Effect of Stage of Lactation on Nutrient Composition of Tswana Sheep and Goat's Milk

Abstract

Seven Tswana goats and seven Tswana sheep suckling single (male or female) kids or lambs were milked to obtain information on the milk composition of Tswana goats and ewes under semi-intensive management. The milk samples collected were from does and ewes 40–166 days post-partum. The aim of this study was to document the chemical composition of Tswana goat and sheep's milk and the effect of stage of lactation on the nutrients. Milk samples were analysed for fat, crude protein (CP) ash, total solids (Ts), acidity, albumin, casein, calcium, magnesium, phosphorus, potassium, sodium, copper, iron, zinc and manganese. The mean values of fat in g/100 g were: goats 4.40 and sheep 3.67, 40 days post-partum and goats 5.42 and sheep 4.71, 166 days post-partum, which was the end of the lactation period. Total solids had a mean of 12.10 for goats and 15.02 for sheep at 40 days and goats 18.19 and sheep 21.34, at 166 days, which was end of lactation period. The mean concentration of minerals fluctuated in both species' milk throughout the lactation period. The results indicated that Tswana ewe's milk contained more nutrients except for fat irrespective of lactation stage than Tswana doe's milk. Regarding minerals, goat's milk showed higher contents of Fe and Mn, whereas that of sheep contained more Ca, Mg, and P. The contents of Na, K and Zn were almost the same in both species. Cu was generally higher in goat's milk. There was significant species difference ( P<0.05) in Ts, CP, ash and fat.