CHANGES DURING LACTATION IN THE COMPOSITION OF THE MILK OF THE BLACK RHINOCEROS Diceros bicornis

Summary 1. Samples of milk were obtained from a lactating rhinoceros five hours, 12 hours, 28 hours, 52 hours, two weeks and four weeks after the birth of the calf. Subsequently, samples were collected at monthly intervals until the calf was removed after sixteen months. 2. The total solids, fat, protein and lactose contents of the samples were determined. The fat content of the milk was low (0.45 per cent) throughout lactation. That of lactose was lower in colostrum (4.38 per cent) than in mature mdk (6.1 to 6.9 per cent), and that of the protein decreased from 6.4 per cent in colostrum to between 1 and 1.65 per cent in the milk. 3. Variations in the contents of acid, calcium, pantothenate, riboflavin, thiamine, Vitamin b6, Vitamin b12 and biotin in the milk were measured. Those of biotin, Vitamin b12 and pantothenate showed marked fluctations from month to month. That of riboflavin remained low in the milk, having been high in colostrum. The Vitamin b6 and thiamine contents both decreased during the first few months of lactation and then increased gradually.