Reproductive Responses to Hormonal Treatment and A.I. or Buck –Effect and Natural Mating in Exotic and Local Breeds of Goats

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Hashim,Hashim Ahmed
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University of Khartoum
In this study, the reproductive responses to hormonal and natural synchronization of oestrus were investigated in 42 goats raised in Sudan for upgrading purposes during the years 1993-1994. Three experiments were conducted on 19 Nubian goats and 23 Saanen goats to evaluate the effect of different protocols of hormonal treatment, variation in responses attributable to breed and to compare fertility indices following Buck Effect (BE) + natural mating with those after a short lasting progestogen treatment SLPT+ Artificial Insemination (A.I) in Saanen goats. Each of the two breeds (Nubian and Saanen) was divided into two groups. The two groups of Nubian goats received either the SLPT for 11 days (9 animals) or long lasting progestogen treatment (LLPT) for 18 days (10 animals). The first Saanen group (n=ll) received the mentioned SLPT + A.I and the other one (n=12) was subjected to the BE followed by natural mating. The percentage responding was 90, 100, 90.9 and 91.6% in the Nubian (LLPT), Nubian (SLPT), Saanen (SLPT) and Saanen (BE), respectively. The differences were not significant (P>0.05). Oestrus responses were obtained earlier with the SLPT as compared to the LLPT, but the difference was not significant (P>0.05). Breed variation was not found to be a factor having a bearing on the number of responding does and the time lapse prior to the occurrence of oestrus after the (SLPT) or (LLPT) protocols. In the Saanen groups subjected to the BE + natural mating or the SLPT + A.I, the percentage responding, conception rates after the first induced heat, the kidding % per treated goats, per responding goats, per kidded goat and the litter size were 91.6 vs. 90.9%), (91.6 vs. 54.4%, P<0.05), (208 vs. 109%, P<0.05), (227 vs. 120%, P<0.05, 227 vs. 200% and 2.27 vs. 2.00 for BE + natural mating vs. SLPT + A.I. groups, respectively. Manifestations of oestrus in the 4 groups were the classical signs, typically displayed with subtle intensification when teaser bucks were introduced temporarily or permanently. The gestation period as recorded in the Saanen SLPT group ranged between 140-155 days with a mean of 148.25±1.48 days, and the kiddings were spread over 21 days (BE) and 16 days (SLPT). The incidence of dystocia were 2 and 1, that of still births were 1 and 2 in the BE group and the SLPT group, respectively. .None of the two adopted protocols (BE and SLPT) seemed to have an influence on the birth weight of the kids, as the overall birth weights were 2.35±0.17 vs. 2.35±0.29 kg, mean weight of twins 2.63±0.12 vs. 2.18±0.20 kg and the mean weight of the triplets 1.85±0.13 vs. 1.55±0.20 kg, for BE vs. SLPT, respectively. However, the only single born kid to a SLPT subjected doe, recorded the heaviest weight (3.2 kg). The mean weights of all male kids (2.41±0.13 kg) were significantly higher than those of all female kids (2.22 0.25 kg) (P<0.00l). Similarly, the mean weight of all twins exceeded those of all triplets (2.37 ±0.15 vs. 1.79 0.14 kg, P<0.05). It was concluded that both SLPT and LLPT protocols were effective inducers of synchronized heat in Nubian and Saanen, simultaneously. Breed effect is rendered negligible when standard quality and adequate quantities of progestogen are used. Also, the BE proved to be a cheaper method for fertile oestrus induction and satisfactory litter production, but, in contrast to the hormonal treatment, resulted in less synchronized kiddings.
Buck ,Natural Mating,Exotic,Local Breeds ,Goats