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Title: Artificial rearing systems for calves and the effects of varying concentrate to forage ratios in finishing diets for beef cattle
Author: Abdul-Latif, Fouad
ISNI:       0000 0001 3389 8097
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1977
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A series of experiments has been carried out to study two aspects of beef production. One experiment was designed to study calf-rearing and involved different weaning methods. Calves were weaned on the basis of either age or their concentrate intake. Another three, experiments were undertaken with either finishing cattle or adult sheep to study the nutritive characteristics of diets with different ratios of silage to supplement and different types of supplement, Calf-rearing experiment Forty-eight Friesian bull calves were used. They were bought at an average age of 4 days and fed on 450 g/day millc substitute twice daily. Concentrate and hay were introduced at 8 days old. They were allocated to six treatments involving different times of weaning: weaning when concentrate intake reached either 1.00 kg/day (a), 0.75 kg/day (b) or 0.5 kg/day (c); at 56 days of age (d) or 42 days of age (e) or 28 days of age (f). All groups received concentrate and hay to appetite. The animals were individually fed and the experiment ended when each calf reached 100 kg. Performances were measured to weaning, to 70 kg live weight and to 100 kg live weight. For both determinants of weaning milk substitute consumption declined significantly (p>0.01) with decrease in either age at weaning or in concentrate level at which the calves were weaned. There were considerable but non-significant differences in concentrate intake between treatments, intake being highest with the calves weaned at an early age. The calves weaned when the concentrate, intake reached 0.5 kg/day were on average 33.9 days of age at weaning and gained slightly less than the calves weaned at 28 days of age. There were no significant differences between treatments in daily live weight gain from the start of the experiment to 100 kg live weight. The number of days from start to weaning was lowest in treatment A and highest in treatment 3, but of similar duration for the remaining treatments. It is concluded that the calves could be weaned successfully at 28 days old or when they eat 0.5 kg concentrate daily. It is recommended that calves should be weaned on the basis of their concentrate intake particularly for bought-in calves since the age may not be known exactly. PART 2 Experiment 1 This experiment was conducted with fattening cattle over a period of 84 days and designed to study the effect of three ratios of silage to supplement on a dry matter basis (80:20, 60:40 and 40:60 and four types of supplement (100% barley, 66% barley, 34% swedes; 34% barley, 66% swedes and 100: swedes) on total dry matter intake and dailj' live weight gain of 96 Friesian steers allocated to eight replicates and given the 12 diets individually. The animals were fed to appetite and initially weighed on average 403 kg. Measurement of in vivo digestibility (indirect Cr203 technique) was carried out on 48 animals. Also measurements of in vitro digestibility were carried out on all the diets studied in this experiment. The animals remained healthy throughout the experiment. Growth rate was increased when the level of supplement (either 100% barley or 66% barley, 34% swedes) increased from 20 to 40% in the diet but was reduced with a further increase in level of supplementation to 60%, The mean growth rates of groups fed on swedes as the sole supplement declined progressively as the level of supplementation increased. Similar growth rates were obtained for different types of supplement in the groups given diets with the ratio 80:20 silage to ' supplement. With higher levels of supplementation the growth rate was not reduced when 34% of the barley was replaced by swedes. The efficiency of conversion of dry matter to live weight gain was not affected by the level of supplementation nor the type of supplement. A depression in digestibility of all dietary constituents occurred as the percentage of supplement containing only barley increased. Increasing the level of supplement consisting of a mixture of barley and swedes resulted in little or no change in values for dry matter, organic matter and energy but lower digestibility values for crude protein and crude fibre. When the level of swedes fed as the sole supplement was increased, the digestibility of all constituents except that for crude protein remained relatively constant, while the digestibility of crude protein was reduced. The results are discussed in relation to previous knowledge of factors affecting food intake and performance of finishing cattle with some recommendation for a semi-intensive beef production system.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available