The effect of protein intake during gestation on ewe and lamb performance

Abstract

Two experiments were carried out in which a total of sixty-four Border Leicester × Scottish Blackface ewes were each individually fed on one of eight experimental diets from six weeks after service to parturition. The eight diets supplied four intakes of crude protein (156, 119, 90 and 65 g/68-kg ewe per day) and two intakes of energy (2923 and 2468 kcal ME/68-kg ewe per day). After parturition the ewes received one of two lactation treatments supplying a standard protein intake of approximately 260 g/68-kg ewe per day at ME intakes of 4700 and 4186 kcal/68-kg ewe per day.The relationship between net body weight change (Y, kg) and ME (X1) and DCP (X2) intakes (per 68-kg ewe) was described by the equation Y = The DCP intake corresponding to maximum efficiency of energy utilization was 98 g/68-kg ewe per day. The relationship between lamb birth weight (Y, kg) and ME and DCP intake was described by the equation Y = 0·0003X1 + 0·0080 X2 + 2·8501.Ewe live-weight loss during early lactation, lamb growth rates from birth to three weeks and ewe milk yield at three weeks tended to decrease with decreasing protein intake during pregnancy.