TASAS DE CONCEPCIÓN EN VACAS CON CRIA AL PIE UTILIZANDO PROTOCOLOS CON ESTRÓGENOS O GnRH PARA SINCRONIZAR LA OVULACIÓN

ZAPATA, LUIS; ROMERO HARRY, HERNÁN; FARCEY, MARÍA FLORENCIA; BAIERBACH, ROMINA; GELID, LUCAS; BORREGO, CHRISTIAN DARÍO; REGALADO, JUAN MANUEL; BILBAO, MARÍA GUILLERMINA; BARTOLOMÉ, JULIÁN

Ciudad Autónoma de Buenos Aires

Congreso; I CONGRESO DE LA SOCIEDAD LATNIOAMERICANA DE REPRODUCCIÓN ANIMAL; 2015

SOCIEDAD LATINOAMERICANA DE REPRODUCCION ANIMAL

The objective was to compare the effect of two synchronization protocols on conception rate of suckled beef cows with more than 30 days postpartum and good body condition score. Cows in group 7-days (n = 136) received an intravaginal progesterone device and estradiol benzoate on Day 0; device removal, PGF2α and estradiol cypionate on Day 7 and TAI on Day 9. Cows in group 5-days (n = 142) received an intravaginal progesterone device and GnRH on Day 1; device removal and two doses of PGF2α (24 h apart) on Day 6 and GnRH plus TAI on Day 9. After TAI cows were reassigned to the same protocols for resynchronization. Ultrasonography was conducted on 28-29 days post-TAI. Dependent variable was conception rate and independent variables were synchronization group, re-synchronization group, stages of estrous cycle at Day 0, postpartum days and sire. Statistical analyses were conducted using SAS. Univariate analyses showed a significate effect of sire on conception rate. Multivariate analyses showed that 5-days synchronization protocol and sire tended to affect conception rate. In summary, 5-days protocol (63,9 %) would enhance conception rate compared to 7-days protocol (54,7 %) in suckled beef cows in good body condition score and with more than 30 days postpartum.