Comparison of two breeding systems for timing of whelpings in farmed silver foxes (Research Note)

Abstract

Two principally different mating systems are practised for farmed silver foxes. In the traditional system the breeding females are kept all the time in cages well separated from each other. In the Nordic system, on the other hand, the breeding females are transferred prior to mating time into a separate shed where they are placed close to each other and sometimes males are put among them. After artificial insemination (AI) or natural matings, the females are transferred in the mating order to new cages. The condensed premating grouping is assumed to enhance the effect of air-borne male and female pheromones leading to a more intense and synchronised heat development. In this study these two systems were compared for timing and synchrony of parturitions. In contrast to the working hypothesis, date of whelpings were positively skewed with a great kurtosis in the traditional system, an indication that the majority of deliveries occurred during a short period and at the beginning of the season. On the other hand, in the Nordic system the whelpings were more uniformly distributed over the whole season and the peak was later. The results show that the most recent system, although widely used, is not necessarily the only possible alternative but other alternatives should also be considered. ;