Thesis (Ph. D.)--Columbia University, 1909. / Vita.

Thesis (Ph. D.)--Columbia University, 1909. / Vita. Description based on print version record.

Abstract The objectives of the current study were to evaluate the estrous response and pregnancy rate following timed artificial insemination (TAI) with frozen-thawed semen in cows. The study was carried out in cows at different villages of KwaZulu-Natal (KZN; n = 160) and Limpopo provinces (L; n = 171). Cows were selected randomly as presented by the farmers, regardless of parity, age, breed and body weight following pregnancy diagnosis. The cows were grouped according to breed type and body condition score (BCS) on a scale of 1 - 5. Selected cows were inserted a controlled intravaginal drug release (CIDR®) and removed on day 8, followed by administration of prostaglandin. Heat was observed on day 9 with the aid of heat mount detectors (HMD) that were placed on the individual cow’s tail head. Cows on heat were then inseminated twice at 12 hours interval. Pregnancy diagnosis was performed by an ultra-sound scanner and rectal palpation 90 days after TAI. Data were analyzed using SAS 2006. Estrous responses were 100% in KZN and 99% in Limpopo. The lowest pregnancy rate was recorded in Brahman and Bonsmara type cows with BCS ≤ 2.5 regardless of province. Interestingly, Nguni type cows with BCS ≤ 2.5 had higher average pregnancy rate of 59.5% in Limpopo and 53.5% in KZN. However, cows with BCS ≥ 3 had better pregnancy rate regardless of breed type and province. In conclusion, village cows can be synchronized successfully and inseminated with frozen-thawed semen. However, pregnancy rates are low in cows with lower body condition. Village Nguni type cows were not affected by body condition scoring as they had higher and similar pregnancy rate as those that had body condition of ≥3.

Abstract The objectives of the current study were to evaluate the estrous response and pregnancy rate following timed artificial insemination (TAI) with frozen-thawed semen in cows. The study was carried out in cows at different villages of KwaZulu-Natal (KZN; n = 160) and Limpopo provinces (L; n = 171). Cows were selected randomly as presented by the farmers, regardless of parity, age, breed and body weight following pregnancy diagnosis. The cows were grouped according to breed type and body condition score (BCS) on a scale of 1 - 5. Selected cows were inserted a controlled intravaginal drug release (CIDR®) and removed on day 8, followed by administration of prostaglandin. Heat was observed on day 9 with the aid of heat mount detectors (HMD) that were placed on the individual cow’s tail head. Cows on heat were then inseminated twice at 12 hours interval. Pregnancy diagnosis was performed by an ultra-sound scanner and rectal palpation 90 days after TAI. Data were analyzed using SAS 2006. Estrous responses were 100% in KZN and 99% in Limpopo. The lowest pregnancy rate was recorded in Brahman and Bonsmara type cows with BCS ≤ 2.5 regardless of province. Interestingly, Nguni type cows with BCS ≤ 2.5 had higher average pregnancy rate of 59.5% in Limpopo and 53.5% in KZN. However, cows with BCS ≥ 3 had better pregnancy rate regardless of breed type and province. In conclusion, village cows can be synchronized successfully and inseminated with frozen-thawed semen. However, pregnancy rates are low in cows with lower body condition. Village Nguni type cows were not affected by body condition scoring as they had higher and similar pregnancy rate as those that had body condition of ≥3.

Abstract The objectives of the current study were to evaluate the estrous response and pregnancy rate following timed artificial insemination (TAI) with frozen-thawed semen in cows. The study was carried out in cows at different villages of KwaZulu-Natal (KZN; n = 160) and Limpopo provinces (L; n = 171). Cows were selected randomly as presented by the farmers, regardless of parity, age, breed and body weight following pregnancy diagnosis. The cows were grouped according to breed type and body condition score (BCS) on a scale of 1 - 5. Selected cows were inserted a controlled intravaginal drug release (CIDR®) and removed on day 8, followed by administration of prostaglandin. Heat was observed on day 9 with the aid of heat mount detectors (HMD) that were placed on the individual cow’s tail head. Cows on heat were then inseminated twice at 12 hours interval. Pregnancy diagnosis was performed by an ultra-sound scanner and rectal palpation 90 days after TAI. Data were analyzed using SAS 2006. Estrous responses were 100% in KZN and 99% in Limpopo. The lowest pregnancy rate was recorded in Brahman and Bonsmara type cows with BCS ≤ 2.5 regardless of province. Interestingly, Nguni type cows with BCS ≤ 2.5 had higher average pregnancy rate of 59.5% in Limpopo and 53.5% in KZN. However, cows with BCS ≥ 3 had better pregnancy rate regardless of breed type and province. In conclusion, village cows can be synchronized successfully and inseminated with frozen-thawed semen. However, pregnancy rates are low in cows with lower body condition. Village Nguni type cows were not affected by body condition scoring as they had higher and similar pregnancy rate as those that had body condition of ≥3.

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