Name: Influence of Supplemental Fats on Reproductive Tissues and Performance of Lactating Cows

Authors: C.R.Staples۲J.M.BurkeW.W.Thatcher

Address:aDepartment of Animal Science, Faculty of Animal Science and Food Technology, Agricultural Sciences and Natural Resources University of Khuzestan, P.O. Box 63517-73637, Mollasani, Ahvaz, Iran, bDepartment of Animal Science, Campus of Agriculture and Natural Resources, University of Tehran, Karaj, Iran, c Department of Animal Science and Industry, Kansas State University, Manhattan, 66502, United States

Abstract: Fat supplementation (about 3% of dietary dry matter) has often positively influenced the reproductive status of the dairy cow, including increased size of the ovulatory follicle, increased numbers of ovarian follicles, increased plasma concentration of progesterone, reduced secretion of prostaglandin metabolite, increased lifespan of the corpus luteum, and improved fertility. Supplemental fat may allay partially negative energy status during the early postpartum period, yet often the positive reproductive influence of supplemental fat has been independent of the energy status of the cow. The fatty acid profile of supplemental fats is influential to their impact. Linoleic acid and eicosapentaenoic acid (found in fish meal) are proven inhibitors of cyclooxygenase in endometrial tissue of dairy cows. As a result, endometrial secretion of PGFα can be suppressed, thus potentially preventing early embryonic death. This process may be aided by the effect fat has in suppressing estradiol- 17β secretion, thus reducing uterine PGF۲α secretion and decreasing the sensitivity of the corpus luteum to PGF۲α. Targeting of dietary fatty acids toward ovarian and uterine function may enhance efficiency of reproductive management and fertility.

Key Words: fat, progesterone, prostaglandin, reproduction

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Name: Effect of fat source differing in fatty acid profile on metabolic parameters, fertilization, and embryo quality in high-producing dairy cows

Authors: R.L.A.Cerri*†S.O.Juchem*R.C.Chebel*H.M.Rutigliano*R.G.S.Bruno*K.N.Galvão*W.W.Thatcher†J.E.P.Santos*†

Address: *School of Veterinary Medicine, University of California-Davis, Tulare 93274†Department of Animal Sciences, University of Florida, Gainesville 32611

Abstract: The objectives were to evaluate the effects of source of fatty acids (FA) on embryo quality of dairy cows. A total of 154 Holstein cows were assigned randomly to 1 of 2 sources of FA supplemented at 2% of the dietary dry matter as calcium salts of either palm oil (PO) or linoleic and trans-octadecenoic acids (LTFA) from 25 d prepartum to 80 d in milk (DIM). Cows were presynchronized beginning at 30 ± ۳ DIM and then subjected to the Ovsynch protocol beginning on d 39 ± ۳ postpartum. Timed artificial insemination was performed 12 h after the final GnRH of the Ovsynch protocol with semen from a single sire of proven fertility. The uteri of cows were nonsurgically flushed at 5 d after artificial insemination for collection of embryos-oocytes. Ovaries were examined by ultrasonography throughout the synchronization protocol. Blood was sampled and plasma was analyzed for concentrations of metabolites and hormones. The body condition score and yields of milk and milk components were measured throughout the first 90 DIM. Treatment did not affect concentrations of nonesterified FA, β-hydroxybutyrate, glucose, and progesterone in plasma. Body condition was similar between treatments. Milk production was similar between treatments, but concentrations of fat in milk and yields of fat and 3.5% fat-corrected milk decreased in cows fed LTFA, whereas concentration of true protein increased. Source of dietary FA did not influence ovulatory responses, diameter of the ovulatory follicle, and diameter of the corpus luteum during synchronization. Embryo-oocyte recovery relative to the number of corpora lutea did not differ between treatments. Fertilization tended to increase in cows fed LTFA compared with cows fed PO. Feeding LTFA improved the proportion of excellent-, good-, and fair-quality embryos, and embryos from cows fed LTFA had a greater number of blastomeres than embryos from cows fed PO. Feeding a more unsaturated source of FA improved fertilization and embryo development in lactating dairy cows, despite similar indicators of metabolic status.

Key Words: dairy cow, embryo quality, fatty acid, reproduction

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