Authors : G. Martinez, P. Perez, G. Torres, O. Hernandez, J.J. Martinez-Tinajero, O.D. Montanez-Valdez, M.E. Ortega-Cerrilla and R. Rojo-Rubio
Abstract: With the objective to evaluate the efficiency of the Controlled Intravaginal Devices Releasing (CIDR) new and reutilized until a 4th occasion and their effect on the pregnancy rate were studied 594 Brahman multiparous cows with their calves with 468.4±33.9 kg of body weight and with a minimum of 90 days postpartum and Fixed Time Artificial Insemination (FTAI) under humid tropical conditions. The cows were randomly assigned to one out to 8 treatments where the CIDR1A was new and anestrous cows; CIDR1C: new and cyclic cows; CIDR2A: Second use and anestrous cows; CIDR2C: Second and cyclic cows; CIDR3A: Third use and anoestrus cows CIDR3C: Third use and cyclic cows; CIDR4A: Fourth use and anestrous cows; CIDR4C: Fourth use and cyclic cows in the following way T1 (n = 116): CIDR1A+estradiol benzoate (E)+D-Cloprostenol+eCG+AI at detected estrus; T2 (n = 34): CIDR1C+E+D-Cloprostenol+AI at detected estrus; T3 (n = 53): CIDR2A+E+D-cloprostenol+eCG+Fixed Time Artificial Insemination (FTAI); T4 (n = 62): CIDR2C+E+D-Cloprostenol+FTAI; T5 (n = 33): CIDR3A+E+D-Cloprostenol+eCG+FTAI; T6 (n = 67): CIDR3C+E+D-Cloprostenol+FTAI; T7 (n = 41): CIDR4A+E+D-Cloprostenol+eCG+FTAI and T8 (n = 188): CIDR4C+E+D-Cloprostenol+FTAI. The pregnancy rate was different among treatments being 35.3, 61.7, 30.1, 64.5, 21.2, 82.0, 41.4 and 48.9% for T1-T8, respectively. In conclusion, the use of new or reutilized CIDR up to a 4th time plus artificial insemination at fixed time in Brahman cows represents an alternative to synchronize estrus and ovulation to improve gestation percentages.
G. Martinez, P. Perez, G. Torres, O. Hernandez, J.J. Martinez-Tinajero, O.D. Montanez-Valdez, M.E. Ortega-Cerrilla and R. Rojo-Rubio, 2011. Effect on Pregnancy Rate of a Previously Used Progesterone-Releasing Device and Fixed Time Artificial Insemination in Brahman Cows. Journal of Animal and Veterinary Advances, 10: 307-310.