth were measured in a cohort of 144 commercial Angus steers consuming a finishing diet containing (on a DM basis) 67.8% dry-rolled corn, 20% wet distillers grains with solubles, 8% alfalfa hay, and 4.2% vitamin/mineral supplement. From the cohort, a subset of steers with DMI within ±0.32 SD of the mean for DMI and the greatest (high) and least (low) ADG were chosen for slaughter and jejunum mucosa collection (n = 8 for each group). Dry matter intake (10.1 ± 0.05 kg/d) was not different (P = 0.41) but ADG was greater in the high-gain group (2.17 and 1.72 ± 0.02 kg/d for the high- and low-ADG groups, respectively; P < 0.01). A total of 13,747 genes were found to be expressed in the jejunum, of which 64 genes were differentially expressed between the 2 groups (corrected P < 0.05). Ten of the DEG were upregulated in the low-ADG group and 54 were upregulated in the high-ADG group. Gene ontology analysis determined that 24 biological process terms were overrepresented (P < 0.05), including digestion, drug and xenobiotic metabolism, and carbohydrate metabolism. Additionally, 89 molecular function terms were enriched (P < 0.05), including metallopeptidase activity, transporter activity, steroid hydrolase activity, glutathione transferase activity, and chemokine receptor binding. Metabolic pathways (28 pathways) impacted by the DEG (P < 0.05) included drug and xenobiotic metabolism by cytochrome P450, carbohydrate digestion and absorption, vitamin digestion and absorption, galactose metabolism, and linoleic acid metabolism. Results from this experiment indicate that cattle with average DMI and greater ADG likely have a greater capacity to handle foreign substances (xenobiotics). It is also possible that cattle with a greater ADG have a greater potential to digest and absorb nutrients in the small intestine.
      PubDate: 2017-08-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1804
      Issue No: Vol. 0, No. 0 (2017)
  • Rapid Communication: 16S ribosomal ribonucleic acid characterization of
    • Authors: M. D. Weinroth; C. R. Carlson, J. N. Martin, J. L. Metcalf, P. S. Morley K. E. Belk
      Abstract: Liver abscesses are a major economic burden to beef producers. Although a few causative organisms have been cultured from purulent material, the full polymicrobial diversity of liver abscesses has not been reported. The objective of this study was to characterize purulent material collected from liver abscess in beef cattle produced in different production systems in 3 cattle producing states in the United States using 16S rRNA gene sequencing. Differences between purulent material microbial communities among geographic region of feeding and application of a common antimicrobial were also investigated. Cattle included in the study were fed in California (dairy type) and Colorado and Texas (both beef type). Liver abscesses from a cross section of feedlots, geographic areas, and tylosin phosphate–administered groups were collected at harvest; DNA from 34 liver abscess samples was extracted; and the V4 region of the 16S rRNA gene was amplified and sequenced. Sequences were classified into 5 phyla, 13 classes, and 17 orders in the domain Bacteria. The phyla identified included Bacteroidetes (35.2% of reads), Proteobacteria (28.6%), Fusobacteria (18.2%), Firmicutes (12.4%), and Actinobacteria (5.5%). Sequences matching the genera Fusobacterium and Trueperella, which have previously been identified as causative agents in liver abscesses, were both present in the abscess bacterial communities at a relative abundance of 15.1 and 3.2%, respectively, of the overall relative abundance. Furthermore, 3 of the most common phyla were Gram-negative bacteria. An analysis-of-similarities test was conducted on Euclidean distances to assess differences between cattle treated and not treated with tylosin as well as to assess differences between geographic regions. Geographical region and treatment with tylosin did affect the microbiome (P = 0.002 and P = 0.026 respectively); however, a more robust sample scheme is needed to explore these differences. To our knowledge, this is the first publication describing the complex community of liver purulent material using next generation sequencing in cattle. These data provide a framework for research on a more targeted approach to liver abscess prevention and treatment.
      PubDate: 2017-08-01T00:00:00-05:00
      DOI: 10.2527/jas.2017.1743
      Issue No: Vol. 0, No. 0 (2017)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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Fax: +00 44 (0)131 4513327
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