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Chilean Journal of Agricultural & Animal Sciences
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ISSN (Print) 0719-3882 - ISSN (Online) 0719-3890
Published by SciELO Homepage  [688 journals]
  • EFFECT OF BREEDING PROGRAMS ON THE FUNCTIONAL LONGEVITY OF IRANIAN
           HOLSTEIN COWS

    • Abstract: ABSTRACT This study aimed to determine the effect of breeding programs on the functional longevity of Iranian Holstein cows. For this purpose, records of 538,873 animals collected by the Animal Breeding Center of Iran from 1990 to 2013 were used. Functional longevity was calculated from the difference between the first calving date and the last recording date. Animals that were alive in the herd or their culling date was unavailable, and less than one year had passed from their last recording were considered censored data, accounting for 34.23% of the records. The effect of milk production, herd size, interaction between lactation period and stage, herd-year-season of calving, Holstein gene percentage, and age at first calving were evaluated, and significant effects were included in the maternal grandsire model on genetic evaluation of longevity. The survival probability in different levels of effects was calculated by cmprsk package, and genetic evaluation of longevity was performed using Survival kit software. All effects were significant on the functional longevity, and thus the culling risk had a decreasing trend with increasing herd size changes and age at first calving, which increases with the increment of Holstein gene percentage. The culling risk decreased with increasing lactation, and animals were more likely to be culled in the first lactation. Direct heritability of longevity was estimated at 0.15, indicating good genetic diversity for breeding this trait. The effect of breeding programs with estimated breeding values for milk, fat, and protein production showed that the culling risk for higher genetic production potential tended to increase.
       
  • GENE EXPRESSION OF HEAT SHOCK PROTEINS IN DUAL-PURPOSE CATTLE EXPOSED TO
           HEAT STRESS CONDITIONS

    • Abstract: RESUMEN El aumento de la temperatura ambiental está afectando el ambiente térmico al que está expuesto el ganado, disminuyendo su desempeño productivo y reproductivo. Las proteínas de choque térmico (HSP) han sido utilizadas como el principal indicador de adaptabilidad de los bovinos a las condiciones de estrés calórico. Se analizó la expresión de los genes hsp60, hsp70 y hsp90 en 33 hembras mestizas bovinas (Holstein x Cebú y Suizo Pardo x Cebú), lactantes y horras. Los animales fueron muestreados dos veces por día en el estado de Veracruz y la expresión de los genes fue realizada mediante PCR de tiempo real con sondas marcadas con fluorescencia. El análisis estadístico de la expresión de los genes se llevó a cabo mediante un modelo de medidas repetidas, utilizando PROC MIXED de SAS. La expresión de los genes hsp60 y hsp70 al medio día fue diferente (p < 0,001 y p = 0,01, respectivamente) a la manifestada durante la madrugada. Los resultados de la expresión de los genes hsp pueden ayudar a desarrollar futuros programas de cruzamiento al reconocer animales que puedan mantener una mayor homeostasis bajo condiciones de estrés calórico.ABSTRACT The increase in environmental temperature is affecting the thermal environment to which cattle are exposed, decreasing productive and reproductive performance. Heat shock proteins (HSP) have been used as the main indicator of bovine adaptability to heat stress conditions. The expression of hsp60, hsp70, and hsp90 genes was analyzed in 33 crossbred female cattle (Holstein x Zebu and Brown Swiss x Zebu), lactating, and non-lactating. Animals were sampled two times per day in the state of Veracruz, and expression was estimated by using real-time PCR with fluorescently labeled probes. Statistical analysis of gene expression was carried out by a repeated measures model using PROC MIXED of SAS. The expression of hsp60 and hsp70 genes at midday was different (p < 0,001 and p = 0,01, respectively) from that manifested during the early morning. The results of hsp gene expression may help in developing future crossbreeding programs by recognizing animals that can maintain higher homeostasis under heat stress conditions.
       
