The utilization of milk diets with different fat content by the preruminant calf 1. Digestibility and metabolizability of the d

Author: L.H.P. Liebenberg and F.J. van der Merwe
Year: 1974
Issue: 1
Volume: 4
Page: 21 - 26

Twenty-eight Friesland bull calves, four days of age, were allotted to four groups and were offered milk diets which supplied 147 g to 444 g butterfat per calf per day for 21 days. Mean daily ME intakes increased from 10,6 MJ to 21,6 MJ while volume intakes differed by only 18%from the lowest to the highest feeding level. Mean daily nitrogen intakes increased from 19,6 g (A) to 20,7 g (D) per calf while protein: energy ratios were widened from 1:90 to 1:168. Metabolizability of GE were 93,0±2,2; 94,2±3,1; 93±3,2 and 91,8±4,0 in the four diets respectively and it was shown that apparent digestibility of fat was depressed on the two highest fat diets, mainly as a result of scouring which occurred with higher incidence in Groups C and D. Urinary energy- and urinary nitrogen losses decreased as energy intakes increased. A better utilization of dietary protein, at the higher levels of energy intake, was shown by an increased nitrogen retention by calves on the higher energy diets, although there was a levelling-off at the highest energy intake. Retention of apparently digested nitrogen increased from 65,9%in Group A to 76,3%in Group C. Mean live mass gains of 314 ±67, 414 ±48,557 ±78 and 567 ±133 g per calf per day were recorded in the four groups respectively. The highly significant regression equation describing the relationship between live mass gain (Y) and ME-intake (X) was Y = 1,7747X – 19,9478; r = 0,8447.

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