THE COMPOSITION OF RABBIT'S MILK.

Abstract

As part of a project on hand-rearing baby rabbits, it was necessary to know the composition of rabbit’s milk so that a suitable milk-substitute diet could be prepared. The gross chemical composition of rabbit’s milk has been studied in some detail by Folin, Denis & Minot (1919), Bergman & Turner (1937) and Neumeister & Krause (1956), but little is known about its vitamin content. We have therefore analysed samples of milk taken from New Zealand White and Chinchilla rabbits at different stages in the lactation cycle and report here their chemical composition and vitamin content. EXPERIMENTAL Milk samples Samples of milk were obtained from one Chinchilla and seven New Zealand White rabbits. Litters were removed from the lactating does on the evening before the sample was taken. The following morning each doe was given 2.5 i.u. oxytocin by injection into the ear vein and milk was expressed by gently massaging the mammary tissue. Milk flow usually began about 3 min after the injection and continued for about 15 min. Up to the 20th day of lactation volumes of 1-35 ml per doe were obtained, the average being about 20 ml; only very small quantities of milk could be expressed from does in later stages of lactation. Samples of colostrum were taken within 24 h of the birth of the litter. For full chemical and vitamin analysis of some of the samples, the milks from two rabbits at similar stages of lactation were bulked. In this way two mixed samples representing the 1st and 3rd weeks of lactation were obtained. Other samples were analysed individually. A portion of each sample (usually 5 ml) was set aside for chemical analysis. The remainder was weighed and centrifuged and the cream layer was removed, weighed and used for the measurement of vitamin A. The fat content of the cream, and thus of the whole milk, was determined. The water-soluble vitamins were measured microbiologically in the skim milk, but the results were recalculated in terms of whole milk.