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|Title: ||The effect of strategic supplementation with trans-10,cis-12 conjugated linoleic acid on the milk production, estrous cycle characteristics, and reproductive performance of lactating dairy cattle|
|Authors: ||Hutchinson, Ian A.|
Hennessy, A. A.
Dewhurst, Richard J.
Butler, Stephen T.
|Keywords: ||conjugated linoleic acid|
|Issue Date: ||May-2012|
|Publisher: ||American Dairy Science Association and Elsevier Inc.|
|Citation: ||I.A. Hutchinson, A.A. Hennessy, R.J. Dewhurst, A.C.O. Evans, P. Lonergan, S.T. Butler. The effect of strategic supplementation with trans-10,cis-12 conjugated linoleic acid on the milk production, estrous cycle characteristics, and reproductive performance of lactating dairy cattle. Journal of Dairy Science, 95(5), May 2012: 2442-2451: DOI 10.3168/jds.2011-4632|
|Series/Report no.: ||Journal of Dairy Science;Vol. 95|
|Abstract: ||The objective was to determine the effects of a protected (lipid-encapsulated) conjugated linoleic acid (LE-CLA) supplement on milk production, estrous cycle characteristics, and reproductive performance in lactating dairy cows on a pasture-based diet. Spring calving dairy cows (n = 409) on a single pasture-based commercial dairy farm were used in a completely randomized block design. Cows were assigned to 1 of 2 dietary supplements [LE-CLA (n = 203) or no supplement (control, n = 206)]. The LE-CLA cows received 51 g/d of a lipid supplement containing 5 g of both trans-10,cis-12 and cis-9,trans-11 CLA from 0 to 60 d in milk. Milk samples were collected 3 times weekly, and each sample was analyzed for progesterone to determine the interval to first ovulation and estrous cycle characteristics. Milk yield and concentrations of fat, protein, and lactose were measured every 2 wk. Cows were inseminated following visual observation of estrus. The breeding season commenced on April 8, 2009 and continued for 16 wk. Transrectal ultrasonography was carried out at 30 to 36 d and 60 to 66 d post-AI to diagnose pregnancy. The LE-CLA treatment resulted in a decrease in milk fat concentration (36.9 ± 0.06 g/kg vs. 30.7 ± 0.06 g/kg for control and LE-CLA, respectively) and yield (0.91 ± 0.02 kg/d vs. 0.84 ± 0.02 kg/d for control and LE-CLA, respectively); however, milk yield was increased by LE-CLA supplementation (24.7 ± 0.7 kg/d vs. 27.2 ± 0.7 kg/d for control and LE-CLA, respectively), resulting in no overall difference in milk energy output. No effect of LE-CLA was observed on any estrous cycle characteristics or measures of reproductive performance. These results support that in pasture-based systems of dairy production, where energy intake limits milk production, energy spared by CLA-induced milk fat depression is partitioned toward increasing milk yield rather than toward body reserves.|
This is the author’s version of a work that was accepted for publication in Journal of Dairy Science. 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 Journal of Dairy Science, Volume 95, Issue 5, May 2012, Pages 2442-2451: DOI 10.3168/jds.2011-4632
|Appears in Collections:||Animal & Bioscience|
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