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Publisher: Cambridge University Press   (Total: 367 journals)

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Showing 1 - 200 of 367 Journals sorted alphabetically
Acta Neuropsychiatrica     Hybrid Journal   (Followers: 4, SJR: 0.421, h-index: 23)
Acta Numerica     Hybrid Journal   (Followers: 3, SJR: 8.044, h-index: 35)
Advances in Animal Biosciences     Full-text available via subscription   (Followers: 8)
Advances in Applied Mathematics and Mechanics     Full-text available via subscription   (SJR: 0.74, h-index: 14)
Africa     Hybrid Journal   (Followers: 19, SJR: 1.02, h-index: 28)
African Studies Review     Full-text available via subscription   (Followers: 18, SJR: 0.532, h-index: 13)
Ageing & Society     Hybrid Journal   (Followers: 38, SJR: 0.87, h-index: 55)
Agricultural and Resource Economics Review     Open Access   (Followers: 5, SJR: 0.326, h-index: 19)
AI EDAM     Hybrid Journal   (SJR: 0.438, h-index: 40)
AJS Review     Full-text available via subscription   (Followers: 2, SJR: 0.203, h-index: 4)
American Political Science Review     Hybrid Journal   (Followers: 252, SJR: 6.112, h-index: 127)
Anatolian Studies     Full-text available via subscription   (Followers: 4, SJR: 0.482, h-index: 10)
Ancient Mesoamerica     Hybrid Journal   (Followers: 10, SJR: 0.507, h-index: 29)
Anglo-Saxon England     Hybrid Journal   (Followers: 34, SJR: 0.144, h-index: 12)
animal     Hybrid Journal   (Followers: 3, SJR: 1.098, h-index: 43)
Animal Health Research Reviews     Hybrid Journal   (Followers: 3, SJR: 0.838, h-index: 41)
Animal Science     Full-text available via subscription   (Followers: 9)
Annals of Actuarial Science     Full-text available via subscription   (Followers: 1)
Annual of the British School at Athens     Full-text available via subscription   (Followers: 15, SJR: 0.101, h-index: 9)
Annual Review of Applied Linguistics     Hybrid Journal   (Followers: 36, SJR: 0.753, h-index: 22)
Antarctic Science     Hybrid Journal   (Followers: 1, SJR: 0.728, h-index: 55)
Antichthon     Full-text available via subscription   (Followers: 1, SJR: 0.126, h-index: 2)
Antiquaries J., The     Full-text available via subscription   (Followers: 8, SJR: 0.156, h-index: 3)
Antiquity     Hybrid Journal   (Followers: 27, SJR: 1.133, h-index: 54)
ANZIAM J.     Open Access   (Followers: 1, SJR: 0.151, h-index: 17)
Applied Psycholinguistics     Hybrid Journal   (Followers: 22, SJR: 1.005, h-index: 59)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 8, SJR: 0.339, h-index: 4)
Arabic Sciences and Philosophy     Hybrid Journal   (Followers: 9, SJR: 0.138, h-index: 13)
Arbor Clinical Nutrition Updates     Full-text available via subscription   (Followers: 3)
Archaeological Dialogues     Hybrid Journal   (Followers: 35, SJR: 0.67, h-index: 17)
Archaeological Reports     Full-text available via subscription   (Followers: 5, SJR: 0.101, h-index: 1)
arq: Architectural Research Quarterly     Hybrid Journal   (Followers: 7, SJR: 0.101, h-index: 3)
Asian J. of Comparative Law     Hybrid Journal   (Followers: 9, SJR: 0.127, h-index: 5)
Asian J. of Intl. Law     Hybrid Journal   (Followers: 12, SJR: 0.218, h-index: 5)
Asian J. of Law and Society     Hybrid Journal   (Followers: 7, SJR: 0.179, h-index: 3)
Astin Bulletin     Full-text available via subscription   (Followers: 1, SJR: 0.979, h-index: 19)
Australasian J. of Organisational Psychology     Hybrid Journal   (Followers: 9)
Australasian J. of Special Education     Full-text available via subscription   (Followers: 7, SJR: 0.199, h-index: 6)
Australian J. of Environmental Education     Full-text available via subscription   (Followers: 7, SJR: 0.299, h-index: 5)
Australian J. of Indigenous Education, The     Full-text available via subscription   (Followers: 10, SJR: 0.293, h-index: 4)
Australian J. of Rehabilitation Counseling     Full-text available via subscription   (Followers: 4, SJR: 0.114, h-index: 1)
Austrian History Yearbook     Full-text available via subscription   (Followers: 8, SJR: 0.127, h-index: 3)
Behavioral and Brain Sciences     Hybrid Journal   (Followers: 33, SJR: 0.826, h-index: 127)
Behaviour Change     Full-text available via subscription   (Followers: 13, SJR: 0.362, h-index: 27)
Behavioural and Cognitive Psychotherapy     Hybrid Journal   (Followers: 139, SJR: 0.831, h-index: 47)
Bilingualism: Language and Cognition     Hybrid Journal   (Followers: 37, SJR: 1.359, h-index: 33)
Biofilms     Full-text available via subscription   (Followers: 1)
Bird Conservation Intl.     Hybrid Journal   (Followers: 23, SJR: 0.831, h-index: 29)
BJPsych Advances     Full-text available via subscription   (Followers: 53)
Brain Impairment     Full-text available via subscription   (Followers: 2, SJR: 0.31, h-index: 13)
Breast Cancer Online     Full-text available via subscription   (Followers: 4)
Britannia     Full-text available via subscription   (Followers: 7, SJR: 0.112, h-index: 0)
British Actuarial J.     Full-text available via subscription  
British Catholic History     Hybrid Journal   (Followers: 1)
British J. for the History of Science     Hybrid Journal   (Followers: 20, SJR: 0.804, h-index: 21)
British J. of Anaesthetic and Recovery Nursing     Full-text available via subscription   (Followers: 8)
British J. of Music Education     Hybrid Journal   (Followers: 23, SJR: 0.391, h-index: 8)
British J. Of Nutrition     Hybrid Journal   (Followers: 73, SJR: 1.587, h-index: 139)
British J. of Political Science     Hybrid Journal   (Followers: 166, SJR: 2.505, h-index: 63)
British J. of Psychiatry     Hybrid Journal   (Followers: 180, SJR: 2.674, h-index: 178)
Bulletin of Entomological Research     Hybrid Journal   (Followers: 10, SJR: 0.918, h-index: 54)
Bulletin of Symbolic Logic     Full-text available via subscription   (Followers: 2, SJR: 1.405, h-index: 26)
Bulletin of the Australian Mathematical Society     Full-text available via subscription   (Followers: 1, SJR: 0.488, h-index: 30)
Bulletin of the School of Oriental and African Studies     Hybrid Journal   (Followers: 18, SJR: 0.122, h-index: 11)
Business and Human Rights J.     Full-text available via subscription   (Followers: 3)
Business Ethics Quarterly     Full-text available via subscription   (Followers: 13, SJR: 1.534, h-index: 46)
Business History Review     Full-text available via subscription   (Followers: 14, SJR: 0.291, h-index: 20)
Cambridge Archaeological J.     Hybrid Journal   (Followers: 128, SJR: 0.743, h-index: 32)
Cambridge Classical J.     Full-text available via subscription   (Followers: 18, SJR: 0.101, h-index: 6)
Cambridge J. of Postcolonial Literary Inquiry     Hybrid Journal   (Followers: 6)
Cambridge Law J.     Hybrid Journal   (Followers: 162, SJR: 0.173, h-index: 3)
Cambridge Opera J.     Hybrid Journal   (Followers: 5, SJR: 0.227, h-index: 9)
Cambridge Quarterly of Healthcare Ethics     Hybrid Journal   (Followers: 11, SJR: 0.295, h-index: 25)
Camden Fifth Series     Full-text available via subscription   (Followers: 3)
Canadian Entomologist     Hybrid Journal   (Followers: 5, SJR: 0.388, h-index: 34)
Canadian J. of Emergency Medicine     Hybrid Journal   (Followers: 11, SJR: 0.532, h-index: 32)
Canadian J. of Law & Jurisprudence     Full-text available via subscription   (Followers: 9)
