29 March 1996

Two diets better than one for calf rearers

CALF rearing costs can be reduced by using two diets rather than one up to eight weeks of age.

Speaking at the BSAS meeting, Dr John Newbold of BOCM Pauls said: "In a commercial situation calves are often offered the same feed, a starter feed, before and after weaning. The aim is to increase intakes, reduce weaning age and cut milk replacer costs.

"But though it is simpler to offer one diet up to eight weeks, continuing with the same feed after weaning reduces food conversion efficiency," said Dr Newbold.

In a study Charolais x Holstein Friesian bulls fed 500g of milk replacer a day were offered an optimal pre-weaning diet with 12MJ/kg ME, 21% crude protein and 17% rumen fermentable starch (RFS) which was replaced by a post-weaning diet (12.2ME, 19.5% protein, 21% RFS). Performance of calves on the two diet regime was compared with that of those on a single starter diet (11.5ME, 19.5% protein and 17% RFS).

Over the period liveweight gains and feed intakes did not differ but feed conversion efficiency was better in the two diet regime. "Costs were calculated using the raw material costs of dry feed and milk replacer of production was 51p/kg gained for two diets as opposed to 55p for a single starter period," said Dr Newbold.

"Maximum effectiveness economically, however, depends on producers weaning when calves are regularly eating 1kg a day of calf starter which in turn depends on accurate recording," he said.