In the study was used 333 15-month-old beef heifers with body condition of 6 on average (scale 1-9). On this, 53.5% presented an active corpus luteum at the beginning of the study. On day 0, an intravaginal device with 0.5 g of progesterone (IVD) was placed and 2 mg of estradiol benzoate was injected. On day 8 the IVD was removed and 0.5 mg of cloprostenol and 0.5 mg of estradiol cypionate were i.m. injected. On day 10, artificial insemination at fixed time (IATF) was carried out, distributing the animals at random to be inseminated in three-time ranges: I) 48-50 h; II: >50-53 h; III) >53-56 h. Frozen semen in 0.5 ml straws was used. Pregnancy diagnosis was performed by ultrasound at 30 days post- IATF. Two animals lost the DISP and were excluded from the analysis. There was no effect on pregnancy rate of the time range in which the IATF was performed after the DISP was removed (I:...

Se utilizaron 333 vaquillonas para producción de carne con 15 meses de edad y condición corporal promedio de 6 (escala 1-9). El 53.5% presentó un cuerpo lúteo activo al inicio del trabajo. En el día 0, se colocó un dispositivo intravaginal con 0.5 g de progesterona (DISP) y se inyectó 2 mg de benzoato de estradiol. El día 8 se retiró el DISP y se inyectó 0.5 mg de cloprostenol y 0.5 mg de cipionato de estradiol i.m. El día 10 se realizó la inseminación artificial a tiempo fijo (IATF), distribuyéndose los animales al azar para ser inseminados en tres rangos horarios: I) 48-50 h; II: >50-53 h; III) >53-56 h. Se utilizó semen congelado en pajuelas de 0.5 ml. El diagnóstico de gestación se realizó mediante ultrasonografía a los 30 días pos-IATF. Dos animales perdieron el DISP y fueron excluidos del análisis. No se observó efecto del rango horario en que se realizÃ...

The aim of this study was to evaluate the effect of a parenteral treatment with vitamins and minerals on the percentage of pregnancy in heifers after a fixed-time artificial insemination (FTAI) scheme as well as to determine possible relationships between the response to the treatment and the Reproductive Tract Score (RTS). A total of 360 heifers from three farms were used (A, B and C). On day 0, the animals were divided into two groups according to their RTS. A group was supplemented via i.m. with a commercial vitamin-mineral complex (V+M Group) and the other one remained as a control group. Simultaneously, an intravaginal device with 0.5 g of progesterone was placed and 2 mg of estradiol benzoate was injected. On day 7, the device was removed and 500 µg of D(+) cloprostenol and 1 mg of estradiol cypionate were injected. The FTAI was performed between 48 and 56 h after the device was r...

The aim of this study was to evaluate the effect of a parenteral treatment with vitamins and minerals on the percentage of pregnancy in heifers after a fixed-time artificial insemination (FTAI) scheme as well as to determine possible relationships between the response to the treatment and the Reproductive Tract Score (RTS). A total of 360 heifers from three farms were used (A, B and C). On day 0, the animals were divided into two groups according to their RTS. A group was supplemented via i.m. with a commercial vitamin-mineral complex (V+M Group) and the other one remained as a control group. Simultaneously, an intravaginal device with 0.5 g of progesterone was placed and 2 mg of estradiol benzoate was injected. On day 7, the device was removed and 500 µg of D(+) cloprostenol and 1 mg of estradiol cypionate were injected. The FTAI was performed between 48 and 56 h after the device was r...