| Summary: | 碩士 === 國立屏東科技大學 === 獸醫學系 === 89 === Reproductive performance analysis of 11 commercial swine farms was performed based on the database of breeding records established in the year of 2000 using the PigCHAMP information system. Results showed that the mean number of pig weaned per sow per year was 16.7 with the largest difference of 6.3 among farms. The averaged number of pig slaughtered per sow per year was only 13.6 due to the high mortality in nursery, fattening, and finishing pigs with a total loss of 20.6%. Statistical analysis indicated that sows with higher born alive, 3-8 parities, lactation length of 18-24 days, a weaning-to-service interval less than 10 days, and weaned at low temperature had a higher (P＜0.05) mean number of pig weaned per year than other sows. The average interval between weaning-to-service for sows was 7.5 days with 87.3% of sows showing estrus 7 days after weaning. Sows with lactation length less than 18 days, first parity, nursing less than 5 piglets, and weaned during high and middle temperatures had a longer (P＜0.05) weaning-to-service interval than other sows. There were 8% of sows showed delayed estrus during the period of 11 to 35 days post weaning. Among them, primiparous sows had the highest frequency for delayed estrus. High frequencies of delayed estrus were observed between 25 and 28 days post weaning, indicating that an estrus cycle had passed for those sows. There was an average of 16% of sows returning to service for pig farms investigated. Among them, regular returning-to-service accounted for 50.1% of the cases. The averaged farrowing rate was 76.1% with regular returning-to-service accounted for 64.3% of cases. Primiparous had the highest frequency of farrowing failure of 29%. In this study, 3 consecutive bleedings with an interval of 7 days were done for 54 anoestrous gilts for the diagnosis of reproductive failure based on the progesterone level. Among the 54 gilts, 25 came into estrus during the period of bleeding. Of the remaining 29 gilts, 23 (79%) had inactive ovaries（with consistent low progesterone levels）, 4 (14%) had silent heat（with fluctuating progesterone levels）and 2 were undiagnosed. The information mentioned above indicates that the application of PigCHAMPÒ to pig farms for the data management not only can decrease the number of animals with reproductive failures but also provide the basis for further improvement of the reproductive performance in pigs farms. The low production efficiency in pig farms in Taiwan is due in part to the low reproductive performance in sows and more importantly the extremely high mortalities of nursery, fattening, and finishing pigs. The relatively high frequency of sows with regular return-to-service post mating indicates that the techniques of artificial insemination performed in pig farms require further refinement. The inactive ovaries were the main cause of anoestrus in gilts but the mechanisms inducing the dysfunction of ovary merit further study.
|
|---|
