DIGESTIBILITY OF MILK REPLACERS CONTAINING RAPESEED OIL, FED TO DAIRY CALVES UNDER A MONTH OLD

Abstract

Sixteen calves 3–28 days of age were fed milk replacers containing 15% added fat with 0, 5, 10 or 15% rapeseed oil (27% erucic acid) substituting for lard. The protein in these replacers was entirely of milk origin. The rapeseed oil was 69% digestible, compared to 94% for the lard, and its use resulted in depression of the digestibility of protein from 80 to 66% as the portion of rapeseed oil rose from 0 to 15%. Three calves were fed a milk replacer containing 10% lard and 10% rapeseed oil, in which 60% of the protein of milk origin was replaced by protein from fish protein concentrate and from brewers’ yeast. The calves showed progressive improvement in their ability to digest amino acids in successive 2-day periods. Average amino acid digestibility increased from 72% at 4–6 days of age to 87% at 16–18 days of age, at which time utilization about equalled that expected on milk-origin diets.