159 COMPARISON BETWEEN EQUINE CHORIONIC GONADOTROPIN AND PORCINE FOLLICLE STIMULATING HORMONE FOR IN VIVO PRODUCTION OF EMBRYOS IN ALPACAS (VICUGNA PACOS) SHOWING NATURAL LUTEAL PHASE AFTER INDUCTION OF OVULATION

Abstract

Alpacas are animals with induced ovulation, andthey show high individual variation in the symptoms, duration, and regularity of oestrus or period of female receptivity to males; their follicular phase does not end in ovulation and subsequent luteal phase unless an external stimulation such as copulation or exogenous application of an ovulation inducing hormone is applied. The objective of the present study was to compare the use of eCG v. porcine (p)FSH as superovulatory hormones for the in vivo production of embryos in alpacas that were selected as being receptive to the male and were treated with an ovulation-inducing hormone to generate a luteal phase. Twenty adult (3 to 5 years old) female alpacas, located at Mallkini, Puno, Peru (at 4100 m elevation), were used for the trial. A group of females was exposed to males to test for breeding receptivity; 20 alpacas were receptive, adopting copulatory position. Each of the selected females received 3.75 mg of LH IM (Lutropin^®, Bioniche Animal Health, Belleville, ON, Canada). Day 0 was then considered the date of LH injection. The 20 alpacas were then distributed into 2 treatments: Treatment 1 (T1 = 10 alpacas) received on Day 2, 1000 IU of eCG IM (Pregnecol^®, Bioniche Animal Health) and on Day 7, a dose of PGF_2α IM (0.263 mg of cloprostenol; Ciclar^®, Andeanvet-Zoovet, Lima, Peru). Treatment 2 alpacas (T2 = 10 alpacas) received from Day 2 and up to Day 5, at 12-h interval, decreasing doses of pFSH IM (100 mg; Folltropin V^®, Bioniche Animal Health) for 4 days, and on Day 7, a dose of PGF_2α IM (0.263 mg of cloprostenol; Ciclar^®, Andeanvet-Zoovet). All alpacas from T1 and T2 were mated twice with fertile males, the first mating at 24 h after the injection of PGF_2α and the second at 12 h after the first mating. All females received a dose of GnRH IM (0.0084 mg of buserelin; Buserelina^®, Andeanvet-Zoovet) at time of first mating. The embryos in both treatments were collected 6.5 days after the first mating by nonsurgical transcervical embryo flushing. There were no significant differences in the mean number of blastocysts collected per treatment (P > 0.05), being 3.0 ± 2.87 blastocyst for T1 and 1.6 ± 2.67 for T2. The number of blastocysts per treatment was 30 and 16 for T1 and T2, respectively. The results show that superovulatory treatment with eCG is more effective for the production of viable blastocysts than treatment with pFSH in alpacas treated for superovulation during the luteal phase.