Authors: ABDUL MALIK, ABD WAHID HARON, ROSNINA YUSOFF, AZHAR KASIM, SABRI MOHD YUSOFF
Abstract: The objective of this study was to investigate the pregnancy rate following artificial insemination (AI) or natural service (NS) in postpartum estrous synchronized beef cattle. A total of 85 Brangus cows, postpartum, were divided into 2 groups. Group 1 consisted of 35 cows and was further subdivided into 7 groups, each consisted of 5 cows that were naturally mated. Group 2 consisted of 40 cows that were artificially inseminated. Estrus synchronization was carried out using a controlled internal drug releasing device (CIDR) containing 1.38 mg of progesterone, for 7 days. Group 1 cows were mixed with bulls at a 1:5 ratio of bull:cows for 7 days and group 2 cows were inseminated 55-58 h after the CIDR removal. Pregnancy was determined using transrectal ultrasonography 32 days after NS and AI. The pregnancy rate was higher in the NS group (28.6%) than in the AI group (18.0%), but the difference was not significant (P > 0.05).
Keywords: Natural service, artificial insemination, estrus synchronization, conception rate
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