GROWTH, DIGESTIBILITY AND NITROGEN RETENTION BY LAMBS FED LIQUID DIETS CONTAINING MILK AND SOYBEAN PROTEINS

Milk and soybean protein sources in liquid diets for 2- to 5-day-old lambs were compared in four experiments. Average weight gains of lambs m experiments 1 and 2 fed an all-milk protein or soy-46 milk replacer (46% of total protein from a soybean protein concentrate), with 15% homogenized lard, for about 7 weeks were 251 and 147 g/day, respectively. Digestibility of dry matter averaged 97 and 95%, and for nitrogen, 97 and 90% (P < 0.05), respectively, for lambs fed the two milk replacers. The same all-milk or soy-46 formulas, or cow’s whole milk, plus a pelleted concentrate and hay were fed to a total of 42 lambs in experiments 3 and 4. Average weight gains to weaning at 9 and 14 kg body weight in experiments 3 and 4, respectively, were 141, 132 and 163 g/day for the three treatments. Weight gains to 40 kg body weight were 185, 190 and 239 g/day. The soybean concentrate settled out of the liquid diet and therefore was not suitable for ad libitum feeding.