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Effects of essential fatty acid supplementation on factors that influence pregnancy establishment in beef females

Abstract

Supplementing Nelore cows with essential fatty acids (EFA) for 21 days after artificial insemination (AI) increased pregnancy rates by approximately 30%. The biological processes responsible for this outcome are still unknown, but are likely associated with early pregnancy establishment. Hence, the objective of this experiment is to evaluate the mechanisms associating postbreeding EFA supplementation and pregnancy establishment/maintenance in beef cows. One hundred multiparous Nelore cows will be assigned to estrus synchronization + fixed time AI. Immediately after AI (day 0), cows will be assigned to receive daily 300 g of a supplement containing: 1) 100 g of kaolin (rumen-inert indigestible substance; n = 50) or 2) 100 g of a commercial EFA source (Megalac-E, Quimica Geral do Nordeste; n = 50). Cows will be maintained on pasture with free access to forage, and will receive treatments individually through self-lock head gates during the experimental period (day 0 to day 28). Blood will be collected and transrectal ultrasonography will be performed immediately prior to AI, and on days 7, 18, and 28. Blood will be analyzed for plasma concentrations of progesterone, pregnancy-associated glycoproteins, and fatty acid profile. On day 19, a subsample of cows diagnosed with a functional corpus luteum on d 7 and 18, but not prior to AI, will be slaughtered (n = 15 per treatment). Upon slaughter, endometrial, corpus luteum, and conceptus tissues will be collected and analyzed for fatty acid content and mRNA expression of genes associate with pregnancy establishment. We expect to demonstrate that supplementing EFA to beef cows after AI alters the fatty acid profile of uterine, ovarian, and conceptus tissues, facilitating establishment and maintenance of pregnancy. (AU)

Articles published in Agência FAPESP Newsletter about the research grant:
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VEICULO: TITULO (DATA)
VEICULO: TITULO (DATA)

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