Effect of replacing a commercial pelleted calf meal with lucerne leaf-meal on performance of neonatal and transitional Holstein heifer calves

Abstract

A study was conducted to (i) determine in vitro ruminal dry matter (DM) fermentation kinetics, effective rumen degradation of DM (EDDM), (ii) estimate energy fractions supply of lucerne leaf-meal (LLM) and composite diets of LLM with commercial pelleted calf meal and also (iii) determine the effects of substituting commercial pelleted calf meal with LLM on the intake, % ruminal nitrogen balance (RNB) and growth of the neonates (21–42 days old) and transition (43–56 days old) Holstein heifer calves. Forty-eight Holstein heifer calves were randomly assigned to three different dietary treatments in a complete randomised design of: (a) pelleted concentrate (PEL), (b) 65% pelleted concentrate: 35% LLM (P65 L35); (c) and 50% pelleted concentrate: 50% LLM (P50 L50). The study comprised of two experiments: neonatal (Experiment 1) and transition (Experiment 2) phases. Lucerne leaf-meal had gross energy of 16.2 MJ/kg and 25% crude protein DM. PEL diet was high in starch and bound protein compared with other diets. Inclusion of LLM in diets increased calcium levels but tended to decrease phosphorus levels. Calves were weaned at the age of 56 days. The feeds were incubated for 0, 4, 10, 18, 24 and 48 h using a DaisyII incubator. Rumen fluid was obtained from calves <50 days old. Large Ruminant Nutrition System was used to predict %RNB and energy density of the diets during neonatal and transition phases. Higher mean EDDM levels were found with LLM inclusions whereas fractions a, a + b and c did not vary. Neonates on diet C had higher (P < 0.05) daily DM and crude protein intakes, %RNB, total digestible nutrients, net energy at maintenance and net energy at gain during neonatal phase. Performance of calves was similar during the transition phase. LLM should be considered as a concentrate replacement in diets of neonates and calves.