Effects of different dietary levels of forage cactus (Opunita ficus-indica) on feedlot performance and carcass characteristics of Fars Torki-Qashqai male lambs

This study was conducted to evaluate the effects of replacing different levels of alfalfa hay with forage cactus in the diet on performance and carcass characteristics of feedlot lambs. A basal experimental diet was formulated with 50% barley grain, 40% alfalfa hay and 10% wheat straw. Different levels (20, 40 or 60%) of alfalfa hay in the basal diet were replaced with forage cactus. Twenty Torki-Qashqai ram lambs (180±30 d and 27±2 kg) were randomly assigned to the experimental treatments (5 lambs per treatment). The lambs had free access to feed and water in individual cages. Body weight change, feed intake and feed conversion ratio were determined for an experimental period of 70 days. At the end of the experiment, the lambs were slaughtered and carcass characteristics (percentage of warm and cold carcass, meat, fat and bone as well as back fat thickness and Longissimus dorsi muscle area) were measure. Increasing levels of forage cactus in the diet caused a numerically decrease in body weight gain. The feed conversion ratio was also increased by increasing replacement of alfalfa with forage cactus. However, no significant differences were observed among experimental treatments for daily gain, feed intake and feed conversion ratio. The experimental treatments had no significant effect on the carcass characteristics of lambs. The findings suggested that the forage cactus can be use to replace over than on half alfalfa hay in feedlot diet without any significant negative effects on performance and carcass characteristics.