  • ECONOMIC WEIGHTS FOR A SELECTION INDEX OF THE HOLSTEIN FRIESIAN BREED IN
           ECUADOR

    • Abstract: RESUMEN El genotipo Holstein Friesian es la raza registrada más antigua en Ecuador. El objetivo de esta investigación fue determinar los pesos económicos de los caracteres productivos y reproductivos más importantes en la raza Holstein Friesian del Ecuador, con la finalidad de diseñar un índice de selección de esta raza bajo el sistema económico de producción local. Los valores económicos para la producción de leche (PL), reproductivos (edad al primer parto (EPP), intervalo entre partos (IEP), crecimiento (peso vivo, PV) y longevidad (vida productiva, VP) se calcularon para un sistema de producción lechero basado en pasturas en el Ecuador. Se estimaron valores económicos bajo dos situaciones de pago de leche, basado en el precio por litro y en el precio por kilogramo de pasto producido. En el modelo inicial, los valores económicos fueron de 24,77 para PL ($USD/kg); -0,88 para EPP (días); 0,26 para IEP (días); -0,60 para PV (kg/vaca); y 0,29 para VP (años/vaca). Con un incremento del 10 % al valor inicial, el valor económico de PL aumentó (50,22), mientras que el precio por kg de pasto disminuyó (23,55). Los valores económicos estimados mostraron cambios importantes en cuanto a precios y cantidad de producción de leche en los sistemas de producción a pastoreo en Ecuador. Desde el punto de vista económico, los resultados obtenidos en este estudio pueden ser utilizados en programas de mejoramiento genético sobre las características que deberían incluirse en un índice de selección para la raza Holstein Friesian.ABSTRACT The Holstein Friesian genotype is the oldest registered breed in Ecuador. The objective of this research was to determine the economic weights of important productive and reproductive traits of the Holstein Friesian breed in Ecuador, in order to design a selection index for this breed under the economic system of local production. Economic values for milk production (PL), reproductive age at first calving (EEP), calving interval (IEP), growth (live weight, PV) and longevity (productive life, VP) were calculated for a dairy production system based on pastures in Ecuador. Economic values were estimated under two milk payment situations, based on the price per liter and on the price per kilogram of pasture produced. In the initial model, the economic values were 24,77 for PL ($USD / kg); -0,88 for EPP (days); 0,26 for IEP (days); -0,60 for PV (kg/cow); and 0,29 for VP (years/cow). With a 10% increase of the initial value, the economic value of PL increased (50.22), while price per kg of grass decreased (23.55). The estimated economic values showed important changes in terms of prices and quantity of milk production in the grazing production systems in Ecuador. From the economic point of view, the results obtained in this study can be used in genetic improvement programs on the traits that could be included in a selection index for the Holstein Friesian breed.
       
