An experiment was carried out to quantitatively characterize production and
reproduction traits of local sheep in southern Sinai and to standardize the nutritional
management of sheep flocks. Since the nutritional requirements of the local breeds
are not known, it was empirical to study diet selection and voluntary food intake and
its regulation during different stages of the production cycle. A total of 85 ewes in four groups were used. A control group was fed
according to the NRC standards. Control rations were balanced using the same
ingredients offered to the experimental groups. Ewes in the three experimental
groups, group-housed in shaded pens, were offered one of three basal roughages;
berseem hay, one-third berseem hay and rice straw, and rice straw with added
molasses-urea feed mixture. Roughages were made available ad lib and comprised
the sole ration during breeding and early pregnancy. A flushing concentrate was fed
to all ewes including the controls before and during breeding at the rate of 200
g/day/ewe. As of the start of the late pregnancy period and up to the weaning of the
offspring, the three experimental groups were offered, in separate feeders, ground
corn grains and cottonseed meal to allow for free-choice intake. Group food intakes
were recorded daily and live body weights biweekly. The hay-fed ewes were able to select diets that satisfied their energy and
protein requirements during the different stages of the production cycle. The physical
characteristics of the selected diets in terms of roughage and crude fibres
percentages in the total DMI and the proportion of dietary protein that is potentially
degradable in the rumen were practically the optimum. It appears that in those ewes
voluntary food intake regulation was predominantly under the control of physiological
factors to satisfy energy requirements. The physical limitation of the fill capacity was
not a factor. The straw-fed groups, on the other hand, failed to control their intake as per
their physiological needs. Their voluntary food intake was apparently under the
control of physical rather than physiological factors, i.e. the limited fill capacity and the
slow rates of degradation and passage of ingested material. The massive increase of
Energy requirements during early lactation obliged the ewes to consume large
quantities of corn grains. Consequently, their roughage and crude fibres intake was
below physiological optimum and the rumen environment and microbial population as
well as the host animal might have been adversely affected.