EFFECTS OF PLANE OF NUTRITION AND REARING METHOD ON YANKASA LAMBS: GROWTH RATE, SCROTAL DEVELOPMENT

Résumé

The study examined the effects of plane of nutrition and rearing method on growth rate, increase in scrotal size; and age, body weight and scrotal circumference at puberty, in Yankasa ram lambs. Thirty-six ram lambs and 18 ewe lambs with mean age and body weight of 1453±17.7 days and 10.1 1±2.6kg respectively were used for the four-month trial. Animalswere randomised in a 3x2 factorial design with plane of nutrition at 3 levels (low, medium and high) and rearing method at 2 levels (males alone and mixture of males and females). Plane of nutrition had bighly significant (P<0.01) effect on average daily gain (ADG). Animals on the low, medium and high planes gained daily  66.8±5.5, 77.8±5.6 and 89.0±5.6 respectively. Effects of plane of nutrition and rearing methods on changes in scrotal circumference were not significant. Age, body weight and scrotal circumference at puberty in the ram lambs averaged 232.5±12.7 days, 18.3±0.4 kg and 22.7±3.1 cm respectively. Body weight at puberty averaged 17.2±1.7, 18.6±0.9 and 19.0±1.4 kg for animals fed low, medium and high planes of nutrition respectively.