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Review: Understanding the causes of variation in reproductive wastage among bulls

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Show simple item record Fair, Seán Lonergan, Patrick 2019-01-17T15:33:38Z 2019-01-17T15:33:38Z 2018
dc.description peer-reviewed en_US
dc.description.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. en_US
dc.language.iso eng en_US
dc.publisher Cambridge University Press en_US
dc.relation 16IA4474 en_US
dc.relation.ispartofseries Animal;12, s1, pp.s53-s62
dc.rights Material on these pages is copyright Cambridge University Press or reproduced with permission from other copyright owners. It may be downloaded and printed for personal reference, but not otherwise copied, altered in any way or transmitted to others (unless explicitly stated otherwise) without the written permission of Cambridge University Press. Hypertext links to other Web locations are for the convenience of users and do not constitute any endorsement or authorisation by Cambridge University Press. en_US
dc.subject sperm en_US
dc.subject semen en_US
dc.subject bovine en_US
dc.subject prediction en_US
dc.subject fertility en_US
dc.title Review: Understanding the causes of variation in reproductive wastage among bulls en_US
dc.type info:eu-repo/semantics/article en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US
dc.identifier.doi 10.1017/S1751731118000964
dc.contributor.sponsor SFI en_US
dc.relation.projectid 16/IA/4474 en_US
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US

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