Reproductive performance with insemination with one boar and two boars

摘要

There are a lot of strategies to try to improve the results in pig artificial inseminations Some of them are the number of inseminations performed, the time interval between them and the use of one or more boars to inseminate are sow. The sucess ofevery strategy will depend on the availability of enough number of capacited spermatozoa that reach the site of fecundation before or after the ovulation. There is also an immunological influence of the boar on the sow caused by the antigens that come from spermatozoa and seminal plasma of the boar ejaculate. Some authors think that this immunological response exert a positive effect on the fertilization proccess and early embrionic survival. There are other components in the ejaculate different from the spermatozoa, that participate in the fertilization proccess. These components influence in the differences of fertilization dominance between males. The aim of this work is to evaluate the reproductive results obtained in sows inseminated twice or three times, and also to value the influence of the use of only one boar or the use of differents boars. A total of 909 artificial inseminations were performed in multiparous sows, crossbreed Landrace X Large White, with weaning to first mating intervals between 4 to 6 days. The boars were of Large White breed The minimum quality of the ejaculates used were a motility upper to 80 percent and a percentage of abnormal forms lower that 15 percent. The number of spermatozoa used was 3 X 1O~9 spzs/dose Al and the conservation length of the doses was less than 48 hours.