Abstract
The main objective of sheep production in Mexico is the production of meat. The greater demand of sheep meat in relation to the offer generated an attractive market that favored the intensification of the fattening, to take advantage of the growth of lambs in its different stages, and reduce the days of fattening. Thirty-two lambs (28.50± 2.67 kg initial shrunk weight) were used in a 63-day feeding trial (4 pens per treatment, randomized complete block design) to evaluate neutral detergent fiber level (4, 8, 12, and 16% diet DM) on finishing-phase growth performance, dietary energetics and carcass traits. Dietary treatments consisted of a cracked corn-based diet in which the NDF concentration of diet was manipulated by replacing cracked corn grain by corn stubble. Dietary NDF level showed a quadratic response on average daily gain and gain efficiency, being those maximal at 8% NDF level. Lambs fed 8% NDF level tended (P = 0.07) to shown greater dry matter intake than others treatments. The ratio of observed-to-expected dietary net energy was 3% lower (0.97) for lambs fed 4% NDF, while the ratio of observed-to-expected dietary net energy for lambs that were fed with 8, 16 and 16% NDF were closely to 1.00. Hot carcass weight (HCW) and dressing percentage (DP) were maximal for the lambs fed 8% NDF level (quadratic effect, P ≤ 0.03); beyond this level, HCW and DP percentage decreased as NDF level increased. Using corn stubble as source of NDF in growing-finishing diets for lambs, the optimal NDF level was 8%. Fiber level below 8% decreases net energy utilization, and this may be cause by digestive disorders. Fiber levels upper 8% did not affect energy utilization; however, affect negatively average daily gain, feed efficiency and carcass characteristics by effect of high levels of fiber on energy dilution of diet.
Effects of Lactobacillus buchneri NCIMB 40788 and forage: Concentrate ratio on the growth performance of finishing feedlot lambs fed maize silage
