Does yeast (Saccharomyces cerevisiae) supplementation in calf starter modify feed intake and liveweight gain of dairy bull calves?

The objective of the experiment was to study the possible effects of supplemental yeast culture in calf starter on feed intake, liveweight gain and health of dairy bull calves. Two feeding treatments consisted of a calf starter containing 0% and 0.1% supplemental yeast culture (Actisaf, 1.0 × 1010 CFU·g–1 Saccharomyces cerevisiae Sc 47) as a percentage of dry matter starter. In each feeding treatment 20 dairy bull calves were included. The calves were housed in insulated barn in four pens (3.0 × 3.5 m; 5 calves in each), providing 2.1 m2 per calf. At the beginning of the experiment, the average liveweight of the calves was 56 ± 3.0 kg and the overall age was 20 ± 2.5 days. During the pre-weaning period (from 20 to 75 day of life) the calves received milk replacer 7.0 l·d–1 and starter concentrate as well as grass silage ad libitum. During the post-weaning period (from 75 to 195 day of life) the calves received grass silage ad libitum, but the amount of concentrate was restricted to 3 kg (air dry) for a calf per day. No treatment differences were observed in dry matter or energy intakes, liveweight gain or feed conversion ratio during pre-weaning or post-weaning periods. The use of Saccharomyces cerevisiae did not affect the incidence of diarrhoea, cough or bloat. Thus, no evidence show that Saccharomyces cerevisiae inclusion could have enhanced calf performance under the studied conditions. In the present experiment, the calves were healthy; however different results might be observed in calves in altered physiological conditions.