Effect of type of roughage on feed intake, milk yield and body condition of pregnant goats

Abstract

In two experiments, 188 goats were fed roughage diets of barn-dried hay, wilted silage of good quality from tower silos or poor quality silage from aerobically damaged round bales. In addition, they received 400 g concentrate kg −1 milk. Dry matter digestibility varied between 66 and 74% and metabolisable energy kg −1 dry matter were 2.17, 2.31 and 2.51 Mcal for silage of poor quality, hay and good silage, respectively. Voluntary dry matter intake (DMI) of roughage was lower ( P < 0.05) in goats fed silage of poor quality compared with those fed hay or good silage in both experiments. Average total DMI varied from 2.91% to 3.73% of body weight. Milk yield was higher ( P < 0.01) in goats fed good silage than those fed either hay or poor silage during Experiment I. In Experiment II, no difference in milk yield was found between hay and good silage groups, however, the yield was lower ( P < 0.01) in goats fed poor silage. There was no significant difference in milk content of fat, protein or lactose between the groups in Experiment I. Milk contents of fat and protein were higher ( P < 0.01) in goats fed hay or good silage compared with those fed poor silage in Experiment II. Somatic cell count was higher ( P < 0.01) and milk yield declined more rapidly in goats fed poor silage compared with those fed hay or good silage. Average body weight gain was higher ( P < 0.05) in goats fed either good silage or hay compared with poor quality silage. Silage quality had significant effects on feed intake, milk yield, milk quality and body condition of goats during late lactation.