Canadian J. of Law and Society     Hybrid Journal   (Followers: 19, SJR: 0.247, h-index: 6)
Canadian J. of Neurological Sciences     Full-text available via subscription   (SJR: 0.477, h-index: 53)
Canadian J. of Political Science/Revue canadienne de science politique     Full-text available via subscription   (Followers: 23, SJR: 1.161, h-index: 23)
Canadian J. on Aging     Hybrid Journal   (Followers: 10, SJR: 0.292, h-index: 29)
Canadian Yearbook of Intl. Law / Annuaire canadien de droit international     Full-text available via subscription   (Followers: 2)
Cardiology in the Young     Hybrid Journal   (Followers: 32, SJR: 0.312, h-index: 40)
Central European History     Full-text available via subscription   (Followers: 30, SJR: 0.201, h-index: 14)
Children Australia     Partially Free   (Followers: 2, SJR: 0.191, h-index: 2)
China Quarterly     Hybrid Journal   (Followers: 50, SJR: 1.058, h-index: 54)
Chinese J. of Agricultural Biotechnology     Full-text available via subscription   (Followers: 4)
Church History: Studies in Christianity and Culture     Full-text available via subscription   (Followers: 72, SJR: 0.113, h-index: 16)
Classical Quarterly     Full-text available via subscription   (Followers: 28, SJR: 0.151, h-index: 24)
Classical Review     Full-text available via subscription   (Followers: 24)
CNS Spectrums     Hybrid Journal   (Followers: 3, SJR: 0.885, h-index: 60)
Cognitive Behaviour Therapist     Hybrid Journal   (Followers: 13)
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4, SJR: 1.013, h-index: 35)
Communications in Computational Physics     Full-text available via subscription   (Followers: 2, SJR: 1.198, h-index: 34)
Comparative Studies in Society and History     Full-text available via subscription   (Followers: 46, SJR: 0.725, h-index: 36)
Compositio Mathematica     Full-text available via subscription   (Followers: 1, SJR: 2.965, h-index: 37)
Contemporary European History     Hybrid Journal   (Followers: 25, SJR: 0.369, h-index: 16)
Continuity and Change     Hybrid Journal   (Followers: 12, SJR: 0.266, h-index: 19)
Dance Research J.     Full-text available via subscription   (Followers: 8, SJR: 0.144, h-index: 5)
Development and Psychopathology     Hybrid Journal   (Followers: 9, SJR: 2.342, h-index: 131)
Dialogue Canadian Philosophical Review/Revue canadienne de philosophie     Full-text available via subscription   (Followers: 3, SJR: 0.126, h-index: 7)
Diamond Light Source Proceedings     Full-text available via subscription  
Disaster Medicine and Public Health Preparedness     Hybrid Journal   (Followers: 11, SJR: 0.274, h-index: 24)
Du Bois Review: Social Science Research on Race     Full-text available via subscription   (Followers: 8, SJR: 0.307, h-index: 5)
Early China     Hybrid Journal   (Followers: 3)
Early Music History     Hybrid Journal   (Followers: 8, SJR: 0.164, h-index: 8)
Earth and Environmental Science Transactions of the Royal Society of Edinburgh     Hybrid Journal   (Followers: 5, SJR: 0.325, h-index: 41)
East Asian J. on Applied Mathematics     Full-text available via subscription   (SJR: 0.424, h-index: 6)
Ecclesiastical Law J.     Full-text available via subscription   (Followers: 6, SJR: 0.1, h-index: 2)
Econometric Theory     Hybrid Journal   (Followers: 16, SJR: 2.219, h-index: 52)
Economics and Philosophy     Hybrid Journal   (Followers: 15, SJR: 0.624, h-index: 19)
Edinburgh J. of Botany     Hybrid Journal   (SJR: 0.324, h-index: 20)
Eighteenth-Century Music     Hybrid Journal   (Followers: 11, SJR: 0.1, h-index: 4)
English Language and Linguistics     Hybrid Journal   (Followers: 24, SJR: 0.387, h-index: 18)
English Profile J.     Hybrid Journal   (Followers: 2)
English Today     Hybrid Journal   (Followers: 8, SJR: 0.302, h-index: 4)
Enterprise & Society : The Intl. J. of Business History     Hybrid Journal   (Followers: 16, SJR: 0.452, h-index: 17)
Environment and Development Economics     Hybrid Journal   (Followers: 32, SJR: 0.617, h-index: 43)
Environmental Conservation     Hybrid Journal   (Followers: 58, SJR: 1.09, h-index: 66)
Environmental Practice     Full-text available via subscription   (Followers: 3, SJR: 0.304, h-index: 15)
Epidemiology & Infection     Hybrid Journal   (Followers: 15, SJR: 1.32, h-index: 85)
Epidemiology and Psychiatric Sciences     Hybrid Journal   (Followers: 3, SJR: 0.699, h-index: 28)
Episteme     Hybrid Journal   (Followers: 12, SJR: 0.678, h-index: 2)
Equine and Comparative Exercise Physiology     Full-text available via subscription   (Followers: 6)
Ergodic Theory and Dynamical Systems     Hybrid Journal   (Followers: 2, SJR: 1.456, h-index: 43)
Ethics & Intl. Affairs     Full-text available via subscription   (Followers: 13, SJR: 0.464, h-index: 6)
European Constitutional Law Review (EuConst)     Full-text available via subscription   (Followers: 31, SJR: 1.269, h-index: 15)
European J. of Applied Mathematics     Hybrid Journal   (SJR: 0.939, h-index: 34)
European J. of Sociology     Hybrid Journal   (Followers: 29, SJR: 0.241, h-index: 26)
European Political Science Review     Hybrid Journal   (Followers: 20, SJR: 0.524, h-index: 5)
European Review     Hybrid Journal   (Followers: 17, SJR: 0.119, h-index: 17)
Experimental Agriculture     Hybrid Journal   (Followers: 12, SJR: 0.486, h-index: 31)
Expert Reviews in Molecular Medicine     Hybrid Journal   (Followers: 1, SJR: 1.776, h-index: 60)
Fetal and Maternal Medicine Review     Hybrid Journal   (Followers: 4, SJR: 0.178, h-index: 14)
Financial History Review     Full-text available via subscription   (Followers: 14, SJR: 0.342, h-index: 11)
Foreign Policy Bulletin     Hybrid Journal   (Followers: 6)
Forum of Mathematics, Pi     Open Access   (Followers: 1)
Forum of Mathematics, Sigma     Open Access   (Followers: 1)
Genetics Research     Hybrid Journal   (Followers: 4, SJR: 0.52, h-index: 59)
Geological Magazine     Hybrid Journal   (Followers: 16, SJR: 1.119, h-index: 64)
Glasgow Mathematical J.     Full-text available via subscription   (Followers: 1, SJR: 0.748, h-index: 25)
Global Constitutionalism     Hybrid Journal   (Followers: 16)
Global Mental Health     Open Access   (Followers: 7)
Government and Opposition     Full-text available via subscription   (Followers: 20, SJR: 0.611, h-index: 32)
Greece & Rome     Partially Free   (Followers: 21, SJR: 0.136, h-index: 15)
Hague J. on the Rule of Law     Full-text available via subscription   (Followers: 12, SJR: 0.12, h-index: 11)
Harvard Theological Review     Full-text available via subscription   (Followers: 65, SJR: 0.237, h-index: 17)
Health Economics, Policy and Law     Hybrid Journal   (Followers: 25, SJR: 0.441, h-index: 21)
Hegel Bulletin     Full-text available via subscription   (Followers: 1)
High Power Laser Science and Engineering     Open Access   (Followers: 3)
Historical J.     Hybrid Journal   (Followers: 32, SJR: 0.337, h-index: 23)
History in Africa     Full-text available via subscription   (Followers: 8)
Horizons     Partially Free   (Followers: 1, SJR: 0.112, h-index: 3)
Industrial and Organizational Psychology     Hybrid Journal   (Followers: 20, SJR: 0.47, h-index: 18)
Infection Control and Hospital Epidemiology     Full-text available via subscription   (Followers: 34, SJR: 1.985, h-index: 108)
