Effect of the short-term progestagen treatments plus PMSG prior ram introduction on the estrus synchronization and the fertility of Ile de France ewes

Abstract

The aim of the present study was to evaluate the effect of the short-term progestagen treatments plus PMSG prior ram introduction on the estrus synchronization and the fertility of Ile de France ewes in the beginning of mating season. The study was carried out with 36 pure-bred ewes (aged 4-6 years) during April 2009. The ewes were divided in 3 groups (n=12 for each group): group I - vaginal sponge impregnated with 30mg FGA for six days, as at the time of placement of sponge 125 ?g cloprostenolum was put i.m At the time of removal of the sponge 250 UI PMSG was put i.m.; group II- the same as the I group, but without cloprostenolum treatment: III group - control. The teasers were introduced to ewes 24h after the sponge removal and ewes in estrus was inseminated artificially. The following parameters were studied: effect of estrus synchronization (EES) ewes in estrus was recorded twice daily for the first 6 days after sponge removal; onset, end and duration of estrus for group I and II, fertility (at first estrus) and fecundity (calculated after lambing). The data for fertility and fecundity for the control group was obtained as ewes were fertilized during 30 days from the begging of the breeding. A significant effect of both schemes to estrus synchronization was determined F=33,33, P<0,001). The EES, fertility and fecundity for group I, II and III were - 91,66%, 63,64% and 142,0%; 91,66%, 45,45% and 140,0 %; 8,33%, 91,66% and 140,0% respectively. The mean onset, end and duration of estrus was 51,27 h, 77,45 h and 27,27h for the I group and 57,82h, 87,27h and 29,45 h respectively for the II group. We conclude that the scheme applied for the first group is better to use for estrus synchronization in the beginning of mating season.