Perfil sanitário e eficiência da inseminação artificial em tempo fixo de rebanhos bovinos de pequenos produtores da região de Piracicaba

Abstract

The objective of this study was to evaluate the reproductive indices of different cattle herds submitted to a fixed-time artificial insemination program (FTAI) in the region of Piracicaba, SP. Twenty herds composed of 10 to 80 crossbred dairy cows were selected to participate in a breeding program through FTAI. First, a survey was conducted to determine the incidence of reproductive system diseases in the herds. For this purpose, blood samples were collected randomly from each herd for the serological diagnosis of brucellosis, leptospirosis, infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), enzootic bovine leukosis (EBL), and neosporosis. The laboratory tests were conducted according to the methods of the World Organisation for Animal Health. All herds had at least one animal that tested positive for one or more reproductive system diseases. Brucellosis was detected in 3/20 (15%) herds, IBR and BVD in 19/20 (95%), EBL in 20/20 (100%), neosporosis in 13/20 (65%), and tuberculosis in 8/8 (100%). Six months later, cows (n=203) of the different herds were submitted to hormone treatment consisting of estradiol-progesterone and PGF2α for heat synchronization and ovulation and subsequent FTAI. The data were analyzed by logistic regression and Fisher’s exact test. The pregnancy rates at 30 and 60 days after FTAI were 55.7% and 48.3%, respectively. These rates were not influenced by herd, inseminator, body score, post-calving days, or number of lactations. The calving rate (42.4%) differed from the pregnancy rate at 30 (P=0.01), but not at 60 (P=0.27) days after FTAI. The gestation loss until calving was 23.2% (26/112), but no exact cause of this event was identified. Despite the presence (seroreactivity) of reproductive diseases, cattle herds owned by small-scale producers exhibit acceptable pregnancy rates after FTAI. However, additional prophylactic measures such as vaccination and improvement of livestock management should be adopted.