The objective was to examine the effects of presynchronization and bovine somatotropin (bST) on pregnancy rates to a timed artificial insemination protocol in lactating dairy cows. Lactating Holstein cows (n = 543) were assigned randomly in a 2 x 3 factorial experiment in which cows received a presynchronization treatment or not, and were treated with bST (500 mg) at 63 +/- 3, 73 +/- 3, or 147 +/- 3 d postpartum. The latter group was used as a control. Presynchronization treatment consisted of two injections of PGF2alpha (25 mg) given 14 d apart, with the second injection of PGF2alpha being administered 12 d before initiation of the timed artificial insemination protocol. All cows received GnRH (100 microg) at 63 +/- 3 d postpartum, an injection of PGF2alpha (40 mg) 7 d later, a GnRH injection at 48 h after PGF2alpha and were inseminated 16 to 20 h later. Cows were resynchronized if determined to be nonpregnant at ultrasonography at 32 d after insemination with a GnRH injection (100 microg), an injection of PGF2alpha (40 mg) 7 d later, and a GnRH injection at 48 h after PGF2alpha and were inseminated 16 to 20 h later. Cows were examined for pregnancy at 32 d and reexamined at 74 d after insemination. No differences in pregnancy rates were observed between cows receiving bST treatment at 63 +/- 3 d postpartum or at 73 +/- 3 d postpartum. An interaction between presynchronization and bST treatment indicated that pregnancy rates were increased for cows treated with bST when cows were presynchronized. When anestrous cows were excluded from the analyses, both an effect of bST and of presynchronization were observed, indicating that bST increased pregnancy rates regardless of presynchronization treatment and that presynchronization also increased pregnancy rates independently of bST treatment. Presynchronization and bST treatment may be used to increase first-service pregnancy rates to a timed artificial insemination protocol.

No abstract

The present study was conducted in order to verify the efficacy of lower doses and alternative routes of a prostaglandin F2α analogue, luprostiol (PGF), for the induction of luteolysis and the precipitation of estrus in nonlactating Nelore cows (Bos taurus indicus). A conventional dose (15 mg) of PGF was compared to doses lower than the conventional dose, which ranges from 10 to 50%, that were administered intramuscularly (IM), intravulvosubmucosally (IVSM), or in the Bai-hui acupuncture site located within the lumbosacral area. The cows were administered PGF 8 day after estrus in the presence of a corpus luteum, and randomly assigned to the following groups: G1 (positive control), 15 mg, IM (n = 23); G2, 7.5 mg, IM (n = 23); G3, 3.75 mg, IM (n = 24); G4, 7.5 mg, IVSM (n = 25); G5, 3.75 mg, Bai-hui acupoint (n = 24); and G6, 1.5 mg, Bai-hui acupoint (n = 25). The results indicated that 50% of a conventional dose of PGF (7.5 mg) resulted in a complete luteal regression (plasma progesterone <1 ng/ml) at Hour 48, and hastened estrus, regardless of whether or not PGF was administered IM or IVSM. Comparatively, 10 or 25% of the conventional dose, even when administered to the Bai-hui acupoint, resulted in an initial reduction in the concentration of progesterone at Hour 24, followed by an increase observed at Hour 48. In conclusion, 25% of a conventional PGF dose administered via the Bai-hui acupoint proved inadequate to induce a complete luteal regression, whereas 50% of a conventional dose administered IM or IVSM was found to be the minimal dose required to induce effectively a complete luteal regression, and to precipitate the onset of estrus in nonlactating Nelore cows.

No abstract

O estudo avaliou os custos e benefícios do programa de inseminação artificial (IA) na Região Central de Rondônia e sua evolução no período de 2011 até 2016.  Dados foram fornecidos pela Entidade Autárquica de Assistência Técnica e Extensão rural do Estado de Rondônia (EMATER-RO) - Regional de Ji-Paraná-RO. Os dados foram registrados durante o Programa de Melhoramento Genético em Bovinos de Leite, por meio do Projeto Inseminar em 13 municípios, nos quais foram incluídas, 278 propriedades rurais de produção de leite. As variáveis utilizadas para mensuração da eficiência do programa foram: quantidade média de nitrogênio (N) líquido consumido, número de associações beneficiadas e número de produtores por município; número médio de vacas inseminadas e porcentagem de bezerros nascidos; porcentagem de bezerros machos e fêmeas; despesas e rentabilidade.  O programa de IA durante o período de 2011 a 2016 apresentou lucratividade de R$ 195.639,17; chegando a valor médio de R$ 1.774.500,00; alcançados nas vendas de bezerros, com índice de 11 % em despesas e uma rentabilidade média de 89 %. Os valores obtidos nas vendas de bezerras reduziram no decorrer do período analisado, enquanto os custos se mantiveram estáveis. Estratégias para o manejo reprodutivo eficiente e conscientização das associações e produtores são necessárias na região para obtenção de melhores resultados.