Intl. & Comparative Law Quarterly     Full-text available via subscription   (Followers: 197, SJR: 0.324, h-index: 25)
Intl. J. of Asian Studies     Hybrid Journal   (Followers: 12, SJR: 0.107, h-index: 1)
Intl. J. of Astrobiology     Hybrid Journal   (Followers: 2, SJR: 0.384, h-index: 18)
Intl. J. of Cultural Property     Full-text available via subscription   (Followers: 13, SJR: 0.154, h-index: 1)
Intl. J. of Disability Management Research     Full-text available via subscription   (Followers: 8, SJR: 0.179, h-index: 2)
Intl. J. of Law in Context     Hybrid Journal   (Followers: 16, SJR: 0.236, h-index: 5)
Intl. J. of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 8, SJR: 0.232, h-index: 11)
Intl. J. of Middle East Studies     Hybrid Journal   (Followers: 65, SJR: 0.501, h-index: 28)
Intl. J. of Technology Assessment in Health Care     Hybrid Journal   (Followers: 12, SJR: 0.854, h-index: 54)
Intl. J. of Tropical Insect Science     Hybrid Journal   (Followers: 1, SJR: 0.299, h-index: 20)
Intl. Labor and Working-Class History     Full-text available via subscription   (Followers: 11, SJR: 0.262, h-index: 14)
Intl. Organization     Full-text available via subscription   (Followers: 88, SJR: 3.67, h-index: 106)
Intl. Psychogeriatrics     Hybrid Journal   (Followers: 11, SJR: 1.068, h-index: 68)
Intl. Review of Social History     Full-text available via subscription   (Followers: 24, SJR: 0.185, h-index: 16)
Intl. Review of the Red Cross     Full-text available via subscription   (Followers: 10, SJR: 0.275, h-index: 10)
Intl. Theory: A J. of Intl. Politics, Law and Philosophy     Hybrid Journal   (Followers: 18, SJR: 0.774, h-index: 4)
Iraq     Full-text available via subscription   (Followers: 2)
Irish Historical Studies     Hybrid Journal   (Followers: 5, SJR: 0.101, h-index: 8)
Irish J. of Psychological Medicine     Hybrid Journal   (Followers: 2, SJR: 0.107, h-index: 14)
Israel Law Review     Hybrid Journal   (Followers: 2, SJR: 0.12, h-index: 2)
Itinerario     Full-text available via subscription   (Followers: 8, SJR: 0.195, h-index: 4)
J. of African History     Hybrid Journal   (Followers: 21, SJR: 0.381, h-index: 25)
J. of African Law     Full-text available via subscription   (Followers: 3, SJR: 0.125, h-index: 6)
J. of Agricultural and Applied Economics     Open Access   (Followers: 1)
J. of Agricultural Science     Full-text available via subscription   (Followers: 7, SJR: 0.56, h-index: 51)
J. of American Studies     Hybrid Journal   (Followers: 20, SJR: 0.133, h-index: 9)
J. of Anglican Studies     Hybrid Journal   (Followers: 6, SJR: 0.101, h-index: 1)
J. of Applied Animal Nutrition     Hybrid Journal   (Followers: 3)
J. of Asian Studies     Full-text available via subscription   (Followers: 36, SJR: 0.331, h-index: 31)
J. of Benefit-Cost Analysis     Hybrid Journal   (Followers: 2)
J. of Biosocial Science     Hybrid Journal   (Followers: 3, SJR: 0.561, h-index: 41)
J. of British Studies     Full-text available via subscription   (Followers: 30, SJR: 0.306, h-index: 23)
J. of Child Language     Hybrid Journal   (Followers: 20, SJR: 0.787, h-index: 55)
J. of Classics Teaching     Open Access  
J. of Dairy Research     Full-text available via subscription   (Followers: 7, SJR: 0.682, h-index: 60)
J. of Demographic Economics     Hybrid Journal   (Followers: 3)
J. of Developmental Origins of Health and Disease     Hybrid Journal   (Followers: 2, SJR: 0.74, h-index: 11)
J. of Diagnostic Radiography and Imaging     Hybrid Journal   (Followers: 4)
J. of Ecclesiastical History     Hybrid Journal   (Followers: 19, SJR: 0.123, h-index: 14)
J. of Economic History     Full-text available via subscription   (Followers: 45, SJR: 1.224, h-index: 44)
J. of Experimental Political Science     Full-text available via subscription   (Followers: 5)
J. of Financial and Quantitative Analysis     Full-text available via subscription   (Followers: 35, SJR: 2.998, h-index: 80)
J. of Fluid Mechanics     Hybrid Journal   (Followers: 139, SJR: 1.45, h-index: 155)
J. of French Language Studies     Hybrid Journal   (Followers: 5, SJR: 0.158, h-index: 8)
J. of Functional Programming     Hybrid Journal   (Followers: 1, SJR: 0.917, h-index: 39)

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Journal Cover animal
  [SJR: 1.098]   [H-I: 43]   [3 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1751-7311 - ISSN (Online) 1751-732X
   Published by Cambridge University Press Homepage  [367 journals]
  • International Bull Fertility Conference – Theory to Practice,
           Westport, Ireland, 2018
    • Authors: Michael G Diskin; Pat Lonergan, David A. Kenny, Sean Fair
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118001155
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Historical and futuristic developments in bovine semen technology
    • Authors: P. Lonergan
      Abstract: Up to the 18th century, the prevailing view of reproduction, or ‘generation’ as it was referred to, was that organisms develop from miniatures of themselves, termed preformation. The alternative theory, epigenesis, proposed that the structure of an animal emerges gradually from a relatively formless egg. The teachings of the Ancient Greeks who argued either that both sexes each contributed ‘semen’ to form the embryo, or held a more male-centred view that the female merely provided fertile ground for the male seed to grow, dominated thinking until the 17th century, when the combined work of numerous scholars led to the theory that all female organisms, including humans, produced eggs. The sequence of events leading to the commercial use of artificial insemination (AI) date back to the discovery of sperm in 1678, although it took almost 100 years to demonstrate that sperm were the agents of fertilisation and a further 100 years for the detailed events associated with fertilisation to be elucidated. The first successful AI, carried out in the dog, dates back to 1780 while it was not until the early to mid-1900s that practical methods for AI were described in Russia. Inspired by the Russian success, the first AI cooperative was established in Denmark in 1936 and later in the United States in 1938. The next major advances involved development of semen extenders, addition of antibiotics to semen, and the discovery in 1949 that glycerol protected sperm during cryopreservation. Almost four decades later, the flow cytometric separation of X- and Y-bearing sperm opened a new chapter in the application of AI for cattle breeding. As we look forward today, developments in imaging sperm and breakthroughs in gene editing and stem cell technology are opening up new possibilities to manipulate reproduction in a way never thought possible by the pioneers of the past. This review highlights some of the main milestones and individuals in the history of sperm biology and the development of technologies associated with AI in cattle.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S175173111800071X
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Ontology and endocrinology of the reproductive system of bulls
           from fetus to maturity
    • Authors: M. McGowan; M. K. Holland, G. Boe-Hansen
