The effect of winter shearing of housed pregnant ewes on food intake and animal performance

Abstract

1987). The effect of winter shearing of housed pregnant ewes on food intake and animal performance. ABSTRACTThe effects of winter shearing on the food intake and performance of housed ewes was studied in a series of three experiments. Winter shearing resulted in a proportional increase of dry-matter intake in ewes of 0-16 and 0-43 on two silage-based diets, of 0-09 on swede-based diets, but of only 0-02 on a hay-based diet. Shearing increased intake by a greater amount in smaller ewes and a similar trend occurred on diets containing a greater proportion of barley. Shearing increased average lamb birth weight by about 600 g (4-65 kg v. 4-06 kg), apparently as an effect of shearing per se rather than as a result of the increased energy intake. An increase in gestation length of around 1-8 days accounted for one-fifth of this increased birth weight. The effect on gestation length of shearing was to increase the unnaturally short gestation of housed unshorn ewes, this short gestation being attributed to problems of heat stress in late pregnancy. Results indicated management advantages of winter shearing in favourable climatic environments. * * 3-Z m /* X m > JO z o o •n X o c m D to tn C/5t Adjusted by covariate within breed for litter size.

Effects of shearing at housing, grass silage feed value and extended grazing herbage allowance on ewe and subsequent lamb performance

“…Kennedy (1985) reported that the food intake of cold-exposed sheep was increased proportionately by 0.13, which was attributed to an increased rate of eating and clearance of digesta from the rumen. Whilst temperature of the ewes in the current study was not recorded, it has been noted previously that shearing decreased the skin and rectal temperature (Vipond et al, 1987). Skelton and Huston (1968) reported a depression in food intake due to heat stress.…”

“…The increased food intake due to winter shearing has been reported previously (Vipond et al, 1987;Black and Chestnutt, 1990a) and persisted until lambing, probably due to the removal of the fleece increasing heat production to maintain body temperature post shearing and a reduction in heat stress in late pregnancy. Kennedy (1985) reported that the food intake of cold-exposed sheep was increased proportionately by 0.13, which was attributed to an increased rate of eating and clearance of digesta from the rumen.…”

“…Skelton and Huston (1968) reported a depression in food intake due to heat stress. Previously, Black and Chestnutt (1990b) reported reduced respiration rate whilst and Vipond et al (1987) reported increased gestation length for shorn relative to unshorn ewes; both are indicative of reduced heat stress in late pregnancy.…”

Effects of shearing on milk yields and milk composition in machine-milked Dorset ewes

“…The higher feed intake (DMI kg MO.75) 1-10 weeks after shearing in Experiment 3 was similar in magnitude to that found by other workers. Intakes of shorn sheep have been shown to increase 20-60% on pasture (Wheeler et al 1963;Wodzicka-Tomaszewska 1964); 14-43% on silagebarley diets (Morgan & Broadbent 1980;Vipond et al 1987), and 2-15% on hay diets (Ternouth & Beattie 1970;Vipond et al 1987). The increases in feed intake lasted 6-7 weeks in both non-pregnant and pregnant ewes (Wodzicka-Tomaszewska 1964;Symonds et al 1988a).…”

Influence of shearing treatment on the performance of pregnant ewes offered silage on an ad libitum or restricted basis

“…In some trials where intake of shorn ewes has been restricted to the level of unshorn ewes, lamb birth weights were not increased (Russel, Armstrong and White, 1985). Other trials have however indicated that shearing exerts its effect on lamb birth weight independently of food intake (Rutter, Laird and Broadbent, 1972;Vipond, King, Inglis and Hunter, 1987). An experiment was therefore designed to examine how these factors operate by offering shorn ewes the same silage either ad libitum or at a restricted level to give equalized intakes between shearing treatments throughout pregnancy.…”