Supplementary value of ensiled brewers spent grain used as replacement to cotton seed cake in the concentrate diet of lactating crossbred dairy cows.

The aim of this study was to investigate the effects of ensiled brewers spent grain (BSG) when used as replacement to cotton seed cake in the concentrate diet of lactating crossbred dairy cows. Eight early lactating F1 Boran X Friesian cows were used in a short term feeding trial to identify optimum level of ensiled BSG substitution of cotton seed cake (0, 33, 66, and 100%) in iso-nitrogenous diets. A 4 × 4 double Latin square design was used to analyze the data set generated from the feeding and digestibility trials. The results showed that as the level of ensiled BSG replacement to cotton seed cake increased, daily intakes on the natural pasture hay: 8.1 (T1) vs 7.6 (T2), 6.0 (T3), and 5.1 (T4); total feed dry matter: 14.6 (T1) vs 14.0 (T2), 12.9 (T3), and 12.2 (T4); crude protein (CP): 2.0 (T1) vs 1.9 (T2), 1.8 (T3), and 1.7 (T4); neutral detergent fiber (NDF): 8.4 (T1) vs 8.2 (T2), 7.4 (T3), and 6.8 (T4); and acid detergent fiber (ADF): 4.8 (T1) vs 4.5 (T2), 3.8 (T3), and 3.3 (T4) decreased (P < 0.05). However, estimated metabolizable energy (EME) intakes (129 vs 126) and body weight of the animals (465 vs 467) on the control diet and dietary T2 (33% BSG replacement for cottonseed cake) were comparable (P > 0.05). Thereafter, differences in daily EME intakes and body weight changes decreased with an increase in the level of ensiled BSG in the concentrate diet (P < 0.05) compared with both the control and animals on T2. Ensiled BSG, on the other hand, substantially improved (P < 0.05) total ration's apparent digestibility of dry matter (DM): 629 (T1) vs 659 (T3), 686 (T4); CP: 676(T1) vs 690(T3), 738(T4); NDF: 524 (T1) vs 544 (T3), 581 (T4); and ADF: 341 (T1) vs 350 (T2), 392 (T3), 440(T4) and daily milk yield: 14.5 (T1) vs 15.4 (T4) and milk production efficiency: 0.98 (T1) vs 1.11 (T3) and 1.26 (T4). So, ensiled BSG can be recommended to fully replace cotton seed cake from the concentrate diet of lactating dairy cows under local conditions. Additional research is needed to minimize and/or avoid body weight loss, milk fat, and total solids.