Desempeño reproductivo en el primer y segundo servicio en borregas Pampinta

Abstract

The study aimed to evaluate the reproductive performance of lambs and sheep of the Pampinta breed during their first and second service, especially considering the body condition of the animals and the seminal quality of the rams used. The work was carried out between 2015 and 2023 at INTA’s Anguil Experimental Station, located in the province of La Pampa. For the first service, seven-month-old lambs were used, previously selected for their body condition (2.5 to 3) and good physical development. As a reproductive management strategy, a feeding plan of type flushing with corn grains for fourteen days prior to service was implemented and the male effect was applied forty-eight hours before the start of the confinement. The service was carried out in a corral, with a duration of thirty-seven days, and the pregnancy assessment was made by ultrasound. Also, the rams used were selected phenotypically and submitted to a physical and seminal examination, with no records of rejection due to low sperm quality. The results showed an average pregnancy rate of 74.7% in the first service and 93.1% in the second, this difference being statistically significant (P<0.05). As for calving, the lambs reached 68% while the ewes reached 92%. There were no significant differences in fertility between the two categories, with about half of births being twins, 35% single births and 10% triplets. It is important to note that the early reproductive experience of the lambs did not negatively affect their performance in the second service. Overall, second-parturition lambs' pregnancy ranged from 90% to 96%, showing that with proper management of body condition, nutrition and health, it is possible to achieve high reproductive rates without compromising future animal productivity. The Pampinta breed showed a favorable early reproductive behavior, which allows to advance the first incarnation and improve the overall efficiency of the production system.