DIGESTIBILITY OF PEA PROTEIN CONCENTRATE AND ENZYME-TREATED PEA FLOUR IN MILK REPLACERS FOR CALVES

Abstract

In an experiment involving enzymatically hydrolyzed pea flour (HPF) and pea protein concentrate (PPC) to provide half the dietary protein in milk replacers, the pea protein was found to be about 25% digestible by calves under 2 wk of age and 65 to 70% digestible by calves 3 wk of age. The younger calves digested 42 to 53% of the pea starch; older calves digested 63 to 84%. The digestibility of dry matter, protein, energy and ether extract increased with calf age (P < 0.01). In the second trial, involving PPC at 7.7, 15.4 and 23.1% of the dry matter in milk replacers, and providing 19, 33 and 46% of the dietary protein, the digestibility coefficients for dry matter, disregarding calf age, declined from 90 to 86% as PPC increased from 15.4 to 23.1%, but the low and intermediate PPC diets were equally well digested. The reduction was due mainly to the corresponding reduction in protein digestibility. Digestibility coefficients for dry matter, protein, energy, ether extract and nitrogen-free extract for milk replacer diets containing 23.1% PPC exceeded 81% with calves over 14 days old. The third experiment involved feeding the control milk replacer until the calves were 2 wk old, then commencing the feeding of PPC and HPF replacers, using formulas similar to those of the first experiment. The digestibility coefficients were similar to those of the first experiment, indicating that the observed improvement in older calves was primarily a function of calf age and not markedly influenced by the formula of the diet. These studies indicate that PPC and HPF are not satisfactory ingredients in milk replacers to be fed to calves under 2 wk of age, but, though less digestible than milk, are effectively digested thereafter.