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Effect of breed, plane of nutrition and age on growth, scrotal development, metabolite concentrations and on systemic gonadotropin and testosterone concentrations following a GnRH challenge in young dairy bulls

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dc.contributor.author Byrne, C.J.
dc.contributor.author Fair, Seán
dc.contributor.author English, A.M.
dc.contributor.author Urh, C.
dc.contributor.author Sauerwein, H.
dc.contributor.author Crowe, M.A.
dc.contributor.author Lonergan, Patrick
dc.contributor.author Kenny, David A.
dc.date.accessioned 2017-07-25T07:56:34Z
dc.date.issued 2017
dc.identifier.citation Byrne, CJ,Fair, S,English, AM,Urh, C,Sauerwein, H,Crowe, MA,Lonergan, P,Kenny, DA (2017) 'Effect of breed, plane of nutrition and age on growth, scrotal development, metabolite concentrations and on systemic gonadotropin and testosterone concentrations following a GnRH challenge in young dairy bulls'. Theriogenology, 96 :58-68. en_US
dc.identifier.uri http://hdl.handle.net/10344/5907
dc.description peer-reviewed en_US
dc.description.abstract The onset of puberty in the bull is regulated by the timing of early GnRH pulsatility release from the hypothalamus, which has been demonstrated to be affected by plane of nutrition during calf-hood. The aim of this study was to determine the effect of plane of nutrition on growth rate, scrotal development, metabolite concentrations and exogenous gonadotrophin (GnRH) induced release of luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone (TT) in pre-pubertal bulls of two contrasting dairy breeds. Holstein-Friesian and Jersey bull calves were assigned to either a high or low plane of nutrition from 3 to 49 weeks of age. Intensive blood sampling was conducted at 16, 24 and 32 weeks of age, every 15 min from 30 min prior to intravenous administration of exogenous GnRH to 135 min after. Monthly blood samples were also collected and analyzed for insulin like growth factor 1 (IGF-1), insulin, leptin, adiponectin and metabolite concentration. Insulin and IGF-1 were higher in bulls on a high plane of nutrition (P < 0.001) but were not affected by breed (P > 0.05). Leptin was not affected by plane of nutrition or breed (P > 0.05). Adiponectin tended to be higher in bulls on a high plane of nutrition (P = 0.05), but was not affected by breed (P > 0.05). Bulls on a high plane of nutrition had a greater concentration of LH in response to GnRH (P < 0.05) but there was no effect of breed (P > 0.05). FSH concentration was not influenced by breed or plane of nutrition but FSH concentrations did decrease with age (P < 0.01), while, LH was not affected by age (P > 0.05). Jersey bulls, particularly those on a high plane of nutrition, had higher TT production in the pre-pubertal period (P < 0.001). Using 28 cm as a proxy for age at puberty, bulls on a high plane of nutrition were predicted to reach puberty earlier than bulls on a low plane. In conclusion, the data clearly demonstrate that a high plane of nutrition positively affects several key nutritional and reproductive hormones which are critical to the endocrinological functionality of the hypothalamic-pituitary-testicular axis in dairy-bred bull calves. en_US
dc.language.iso eng en_US
dc.publisher Elsevier en_US
dc.relation.ispartofseries Theriogenology;96, pp. 58-68
dc.relation.uri https://doi.org/10.1016/j.theriogenology.2017.04.002
dc.rights This is the author’s version of a work that was accepted for publication in Theriogenology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Theriogenology, 96, pp. 58-68, https://doi.org/10.1016/j.theriogenology.2017.04.002 en_US
dc.subject calf-hood nutrition en_US
dc.subject puberty en_US
dc.subject insulin en_US
dc.subject IGF-1 en_US
dc.subject hypothalamus en_US
dc.subject endocrinology en_US
dc.title Effect of breed, plane of nutrition and age on growth, scrotal development, metabolite concentrations and on systemic gonadotropin and testosterone concentrations following a GnRH challenge in young dairy 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.date.updated 2017-07-24T15:37:52Z
dc.description.version ACCEPTED
dc.identifier.doi 10.1016/j.theriogenology.2017.04.002
dc.contributor.sponsor Department of Agriculture, Food and the Marine en_US
dc.relation.projectid 11/S/116 en_US
dc.date.embargoEndDate 2018-04-03
dc.embargo.terms 2018-04-03 en_US
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US
dc.internal.rssid 2716381
dc.internal.copyrightchecked Yes
dc.identifier.journaltitle Theriogenology
dc.description.status peer-reviewed


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