      Abstract: This review focuses on current understanding of prenatal, prepubertal and post-pubertal development of the male reproductive system of cattle. The critical developmental events occur during the first 3 to 4 months of gestation and the first ~6 to 9 months after birth. The Wilms Tumor-1 and SRY proteins play critical roles in early development and differentiation of the fetal testis, which in turn drives gestational development of the entire male reproductive system. The hypothalamic–pituitary–gonadal axis matures earlier in the bovine fetus than other domestic species with descent of the testes into the scrotum occurring around the 4th month of gestation. An array of congenital abnormalities affecting the reproductive system of bulls has been reported and most are considered to be heritable, although the mode of inheritance in most cases has not been fully defined. Early postnatal detection of most of these abnormalities is problematic as clinical signs are generally not expressed until after puberty. Development of genomic markers for these abnormalities would enable early culling of affected calves in seedstock herds. The postnatal early sustained increase in lutenising hormone secretion cues the rapid growth of the testes in the bull calf leading to the onset of puberty. There is good evidence that both genetic and environmental factors, in particular postnatal nutrition, control or influence development and maturation of the reproductive system. For example, in Bos taurus genotypes which have had sustained genetic selection pressure applied for fertility, and where young bulls are managed on a moderate to high plane of nutrition puberty typically occurs at 8 to 12 months of age. However, in many Bos indicus genotypes where there has been little selection pressure for fertility and where young bulls are reared on a low plane of nutrition, puberty typically occurs between 15 to 17 months. Our understanding of the control and expression of sexual behavior in bulls is limited, particularly in B. indicus genotypes.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000460
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Spermatogenesis in the bull
    • Authors: C. Staub; L. Johnson
      Abstract: Spermatogenesis is a finely regulated process of germ cell multiplication and differentiation leading to the production of spermatozoa in the seminiferous tubules. Spermatogenesis can be divided into three parts: spermatocytogenesis, meiosis and spermiogenesis. During spermatocytogenesis, germ cells engage in a cycle of several mitotic divisions that increases the yield of spermatogenesis and to renew stem cells and produce spermatogonia and primary spermatocytes. Meiosis involves duplication and exchange of genetic material and two cell divisions that reduce the chromosome number and yield four haploid round spermatids. Spermiogenesis involves the differentiation of round spermatids into fully mature spermatozoa released into the lumin of seminiferous tubules. The seminiferous epithelium is composed of several generations of germ cells due to the fact that new generations of sperm cells engage in the spermatogenic process without waiting for the preceding generations to have completed their evolution and to have disappeared as spermatozoa into the lumen of the tubules. In bulls, the duration of the seminiferous epithelium cycle is 13.5 days. The total duration of spermatogenesis is 61 days, that is 4.5 times the duration of the cycle of the seminiferous epithelium. The spermatogenetic wave is used to describe the spatial arrangement of cell associations along the tubules. Several theories have been described to explain the renewal of spermatogonia. Depending on the model, there are five or six spermatogonial mitoses explaining the renewal of stem cells and the proliferation of spermatogonia. Daily sperm production and germ cell degeneration can be quantified from numbers of germ cells in various steps of development throughout spermatogenesis. Bulls have a lower efficiency of spermatogenesis than most species examined, but higher than that of humans.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000435
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: The effect of nutrition on timing of pubertal onset and subsequent
           fertility in the bull
    • Authors: D. A. Kenny; C. J. Byrne
      Abstract: The advent of genomic selection has led to increased interest within the cattle breeding industry to market semen from young bulls as early as possible. However, both the quantity and quality of such semen is dictated by the age at which these animals reach puberty. Enhancing early life plane of nutrition of the bull stimulates a complex biochemical interplay involving metabolic and neuroendocrine signalling and culminating in enhanced testicular growth and development and earlier onset of sexual maturation. Recent evidence suggests that an enhanced plane of nutrition leads to an advancement of testicular development in bulls at 18 weeks of age. However, as of yet, much of the neuronal mechanisms regulating these developmental processes remain to be elucidated in the bull. While early life nutrition clearly affects the sexual maturation process in bulls, there is little evidence for latent effects on semen traits post-puberty. Equally the influence of prevailing nutritional status on the fertility of mature bulls is unclear though management practices that result in clinical or even subclinical metabolic disease can undoubtedly impact upon normal sexual function. Dietary supplements enriched with various polyunsaturated fatty acids or fortified with trace elements do not consistently affect reproductive function in the bull, certainly where animals are already adequately nourished. Further insight on how nutrition mediates the biochemical interaction between neuroendocrine and testicular processes will facilitate optimisation of nutritional regimens to optimise sexual maturation and subsequent semen production in bulls.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000514
      Issue No: Vol. 12, No. s1 (2018)
       
  • v.+natural+service+in+beef+herds&rft.title=animal&rft.issn=1751-7311&rft.date=2018&rft.volume=12&rft.aulast=Baruselli&rft.aufirst=P.&rft.au=P.+S.+Baruselli&rft.au=R.+M.+Ferreira,+M.+F.+Sá+Filho,+G.+A.+Bó&rft_id=info:doi/10.1017/S175173111800054X">Review: Using artificial insemination v.
           natural service in beef herds
    • Authors: P. S. Baruselli; R. M. Ferreira, M. F. Sá Filho, G. A. Bó
