Estrous cycle synchronization in dairy heifers with the prostaglandin analog alfaprostol (I).
The prostaglandin F(2alpha) analog (PGFA) alfaprostol was used in 277 cyclic dairy heifers for the purpose of estrous cycle synchronization. A dose of 5 mg was used in all the trials during spring 1979 and 1.5 mg 100 kg body weight were used during winter 1979/80. Animals were treated according to 3 schedules: two doses 11 days apart without prior examination (Schedule I), one dose without prior observation and a second dose 11 days later only for those animals that failed to show estrus after the first treatment (Schedule II) and one dose for animals not showing estrus after a 5-day observation period (Schedule III). Estrus synchronization was achieved with peak estrus activity occurring form 32 to 72 h after treatment in 95% of the responding animals. Of the animals treated according to schedules I, II and III, 93%, 100% and 100% showed synchronized estrus activities respectively. Conception rates in all trials, from insemination at observed heat (Schedules I, II and III) or from fixed time insemination at 48 and 72 h after the first or second treatments in schedules III and I, respectively, compared well with that of untreated contemporary controls with a range of 34.2 to 66.7% for animals in these trials, and an overall conception rate of 49.48% for treated and of 48.30% for control animals. This observation, together with the pregnancy rate at 60 days after breeding (78.30% for all treated animals and 73.50% for all untreated controls), indicates that alfaprostol had no adverse effects on fertility.
Jöchle
W
W
Wolfgang Jöchle Associates, Inc. 10 Old Boonton Road, Denville, NJ 07834, USA.
Kuzmanov
D
D
Vujosevic
J
J