  • GENETIC PARAMETERS AND TRENDS FOR BIRTH AND WEANING WEIGHT IN HARTÓN DEL
           VALLE CREOLE CATTLE IN COLOMBIA

    • Abstract: RESUMEN El manejo adecuado de los recursos zoogenéticos es esencial para mejorar los sistemas de producción pecuaria, lo que ha sido reconocido por el sector ganadero en Colombia. Sin embargo, aún es necesario fortalecer el conocimiento sobre estos recursos para contar con información que permita tomar mejores decisiones sobre su conservación. El objetivo de este estudio fue determinar parámetros y tendencias genéticas para peso al nacimiento (PN) y peso al destete ajustado a 240 días (PD240) en ganado Hartón del Valle (HDV) en Colombia. Se utilizó información obtenida del Banco de Germoplasma Animal - Agrosavia Centro de Investigación Palmira, correspondiente a 327 animales en el período 2013-2021. Los datos para PN y PD240 se analizaron usando un modelo bicarácter que incluyó sexo, familia, año de nacimiento y destete como efectos fijos. La edad de la madre al destete se utilizó como covariable y se incluyeron los efectos genéticos aditivos directos, aditivos maternos y el residual. Los componentes de (co)varianza y parámetros genéticos se obtuvieron mediante el método de máxima verosimilitud restringida (programa AIREMLF90). El PN y PD240 promedio fueron de 33,26 ± 4,46 kg y 186,99 ± 28,20 kg, respectivamente. La heredabilidad directa y materna fue 0,44 y 0,16 para PN, y de 0,29 y 0,10 para PD240, respectivamente. La correlación genética directa y fenotípica entre PN y PD240 fue 0,25 y 0,26, respectivamente. La tendencia genética directa para PN y PD240 fueron positivas, mientras que para el efecto materno fue baja para ambas características. Las heredabilidades estimadas evidencian que estos rasgos se podrían mejorar a través de procesos de selección. Este trabajo es la primera evaluación genética realizada en la raza HDV, lo que representa un avance importante en su caracterización.ABSTRACT Proper management of animal genetic resources is essential to improve livestock production systems, which has been recognized by the livestock sector in Colombia. However, there is still a need for more in-depth knowledge of these resources in order to enable stakeholders make conservation-oriented decisions. The objective of this study was to determine genetic parameters and trends for birth weight (BW) and adjusted weaning weight at 240 days (AWW240) in Hartón del Valle (HDV) cattle in Colombia. Information was obtained from the Animal Germplasm Bank - Agrosavia Palmira Research Center, corresponding to 327 animals for the period 2013-2021. The data for BW and AWW240 were analyzed using a bi-character model that included sex, family, year of birth and weaning as fixed effects. The age of the mother at weaning was used as a covariate, while direct additive genetic, additive maternal genetic, and residual effects were also included. The (co)variance components and genetic parameters were obtained using the restricted maximum likelihood method (AIREMLF90 program). The average BW and AWW240 were 33,26 ± 4,46 kg and 186,99 ± 28,20 kg, respectively. The direct and maternal heritability was 0,44 and 0,16 for BW and 0,29 and 0,10 for AWW240, respectively. The direct genetic and phenotypic correlation between BW and AWW240 was 0,25 and 0,26 respectively. The trends of direct breeding values for PN and PD240 were positive, while those of maternal effects were negative for both traits. Heritability estimates show that these traits could be improved by genetic selection processes. This is the first genetic evaluation carried out in this HDV breed, which represents an important advance in its characterization.
       
  • EFFECT OF METOCLOPRAMIDE ON PASSIVE TRANSFER IN CALVES FED MATERNAL
           COLOSTRUM OR COLOSTRUM REPLACER

    • Abstract: RESUMEN El fallo de la transferencia pasiva es uno de los problemas más importantes en la cría de reemplazos. Los objetivos de este estudio fueron determinar el efecto de la metoclopramida (MCP) sobre la transferencia pasiva (TP), y comparar la calidad de la TP en terneros alimentados con calostro materno (CM) o reemplazador de calostro (RC). En total, 40 terneros fueron asignados a 1 de 4 grupos: [1] suministro de CM sin MCP (A1P0), [2] suministro de CM con aplicación de MCP (A1P1), [3] suministro de RC sin MCP (A2P0) y [4] suministro de RC con aplicación de MCP (A2P1). Se recolectaron muestras de sangre antes (cero días) y después (dos días) del calostrado para estimar el hematocrito y cuantificar glucosa, proteína y sólidos totales asociados con la calidad de la TP. Dos días después del calostrado, la concentración de glucosa fue elevada para el grupo A1P0 (85,5 mg/dL) comparado con el grupo A2P0 (54,0 mg/dL) (p<0,05). El grupo A1P1 mostró la concentración más alta de proteína (6,3 g/dL) en comparación con el grupo A2P0 (4,0 g/dL) (p<0,05). El porcentaje Brix fue más elevado en los grupos A1P0 y A1P1 (10,3%) comparados con el grupo A2P0 (7,8%) (p<0,05). No se demostró efecto significativo de la MCP sobre la TP ni interacción entre el calostrado x procinético (p>0,05). Los resultados de este estudio indicaron que la MCP no afecta la TP y que el calostrado con CM fue mejor porque aumentó la calidad de la TP de glucosa, proteína y sólidos totales en sangre en comparación con el RC.ABSTRACT Passive transfer failure is one of the most important problems in replacement breeding. The objectives of this study were to determine the effect of metoclopramide (MCP) on passive transfer (PT), and to compare the quality of PT in calves fed maternal colostrum (MC) or colostrum replacer (CR). In total, 40 calves were assigned to 1 of 4 groups: [1] fed MC without MCP (A1P0), [2] fed MC with MCP application (A1P1), [3] fed CR without MCP (A2P0), and [4] fed CR with MCP application (A2P1). Blood samples were collected before (0 days) and after colostrum intake (2 days) to estimate hematocrit, serum concentration of glucose, protein and total solids associated with the quality of PT. At 2 days after colostrum intake, glucose concentration was high for the A1P0 group (85.5 mg/ dL) compared to the A2P0 group (54.0 mg/dL) (p<0.05). The A1P1 group showed the highest protein concentration (6.3 g/dL) compared to the A2P0 group (4.0 g/dL) (p<0.05). The Brix percentage was higher in the A1P0 and A1P1 groups (10.3%) compared to the A2P0 group (7.8%) (p<0.05). The application of MCP had no significant effect on PT and there was no interaction between the types of colostrum and the prokinetic agent (p>0.05). The results of this study indicated that MCP does not affect PT and that intake of MC was better compared to the CR because it increased the quality of PT to glucose, protein, and total solids in blood.
       
