SYNCHRONIZATION OF ESTRUS IN GILTS WITH A PROGESTIN [OXOLVEN (SA-45.249)]

  • 1 January 1983
    • journal article
    • research article
    • Vol. 35  (10) , 360-363
Abstract
An orally active synthetic progestin (Oxolven) was given in capsules to sexually mature gilts once daily for 12-14 days. The daily dose per animal was 6 mg (= 3 capsules). In trial I, 14 pairs of full-sibs were housed in pens (4-6 animals/pen). All animals were individually fed. Estrus was checked twice daily in the presence of a boar. The gilts were mated with 1 boar on their 1st post-treatment heat and slaughtered 30 days after mating if not returning to estrus. In trial II, the gilts were housed in pens (3 animals/pen). Group feeding was practiced. Estrus was checked as in trial I. Fifteen gilts were fed Oxolven together with their morning feed. They were slaughtered 3-4 days after their 1st post-treatment heat. Eight gilts originating from the same herd were used as reference material. They were slaughtered 3-4 days after their 2nd recorded heat for examination of the genital organs. Ten of 14 gilts (71.4%) in trial I and 9 of 15 gilts (60%) in trial II displayed estrus within 3-6 days after the end of Oxolven treatment. The numbers of corpora lutea and fetus were similar among treated and non-treated animals in trial I. Of the group-fed gilts receiving Oxolven, 27% developed multiple ovarian cysts while none of the non-treated gilts showed ovarian abnormalities (trial II). It is tempting to suppose that the group-fed gilts developing cysts had received less than 3 capsules per day, due to competition with pen-mates at eating. Another form of administration of Oxolven is therefore recommended for large scale use in the pig production.