EFFECT OF PROTEIN SUPPLEMENTATION ON MILK-YIELD OF GOATS GRAZING A SEMIARID TEMPERATE RANGELAND

For two consecutive 24-week lactations (winter/spring and summer/autum n), a herd of crossbred Nubian goats was allowed to graze for 5 h/d an d offered daily 1 kg supplement to provide 120 g protein from soybean meal or corn gluten meal. During the dry season they were also given 5 00 g corn silage daily. Goats were milked once daily during the 8 week s that they were nursing, and twice daily for the remainder of the lac tation. During the first third of both lactations, corn gluten meal re sulted in statistically higher milk yields and kids' weight gains. Alt hough data between lactations were not statistically compared, it appe ared that milk yields and offspring's weight gains were higher in summ er/autumn, probably as a result of increased availability and quality of range forages at the onset of the rains. Milk production in the las t two-thirds of the rainy season lactation appeared to be higher (alth ough not significantly) for the com gluten meal group; during the dry season, the trend was reversed. In general, there was a positive produ ctive response to by-pass protein supplementation; however, the practi ce could be economically not feasible in low milk yielding herds as th e one used.