Evaluation of Reproductive Performance of Begait Cattle Before and After Application of Estrus Synchronization Protocols in Northern Ethiopia
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Date
2011-06-01
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Addis Ababa University
Abstract
Retrospective and prospective studies were conducted in Kafta-Humera and Wukro area of Tigray region. A retrospective study was carried out on 12 herds consisting 2144 Begait cattle from pastoral and agro-pastoral areas to assess herd composition and calf-crop. To evaluate the reproductive and lactation performance, 210 and 61 cows, respectively were selected randomly from pastoral. agro-pastoral, confinement and crop-livestock production systems. All necessary data of reproductive and lactation parameters were collected through questionnaire surveys, group discussions and follow-up observations. Another experimental study was conducted to evaluate the estrus characteristics, estrus response and reproductive performance of Begait cattle following estrus synchronization using PGF2a alone and GnRH + PGF2a treatments. Forty heifers and 47 cows were purposively selected for this study and randomly assigned in the two treatment groups. Thirty-eight cattle were treated with PGF2a (GI) followed by mating aftcr estrus exhibition and second PGF2a injection was given for those that didn 't exhibit estrus signs in the first injection. The rest, 49 cattle were treated with GnRH followed by PGF2a (GIl) 7 days later and observed for estrus that followed by mating. SPSS software was applied to analyze the da.a. The result of the present study showed that the average calf-crop of 53% and 42.4% and annual calf mortality rate of 20.8% and 9.4%, were observed for pastoral and agro-pastoral production systems, respectively. The mean AFC and CI in months were 43.9 and 12.9 in pastoral. 45.0 and 14.0 in agro-pastoral, 44.9 and 15.0 in confinement and 49.5 and 19.6 in crop-livestock production systems, respectively. Both parameters were significantly (P<0.05) affected by site and production system. Significantly longer AFC and CI were noticed in crop-livestock system than in the other 3 production systems. However, CI was not affected by age and parity. Likewise, the mean daily milk yield at early, middle and late lactation of Begait cows was significantly higher (P<0.05) in the agro-pastoral (4.5, 6.7 and 3.1 liters, respectively) than in pastoral (2.2, 4.0 and 1.4 liters, respectively) production system. On the other hand, lactation lengths were shorter in pastoral (150 ± 4.39 days) and crop-livestock (148.4 ± 5.48 days) than in confinement (209.7 ± 7.90 days) and agro-pastoral (189.2 ± 4.45 days) production systems. Younger and first parity animals as well as those with once milking practice per day also had significantly lower lactation performance while site did not have effect. The hormonal experiment study showed that an overall 71.3% of cows responded in both treatment groups. The most frequently observed estrus behaviors and physical changes were standing to be mounted, restlessness. swelling and redness of vulva and vaginal discharge with the value of 100. 100. 96.7 and 90%. respectively. The mean time interval from PGF2a injection to the onset of estrus in GI and Gll was 73 .8±5.26 and 67±2.42 hours. respectively. Both the estrus response and pregnancy rate in GIl (83 .7 and 92.7%) were significantly higher (P<0.05) as compared to GI (55 .3 and 85 .7%), respectively. The present study showed that heifers and moderate body condition cattle became more responsive (P<O.05) to the therapy than cows and those with poor body condition cattle. In conclusion, acceptable results of estrus responses and pregnancy rates obtained following PGF2a and GnRH + PGF2a treatments in the present study appear to be promising for enhancing reproductive performance in Begajt cattle breed and may help as a stepping- stone for researchers and developmental agencies for further innovation, adoption and extension in the area. .
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Keywords
Begait callie, production systems, reproductive pelj ormance, estrus synchronization, PGF2a, GnRH