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Single oral doses of 100 microg kg(-1) cabergoline (CAB) were previously found to affect the reproductive success of silver fox (Vulpes vulpes) vixens from Day 28 post insemination (PI) onwards by causing abortions and postnatal mortality. The present trial investigated the effect of a single oral dose of 100 microg kg(-1) CAB given to farmed silver fox vixens at 7, 14, 21 or 28 days PI. Six vixens were dosed with CAB at each day PI and abortions, total post-partum litter loss and the combined effects of both were compared with a group of vixens that received a placebo and a control group of vixens that received no treatment. No significant difference existed between the placebo and control groups in the incidence of abortion, postnatal litter loss and litter size at 3 weeks post partum. Overall, a significantly higher frequency of abortions were detected in vixens dosed with CAB (6/24) compared with the combined placebo and control (0/41) groups (P<0.01). Cabergoline administration was significantly associated with complete litter loss (P<0.01) and the combined effects of abortion and litter loss (P<0.001). Oral CAB significantly reduced the reproductive success of vixens when given at Day 21 and Day 28 PI, but not at Day 7 and Day 14 PI.

Abstract. The aim of this study was to determine at what level of artificial illumination the best reproduction performance can be achieved, as well as how varied light intensity affects chinchillas of different genetic groups. Reproduction performance was evaluated for 100 Polish, 52 Swedish, and 83 Danish females. Light intensity, measured with a photoelectric light meter LS-200, ranged between 0 and 100 lx. The chinchillas were assigned to 5 groups, 20-lx interval each. The analysis included: mean litter size, mean number of weaned per litter, death rate during nursing, number of litters per female per year, as well as litter size and number of weaned per female per year. For each genetic group, the highest death rate of the young was found at the lowest light intensity level, i.e. 0-20 lx, while the lowest mortality was at 41-60 lx. Both Swedish and Danish chinchillas had lower nursing mortality at a higher level of illumination (61-100 lx), while higher mortality was recorded at lower light intensity (0-40 lx), compared to Polish chinchillas. It can be concluded that light intensity affects chinchilla reproduction, since higher litter sizes and reduced offspring mortality were observed under stronger light. Danish females attained the highest number of litters per year, the largest litter size and the highest number of weaned per year at the light intensity of 61-80 lx, compared to the other genetic groups. Chinchillas proved to be sensitive to very small changes in light intensity.

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