Effect of feed intake on heat production and protein and fat deposition in milk-fed veal calves.

摘要: Energy requirements for veal calves have not been updated recently despite the increased age at slaughter and predominance of Prim’Holstein breed in Europe. The objectives this study were to determine effects four feeding levels (FLs) on protein fat deposition heat production milk-fed three stages fattening energy calves. At each stage, 16 male (mean body weight (BW): 73.4, 151.6 237.4 kg) fed a milk replacer 79%, 87%, 95% or 103% reference FL. Measurements one stage conducted over 4 successive weeks two open-circuit respiration chambers consisted 6-day nitrogen balance followed by fasting day estimating (FHP) Heat (HP) measurements analyzed using modeling approach partition it between HP due physical activity (AHP), feed intake (thermic effect (TEF)) FHP. There was no FL apparent digestibility coefficients, except tendency coefficient as animals got older. metabolizable (ME)/digestible (DE) ratio did depend but decreased (P , 0.01) older connection with marked increases urinary glucose urea excretion. AHP TEF components affected averaged 8.4% 7.8% ME intake, respectively. FHP, expressed per kg BW 0.85 increasing FL, suggesting that also requirement maintenance (MEm) may For an average 625 kJ ME/kg (95% FL), FHP 298 kJ/kg day. retention resulted higher gain. But rate increase depended growth. slope relating lower finishing phase than growing phase, while lipid greater. Protein contents gain From these results, are proposed according new approach, which considers MEm (expressed ) depends (kJ/kg following relationship: 5 197 1 0.25 3 intake. corresponding marginal efficiencies utilization then 82%