NIPPLE FEEDING OF TWO TYPES OF PROTEIN SUPPLEMENTS TO CALVES

Abstract

Sixty Holstein bull calves initially averaging 94 kg were used in a 2 × 2 factorial design to compare two methods of feeding supplemental skim milk or soyaflour. A high moisture shelled corn ration, supplemented with excess urea to give an average of 13.2% crude protein (dry matter basis), was fed ad libitum. Soyaflour or skim milk, providing an additional 80 g of crude protein per day, was fed either suspended in 1.2 ℓ of warm water in a nipple bottle in two equal portions every day, or was mixed dry into the basal ration. Calves were housed five per pen on slatted floors and were fed for 140 days to an average liveweight of 272 kg. No significant differences (P >.05) were found between treatments in gain, dry matter intake or feed/gain. Rumen strontium tracer and plasma glucose load tests suggested persistence of reticular groove closure with nipple feeding of protein supplements up to 272 kg average liveweight. A subsequent experiment utilized 24 of the nipple-trained calves. Twelve were abruptly switched to twice daily bucket feeding while 12 remained on nipple feeding of skim milk. Strontium tracer tests on days 0, 14 and 28 of the trial suggested extinction of reflex groove closure and/or mechanical failure of the groove in calves changed to bucket feeding. Groove closure was maintained in nipple-fed calves to 332 kg average liveweight.