No abstract

An intake of spray-dried whole-ll)ilk powder equivalent to 2% of body weight was maintained in calves during the first 12 weeks of life when the powder was supplemented with iron, copper, and magnesium.Intakes relative to body weight declined after the age of 12 weeks when fortification with iron and copper ceased. Gradual increases in the dry-matter content of milk to compensate for the decline in abomasal capacity relative to body weight did not enhance intake between the age of 12 and 16 weeks.Supplementation of spray-dried whole-milk powder with iron and copper at levels of 46.7 and 5.1 mg/kg respectively maintained blood haemoglobin concentrations. Fortification of the powder with 0.25 g of magnesium per kg did not prevent, but appeared to delay, the onset of progressive hypomagnesaemia.An increase in the apparent digestibility of fat and a decrease in the digestibility of lactose and ash were noted with advancing age. Reconstitution rate did not affect the digestibility of milk nutrients up to the age of 16 weeks.

No abstract

Forty Friesian bull calves were reared by the "restricted whole milk and early weaning concentrate mixture" method. The daily allowance of milk was offered in two equal feeds at 7.00 a.m. and 4 p.m. to 20 animals in one group and in a single feed at 7.00 a.m. to the 20 remaining calves in the other group. Both groups grew at similar rates and consumed the same amount of concentrate during the pre-and post-weaning periods.

ABSTRACfThe carcass composition of 38 Friesian bull calves fed exclusively on reconstituted spray-dried whole-milk powder supplemented with iron, copper, and magnesium, and averaging 90 kg in hot carcass weight, was studied. The calves came from five nutritional treatments. There were no differences between treatments in carcass weight or composition. The carcasses averaged 61.3% salable meat, 26.4% bone, 11.6% fat trim and waste, and 0.7% kidneys.

No abstract

Forty-two Friesian bull calves were allocated to two treatments; the animals in one group were individually penned and fed indoors. and those in the other were penned in groups of seven under a lean-to on wooden shavings. The calves were fed reconstituted commercial milk powder for 12 weeks and were then slaughtered.The feed intake and carcass growth of the calves on both treatments were very similar, but the lean-to calves were 5 kg heavier in starved live weight at slaughter, largely because of increased gastrointestinal fill resulting from eating wood shavings. The cut-out data on the carcasses indicated similar composition for the two treatments, with the exception that the calves fed indoors had a higher proportion of perinephric and channel fat, and a slightly greater fat cover and a lower eye muscle area than the lean-to calves.Blood haemoglobin and muscle colour and pigment measurements showed that the calves were not anemic, but the m, longissimus dorsi was very pale. The necessity for anaemia in order to produce white veal of suitable muscle colour is questioned.

The ability of calves to absorb and metabolise steam volatile fatty acids (VFA) was investigated by the introduction of acetate-loCH into the rumen of three anaesthetised animals 3 to 4 days old. Acetate-l-C14 appearance in rumen effluent blood and clearance from peripheral blood were considered sufficient evidence of assimilation and utilisation respectively. All the calves absorbed and rapidly metabolised the isotope.