The enrichment of chocolate byproducts and protected fats with zinc to partially replace corn in diets of early lactation Holstein cows

Abstract The present experiment aimed to evaluate the effect of partial replacement corn with chocolate byproducts, protected fats, or their mixture supplemented zinc in diet lactating cows on feed utilization and lactation performance for 90 days. Fifty multiparous Holstein (565±25 kg BW, 3±1 parity, 7±1 days milk, a previous milk production 35±2.9 kg/d), were randomly assigned 5 treatments completely randomized design. control contained (per DM): 412 g concentrate mixture, silage, 176 berseem hay. was 1 daily (Zinc diet). In other diets, each crushed grain replaced (DM basis) 600 byproducts (CH diet), 400 fats (PF 500 (1:1 DM (CHPF Both amounts had same energy concentration as corn. total mixed ration prepared distributed using horizontal mixer system after mixing 20 min. Chemical analysis showed that minimally affected composition rations. Additionally, did not affect intake. Compared treatment, treatment production, composition, efficiency. Increased (P<0.05) component yields, efficiency well fat observed by CH, PF CHPF treatments. Without affecting measured blood parameters hematocrit, increased concentrations proteins, albumin, glucose, cholesterol, triglyceride, cows. (P<0.01) digestibility nutrients compared treatment. It is concluded addition cow performance; however, its partially replace improved