The effects of hay and silage on growth and rumen function in young Holstein calves

Abstract

Newborn calves were fed one of four different roughages (timothy hay, alfalfa hay, grass silage or two parts grass silage mixed with one part alfalfa hay) and a starter ration to a maximum of 2000 g d−1 beginning at 10 d of age along with whole milk to weaning at 28 d of age to measure the effect of forage type and method of conservation on voluntary intake and animal performance up to 112 d of age. Rumen fluid was sampled to determine whether the type of forage had a measureable effect on some gross parameters associated with rumen development. Forage dry matter became a larger proportion of total feed consumed as the animals became older. Overall alfalfa hay and silage:alfalfa mixture were consumed more than timothy hay (P < 0.01). Calves fed silage:alfalfa grew more rapidly than those fed timothy (P < 0.01). These differences were attributable to differences in forage protein and plant cell wall material. The differences in rumen fluid volatile fatty acid composition, pH, or in vitro gas production were found for treatments in only two sampling periods. In the 3rd period, gas production was more rapid from alfalfa hay than from silage (P < 0.05) and in the 4th period, pH was greater for alfalfa hay than timothy hay (P < 0.05). Rumen pH increased in the 3rd and 4th periods (P < 0.01). The acetate:propionate ratio increased over time when the propionate values decreased from the 2nd to the 3rd period (P < 0.01) and acetate values increased from the 3rd to the 4th period (P < 0.01). Silage was equal to hay in terms of consumption, animal performance and those rumen fluid parameters examined and can be fed to young calves without any anticipated problems. Key words: Silage, hay, rumen, development, methane, calves