      Abstract: The aim of this review is to compare the performance of different reproductive programs using natural service, estrus synchronization treatment before natural service (timed natural breeding (TNB)), artificial insemination (AI) following estrus detection and timed artificial insemination (TAI) in beef herds. It is well known that after parturition the beef cow undergoes a period of anestrous, when they do not exhibit estrus, eliminating the opportunity to become pregnant in the early postpartum by natural mating or by AI after detection of estrus. Hormonal stimulation is already a consistent and well-proven strategy used to overcome postpartum anestrus in beef herds. Basically, hormones that normally are produced during the estrous cycle of the cow can be administered in physiological doses to induce cyclicity and to precisely synchronize follicular growth, estrus and ovulation. Furthermore, two options of mating may be used after hormonal stimulation: natural service (i.e. utilization of bull service after synchronization, referred to as TNB) and TAI. These strategies improve the reproductive efficiency of the herds compared with natural service without estrus induction or synchronization. After the first synchronized service, the most common strategy adopted to get non-pregnant cows pregnant soon is the introduction of clean-up bulls until the end of the breeding season. However, methods to resynchronize non-pregnant cows after the first service are already well established and offer a potential tool to reduce the time for subsequent inseminations. Thus, the use of these technologies enable to eliminate the use of bulls by using resynchronization programs (i.e. two, three or four sequential TAI procedures). The dissemination of efficient reproductive procedures, such as TNB, TAI and Resynch programs, either isolated or in combination, enables the production of a greater quantity (obtaining increased pregnancy rates early in the breeding season) and quality (maximization of the use of AI with superior genetic sires) of beef calves. These technologies can contribute to improve the production efficiency, and consequently, improve livestock profitability.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S175173111800054X
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Understanding the causes of variation in reproductive wastage
           among bulls
    • Authors: S. Fair; P. Lonergan
      Abstract: The ability to predict the fertility of bulls before semen is released into the field has been a long-term objective of the animal breeding industry. However, the recent shift in the dairy industry towards the intensive use of young genomically selected bulls has increased its urgency. Such bulls, which are often in the highest demand, are frequently only used intensively for one season and consequently there is limited time to track their field fertility. A more pressing issue is that they produce fewer sperm per ejaculate than mature bulls and therefore there is a need to reduce the sperm number per straw to the minimum required without a concomitant reduction in fertility. However, as individual bulls vary in the minimum number of sperm required to achieve their maximum fertility, this cannot be currently achieved without extensive field-testing. Although an in vitro semen quality test, or combination of tests, which can accurately and consistently determine a bull’s fertility and the optimum sperm number required represent the ‘holy grail’ in terms of semen assessment, this has not been achieved to date. Understanding the underlying causes of variation in bull fertility is a key prerequisite to achieving this goal. In this review, we consider the reliability of sire conception rate estimates and then consider where along the pregnancy establishment axis the variation in reproductive loss between bulls occurs. We discuss the aetiology of these deficiencies in sperm function and propose avenues for future investigation.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000964
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Integrating a semen quality control program and sire fertility at
           a large artificial insemination organization
    • Authors: B. R. Harstine; M. D. Utt, J. M. DeJarnette
      Abstract: The technology available to assess sperm population characteristics has advanced greatly in recent years. Large artificial insemination (AI) organizations that sell bovine semen utilize many of these technologies not only for novel research purposes, but also to make decisions regarding whether to sell or discard the product. Within an AI organization, the acquisition, interpretation and utilization of semen quality data is often performed by a quality control department. In general, quality control decisions regarding semen sales are often founded on the linkages established between semen quality and field fertility. Although no one individual sperm bioassay has been successful in predicting sire fertility, many correlations to various in vivo fertility measures have been reported. The most powerful techniques currently available to evaluate semen are high-throughput and include computer-assisted sperm analysis and various flow cytometric analyses that quantify attributes of fluorescently stained cells. However, all techniques measuring biological parameters are subject to the principles of precision, accuracy and repeatability. Understanding the limitations of repeatability in laboratory analyses is important in a quality control and quality assurance program. Hence, AI organizations that acquire sizeable data sets pertaining to sperm quality and sire fertility are well-positioned to examine and comment on data collection and interpretation. This is especially true for sire fertility, where the population of AI sires has been highly selected for fertility. In the December 2017 sire conception rate report by the Council on Dairy Cattle Breeding, 93% of all Holstein sires (n=2062) possessed fertility deviations within 3% of the breed average. Regardless of the reporting system, estimates of sire fertility should be based on an appropriate number of services per sire. Many users impose unrealistic expectations of the predictive value of these assessments due to a lack of understanding for the inherent lack of precision in binomial data gathered from field sources. Basic statistical principles warn us of the importance of experimental design, balanced treatments, sampling bias, appropriate models and appropriate interpretation of results with consideration for sample size and statistical power. Overall, this review seeks to describe and connect the use of sperm in vitro bioassays, the reporting of AI sire fertility, and the management decisions surrounding the implementation of a semen quality control program.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000319
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Semen handling, time of insemination and insemination technique in
           cattle
    • Authors: M. G. Diskin
      Abstract: In cattle artificial insemination plays not only a vital role in the successful establishment of pregnancy, which is a prerequisite for initiation of the subsequent lactation, but also in accelerating genetic improvement and facilitating the distribution of semen from genetically elite sires. The latter has been greatly facilitated by the ability to successfully cryopreserve semen. The objective of an insemination is to ensure that there is an adequate reservoir of competent, capacitated, motile sperm in the caudal region of the oviductal isthmus, the site of the main sperm reservoir in the cow, at the time of ovulation to ensure fertilisation. Handling of semen, particularly the 0.25 ml straw, is critically important. Thawed semen needs to be protected from cold and heat shocks and inseminated within 6 to 8 min of thawing. Uterine horn insemination give a modest improvement in conceptions rates particularly in situations where conception rates are low following uterine body inseminations. Most of the studies that evaluated heterospermic insemination were conducted on fresh semen only, and many lacked adequate replication. Consequently, it is difficult to deduce if there are real benefits from using heterospermic semen. While the interval from oestrous onset to time of ovulation would appear to be similar for cows and heifers at about 28 h there is huge variation (standard deviations of 5 to 6 h) around this average. While best conception rates are achieved when cows are inseminated from mid oestrus to a few hours after the onset of oestrus, this is difficult to achieve in practice. There is emerging evidence that having one insemination time, when all cows requiring insemination in the herd on that day are inseminated, does not compromise fertility provided insemination technique is good and the semen used is of high fertility.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000952
