A study of food intake and production in grazing ewes II. The interrelationships between food intake and productive output

Abstract

1. Observations were made during the autumn and spring of 1959–60, 1960–61, and 1961–62 on pregnant and lactating Clun ewes of mixed ages grazing under natural conditions. The pattern of food intake during pregnancy and lactation, the output achieved in the form of weight of lambs produced at parturition, milk yield, and bodyweight change of the ewes themselves was investigated. The interrelationships between these factors, as influenced by the feeding of supplementary concentrate, either for 7 weeks before or 7 weeks after lambing, or during both periods, was elucidated.2. Daily dry-matter intake was found to be of the order of 1·5–2·0 kg. for this type of ewe, but there was considerable individual variation (coefficient of variation about 20%). Intake did not increase concurrently with the demands of the foetus during the later stages of pregnancy, and even became depressed as parturition approached. Immediately after lambing there was a spectacular increase in intake, which, after rising to a peak, was maintained at a high level during the lactation. Ewes receiving supplementary concentrates showed an increase in food intake over those unsupplemented, but this increase was less than the amount of dry matter fed in the supplement, even on rather bare pasture.3. During the early stages of pregnancy there was no apparent difference in the weight gains of singleand twin-bearing ewes, but during the last 8 weeks prior to lambing twin-bearing ewes made greater weight gains. In relation to weights taken just after parturition ewes producing twins had lost most weight. Unsupplemented ewes lost more weight than those receiving supplements. Lack of supplementation prior to lambing only limited production in the case of twin-bearing ewes.

The intake of silage and grazed herbage by Masham ewes with single or twin lambs and its repeatability during pregnancy, lactation and after weaning

“…Body condition scores at weaning were 3 9, 3 6 and 3-75 for the ewes with singles, the TL group and the TS group respectively. These results agree with those of Foot and Russel (1979) for pregnancy and with those of Owen and Ingleton (1963) for lactation, but the question remains as to why a difference in intake between ewes rearing singles and twins should occur indoors and not outdoors. However, during lactation the ewes suckling twins indoors ate more than ewes with singles.…”

“…Owen and Ingleton (1963) found a similar repeatability for intake with Clun ewes during pregnancy and lactation. The same ewes consistently ate the most or the least, either in absolute terms or after energy for maintenance had been subtracted, using the same coefficient for maintenance for each animal.…”

The effect of the reproductive state of ewes on their voluntary intake of diets varying in straw content

“…First there is broad agreement with previous observations on the pattern of food intake in the ruminant female in relation to reproductive state (Owen & Ingleton, 1963). This indicates low intakes in dry ewes, with a tendency for a gradual slight decrease in late pregnancy.…”

A quantitative model of energy intake and partition in grazing sheep in various physiological states

“…Observations with pen-fed ewes offered good quality roughage (Reid and Hinks, 1962), grass cubes (Hadjipieris and Holmes, 1966) or semi-concentrate diets (Fell, Campbell, Mackie and Weekes, 1972;Heaney and Lodge, 1975) have shown no change in appetite. A similar result has been observed in grazing experiments (Owen and Ingleton, 1963), whereas still others have shown an increased intake during pregnancy (Arnold and Dudzinski, 1967;Arnold, 1975). Based on the above evidence, it was decided that pregnancy would not be represented as an effector of food intake.…”