50428
document
Effectiveness of a short-term treatment with progesterone injections on synchrony of lambing and fertility in tropical hair sheep . The efficacy of using a low cost system for delivering progesterone as part of an estrous synchronization protocol in sheep was evaluated . In experiment 1 , Barbados Black Belly ewes ( n=34 ) and ewe lambs ( n=35 ; 37.5±0.9 kg ) were assigned to be untreated , control animals ( C ) , or to receive PGF ( 2α ) on d0 ( PG ) , or receive two injections of progesterone ( 200mg , i.m . each ) on D -5 and on D -2.5 , prior to PGF ( 2α ) , on D 0 ( 2PPG ) . Treatment with 2PPG increased the proportion of animals lambing to the first service ( P < 0.05 ) , an effect that was greater in ewe lambs than ewes ( treatment × parity ; P < 0.05 ) . The interval from ram introduction to lambing and the mean lambing day was less ( P=0.04 ) in the 2PPG-treated animals compared to control animals . In Experiment 2 , lactating ewes from experiment 1 ( n=61 ) 60-85 days postpartum were assigned within parity and number of lambs reared to remain nursing ( S ; n=29 ) or weaned ( W ; n=32 ) 3 weeks prior to treatment with the 2PPG protocol . There was no effect of treatment on the proportion of animals lambing to the first service or overall , interval from ram introduction to lambing and lambing interval . An 8-month lambing interval was observed in ewes in which estrus was synchronized regardless of physiological state . In conclusion , the two-progesterone injection synchronization protocol may be used as a practical low cost and efficient method of synchronizing estrus to reduce the lambing interval and maximize productivity in tropical breeds of sheep .
50429
Intervention_Pharmacological
progesterone
50430
Intervention_Pharmacological
progesterone