Quantitative and compositional variations in milk yield of west african dwarf ewes
Twelve lactating ewes were used to study the variations in quantity and composition of milk of WAD ewes over a 12 week lactation period. The ewes were managed intensively, and placed on 1 kg concentrate mixture per animal, in addition to forage. They were given water ad libitum. The week of lactation significantly influenced milk yield (p<0.05). The mean highest yield of 68.86 ±4.80 g was observed in week 1 of lactation. Thereafter, there was a steady decline in milk yield until week 12 at which mean milk yield was 23.53 ±4.80 g. There were variations in all milk constituents across week of lactation, with significant differences in protein, lactose, butterfat, solids not fat and energy (p<0.05). However, total solids, and ash content of milk were not significantly affected by lactation week (p<0.05). Milk protein, lactose ash and butterfat increased with lactation week, while total solids and solids not fat decreased with lactation week. At week 2, the percentage composition of milk protein, lactose, ash and butterfat were 4.60, 3.86, 0.82, and 4.90, respectively. These gradually increased to 5.77, 4.43, 0.99 and 5.15 at week 12. Percentage
composition of total solids and solids not fat of milk were 15 .97 and 11.06 at week 2 and decreased steadily to 15.16 and 6.14 respectively by week 12. These results could serve as baseline information for comparison in conditions of mastitis, nutrient deficiency and changes in environment in WAD ewes kept under intensive management.
Keywords: Quantity, composition, milk, WAD ewes