Composition of White Rhinoceros Colostrum and Changes During Early Lactation to Mature Milk

The proximate composition of milk from seven free-ranging white rhinoceroses during the first 20 days of lactation is reported with detailed analysis of minerals and fatty acids. The composition of colostrum (day 1) is marked by a high content of dry matter at 23.8 g/100 g milk, mainly consisting of 18.0 g/100 g proteins, 5.6 g/100 g lactose, 0.6 g/100 g fat, 0.7 g/100 ash and 0.2 g/100 g NPN. The major minerals consisted of 24.0 mg/100 g Na, 55.2 mg/100 g K, 33.4 mg/100 g Ca, 10.3 mg/100 g P, 10.1 mg/100 g Mg and 0.4 mg/100 g Zn. The gross energy was 123.2 kCal/100 g. On day 2 the dry matter decreased to 11.9 g/100 g, specifically the ash and protein, and an increase of lactose, Ca and P. The change from colostrum to milk was complete at day two and transitional changes continued to day 5. Changes up to twenty days were minimal with lactose as main component at 6.6 g/100 g, followed by 1.3 g/100 g protein, 1.0 g/100 g fat, 0.2 g/100 g ash, 0.1 g/100 g NPN, 5.6 mg/100 g Na, 15.0 mg/100 g K, 53.3 mg/100 g Ca, 19.9 mg/100 g P and a gross energy of 41.4 kCal/100 g. At days 3 and 4 of lactation the fat content of the rhinoceros milk peaked at 1.6 g/100 g milk. The milk fatty acid composition was characterized by a high saturated content of 68-82%. Capric-, lauric, myristic, and palmitic fatty acids were the major fatty acids, followed by oleic- and linoleic acids. Caprilic- and capric acid, as well as the sum of medium chain fatty acids content, steadily increased to stabilize after day 5. The Δ9-desaturase 16 and -18 indexes reached peak activity at days 2-3 of lactation.