115 EFFECT OF FEED SUPLEMENTATION ON PREGNANCY RATE AND EMBRYONIC SURVIVAL IN ALPACAS (VICUGNA PACOS)

Abstract

Alpacas, like all camelids are induced ovulators which means mating is required to induce ovulation. Studies over the last decades have clearly established the link between nutrition and ruminant fertility. These animals live above 4000 m with a deficient quality and quantity of pastures and with a rate of birth less than 50%. The study was carried out with the objective to evaluate feed supplementation before service on the pregnancy rate and embryonic survival in alpacas. One hundred ninety-four alpaca adults of 4–6 years were assigned to 4 treatments: T1 (n = 49): alpacas lactating with supplementation; T2 (n = 48): alpacas lactating without supplementation; T3 (n = 49): alpacas non-lactating with supplementation and T4 (n = 48): slpacas non-lactating without supplementation. Body weight and body condition score were measured before the initiation of the experiment and every two weeks. Animals in T1 and T3 were supplemented with 2 kg of alfalfa hay and 500.00 UI mL–1 of vitamin A, 75 000 UI mL–1 vitamin D3 and 500 mg mL–1 vitamin E four weeks before the initiation of the experiment. Animals were maintained on Festuca dolichophylla and Calamagrostis vicunarum grasses. Ultrasound examinations with a rectal probe of 7.5 MHz were performed on mating day (Day 0) and Days 2, 9, 20, 30, and 60 after mating. Pregnancy rate was evaluated with a Fisher test. Follicular size before mating was 9.1 ± 0.7, 8.3 ± 0.5, 8.2 ± 0.6 and 7.9 ± 0.8 mm for T1, T2, T3, and T4; differences between T1 and T4 were significant (P < 0.05); corpus luteum size: 13.6 ± 1.1; 11.2 ± 0.9; 11.6 ± 1.3 and 10.8 ± 1.9 mm for T1, T2, T3, and T4; different T1 and T3 and T4 (P < 0.05); conception rate on Day 20: 65.6; 51.7; 52.9 and 51.1% for T1, T2, T3, and T4 different between T1 with respect to T2, T3, and T4 (P < 0.05). Day 30: 62.5; 37.9; 47.1 and 33.3% for T1, T2, T3, and T4 different T1 with respect to T2, T3, and T4 (P < 0.05); D60: 62.5; 34.5; 47.1 and 30.3% different for T1 with respect to T2, T3, and T4 (P < 0.05). Feed supplementation before mating was important to conception rate on Day 20 but appeared to be more important to embryo and fetal survival.