113 EFFECT OF SOME FACTORS ON CONCEPTION RATE IN ALPACAS UNDER PERUVIAN HIGHLAND CONDITION

Abstract

Alpacas are a domestic species of South American camelids with a great importance to highland people because of their high-quality fibre production. However, their reproductive performance has been reported to be poor, with a birth rate of 50% under the Andean community’s conditions. Two experiments were designed to evaluate the effect of some factors on the pregnancy rate of alpacas at first service in lactating, 3- to 8-years old, without parity problems. The objective of the first experiment (n = 85) was to evaluate the effect of age (G1: 3, G2: 4 to 5, G3: ≥ 6 years old); mating time (G1: 15 min, G2: 16–24 min, G3: ≥ 25 min), and interval from parturition to mating (G1: 20 days, G2: ≥ 20 days) on first service conception rate. A second experiment (n = 174) evaluated the effect of month of calving (January, February, or March) on conception rate in females with a postpartum interval ≥20 days. Animals were mated with male of good fertility after a receptivity test and confirmation of presence of a dominant follicle ≥7 mm by ultrasonography. Pregnancy was determined by ultrasonography 25 days after mating. Proportional data were compared by Fisher’s exact test. In the first experiment, conception rates were 57.9, 66.7, and 47.2% in females of G1, G2, and G3, respectively (P ≤ 0.05); 50.0, 54.5, and 59.0% in females with mating time of 15, 16–24, or ≥ 25 min of mating; 48.0 and 59.4% in those with a postpartum interval <20 days and ≥20 days (P ≤ 0.05). In the second experiment, conception rates were 58.3, 70.7, and 82.1% in alpacas calving in January, February, and March, respectively (P ≤ 0.05). The results suggest that age of female, postpartum interval, and month of calving are factors that affect conception rates in alpacas. Therefore, a reproductive management system that includes these factors would improve the pregnancy rate in alpacas under highland Peruvian conditions.