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Semen sexing – current state of the art with emphasis on
           bovine species
    • Authors: R. Vishwanath; J. F. Moreno
      Abstract: It is approaching three decades since the first public evidence of sex-sorting ofsemen. The technology has progressed considerably since then with a number ofinstitutions and researchers collaborating to eventually bring this toapplication. The technical challenges have been quite substantial and in theearly years the application was limited to only heifer inseminations. Comparablefertility of sex-sorted semen with conventional semen has been an aspirationalbenchmark for the industry for many years. Significant investment in research inthe primary biology of sex-sorted sperm and associated sorting equipment ensuredsteady progress over the years and current methods particularly the newSexedULTRA-4M™ seems to have now mostly bridged this fertility gap.The dairy and beef industry have adopted this technology quite rapidly. Otheranimal industries are progressively testing it for application in their specificniches and environments. The current state of the art in the fundamentals ofsex-sorting, the biology of the process as well as new developments in machineryare described in this review.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000496
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Applications and benefits of sexed semen in dairy and beef herds
    • Authors: S. A. Holden; S. T. Butler
      Abstract: The use of sexed semen in dairy and beef cattle production provides a number of benefits at both farm and industry levels. There is an increasing demand for dairy and beef products across the globe, which will necessitate a greater focus on improving production efficiency. In dairy farming, there is surplus production of unwanted male calves. Male dairy calves increase the risk of dystocia compared with heifer calves, and as an unwanted by-product of breeding with conventional semen, they have a low economic value. Incorporating sexed semen into the breeding programme can minimise the number of unwanted male dairy calves and reduce dystocia. Sexed semen can be used to generate herd replacements and additional heifers for herd expansion at a faster rate from within the herd, thereby minimising biosecurity risks associated with bringing in animals from different herds. Furthermore, the use of sexed semen can increase herd genetic gain compared with use of non-sorted semen. In dairy herds, a sustainable breeding strategy could combine usage of sexed semen to generate replacements only, and usage of beef semen on all dams that are not suitable for generating replacements. This results in increased genetic gain in dairy herd, increased value of beef output from the dairy herd, and reduced greenhouse gas emissions from beef. It is important to note, however, that even a small decrease in fertility of sexed semen relative to conventional semen can negate much of the economic benefit. A high fertility sexed semen product has the potential to accelerate herd expansion, minimise waste production, improve animal welfare and increase profitability compared with non-sorted conventional semen.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000721
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: The potential of seminal fluid mediated paternal–maternal
           communication to optimise pregnancy success
    • Authors: J. J. Bromfield
      Abstract: Artificial insemination has been a landmark procedure in improving animalagriculture over the past 150 years. The utility of artificial insemination hasfacilitated a rapid improvement in animal genetics across agricultural species,leading to improvements of growth, health and productivity in poultry, swine,equine and cattle species. The utility of artificial insemination, as with allassisted reproductive technologies side-steps thousands of years of evolutionthat has led to the development of physiological systems to ensure thetransmission of genetics from generation to generation. The perceivedmanipulation of these physiological systems as a consequence of assistedreproduction are points of interest in which research could potentially improvethe success of these technologies. Indeed, seminal fluid is either removed orsubstantially diluted when semen is prepared for artificial insemination indomestic species. Although seminal fluid is not a requirement for pregnancy,could the removal of seminal fluid from the ejaculate have negative consequenceson reproductive outcomes that could be improved to further the economic benefitof artificial insemination' One such potential influence of seminal fluid onreproduction stems from the question; how does the allogeneic foetus survivegestation in the face of the maternal immune system' Observation of the maternalimmune system during pregnancy has noted maternal immune tolerance topaternal-specific antigens; a mechanism by which the maternal immune systemtolerates specific paternal antigens expressed on the foetus. In species likehuman or rodent, implantation occurs days after fertilisation and as such themechanisms to establish antigen-specific tolerance must be initiated very earlyduring pregnancy. We and others propose that these mechanisms are initiated atthe time of insemination when paternal antigens are first introduced to thematernal immune system. It is unclear whether such mechanisms would also beinvolved in domestic species, such as cattle, where implantation occurs weekslater in gestation. A new paradigm detailing the importance ofpaternal–maternal communication at the time of insemination isbecoming evident as it relates to maternal tolerance to foetal antigen andultimately pregnancy success.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000083
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: The epic journey of sperm through the female reproductive tract
    • Authors: D. J. Miller
