| Abstrakt: |
Ninety-two Northwestern dark-faced crossbred ewes were used in a study to compare MAP administered orally and in vaginal sponges for synchronization of estrus in ewes at the onset of the estrous season. The reproductive performance of ewes treated with vaginal sponges was similar to ewes fed MAP. Intervals to conception in control ewes and in ewes implanted with 40- and 60-mg sponges or fed MAP were 17.1, 10.8, 12.7 and 14.2 days, respectively. Lambing rates and percents of ewes lambing in the four groups were 1.74, 95.7; 1.83, 100.0; 1.71, 91.3 and 1.75, 87.0; respectively. Ewes treated with 40-mg sponges had shorter intervals to conception, higher lambing rates and a higher percent of the ewes lambing than in the other treated groups but none of these differences were significant. Breeding and lambing performance of the 60-mg sponge ewes were similar to those of the oral-MAP ewes. These data demonstrate that synchronization of estrus in ewes with impregnated vaginal sponges is as effective as use of MAP in feed. The 40-mg sponge gave the best results in terms of lambing rate, percent of ewes lambing, lambing percent and average interval to conception. |
