Extended lactations in a seasonal-calving pastoral system of production to modulate the effects of reproductive failure

Milk production and component profiles during the 22-mo extended lactation of cows offered low (3kg) or high (6kg) levels of concentrate supplement during the winter confinement housing period. The approximate times of the first breeding season (BS 1), the winter feeding treatment (WF), and the second breeding season (BS 2) are indicated by the solid bars.

The effect of winter feeding treatment (high, ■; low, □) on daily milk yield in extended lactations in a seasonal-calving pastoral system. Significant effects of treatment (P<0.001) and week (P<0.001) were observed, but not for the interaction between treatment and week (P=0.1). The pooled SEM was 0.63 kg/d.

Milk production and component profiles during the 22-mo extended lactation of cows separated into 3 ranks based on cumulative milk solids production (CMSP) during the entire lactation period in a seasonal-calving pastoral system. The approximate times of the first breeding season (BS 1), the winter feeding treatment (WF), and the second breeding season (BS 2) are indicated by the solid bars. R1=15 highest CMSP; R2=15 intermediate CMSP; and R3=16 lowest CMSP.