      Abstract: Millions or billions of sperm are deposited by artificial insemination or natural mating into the cow reproductive tract but only a few arrive at the site of fertilization and only one fertilizes an oocyte. The remarkable journey that successful sperm take to reach an oocyte is long and tortuous, and includes movement through viscous fluid, avoiding dead ends and hostile immune cells. The privileged collection of sperm that complete this journey must pass selection steps in the vagina, cervix, uterus, utero-tubal junction and oviduct. In many locations in the female reproductive tract, sperm interact with the epithelium and the luminal fluid, which can affect sperm motility and function. Sperm must also be tolerated by the immune system of the female for an adequate time to allow fertilization to occur. This review emphasizes literature about cattle but also includes work in other species that emphasizes critical broad concepts. Although all parts of the female reproductive tract are reviewed, particular attention is given to the sperm destination, the oviduct.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000526
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Sperm–oocyte interactions and their implications for bull
           fertility, with emphasis on the ubiquitin–proteasome system
    • Authors: P. Sutovsky
      Abstract: Fertilization is an intricate cascade of events that irreversibly alter the participating male and female gamete and ultimately lead to the union of paternal and maternal genomes in the zygote. Fertilization starts with sperm capacitation within the oviductal sperm reservoir, followed by gamete recognition, sperm–zona pellucida interactions and sperm–oolemma adhesion and fusion, followed by sperm incorporation, oocyte activation, pronuclear development and embryo cleavage. At fertilization, bull spermatozoon loses its acrosome and plasma membrane components and contributes chromosomes, centriole, perinuclear theca proteins and regulatory RNAs to the zygote. While also incorporated in oocyte cytoplasm, structures of the sperm tail, including mitochondrial sheath, axoneme, fibrous sheath and outer dense fibers are degraded and recycled. The ability of some of these sperm contributed components to give rise to functional zygotic structures and properly induce embryonic development may vary between bulls, bearing on their reproductive performance, and on the fitness, health, fertility and production traits of their offspring. Proper functioning, recycling and remodeling of gamete structures at fertilization is aided by the ubiquitin–proteasome system (UPS), the universal substrate-specific protein recycling pathway present in bovine and other mammalian oocytes and spermatozoa. This review is focused on the aspects of UPS relevant to bovine fertilization and bull fertility.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000253
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Testicular vascular cone development and its association with
           scrotal thermoregulation, semen quality and sperm production in bulls
    • Authors: J. P. Kastelic; G. Rizzoto, J. Thundathil
      Abstract: Several structural and functional features keep bull testes 2°C to 6°C below body temperature, essential for the production of morphologically normal, motile and fertile sperm. The testicular vascular cone (TVC), located above the testis, consists of a highly coiled testicular artery surrounded by a complex network of small veins (pampiniform plexus). The TVC functions as a counter-current heat exchanger to transfer heat from the testicular artery to the testicular vein, cooling blood before it enters the testis. Bulls with increased TVC diameter or decreased distance between arterial and venous blood, have a greater percentage of morphologically normal sperm. Both the scrotum and testes are warmest at the origin of their blood supply (top of scrotum and bottom of testis), but they are cooler distal to that point. In situ, these opposing temperature gradients result in a nearly uniform testicular temperature (top to bottom), cooler than body temperature. The major source of testicular heat is blood flow, not testicular metabolism. High ambient temperatures have less deleterious effects on spermatogenesis in Bos indicus v. Bos taurus bulls; differences in TVC morphology in B. indicus bulls confer a better testicular blood supply and promote heat transfer. There is a long-standing paradigm that testes operate on the brink of hypoxia, increased testicular temperature does not increase blood flow, and the resulting hypoxia reduces morphologically normal and motile sperm following testicular hyperthermia. However, in recent studies in rams, either systemic hypoxia or increased testicular temperature increased testicular blood flow and there were sufficient increases in oxygen uptake to prevent tissue hypoxia. Therefore, effects of increased testicular temperature were attributed to testicular temperature per se and not to secondary hypoxia. There are many causes of increased testicular temperature, including high ambient temperatures, fever, increased recumbency, high-energy diets, or experimental insulation of the scrotum or the scrotal neck. It is well known that increased testicular temperatures have adverse effects on spermatogenesis. Heat affects all germ cells and all stages of spermatogenesis, with substantial increases in temperature and/or extended intervals of increased testicular temperature having the most profound effects. Increased testicular temperature has adverse effects on percentages of motile, live and morphologically normal sperm. In particular, increased testicular temperature increases the percentage of sperm with abnormal morphology, particularly head defects. Despite differences among bulls in the kind and percentage of abnormal sperm, the interval from increased testicular temperature to the emergence of specific sperm defects is consistent and predictable. Scrotal surface temperatures and structural characteristics of the testis and TVC can be assessed with IR thermography and ultrasonography, respectively.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118001167
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Principles of maximizing bull semen production at genetic centers
    • Authors: J. L. Schenk
      Abstract: Knowledge of the capabilities and limitations of the reproductive capacity of bulls is vital in maximizing reproductive efficiencies. Bull semen collection guidelines established by researchers and industry personnel to maximize the sperm harvest from bulls have been evolving for more than 60 years. Today, a mature artificial insemination industry employs those strategies to meet demands. These efficient management schemes exploit the reproductive potential of each sire while minimizing the associated risk of injury to bulls and reduce associated production costs. Personnel employed by a semen producing facility must be authorized to make effective and rational decisions based on principles of bull sexual behavior and reproductive physiology. Furthermore, collection facilities must be well planned to allow for the safe presentation of novel sexual situations while affording maximum safety for employees and proper footing for bulls. Normal bulls produce and ejaculate tremendous numbers of sperm. Most bulls have a sufficient libido for routine sexual activity, but become satiated to predictable stimulus situations. Frequent changes to the novelty should allow weekly harvest of four to six ejaculates per week for most bulls. Utilizing the physiological characteristics associated with each ejaculate to establish the collection frequency of each bull, and empowering an integrated collection and laboratory staff to monitor and make adjustments to the ejaculation frequency are necessary in maximizing the sperm harvest. Young bulls can ejaculate 10 to 20 billion sperm per week, and mature bulls should ejaculate 40 to 60 billion sperm per week. Semen collection management procedures should be reviewed when bulls do not meet production goals.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000472
