The nutrition of the early-weaned calf VIII. The effect on nitrogen retention of diets containing different levels of fish meal

The effect of cereal and protein source on the energy intake and nitrogen balance of fattening lambs given all-concentrate diets

Energy intake and nitrogen balance studies have been conducted on 12 lambs fedad libitumon four all-concentrate diets of equal crude-protein content in an experiment of latin square design. Each diet contained one cereal, either barley or oats and one protein supplement, either white-fish meal or soya bean meal.

Protein supplements had no influence on energy intake, but intake was significantly higher when the lambs were given barley rather than oat diets.

There were highly significant differences in the degree of utilization of digested nitrogen between diets containing fish meal and soya bean meal, and between diets containing barley and oats.

The energy: nitrogen ratio of urine was inversely related to the proportion of urinary nitrogen present as urea and directly related to the degree of utilization of digested nitrogen.

The nutrition of the early-weaned calf. X. The effect of replacement of fish meal with either urea or ammonium acetate on growth rate and nitrogen retention in calves fed ad libitum

1. A growth trial and nitrogen balance studies were carried out on 32 early-weaned calves fed on a basal diet containing fish meal or diets in which the fish meal nitrogen was partially replaced by urea or ammonium acetate or totally replaced by urea.

2. Growth rate and feed conversion efficiency were highest on the fish meal diet and fell as urea replaced the fish meal.

3. Rumen ammonia levels and urinary nitrogen excretion were highest, and nitrogen retention lowest, in the calves receiving the diet in which fish meal nitrogen was completely replaced by urea nitrogen.

The protein requirement of the ruminant calf. II. Further studies on the effect of protein content of the concentrate mixture on the performance of calves weaned at an early age

1. Eighty-four Friesian heifer calves were used in two experiments (Experiments 4 and 5) to study the protein requirement of the ruminant calf to 12 weeks of age. The calves were weaned at 5 weeks of age and given a concentrate containing one of several protein levels, together with hay and water.

2. In Experiment 4, the effect of changing the protein content of the concentrates at 8 weeks of age under ad libitum feeding conditions was studied. A concentrate containing 20·6% crude protein (air-dry basis) tended to promote more rapid weight gains in calves to 8 weeks than a similar concentrate with 12·1% crude protein. Following the change in diet at 8 weeks, both groups of calves given the low-protein diet gained weight at similar rates in the period 8–12 weeks, irrespective of the protein level to 8 weeks. During the period 8–12 weeks calves given the high-protein diet, after receiving a low-protein diet to 8 weeks, tended to gain weight at a faster rate than those given the high-protein concentrate throughout. After adjustment for differences between treatment groups in mean concentrate consumption and mean live-weight at 8 weeks, the live-weight gain from 8 to 12 weeks was significantly greater in calves given the high-protein diet after 8 weeks.

3. In Experiment 5, a significantly lower growth rate was obtained when concentrate intake was restricted to a maximum of 2 kg./day than when given ad libitum. Calves given the concentrates containing 15·9% or 20·6% crude protein gained weight significantly faster than those given the concentrate containing 12·1% crude protein, at both levels of feeding, after live-weight gain was adjusted for differences between treatment groups in mean food consumption and live-weight at 1 week.

4. It is concluded that no advantage is obtained by giving a concentrate containing more than 15·9% protein to Friesian heifer calves weaned at 5 weeks of age. The results indicate clearly the importance of an adequate supply of energy in the diet of the ruminant calf if maximum live-weight gain is to be achieved.

The effect of different proportions of dried grass and concentrates in the diet on voluntary intake and performance of calves

Complete diets each containing (1) 0%, (2) 20%, (3) 40%, (4) 60% high-quality, (5) 20% and (6) 40% low-quality dried grass were given ad libitum to 48 British Friesian calves.

The performance of the animals was studied over the stages of growth from 50 to 100 kg and 150 to 200 kg live weight. At each stage of growth the live-weight gain was similar on all treatments while the daily intake of dry matter was significantly affected by the treatments. Over the stage of growth from 50 to 100 kg live weight the intake of metabolizable energy was greatest on treatment 2 and lowest on treatment 4. The conversion ratio of metabolizable energy decreased with increasing levels and with both qualities of dried grass over the weight range 50 to 100 kg.

