Effects of temporary calf removal and eCG on pregnancy rates to timed-insemination in progesterone-treated postpartum Nellore cows

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of Sperm DNA Peroxidation in Fertile and Subfertile Dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of the breed of bull (Bos taurus indicus vs. Bos taurus taurus) and the breed of cow (Bos taurus indicus, Bos taurus taurus and crossbred) on the resistance of bovine embryos to heat

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of bovine Herpesvirus Type 5 on development of in vitro-produced bovine embryos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of developmental changes in bovine in vitro produced embryos following exposure to bovine Herpesvirus type 5

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito da duração do cio sobre a fertilidade de éguas inseminadas com sêmen eqüino diluído, resfriado a 20°C e transportado

The objective of this study was to evaluate the effect of different interval from the beginning of the heat to the ovulation on the fertility of inseminated mares with diluted equine semen, cooled at 20°C and transported. The mares were grouped with the following interval periods: T1 - period less than five days, T2 - period from five to seven days and T3 - period from 8 to 21 days. The conception rates in the first cycle were 53.85 (7/13), 52.17 (12/23) and 66.67% (10/15) for treatments 1, 2 and 3, respectively, and after three cycles, 50.00 (9/18), 48.15 (13/27) and 64.71% (11/17), in the same preceding order. The duration of heat, in the conditions of this experiment, did not influence the fertility of inseminated mares.

Efeito de diferentes concentrações espermáticas sobre a fertilidade de éguas inseminadas com sêmen eqüino diluído, resfriado a 20°C e transportado

One hundred and one estral cycles of 92 Mangalarga Marchador breed mares were analyzed to study the effect of different spermatic concentrations on different reproductive characteristics. The mares were inseminated with diluted equine semen, cooled at 20°C and transported: T1 - concentrations below 250×10 6 (177.58±41.74×10 6 viable spermatozoa per inseminate dose), T2 - concentrations between 250 and 350 10 6 sptz (315.51±20.78×106), and T3 - concentrations above 350×10 6 sptz (477.71±136.83×10 6). The conception rates in the first cycle were 43.75 (7/16), 57.89 (11/19) and 54.55% (18/33) for treatments 1, 2 and 3, respectively. After five cycles, the conception rates were 36.00 (9/25), 44.12 (15/34) and 54.76% (23/42) for treatments 1, 2 and 3, respectively. Concentrations of 177.58±41,74×10 6 viable spermatozoa per inseminate dose had moderate fertility index in a commercial program using cooled and transported semen.

Comprimento da peça intermediária de espermatozóides bovinos e suas relações com características do sêmen e fertilidade

With the objective of identifying predictors of fertility in bulls, the correlation coefficients of the midpiece length of bovine spermatozoa with semen traits and fertility were estimated. Data were obtained from semen samples of 50 crossbred bulls submitted to a progeny test. The midpiece length was determined in 40 midpieces of each bull through a image analysis system (Videoplan). Besides the physical traits before and after semen freezing, the oxygen consumption rate and the cytochemical activity index were observed. The correlation coefficients were low and non-significant (P> 0.05), indicating that the midpiece length is not a good predictor of fertility.

Repeatability and heritability of response to superovulation in Holstein cows

The objective of this study was to estimate the relative effects of genetic and phenotypic factors on the efficacy and efficiency of superovulation for Holstein-Friesian cows reared in Brazil. A database, established by the Associacao Brasileira de Criadores de Bovinos da Raca Holandesa, consisting of a total of 5387 superovulations of 2941 cows distributed over 473 herds and sired by 690 bulls was used for the analysis. The records were analyzed by MTDFREML (Multiple Trait Derivative-Free Restricted Maximum Likelihood), using a repeatability animal model. The fixed effects included in the model were contemporaneous group (veterinarian, herd, year and season of the superovulation); number of semen doses; cow age; and superovulation order. The estimated repeatability of the number of the transferable embryos was low (0.13), and the estimated heritability was 0.03. These results indicate that environmental factors play a critical role in the response of a cow to a superovulation treatment. There is little evidence that future responses to superovulation by individual females can be predicted by previous treatment(s) or that superovulation response is an heritable trait.

Testicular ultrastructure and morphology of the seminal pathway in Prochilodus scrofa

The seminiferous tubules of Prochilodus scrofa present a coiled morphological arrangement with intertubular anastomoses and unrestricted spermatogonial distribution. The structural pattern of the seminiferous tubules is cystic, with cysts formed by cytoplasmic prolongations of Sertoli cells. Inside the cysts are observed different types of germ cells. The seminiferous tubules open individually on the ventral surface of the main testicular duct present in each testis. Each main testicular duct prolongs as a spermatic duct, fusing with the spermatic duct of the opposite side to form the common spermatic duct which opens into the urogenital papilla. The mature sperm cysts break and extravasate their content into the lumen of the seminiferous tubules from which the seminal fluid and the spermatozoa penetrate the main testicular duct, the spermatic duct and the common spermatic duct for semen ejaculation.