Use of prostaglandin F2 alpha as a method to synchronize heat in ovines

Abstract

Estrus sinchronization was studied by three methods on 120 adult ewes Merino Precoz Frances. Four groups of 30 ewes were treated in the following: C - Control: The ewes were isolated from rams until the beginning of the mating period (Dec. 16, 1981). P - Prostaglandins: The ewes were treated with two does of PG F2 alfa (16 mg each time) : One at the beginning of the mating and the other 9 clays latter. CH- The ewes wer e maintained with a ram chastityd harness from the 15th day before the beginning of the mating. CP - These ewes received the combined treatment of the P and CH groups. The early lambing was analized by statistical model of the ramdom desigfn and the concentration of lambing was studied by the "t" method, which was also used to stablish the prolificity of the ewes. The results showed that 100% (30 ewes) presented estrus 48-72 hs. after the second injection of PC which were fertile as it could later be demostrated. No fertility differences, no prolificity differences as well no differences of the weight at birth could be established among The treatment of the CP groups showed to be more efective (62 %) get early pregnancy was stablished between the C P groups and CH-CP groups. But no differences were observed among th e different groups of treatments. The lambing during the first 16th days was different for the CP and CH groups (P < 0,01). The treatment of the CP groups showed to be more efectiva (62%0)' get early estrus sinchronization and concentrated lambing than the other treatments. The results showed that the uses of PG is effective to sinchronize estrus in ewes wen they are in the normal sexual cicling activity. Besides, the uses of tha ram with chastity harness showed to be useful to start and to regularize the sexual cycle of the ewes. On the contrary, the administration of PG without the previous stimulus of the ram with chastity harness was not effective on the estrus sinchronization, neither on the early pregnancy and lambing concentration during the first 16th days of the lambing season, at the beginning of the mating season.