Comparative yield and nutritive value of forages from two cereal-legume based cropping systems. 2. Milk production and reproductive performance of crossbred dairy cows

Thirty-six crossbred cows were used in a 2 × 2 factorial arrangement in a randomized block design to evaluate forages from two cropping systems (1 and 2) and feeding levels [ad libitum, (Level 1)] or 80% of ad libitum (Level 2) on milk yield, live weight, and reproductive performance. Crops in System 1 were: oat-vetch, wheat-trifolium, teff straw, and cowpea, and in System 2 maize-lablab replaced wheat-trifolium. The presence of legumes in crop mixtures improved forage quality. System x feeding level interaction effect was included in the analytical model. Mean (±SE) daily milk yield was higher (P < 0.01) in System 2 (4.02 ± 0.13 kg) than in System 1 (3.12 ± 0.13 kg) and higher in cows fed ad libitum (3.94 ± 0.13 kg, P < 0.01) than in cows on the restricted regime (3.21 ± 0.13). Milk composition was not influenced by treatments. Cows on Level 1 lost more (P < 0.05) live weight than those on Level 2 (4.8 vs 1.8%) from mobilization of body reserves to support the increasing milk production. Conception rate was similar between systems but higher (P < 0.05) for cows on Level 1 than Level 2. Supplementary feeding strategies for the type and level of feeding used, have to be developed in order to improve milk production and reproductive efficiency.