EVALUATION OF EARLY REPRODUCTIVE-PERFORMANCE IN THE POSTPARTUM ALPACABY PROGESTERONE CONCENTRATIONS

The proportion of female alpacas ovulating, conceiving and remaining p regnant up to 40 days after copulation was evaluated using progesteron e concentrations. One hundred and seventy six parous, postpartum alpac as were divided into three groups for breeding at 10, 20, and 30 days postpartum at the La Raya research station, Cusco, Peru. Females were further subdivided into three groups to allow copulation once, twice, or three times at 24-h intervals, within different postpartum times. B lood samples were collected at time of breeding, at Day 7 (ovulation), at Day 21 (conception), and Day 40 (pregnancy) from all females after breeding. Progesterone analysis was performed by enzyme immunoassay. There was significant difference in the proportion of females ovulatin g at Days 10 (40/62), 20 (40/52) or 30 (52/62) postpartum; however, fr equency of breeding did not increase the number of females ovulating. There was significant difference in the proportion of females conceivi ng at Days 10 (25/40), 20 (35/40), and 30 (47/52) postpartum, compared with females ovulating at the three times of breeding. There was also a significant difference in the number of females in which pregnancy was sustained at Day 40 when bred at 10 (19), 20 (31) and 30 (44) days postpartum. There were significant differences in the concentration o f progesterone of ovulating females (4.2 ng ml(-1)), conceiving female s (3.1 ng ml(-1)) and females remaining pregnant (1.4 ng ml(-1)), comp ared with the overall mean of 0.4 ng ml(-1) for females that did not o vulate, did not conceive and that experienced embryonic mortality. Alt ogether, these results suggest that breeding as early as Day 10 postpa rtum does not yield acceptable fertility rates as compared with breedi ng on Days 20 or 30 postpartum, and that repeated breeding does not in crease the number of females ovulating or conceiving.