The impressive increase in the use of assisted reproductive technologies (ARTs), especially in cattle, during the last few years in Brazil is well known worldwide. In 2015, there were over 13.7 million artificial inseminations (AI), of which, about 77% were carried out using fixed-time AI (FTAI). This technology has helped to substantially improve reproductive efficiency in beef and dairy cattle. In relation to embryo transfer, production of in vivo derived (IVD) embryos remained relatively stable, with average production of 30-40,000 embryos per year, whereas in vitro production (IVP) of embryos had a substantial increase, from about 12,500 IVP embryos in 2000 to more than 300,000 IVP embryos after 2010. The increasing availability and use of sex-sorted sperm was one of the factors responsible for a recent shift from the predominance of IVP embryos from beef breeds to dairy breeds in Brazil. Moreover, there was also an increase from 13% in 2014 to 29% in 2015 in the percentage of vitrified/frozen embryos. Moreover, the successful use of protocols for fixed-time ET (FTET) due to their high efficiency and ease of implementation, has facilitated the dissemination of ET programs all over Brazil. However, there is room for improvement, since there are several reports of high pregnancy loss and high peripartum loss, when IVP embryos are used. The production of healthy cattle by somatic cell nuclear transfer has also increased in the last few years in Brazil, but despite substantial progress in reducing postnatal losses, no drastic increase in cloning efficiency up to parturition has occurred.

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The objectives were to evaluate the effects of injectable vitamin E during the last 3 wk prepartum on the incidence of retained fetal membranes (RFM) and reproductive performance. Dairy cows (n=890), 390 Holsteins (132 nulliparous and 258 parous) and 500 crossbred Holstein × Gyr (199 nulliparous and 301 parous), from 3 dairy farms in Brazil were assigned to the study. In all 3 farms, from October to March, prepartum cows grazed tropical grasses and received 2 kg/d of a mixture of finely ground corn, soybean meal, and minerals and vitamins. From April to September prepartum cows received a total mixed ration composed of corn silage, finely ground corn, soybean meal, and minerals and vitamins. During the prepartum period, cows were fed 280 (farm 1), 390 (farm 2), and 480 IU (farm 3) of supplemental vitamin E per day, and throughout postpartum, cows were fed 370 (farm 1), 500 (farm 2), and 600 (farm 3) IU of supplemental vitamin E. Within each farm, cows were randomly assigned to remain as untreated controls or to receive 3 i.m. injections of 1,000 IU each of dl-α-tocopherol administered at 19.2 ± 4.3, 12.9 ± 3.3, and 6.2 ± 2.9 d before calving (VitE). Blood was sampled from 141 cows immediately before enrollment to determine the α-tocopherol and cholesterol statuses. Blood was also sampled and analyzed for concentrations of cortisol and nonesterified fatty acids in the last 3 wk of gestation. The serum concentration of α-tocopherol or α-tocopherol:cholesterol ratio did not differ between treatments and averaged 2.97 ± 0.10 μg/mL and 4.46 ± 0.16 × 10(-3), respectively. In total, 53.2% of the cows had an inadequate concentration of serum α-tocopherol based on the 3.0 μg/mL cut-off for adequacy. The risk of RFM decreased as serum α-tocopherol increased. Milk production did not differ between controls and VitE cows. Treatment with injectable α-tocopherol decreased RFM from 20.1 to 13.5%, decreased incidence of stillbirth from 14.9 to 6.8%, and tended to decrease death by 200 d postpartum. VitE cows tended to have improved pregnancy per insemination at first AI (36.7 vs. 30.1%) because of decreased pregnancy loss from 31 to 62 d of gestation (12.5 vs. 20.5%). Despite a similar insemination rate, VitE cows had 22% greater pregnancy rate than control cows. Cows receiving vitamin E had decreased circulating cortisol and nonesterified fatty acids around calving. In summary, when cows were fed limited amounts of supplemental vitamin E, 28 to 48% of the recommendations, prepartum supplementation with injectable α-tocopherol decreased incidence of RFM and improved reproduction.

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The objectives were to describe the incidence of retained fetal membrane (RFM) and its effect on production and reproduction of dairy cows in tropical environments. Holstein and crossbred Holstein × Gyr cows and heifers calving between May 2012 and May 2013 from 4 dairy farms were enrolled in this study. Retained fetal membranes were defined as the non-expelling of placenta within 12 to 24 h after calving. All cows with RFM were treated with 10 mg kg–1 of oxitetracycline IV and drenching containing 100 g of CaCl2, 100 g of KCl, 200 g of Mg(SO4), and 350 mL of propylene glycol in 25 L of water once per day for 3 days. The incidence of RFM was 14.7% (92/624) in multiparous cows and 11.5% (67/583) in primiparous cows (P = 0.003). The incidence of retained placenta was 14.7% (92/624) during the summer and 14.8% (108/731) during the winter (P = 0.99). Conception rates after first postpartum AI were 32.5% (276/850) and 25.8% (34/132) for healthy cows and cows with RFM, respectively (P = 0.12). More cows that did not have RFM were pregnant at 150 DIM than cows with retained placenta (42.3 v. 29.3%; P = 0.003). Based on predicted 305-day milk yield, cows with retained placenta produced less milk than healthy cows (5924.0 ± 158.0 v. 6315.3 ± 61.0 kg, respectively; P = 0.009). The average peak production was 30.8 ± 0.3 and 29.1 ± 0.7 kg for healthy and RFM cows, respectively (P = 0.02). During the first 60 days in milk, the total milk production for RFM and healthy cows was, respectively, 1305.7 ± 37.3 and 1441.2 ± 15.8 L (P = 0.0008). In conclusion, although season did not influence the incidence of RFM in dairy cows, parity had an effect. Moreover, RFM was associated with a decrease in reproductive efficiency and milk production in dairy cows managed in the tropics. Financial support was received from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) of Brazil.