Variations in milk yield and composition of pastured crossbred (West African Dwarf X Yankasa) ewes in the humid tropics, Southern Nigeria

Abstract

The aim of this experiment was to determine the milk yield and composition of lactating crossbred ewes grazed extensively on pastures. Eight crossbred (West African dwarf x Yankasa) ewes in their 4th parity with single lamb were used. The animals grazed on a pastureland which forage composition included carpet grass (Axonopus compressus), guinea grass (Panicum maximum), elephant grass (Pennisetum purpureum) Urena lobata, Palisota hirsute, Manniophyton fulvum and Gliricidia sepium. Milking commenced 8 days post-partum. The animals were milked once a week for eleven weeks to determine milk yield and composition. Milk samples were analyzed weekly for proximate and mineral constituents. The caloric values of the milk were calculated. There were significant differences (p<0.05) in weekly milk yield (87.41 – 617.37g/d), total solids (16.95 - 19.52%), butter fat (7.77 – 8.74%), protein (4.40 - 5.15%), lactose (4.25 - 5.23%), solids-not-fat (8.20 - 9.75%), ash (0.72 – 0.83%), energy (4.62 - 5.15 MJ/kg), calcium (0.20 – 0.56%) and potassium (0.09 – 0.13%). Values for milk yield and constituents obtained in this study were comparable and in some parameters higher than those reported for milk of small ruminants whose diets were supplemented with concentrate. Thus, depending on forage composition, crossbred (West African dwarf x Yankasa) ewes can produce high milk yield with optimal nutrient composition.