title: Alteration of energy metabolism of calves fed below maintenance during 6 to 14 days of age.
abstract: A study was conducted with seven groups of five to six Holstein-Friesian male calves to evaluate the effect of feeding level during 6 to 14 d of age on energy metabolism of unadapted young calves. Calves were transported at 2 to 3 d of age to their new environment. At 6 d of age measurements of heat production (HP) and ME intake started and continued over a period of 8 d. Calves were fed below (four groups) or near (three groups) the maintenance requirement (19 or 30 g of milk replacer powder.kg-.75.d-1). In contrast to ME intake, HP decreased throughout the experimental period. This decrease was larger at the low than at the high feeding level (3.1 vs .9 kcal.kg-.75.d-2; P less than .001). The relationship between HP and ME intake was estimated as HP = 91 + .318 x ME intake (kilocalories.kilogram-.75.day-1). The decrease in HP, together with the constant ME intake with time, resulted in a time-dependent relationship between HP and ME intake. Estimated basal metabolic rate and efficiency of ME utilization below maintenance decreased with time, whereas the maintenance requirement remained virtually unchanged (134 kcal.kg-.75.d-1). The influence of feeding level on energy metabolism in young calves increased with time. For at least 12 d after transportation the energy metabolism of young calves had not reached steady-state levels.
authors.affiliation: Department of Animal Husbandry, Agricultural University, Wageningen, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: Schrama
authors.forename: W
authors.initials: W
authors.lastname: van der Hel
authors.forename: A
authors.initials: A
authors.lastname: Arieli
authors.forename: M W
authors.initials: MW
authors.lastname: Verstegen
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation; D002417:Cattle / Q000378:metabolism*; D002149:Energy Intake; D004734:Energy Metabolism; D005508:Food Deprivation / Q000502:physiology*; D008297:Male; D014186:Transportation