[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to evaluate embryo production and embryonic quality of locally adapted Curraleiro Pé-duro cows, using protocols with different progesterone exposure. Cows were divided in three groups: Control, P24 and P36. All cows had the estrus previously synchronized and in the fifth day of the estrus cycle, the cows of the groups P24 and P36 received an intravaginal progesterone device and estradiol benzoate. Starting from the ninth day of the cycle, all cows received eight decreasing doses of FSH and two doses of D-cloprostenol together with the two last doses of FSH. Treatments P24 and P36 had the progesterone device removed 24 and 36 hours after the first application of D-cloprostenol, respectively. All cows received lecireline in the thirteenth day, with the inseminations accomplished 12 and 24 hours later. There was no difference (P > 0.05) for superestimulatory response among treatments. The number of total structures was greater (P < 0.05) in P24 than in the Control and the number of viable structures was greater (P < 0.05) in both P24 and P36 than in the Control. The use of exogenous progesterone in superovulation protocols improved embryo production and quality of locally adapted Curraleiro Pé-duro cows.
[Show abstract][Hide abstract] ABSTRACT: Studies were conducted to characterize the effect of season of the year on testicular morphology, fresh and frozen/thawed semen quality from Curraleiro (Pé-duro) bulls in the Brazilian Central west region. Five adult, healthy bulls underwent an andrological examination and semen collection using an electroejaculator, once a month for a year. Fresh and thawed semen were evaluated for progressive sperm motility and sperm vigor, sperm morphology and acrosomal integrity. Testicular length and volume were less (P<0.05) in April than in the other months of the year. For fresh semen, the ejaculate in April had less volume and sperm concentration (P<0.05), while sperm vigor was less (P<0.05) in June, increasing in January and February. With the frozen/thawed semen, the proportion of sperm was greater (P<0.05) in April to July, decreasing from October to December. Semen collected in December had the greatest (P<0.05) proportion of major defects while that collected in February/March had the highest proportion of minor defects. The proportion of live intact sperm reduced progressively from December to April/May. The marginal influence of the time of the year on testicular biometry and fresh semen in Curraleiro bulls shows the adaptation of this breed to the environmental conditions in the region. Thus, reproduction with natural mating should be successful at any time of year. For frozen semen collection for conservation programs, the best time of year is from June to September.