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Abnormalities of the bull – occurrence, diagnosis and treatment
           of abnormalities of the bull, including structural soundness
    • Authors: D. F. Wolfe
      Abstract: Selecting bulls for reproductive soundness requires that the bull be structurally sound, free of abnormalities that impair his ability to produce adequate numbers of motile, morphologically normal spermatozoa, and be able to successfully complete coitus. This review discusses the diagnosis and etiology of abnormalities of the penis, prepuce as well as common musculoskeletal conditions that prevent normal pasture breeding soundness. A review of testicular and thermoregulation addresses the potential impact of musculoskeletal disorders on normal sperm production.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000939
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: The use of bull breeding soundness evaluation to identify
           subfertile and infertile bulls
    • Authors: A. D. Barth
      Abstract: Efficient and economical herd management depends a great deal on maintaining a short, well-defined calving season. This requires highly fertile females and bulls. Low pregnancy rates are very noticeable, however; potentially greater economic loss may be due to delayed conception. Many studies showed that approximately one of every five bulls had inadequate semen quality, physical soundness, or both, but when evaluation of serving capacity is included about one in four bulls is unsatisfactory. Due mainly to the time and expense that the market will bear, usually only physical soundness and semen quality are evaluated. Breeding soundness evaluation is a useful, low-cost screening method for reducing the risk of using low fertility bulls. The biggest problem with breeding soundness evaluations is not our lack of knowledge or ability, but in the willingness of veterinary schools to provide adequate equipment and training in this area, a lack of diagnostic laboratories equipped to handle the more difficult cases and, most importantly, the weaknesses of human nature that result in negligent testing procedure.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000538
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Risks of disease transmission through semen in cattle
    • Authors: M. D. Givens
      Abstract: The purpose of this paper is to review scientific evidence concerning pathogens that could potentially be transmitted via bovine semen. As a result of a careful analysis of the characteristics of infections that may cause transmission of disease through semen, effective control procedures can be identified that provide minimal constraint to the introduction of new bulls into herds for natural breeding and importation of valuable novel genetics through artificial insemination. The potential for transmission through bovine semen and corresponding effective control procedures are described for bovine herpesvirus 1, bovine viral diarrhea virus, bovine leukemia virus, lumpy skin disease virus, bluetongue virus, foot-and-mouth disease virus, and Schmallenberg virus. Brief consideration is also provided regarding the potential for transmission via semen of Tritrichomonas foetus, Campylobacter fetus venerealis, Brucella abortus, Leptospira spp., Histophilus somni, Ureaplasma diversum, Mycobacterium avium subsp. paratuberculosis, Chlamydiaceae, Mycobacterium bovis, Coxiella burnetii, Mycoplasma mycoides ssp. mycoides and Neospora caninum. Thoughtful and systematic control procedures can ensure the safety of introducing new bulls and cryopreserved semen into cattle production systems.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000708
      Issue No: Vol. 12, No. s1 (2018)
       
  • Review: Genomics of bull fertility
    • Authors: Jeremy F. Taylor; Robert D. Schnabel, Peter Sutovsky
      Abstract: Fertility is one of the most economically important traits in both beef and dairy cattle production; however, only female fertility is typically subjected to selection. Male and female fertility have only a small positive genetic correlation which is likely due to the existence of a relatively small number of genetic variants within each breed that cause embryonic and developmental losses. Genomic tools have been developed that allow the identification of lethal recessive loci based upon marker haplotypes. Selection against haplotypes harbouring lethal alleles in conjunction with selection to improve female fertility will result in an improvement in male fertility. Genomic selection has resulted in a two to fourfold increase in the rate of genetic improvement of most dairy traits in US Holstein cattle, including female fertility. Considering the rapidly increasing rate of adoption of high-throughput single nucleotide polymorphism genotyping in both the US dairy and beef industries, genomic selection should be the most effective of all currently available approaches to improve male fertility. However, male fertility phenotypes are not routinely recorded in natural service mating systems and when artificial insemination is used, semen doses may be titrated to lower post-thaw progressively motile sperm numbers for high-merit and high-demand bulls. Standardization of sperm dosages across bull studs for semen distributed from young bulls would allow the capture of sire conception rate phenotypes for young bulls that could be used to generate predictions of genetic merit for male fertility in both males and females. These data would allow genomic selection to be implemented for male fertility in addition to female fertility within the US dairy industry. While the rate of use of artificial insemination is much lower within the US beef industry, the adoption of sexed semen in the dairy industry has allowed dairy herds to select cows from which heifer replacements are produced and cows that are used to produce terminal crossbred bull calves sired by beef breed bulls. Capture of sire conception rate phenotypes in dairy herds utilizing sexed semen will contribute data enabling genomic selection for male fertility in beef cattle breeds. As the commercial sector of the beef industry increasingly adopts fixed-time artificial insemination, sire conception rate phenotypes can be captured to facilitate the development of estimates of genetic merit for male fertility within US beef breeds.
      PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118000599
      Issue No: Vol. 12, No. s1 (2018)
       
  • ANM volume 12 issue s1 Cover and Front matter
    • PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S175173111800126X
      Issue No: Vol. 12, No. s1 (2018)
       
  • ANM volume 12 issue s1 Cover and Back matter
    • PubDate: 2018-06-01T00:00:00.000Z
      DOI: 10.1017/S1751731118001271
      Issue No: Vol. 12, No. s1 (2018)
       
 
 
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