The proportion of female alpacas ovulating, conceiving and remaining pregnant up to 40 days after copulation was evaluated using progesterone concentrations. One hundred and seventy six parous, postpartum alpacas 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. Blood 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 ovulating at Days 10 ( 40 62), 20 ( 40 52) or 30 ( 52 62) postpartum; however, frequency of breeding did not increase the number of females ovulating. There was significant difference in the proportion of females conceiving 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 of progesterone of ovulating females (4.2 ng ml-1), conceiving females (3.1 ng ml-1) and females remaining pregnant (1.4 ng ml-1), compared with the overall mean of 0.4 ng ml-1 for females that did not ovulate, did not conceive and that experienced embryonic mortality. Altogether, these results suggest that breeding as early as Day 10 postpartum does not yield acceptable fertility rates as compared with breeding on Days 20 or 30 postpartum, and that repeated breeding does not increase the number of females ovulating or conceiving. © 1995.
Bravo, P. W., Pezo, D., & Alarcon, V. (1995). Evaluation of early reproductive performance in the postpartum alpaca by progesterone concentrations. Animal Reproduction Science, 71-77. https://doi.org/10.1016/0378-4320(94)01374-U