Abstract

Dorset ewes from the Flock House sheep milking flock were used to investigate the effects of season-of-lambing, stage-of-lactation and ewe-age on milk yield and composition. Lambs were removed 4 days after birth and ewes machine milked twice a day. Age of ewe effects were significant (P<0.05) for total and daily milk yield, duration of lactation and concentration of milk solids. Total milk yield increased from two (77 ± 4 L/ewe) to four years (108 ± 3 L/ewe) of age and declined in ewes five years and older (78 ± 4 L/ewe). The concentration of milk solids was highest for ewes five years and older. Ewes lambing in Spring and Winter had higher (P<0.05) total milk yields, durations of lactation and daily yields of milk solids, but lower daily concentrations of milk fat and total milk solids, than Summer and Autumn lambing ewes. Average concentrations of milk fat, milk protein and total milk solids increased as lactation progressed, while lactose concentration, daily milk yield and yield of milk solids decreased. Milk yield, milk solids concentration and milk solids yield can be modified by ewe-age, season-of-lambing and stage-of-lactation.

LS, Gosling, TW Knight, and S-AN Newman

Proceedings of the New Zealand Society of Animal Production, Volume 57, , 212-215, 1997