The aim of this work was to evaluate the effects of long-acting progesterone (LAP4) administered in the early stages of gestation on plasma P4 concentration and pregnancy and embryonic / fetal mortality rates between 30 and 60 days of gestation. Adult females (n = 92) with the presence of an ovarian follicle >7 mm were naturally mated with males of proven fertility (day -2). At day 0, ovarian ultrasonography was performed to confirm the occurrence of ovulation. On day 2, females that ovulated were assigned to receive a dose of 50 mg IM of LAP4 (LAP450, n = 26), 100 mg of LAP4 (LAP4100, n = 22), or 5 ml of saline (Control, n = 25). Pregnancy diagnosis and gestational losses were determined by ultrasonography at 30 and 60 days of gestation. Blood samples were collected on days 0, 3, 7, 10 and 14 after ovulation to determine the plasma P4 concentration by microparticle chemiluminescence ...

The aim of this work was to determine the sex ratio of the offspring born from ovulations of the left or right ovaries in naturally mated llamas. Females (n=188) with the presence of an ovarian follicle ≥7 mm received controlled natural mating (Day 0). Ovulation was confirmed on day 2 by the disappearance of the ovarian follicle (n=146). Then, 104 (71.2%) females diagnosed pregnant by ultrasonography were obtained 40-45 days after mating. The mating and calving date, sex and body weight of the calf at birth were recorded in 92 individuals. The overall sex ratio of the offspring and the sex ratio of the offspring from each ovary were compared using the Chi-square goodness-of-fit test, with the expected ratio being 1:1. Ovulations from both ovaries produced a similar (p=0.14) proportion of calves born and the male: female ratio was similar. However, more male offspring originated from th...