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    Early Embryonic Mortality in Modern Dairy Cows: Causes, Consequences and Remedies
    (Univ Ghent, 2006) Thatcher, W. W.; Güzeloğlu, Aydın; Bilby, T. R.
    Lactating dairy cows experience a temporary infertility syndrome. There is a multiplicity of factors contributing to early and late embryonic losses. Some of these factors begin within the postpartum period in association with dynamic metabolic and condition changes of the cow. Other factors include uterine health, as the cow enters the breeding period. Programming the preovulatory period with optimal recruitment and growth of the follicle influences subsequent quality, viability and survival of the embryo via direct effects associated with quality of the oocyte and indirectly via endocrine regulation (i.e., follicle and corpus luteum function) of the oviduct and uterus. The maternal-embryo unit appears to be responsive to reproductive management as well as pharmaceutical and nutraceutical programs to enhance pregnancy rates.
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    Effect of the administration of flunixin meglumine on pregnancy rates in Holstein heifers
    (BMJ PUBLISHING GROUP, 2007) Guzeloglu, A.; Erdem, H.; Saribay, M. K.; Thatcher, W. W.; Tekeli, T.
    Fifty-two 15-month-old Holstein heifers were synchronised with single or double injections of prostaglandin F-2 alpha, followed by an injection of gonadotrophin-releasing hormone (GnRH) 48 hours later, and inseminated 12 to 14 hours after the injection of GnRH (day 0). Half of them were then injected twice intramuscularly with 1.1 mg/kg flunixin meglumine 12 hours apart, on the evening of day 15 and the morning of day 16, and the other 26 were not treated. Pregnancy was diagnosed by ultrasound 29 and 65 days after they were inseminated. On day 29, 20 of the treated heifers were pregnant compared with 13 of the control heifers (P<0.05); on day 65, 18 of the treated heifers were still pregnant compared with 12 of the control heifers (P<0.10).
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    Pregnancy, bovine somatotropin, and dietary n-3 fatty acids in lactating dairy cows: II. Endometrial gene expression related to maintenance of pregnancy
    (ELSEVIER SCIENCE INC, 2006) Bilby, T. R.; Guzeloglu, A.; MacLaren, L. A.; Staples, C. R.; Thatcher, W. W.
    The objectives were to examine the effects of bovine somatotropin (bST), pregnancy, and dietary fatty acids on expression of key endometrial genes and proteins regulating prostaglandin synthesis in lactating dairy cows. Two diets were fed, at about 17 d in milk (DIM), in which oil of whole cottonseed (control diet) was compared with calcium salts of fish oil-enriched lipid (FO). Ovulation was synchronized in cows with a presynchronization plus Ovsynch protocol and cows were inseminated artificially or not inseminated on d 0 (d 0 = time of synchronized ovulation; 77 +/- 12 DIM). On d 0 and 11, cows received bST (500 mg) or no bST, and were slaughtered on d 17 to recover uterine secretions and endometrial tissue. Number of cows in the control diet: 5 bST-treated cyclic (bST-C), 5 non-bST-treated cyclic (no bST-C), 4 bST-treated pregnant (bST-P), and 5 non-bST-treated pregnant (no bST-P) cows and in the FO diet: 4 bST-treated FO-cyclic (bST-FO-C) and 5 non-bST-treated cyclic (no bST-FO-C) cows. The FO diet increased progesterone receptor (PR) mRNA, and treatment with bST increased PR mRNA concentration in endometrium of no bST-C, but not in no bST-FO-C or no bST-P cows. Concentrations of estrogen receptor-alpha (ER alpha) mRNA and protein, and oxytocin receptor (OTR) mRNA were decreased in no bST-P cows compared with no bST-C cows. Treatment with bST tended to increase OTR and ERa mRNA concentrations in cyclic cows fed control or FO diets. Immunohistochemistry demonstrated effects of bST, FO, and pregnancy on distributions of ERa and PR proteins in endometrium. Pregnancy and FO feeding decreased ERa abundance in luminal epithelium. Prostaglandin H synthase-2 (PGHS-2) protein was elevated in pregnant cows and localized to the luminal epithelium. Both FO and bST treatments reduced staining intensity of PGHS-2 protein. Concentrations of prostaglandin E synthase mRNA were elevated in either cyclic or pregnant cows in response to bST, whereas bST decreased prostaglandin F synthase mRNA in pregnant cows. Uterine lumen fluids had more PGF(2 alpha) and prostaglandin E-2 in pregnant than cyclic cows. Uterine lumen fluids of bST-P cows contained more prostaglandin E-2 than those from no bST-P cows. In summary, both pregnancy and bST altered endometrial gene expression, and cyclic cows responded differently to bST than pregnant cows. Feeding FO modulated PR, ER alpha, and PGHS-2 expression and distribution among endometrial cell types in a manner that may favor establishment and maintenance of pregnancy.