Nutritional consequences among ingredients of free-choice feeding Awassi lambs

The present study was designed (1) to test whether growing lambs can select an adequate diet when offered an unrestricted choice among feed ingredients, and (2) to determine whether choice feeding compared with single-feeding would alter the fattening performance of lambs reared under normal husbandry conditions. Thirty, 3-month-old male Awassi lambs were used. Each dietary treatment had three replicate groups, comprising five lambs each. Ground barley, wheat bran, cottonseed meal and alfalfa hay were used as the main feed ingredients. One of the dietary treatments (choice-fed) was offering the main feed ingredients as choices, while the other (single-fed) was feeding with a control diet (containing 2.4 Meal ME kg-1 and 17.0% CP) prepared using the same feed ingredients for a 56 day fattening period. Lambs offered choices among the feed ingredients could select diets to meet their nutrient requirements according to age throughout the fattening period. For the entire experimental period the choice-fed group attained higher daily live-weight gain (346 g vs. 299 g; P < 0.01) and better feed conversion efficiency (feed/gain; 5.1 vs. 5.7, P < 0.05) than the group given access to the single diet. No difference (P > 0.05) between daily feed intake of the choice-fed and single-fed groups (1776 g vs. 1704 g) was observed. The lambs consistently selected diets high in CP relative to ME when allowed to choose feed ingredients. It is concluded that lambs, when given choices among feed ingredients (ground barley, cotton seed meal, wheat bran and alfalfa straw), can select diets that meet their nutrient requirements according to stage of maturity and they attain better growth performance than lambs fed with a single diet