The intensive rearing of lambs 2. Voluntary food intake and performance on diets of varying oat husk and beef tallow content

Abstract

1. Two experiments concerned with the voluntary intake of food by artificially reared lambs are described and the results discussed.2. When the diets were pelleted the addition of finely ground oat husks to form as much as 40% of the diet had practically no effect on live weight gain since the lambs controlled their consumption to achieve the same energy intake on the various diets. When the diets were given as a meal, the addition of 20% oat husks caused food intake to increase, digestible dry-matter intake to remain the same and growth rate to be somewhat poorer; but the addition of 40% oat husks caused no further increase in intake so that digestible drymatter intake fell markedly and growth rate was much reduced. It is argued that the relationship between food intake and digestibility is dependent on the physical form of the diet.3. Addition of beef tallow to the meal diets had very little effect on the lambs' performance.4. Lambs which had received a restricted quantity of milk replacer from birth to 11·4 kg live weight had a slower growth rate and poorer food conversion efficiency during the subsequent feeding period (13·6–34·1 kg) than lambs which had received milk ad libitum. This effect was greater with meal diets containing 40% oat husks than with more concentrated diets.5. On a pelleted diet containing 85% barley a conversion ratio of 3·21 was achieved over the whole fattening period, indicating the commercial feasibility of intensive lamb production on cereal diets.