  • DIGESTIBILITY, RUMEN FERMENTATION, RUMEN MICROBIOTA, AND LIPID
           PEROXIDATION IN SHEEP SUPPLEMENTED WITH LIPOIC ACID

    • Abstract: ABSTRACT Lipoic acid (LA) reduces oxidative stress and stimulates the immune system. However, data on its use in ruminants is limited. The objective of this study was to determine the effects of LA supplementation on free radical production, rumen variables, and feed digestibility in sheep fed high-grain diets. Nine rumen-cannulated Suffolk sheep were randomly assigned to three treatments: control (LA0), no LA inclusion; supplementation of 10 (LA10) mg LA kg-1 body weight (BW); and supplementation of 20 (LA20) mg LA kg-1 BW. In situ (ISDMD) and in vitro (IVDMD) degradation of dry matter and ruminal variables were evaluated. Total bacteria (TB), cellulolytic bacteria (CB), and protozoa (P) were also determined. Thiobarbituric acid reactive substances (TBARS) were evaluated in blood samples at the beginning and end of each experimental period. The ruminal variables and IVADDM were analyzed using a PROC GLM model with a repeated 3 x 3 latin square design, while means were compared using pairwise Tukey tests. LA supplementation did not affect (p > 0.05) the ruminal variables under study. LA modified (p < 0.05) ISDMD at 4 h in LA10, while no differences were found in terms of IVDMD among the treatments. The LA dose of 10 mg kg-1 BW increased CB (p < 0.05) and decreased TB (p < 0.05). TBARS differed (p < 0.01) among the treatments and evaluation periods and were higher (p < 0.05) 15 d after administration. In conclusion, LA supplementation in sheep had an antioxidant effect, reducing oxidative stress 15 d after administration, with slight differences in the ruminal variables evaluated.
       
  • OPTIMIZATION OF NEUTRALIZING POWER OF Mytilus chilensis SEASHELLS IN ACID
           ALLUVIAL SOIL OF ÑUBLE COAST

    • Abstract: ABSTRACT Seashells, residues from mussel (Mytilus chilensis), Hupé 1854 processing, are an environmental load on the coasts of southern Chile. The main component of this waste is calcium carbonate, which is commonly used to neutralize soil acidity. Its application in meadows is limited due to the large quantities (tons) required. The objectives of this work were to determine the most appropriate type of mussel seashells (M. chilensis) as a source of calcium carbonate (CaCO3) for pH neutralization of an alluvial acidic soil collected from Ñuble Coast, and to identify its optimal dose. The seashell doses were optimized using response surface methodology (RSM) to achieve a soil pH close to neutral and a relatively high neutralizing power, which was defined in comparison to the pH increase achieved with commercial CaCO3. Seashells with organic matter was the most suitable formulation for increasing soil pH with a high relative neutralizing power (~ 94%), requiring a dose of 23% (w/w) to achieve soil pH values close to neutral. The fitted quadratic model explains 98.9% of variation in experimental data. This work lays the foundations for future studies aimed to find new agricultural and/or livestock applications of wastes from the shellfish industry.
       
