Effects of pen flooring type and bedding on lamb growth and carcass characteristics

- Straw bedding improved feedlot lamb performance over sand.
- Expanded metal flooring resulted in the poorest lamb growth.
- Straw bedding increased visceral organ weights, but improved performance.

Two studies were conducted to determine the effects of floor or bedding type on lamb performance, carcass characteristics, and visceral organ mass. In Exp. 1, seventy-two early weaned Targhee × Hampshire ram lambs (initial BW = 35.2 kg) were used in a randomized complete block design experiment to determine the effects of floor type and bedding with lambs fed an 80% concentrate diet. The types of flooring investigated were expanded metal, dirt with a sand top-dress, and dirt with straw bedding. Flooring type affected DMI (P < 0.001), with lambs on expanded metal consuming the least (1.23 kg/day), lambs on straw consuming the most (1.28 kg/day), and lambs on sand being intermediate (1.25 kg/day). The differences in DMI resulted in lambs on expanded metal having a lower (P < 0.05) ADG than lambs on straw (0.26 vs. 0.28 kg/day, respectively). Lambs bedded with straw had greater (P < 0.05) total digestive tract mass compared to lambs on expanded metal flooring. No significant differences were found for lamb carcass characteristics due to flooring type. In Exp. 2, ninety-two Dorset × Hampshire lambs (initial BW = 31 kg) were used in a randomized complete block design experiment to determine the effects of bedding, dirt with a sand top-dress, and dirt with straw bedding, on animal performance with alfalfa silage and corn-based growing and finishing diets, respectively. Lambs were allotted to pens based on sex (wethers = 46 and ewes = 46) and initial BW (small or large), with 11 or 12 lambs per pen. Lambs bedded with straw had significantly greater (P < 0.05) ADG, DMI, and G:F compared with lambs bedded with sand during the growing period. However, lambs bedded with sand had significantly greater G:F (P < 0.05) compared to lambs bedded with straw during the finishing period.