Comparative Digestibility in Creep-fed Ram Lambs Weaned at 2, 3 or 4 Months of Age and Mature Wethers.

Abstract

The in vivo digestibility was measured in Suffolk ram lambs, aged 2, 3 and 4 months, and Suffolk castrated male sheep (wethers), aged two years, fed hay with calf starter or formula feed for raising dairy cattle. Lambs had access to creep-feed (hay, concentrate) from 2 weeks of age, and were weaned 2, 3 or 4 months of age. Animals were housed in metabolism cages for digestion period. During digestion period, the daily dry matter intake, with hay to concentrate ratio of approximately 40:60, was fixed in approximately 55g/kg W^<0.756gt;. Rumen fluid samples were obtained from lambs of 4 months weaned at 2 months, lambs of 4 months weaned at 4 months, and wethers via stomach tube. Digestibility of dry matter, organic matter, crude protein, crude fat, nitrogen free extract and crude fiber in lambs were relatively lower than in mature wethers, but significant differences were detected only in crude protein and crude fat. No significant differences were observed in rumen volatile fatty acids concentrations among lambs of 4 months weaned at 2 months, lambs of 4 months weaned at 4 months and wethers. These results indicate that dry feed was digested as nearly in creep-fed lambs aged 2 months, as in mature wethers.