Urea treatment of mature whole-crop cereal mixtures as salvage forage for small-scale dairy systems in the dry season

Abstract

Forage from small-grain cereals is an option to diversify feeding strategies in small-scale dairy systems (SSDS), due to their short cycle and ample adaptation. Mixtures of cereal species may have synergic advantages; however, grazing or ensiling are not always possible due to climatic factors, so that forage crops are left to mature and lose quality. Urea treatment of whole-crop mature cereal mixtures may be an option to salvage forage that could not be grazed or ensiled. The objective was to evaluate the performance of dairy cows fed urea-treated mature whole-crop forage mixtures of triticale (TRT), rye (RYE), and barley (BLY), in the dry season for SSDS. Treatment mixtures were TRT+RYE, TRT-BLY, and RYE+BLY. Fully mature cereal mixtures crops were treated with 4 - 6% granular urea (plus water) on a fresh basis. Forage variables were analysed with a split-plot design. Whole-crop forage yields were 3.4 ton/ha, with highest yields for RYE-BLY. Crude protein content increased two-fold in treated forages, and dry matter digestibility was moderate with a mean estimated ME content of 7.9 MJ ME/kg DM. Performance was evaluated by an on-farm 3x3 Latin square experimental design repeated 3 times with nine Holstein cows. Cows were offered daily 9.0 kg DM of urea treated forage; complemented with 4.4 kg DM of concentrate, day-grazing, and 1.5 kg of cut pasture. There were no statistical differences (P>0.05) for any of the animal variables. Urea treatment of whole-crop mature cereal mixtures resulted in a complementary moderate quality salvage forage for the dry season.