8 RESPONSE OF COMMUNAL COWS TO OESTRUS SYNCHRONIZATION AND TIMED ARTIFICIAL INSEMINATION

Abstract

Reproductive technologies such as oestrus synchronization and AI have been tested in controlled environments in the commercial farms in South Africa but not in an uncontrolled communal setup. The aims of the study were to evaluate the response of communal cows to oestrus synchronization and timed AI. The effects of age and body condition score (BCS) on oestrus response and conception rate were also studied. A total of 96 cows were selected from the communal villages. Cows with the BCS of 2.5 to 4.5 (on a scale of 1–5) and age between 3 and 10 years were used. Cows were grouped into 2 BCS groups (<3 and = 3) and 2 age groups (<6 and = 6). All groups were subjected to a 9-day Ovsynch + CIDR (CIDR®; Pfizer Laboratories, New York, NY, USA) protocol. A CIDR® was inserted into the vagina on Day 0 (random days of the cycle), and 2 mg of oestradiol benzoate (Ciderol®; Pfizer Laboratories) was administered. On Day 8, the CIDR® was removed, and the cows were administered with 500 μg of cloprostenol (PGF; Estrumate®, Schering-Plough Animal Health). In addition, on Day 9, cows were given 1 mg of oestradiol benzoate, and a heat mount detector (Karma®; Four Lakes) was placed on the tail head of the cows to detect oestrus response (standing heat). All the synchronized cows were then inseminated at 36 and 42 h with frozen-thawed Nguni bull semen following oestradiol benzoate injection. Pregnancy diagnosis was performed 90 days following timed AI using ultrasound scanner and transrectal palpation. Data were analysed using ANOVA. An overall 73% oestrus response and 45% conception rate were achieved in this study. There was no significant difference in oestrus response in cows with a BCS <3 (67%) and = 3 (83%) or age <6 (77%) and = 6 (72%). There was no significant difference in conception rate between those <6 (41%) and = 6 (47%) years of age. However, cows with a BCS of = 3 had greater (P < 0.05) conception rate (55%) compared with those with a BCS <3 (35%). In conclusion, communal cows responded to an oestrus synchronization program involving timed AI. The BCS and age did not alter the oestrus response, but conception rate was higher in communal cows with BCS of = 3.