Live weight and body condition changes in dry cows at pasture and effects on subsequent performance

Abstract

During a 720-d experiment in a Holstein and Brown Swiss herd, two feeding regimens were compared during the grazing phase of dry cow management until confinement before expected calving.The two treatments involved rotational grazing (24-d cycles) at a stocking rate of 2.5 animals per hectare in; (A) all-grass swards or (B) all-grass plus 3 h daily access to swards of Leucaena leucocephala and grasses, Large heifers were added as needed to maintain constant group size at pasture. A daily supplement of 2 kg/head of bulky concentrate was fed. During the first 19 mo of the study, while rainfall was adequate, dry cows in treatments A and B gained live weight (LW) satisfactorily (0.69 ± 0.26 and 0.67 ± 0.23 kg/d) and increased in body condition score (BCS) on a scale of 1 to 5 at rates of 0.40 and 0.34 point/100 d, respectively. During the final 5 mo, pasture conditions and LW gains were poor because of prolonged drought. Monthly rainfall of 50 mm or more maintained grazing conditions adequate for use with the present level of supplemental feeding. There were no differences (P > 0.05) between treatments. Under common postpartum management, standard 305-d lactational milk yields were unaffected by previous treatments A or B. However, a positive trend (P < 0.10) was associated with higher prepartum BCS. Cows that scored 3.5 produced 4,013; 4,111; 4,367; 4,627 and 4,450 kg, respectively. Postcalving reproductive performance was not affected by previous treatment or by BCS prepartum or BCS at 6 wk postpartum.