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dc.contributor.authorHutchinson, Ian A.*
dc.contributor.authorDewhurst, Richard J.*
dc.contributor.authorEvans, A.C.O.*
dc.contributor.authorLonergan, P.*
dc.contributor.authorButler, Stephen*
dc.date.accessioned2012-12-05T11:45:55Z
dc.date.available2012-12-05T11:45:55Z
dc.date.issued2012-09-01
dc.identifier.citationI.A. Hutchinson, R.J. Dewhurst, A.C.O. Evans, P. Lonergan, S.T. Butler. Effect of grass dry matter intake and fat supplementation on progesterone metabolism in lactating dairy cows. Theriogenology, 78(4), September 2012: 878-886. DOI:10.1016/j.theriogenology.2012.04.001en_GB
dc.identifier.issn0093-691X
dc.identifier.urihttp://hdl.handle.net/11019/294
dc.descriptionPeer-revieweden_GB
dc.descriptionThis 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, volume 78 (4), September 2012: pages 878-886. DOI:10.1016/j.theriogenology.2012.04.001
dc.description.abstractProgesterone (P4) metabolism in dairy cattle can be manipulated by alterations in dry matter intake and diet composition. Our objectives were to determine the effects of grazing allowance and fat supplementation on P4 metabolism in lactating dairy cows. Forty mid- to late-lactation Holstein-Friesian dairy cows were used in a completely randomized block design, with a 2 × 2 factorial arrangement of treatments. Cows were assigned to receive 1 of 2 pasture allowances (ad libitum allowance [AL], 9.5 kg dry matter per day, or restricted allowance [R] 7 kg dry matter per day) and 1 of 2 fat supplementation treatments (750 g per day saturated fat [F] or no fat supplement [NF]). All cows received an additional 4 kg per day of concentrate. Grass dry matter intake (GDMI) was measured 5 wk after the initiation of dietary treatment. Cows were treated with prostaglandin F2α (PGF2α) to eliminate the endogenous source of P4, and two intravaginal progesterone-releasing devices (CIDR) were inserted into each cow for a period of 8 days. Regular blood samples were taken before and after the removal of the intravaginal progesterone-releasing devices, and analyzed for P4 concentrations. The half-life (t½) and metabolic clearance rate (MCR) of P4 was calculated for each cow. There was no effect of GDMI or fat supplementation on the t½ or MCR of P4. There was a tendency for an interaction between GDMI and fat supplementation on the t½ of P4; cows on the restricted-F diet tended to have a longer P4 t½ than cows on the ad libitum-F diet. It was concluded that greater alterations in GDMI than achieved in the current study are required to change P4 metabolism. A combination of fat supplementation and restricted feeding slows P4 clearance, which may have beneficial implications for fertility.en_GB
dc.language.isoenen_GB
dc.publisherElsevier Science B.V.en_GB
dc.relation.ispartofseriesTheriogenology;Vol 78
dc.subjectProgesterone metabolismen_GB
dc.subjectDairy cattleen_GB
dc.subjectFat supplementationen_GB
dc.subjectDry matter intakeen_GB
dc.titleEffect of grass dry matter intake and fat supplementation on progesterone metabolism in lactating dairy cowsen_GB
dc.typeArticleen_GB
dc.identifier.rmis5890
dc.identifier.doihttp://dx.doi.org/10.1016/j.theriogenology.2012.04.001
dc.contributor.sponsorNational Development Plan Ireland
dc.contributor.sponsorDairy Levy Research Trust Ireland
refterms.dateFOA2018-01-12T07:46:50Z


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