Evaluation of two intravaginal implants for the synchronization of estrus in Criollo cattle in Peru

The objective of this study was to compare the effect of two vaginal implants protocols on the follicular characteristics, the vaginal electrical resistance and the pregnancy rate of criollo cattle reared in altitude (3100 meters).
All the cows (n=53) were selected after manual palpation and ultrasound examinations of their genital tract. All the cows had a body condition between 2.5 and 3.5 (range 1 to 5). On day 1 et for 7 days the first group of cows (n=23) was treated with 1,38 g of progesterone (Easi-breedTM CIDR® Zoetis) and the second group (n=30) with 1 g of progesterone (DIB system Agrihealth New Zealand). All the cows were treated at day 1 with 2 mg of estradiol benzoate (im), at day 9 with 2 ml of prostaglandin (im) and at day 10 with 1 mg of estradiol benzoate. A timed artificial insemination was realized 54 hours after the CIDR® or DIB removal. The pregnancy diagnosis was made by ultrasound 45 days later. Vaginal conductivity, diameter and perimeter of the follicle were measured at the time of insemination.
There were no significant differences (p> 0.05) between both treatments in the electrical resistance of the vaginal mucus, diameter and perimeter of the preovulatory follicule. The averages of these variables respectively were 233 ± 36 ohms, 9.1 ± 1.9 mm and 24.6 ± 4.7 mm. Pregnancy rates of cows treated with DIB and CIDR respectively were 63.3 % and 69.6%. No significant statistical differences (p> 0.05) have been seen. In conclusion, both treatments showed similar ovarian response, electrical resistance and pregnancy rate in criollo cattle reared in altitude.