Germinal vesicle (GV) oocytes are susceptible to heat stress. However, neither the cellular mechanisms triggered by elevated temperature nor the thermoprotective effects of insulin-like growth factor (IGF) on GV oocytes are completely understood. Therefore, a series of experiments was conducted to determine the direct effects of IGF1 (0, 12.5, 25, 50 and 100ng mL) on heat-treated GV oocytes. Butyrolactone-arrested GV oocytes were cultured at 38.5°C (control) or 41°C (heat shock; HS) for 14h in the presence of different concentrations of IGF1. Exposure of GV oocytes to 41°C increased (P<0.05) the number of terminal deoxyribonucleotidyl transferase-mediated fluorescein-dUTP nick end-labelling (TUNEL)-positive oocytes. At concentrations of 12.5 and 25ng mL, IGF1 tended to minimise these negative effect of HS (P=0.07). However, neither HS nor IGF1 had any effect on caspase activity. HS also decreased (P<0.05) GV oocyte mitochondrial activity and developmental competence to the blastocyst stage. These deleterious effects of HS were alleviated (P<0.05) by 12.5ng mL IGF1. This concentration of IGF1 did not affect cleavage rate, the percentage of TUNEL-positive blastomeres and total blastocyst cell number regardless of temperature. In conclusion, exposure of GV oocytes to HS triggered the apoptotic cascade and compromised oocyte developmental competence. Physiological concentrations of IGF1 had a beneficial effect on heat-shocked GV oocytes.

Inadequate pre-slaughter handling conditions can compromise animal welfare and productivity. This study aimed to evaluate the animal welfare (AW) indexes during pre-slaughter handling and quantify the carcass lesions of beef cattle submitted to different loading densities. A total of 270 Nellore cattle, at 30 months of age, from three farms were used in the study. Each farm presented a different loading density: higher density (500kg/m2), intermediate density (450kg/m2), and lower density (420kg/m2). Three shipments of cattle from each farm with 30 animals each were used in the AW analysis. Ten animals from each shipment were considered for quantification of carcass bruises. The AW indexes were classified according to the five-freedom criterion (physiological, environmental, sanitary, behavioral, and psychological). After slaughter, the carcasses were inspected in the routine line and evaluated for the presence of lesions. Statistically significant differences (p<0.001) were found for all variables studied as a function of AW and bruises. The best AW index and the lowest mean weight of lesions were found at the loading density of 450kg/m2. The highest carcass weight was observed at the loading density of 500kg/m2. Lesions were found in 100% of the animals at the loading densities of 500 and 420kg/m2. In conclusion, the best AW indexes and the smallest occurrence of bruises were verified at the loading density of 450kg/m2. This study confirmed the importance of adequate pre-slaughter handling to ensure cattle welfare and, consequently, greater profitability for producers and slaughterhouses.

Matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS) allows the lipid profile study of individual mammal embryos. The data collection is rapid, highly sensitive, can tolerate some level of impurities, and is easy to interpret. The aim of this study was to report the lipid profile obtained from a single equine embryo by MALDI-MS. Follicles ≥30 mm in diameter were monitored daily until ovulation (Day 0). The insemination was performed close to ovulation with fresh diluted semen, and the embryo recovery was performed on Day 9 (D9) post ovulation. The equine embryo was placed in 50/50 (v/v) methanol/phosphate buffer solution and transported at 4°C to the laboratory. MALDI-MS spectra were acquired in the positive ion mode using MALDI Synapt HDMS mass spectrometer (Waters, Manchester, UK) m/z 700–950 range. The sample was coated with a 1.2 μL matrix of 2,5-dihydroxybenzoic acid (DHB) 1.0 mL L–1 in methanol. Due to the equine embryo volume, it was possible to divide it and get two mass spectra, which were identical. Spectra processing was performed using the MassLynx 4.0 software (Waters, Manchester, UK). It was observed the presence protonated and sodiated species of sphingomyelins (SM), phosphatidylcholines (PC), and triacylglycerols (TAG). The most intense ions assigned by comparison with data obtained from bovine embryos were m/z 723.5 [PC (34:1) and loss of N(CH3)3]+, 725.5. [SM (16:0) + Na]+, 754.6 [PC (32:1) + Na]+, 778.6 [PC (36:1) + Na]+, 780.6 [PC (34:2) + Na]+ or [PC (36:5) + H]+, 782.6 [PC (36:4) + H]+ or [PC (34:1) + Na]+, 788.6 [PC (36:1) + H]+, 806.6 [PC (38:6) + H]+ or [PC (36:3) + Na]+, 808.6 [PC (38:5) + H]+ or [PC (36:2) + Na]+, 810.6 [PC (38:4) + H]+ or [PC (36:1) + Na]+, 907.7 [TAG (54:3) + Na]+ and 909.7 [TAG (54:2) + Na] +. Regarding the lipid profile by MALDI-TOF previously reported for oocytes and embryos of several species (Ferreira et al. 2010, J. Lipid Res., 51, 1218–1227), it detected similar lipid species, but with different relative intensities. Because of the single equine embryo volume and MALDI-MS technique sensitivity, we intend to observe if there will be differences between the lipid profile of the inner cell mass and trophoblast in the future. The analysis of a greater number of embryos as well as different development periods and MS/MS experiments will contribute to building a database of lipid profiles that allows a better understanding of the lipid profile physiology in equine embryos and the meaning of differences among other mammalian embryos. FAPESP (São Paulo Research Foundation).