Morphological and functional events associated to weaning in rabbits

Abstract

It is acknowledged that the most critical period of rabbit post natal development comprises the first 10-15 days after weaning, when the animals are most susceptible to gastrointestinal infections and at greatest risk of a fatal outcome. Detailed information on rabbits' weaning is provided. The advantages and disadvantages of early weaning (under 23 days of age) are summarised. Regardless of the numerous reports, the effects of early weaning on the growth and development of bunnies and the physiological status of rabbit does are contradictory. The morphological changes in rabbit digestive tract related to weaning - development of intestinal mucosa, height of villi, crypt depth and villus height to crypt depth ratio - are described in detail. The review also goes over several functional changes in rabbits' organism during weaning: blood cholesterol, triglycerides, α-amylase, lysozyme, complement, triiodothyronine and thyroxine concentrations, and the time course of epidermal growth factor in the milk of lactating does. Based on published research reports, both ours and of other authors, we suggest that from a physiological point of view, the early weaning of rabbits is not fully justified at present. Nevertheless, the increasing market demand for rabbit meat makes early weaning an attractive alternative for farmers and necessitates further studies on the optimisation of weaning in this species.

Keywords: early weaned rabbits; morphological and functional events; thyroid hormones.