Effect of whole-crop barley and oat silages on the performance of mature suckler cows and their progeny in outdoor winter feeding

The ME values of G, B and O evaluated by the in vivo method were 11.2, 10.5 and 9.5 MJ/kg DM, respectively. The DM intake on diets G, B and O averaged 9.2, 10.5 and 10.3 kg which resulted in ME intakes of 102, 109 and 97 MJ ME/d, respectively. The type of roughage affected the in vivo apparent protein digestibility co-efficients which for G, B and O were 0.841, 0.698 and 0.498, respectively (G versus B, P < 0.05; G versus O and B versus O, P < 0.01). The initial cow body condition score (BCS) averaged 3.2 (S.D. 0.23). Pre-grazing the change of BCS and the live weight gain (LWG) for G, B and O cows was on average 0.23, 0.09 and −0.39 (G versus O and B versus O, P < 0.001) and −20, −9 and −56 kg (G versus O, P < 0.05; B versus O, P < 0.01), respectively. All calves were born before the grazing season and milk and grass were the sole feeds at pasture. The pre-weaning calf LWG was not affected by the diets averaging 1357 g/d. The daily milk yield on diets G, B and O averaged 11.4, 10.3 and 9.5 kg (G versus O, P < 0.05), respectively. Forty-two out of 48 cows entered the mating period of which all were observed to be pregnant. The interval from calving to conception averaged 89 days. B and O proved to be suitable winter feeds for mature suckler cows in cold winter circumstances. Especially O had a lower energy and protein content than G but fulfilled the energy and protein demands of mature, pregnant beef cows in good body condition.