  • BIOLOGICAL RELATIONSHIPS AMONG Fusarium graminearum s.l. ISOLATES FROM
           DIVERSE HOSTS AND ENVIRONMENTS OF ARGENTINA

    • Abstract: ABSTRACT Fusarium graminearum (teleomorph Gibberella zeae) is an important plant pathogen that causes diseases on roots, stems, fruits, and seeds of diverse plant families. The fungus obtains nutrients through saprotrophic and parasitic relationships. Mycotoxins produced by F. graminearum, which can be found in contaminated grains and flours, constitute a threat to human and animal health. The aim of this study was to infer biological relationships among isolates of F. graminearum, obtained from different botanic hosts and locations of the central region of Argentina, by assessment of biodiversity from morphological and molecular markers. F. graminearum (local isolates and a foreign control isolate) established closed morphological and molecular (genetic) relationships beyond the diversity of origin. The identity of the collection was validated as F. graminearum -sensu lato- and it was the predominant specific-clade in the analyzed population. Furthermore, the capacity of F. graminearum to adapt to diverse plant substrates (Fabaceae, Poaceae, Asteraceae and Rosaceae families) and ecologic environments (between 30 ° and 36 ° south latitude) observed in this study revealed the large plasticity of this fungus in Argentina.
       
  • RELATIONSHIP BETWEEN SOIL ACIDITY AND PRODUCTIVITY OF BANANA (Musa spp.)
           IN URABÁ, COLOMBIA

    • Abstract: ABSTRACT Soil acidity plays an important role in the productivity of export bananas as it affects nutrient availability and phototoxicity depending on soil pH. The objective of this research was to evaluate the relationship between soil pH and banana productivity in Uraba, Colombia. The study was conducted at the Ramiro Jaramillo Sossa experimental station, Banana Research Center (Cenibanano), Urabá, Antioquia. The sampling grid consisted of 110 points. Determination of pH was conducted in situ, and soil samples were processed in the laboratory using two solutions: distilled water and KCl. Significant differences were found between the solutions, aluminum extraction and field sampling. Additionally, the presence of Al3+ was confirmed in the pH range H2O < 5.5. Finally, the pH values were pH KCl < pH H2O < pH in-situ. The latter best explained the behavior of bunch weight, indicating that in situ determination of pH better reflects the real conditions of this variable, with a greater relationship with productivity.
       
  • REDESIGN AND OPTIMIZATION OF A SPRAY-DRYER USING CFD

    • Abstract: RESUMEN Desde los primeros desarrollos en el secado por aspersión en 1870, se han realizado numerosas contribuciones para obtener parámetros de diseño. Sin embargo, se requieren estudios experimentales para diseñar, optimizar y construir equipos de secado por aspersión para aplicaciones específicas. A partir de la información disponible en libros, catálogos y patentes, se han seleccionado las dimensiones y condiciones de operación para realizar el modelado matemático de un secador por aspersión en co-corriente, comenzando con un modelo relativamente simple de flujo monofásico incompresible y luego utilizando un modelo más complejo que contempla el flujo multifásico. Los objetivos de este trabajo fueron: (i) evaluar tres diseños diferentes de un equipo de secado por aspersión mediante Dinámica de Fluidos Computacional (CFD); y (ii) seleccionar el diseño con las mejores características de flujo y transferencia de calor. Se evaluaron los perfiles de velocidad, las líneas de flujo, los mapas de presión y los perfiles de temperatura en cada diseño. A partir de los resultados, se construyó un nuevo prototipo con la modificación en la tapa del equipo y se realizaron pruebas experimentales para demostrar la efectividad del nuevo diseño.ABSTRACT Since the first developments in spray drying in 1870, attempts have been made to obtain design parameters. However, experimental studies are required to design, optimize, and build spray drying equipment for specific applications. From the information reported in books, catalogs and patents, the dimensions and operating conditions have been selected to develop the mathematical modeling of a co-current spray dryer, starting with a relatively simple model of incompressible single-phase flow, and then using a more complex method with multi-phase flow. The objectives of this study were to: (i) evaluate three different designs of spray-drying equipment; and (ii) select the design that provided the best flow and heat transfer characteristics. The velocity profiles, flow lines, pressure maps and temperature profiles of each design were evaluated. Based on the results obtained, a new prototype with the modification on the equipment lid was built and experimental tests were conducted to demonstrate the effectiveness of the new design.
       
 
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