Abstract
The gestation period in ferrets lasts 42 days (range 38-42). Numerous cases of maternal and paternal cannibalism have been reported, so it is important for breeders to know the exact date of parturition in order to separate the mother from the other ferrets in the herd. Fetal ultrasonographic biometry and specific formulae for assessing fetal growth have not yet been developed in ferrets as they have been in dogs and cats. The aim of this study was to develop a formula, similar to those available for other domestic species, that could be used in ferrets to date the birth of a litter to within one day. Among the different ultrasonographic parameters, the biparietal diameter (BP) gave a very accurate prediction and showed a significant relationship with days before parturition. The formula developed could allow better planning of care before, during and after parturition, thus helping to reduce neonatal mortality.