Changes in Milk Products Sham Fed to Calves. IV. Suckling from a Nurse Cow versus Consuming from Either a Nipple Feeder or an Open Pail

Abstract

Lipolysis and associated changes in whole milk sham fed by different systems to two pairs of calves (Guernseys and Holsteins, 2 to 5 mo of age) were compared. Each calf was sham fed milk from the respective halves of the udder of a Holstein cow by: (a) nursing directly from the udder, (b) sucking from a nipple pail, and (c) drinking from an open pail. Increasing rates of consumption by these methods were in the order listed. Exposures during ingestion increased lipolysis and numbers of bacteria. Lipolysis, evidenced by increased soluble volatile fatty acids and decreased concentrations of fat, was accompanied by lowered pH and by accelerated rates of rennet coagulation. Lipolytic changes were accentuated throughout an 8-h incubation at 38C. Magnitudes of lipolysis in milks removed by hand from the respective udder halves and subsequently sham fed by pail systems were related closely to the duration of ingestion. Hence, changes in milk sucked from nipple pails were more marked than in that drunk from open pails. Nursing from the udder was slower than by sucking from a pail, but lipolytic modifications were less, which difference is attributed to the lower fat content of nursed milk.