When the calves reached 100 kg live weight, digestibility and N balance studies were carried out. The metabolizable energy (ME) expressed as a percentage of the gross energy decreased with increasing levels and with the lower quality of dried grass. Nitrogen retention was not significantly affected by treatment differences.

The relationships of the voluntary intake of dry matter, ME intake and the conversion ratio of ME with the ME expressed as a percentage of gross energy over the lower live-weight range are also presented.

The crude protein requirement of the early-weaned calf given urea, meat meal or soya bean meal with and without sulphur supplementation

Two experiments were conducted with 84 male British Friesian calves to estimate their nitrogen and sulphur requirements between 5 and 11 weeks of age. A basal 12 % crude protein (CP) diet was supplemented with meat meal, soya bean meal or urea to 15 or 18 % CP, and with sulphur to reduce the nitrogen to sulphur ratios of the diets to about 10 to 1.

The weight gains and feed conversion ratios of the calves given the 12% CP diets were significantly poorer than those of the calves fed on the diets containing 15 or 18% CP, irrespective of the CP supplement used. The supplementation of the urea-containing diets with sulphur caused a significant increase in feed intake and weight gain.

The digestibility of nitrogen and dry matter increased with increasing CP content of the diets and was greater for the diets supplemented with urea than for those supplemented with meat meal or soya bean meal. Sulphur additions also increased the nitrogen digestibility. The retention of nitrogen, when corrected for feed intake, was greater in the calves fed on the diets containing 18% CP than in those fed on the 15% and 12% CP diets.

The supplementation of the diets with sulphur increased the digestibility of sulphur, its excretion in urine and its retention. The concentration of urea in the blood plasma increased with increasing dietary CP content, and was higher in calves given urea.

A note on energy intake and nitrogen balance of fattening lambs given all-concrate diets

The growth rate and food conversion efficiency of fattening lambs given all-concentrate diets have been reported by Philip Preston and Greenhalgh (1964). The lambs were weaned abruptly at 8 weeks old and fed thereafter ad libitum on cereal and protein supplement. Owen, Davies and Ridgman (1965) have reported the same measures of performance for artificially reared lambs fed from 30 lb. to slaughter at 75 lb. on diets varying indigestibility. A considerable amount of information has been obtained recently on the nitrogen metabolism of young calves fed on all-concentrate diets (see Preston, Whitelaw, MacLeod and Philip, 1965, and Bowers, Preston, McDonald, MacLeod and Philip, 1965) but there is less information of a similar nature for lambs fed on such diets. The following experiment was carried out to assess the intake of energy and utilisation of dietary nitrogen by lambs fed ad libitum on three simple all-concentrate diets during the latter stages of fattening.

Amounts and sources of protein for dairy calves

Female Holstein calves (178) were fed rations varying from 10 to 17% crude protein (air dry) from 30 to 102 days of age. Ten percent was inadequate resulting in less body weight, gain, withers height, and heart girth than rations containing 12 to 17% crude protein. In trial 1 addition of urea, biuret, or ammonia-molasses to a 12% diet to make a 16% crude protein diet allowed gains and weights indistinguishable from those on a 12 or 16% crude protein soybean meal ration. In another trial, addition of urea, biuret, or ammonium propionate to a 10% ration to make a 14% ration allowed insignificantly greater gains and body weight. Gains and body weight were greater for the 14% soybean meal ration than the three non-protein-nitrogen rations for calves to 71 days of age but equal for 71 to 102 days. Gain, body weight, dry matter, and protein intakes at most dates and intervals were greater for calves fed the 14% soybean meal ration than the 10% ration. When 10, 12, 14, and 16% soybean meal rations were compared simultaneously, only the 10% crude protein ration gave inferior performance. Gains were reduced when average daily crude protein intake for the 72 day trail was 258 g or less. Calves fed lupine or dried poultry waste did not gain or consume as much as those fed comparable soybean meal rations. Calves fed a 17% crude protein ration from several protein sources plus alfalfa hay gained no much than those fed the 12 to 16% crude protein rations. Regression analysis relating dry matter and protein intake to body weight or gains indicated both dry matter intake and protein percentage were about equally important from day 41 to 72 and that after this age dry matter intake was of much greater importance than protein percentage. Protein intake expressed as g/day was not of importance in this regression. Weaning at day 42 allowed for greater body weight and gains than weaning at day 32. The difference in body weight was 2.5 kg at day 42 and 7 kg at day 102.