Document Type : Research Paper
Assistant Professor, Department of Animal Science, Faculty of Agriculture and Natural Resources, Arak University, Iran
Associate Professor, Department of Animal Science, Faculty of Agriculture and Natural Resources, Arak University, Iran
Hundred and thirty lactating Holstein cows (36 primiparous and 94 multiparous) in early lactation period (34.3 ± 9.1 days in milk) with averaging milk yield 52.2 ± 9.2 kg/d were allocated in a change-over design to compare the feeding of finely ground (FGC) versus steam flake corn grain (SFC). The performance, some blood metabolites, liver enzymes and insulin hormone were evaluated. The study lasted 44 days in two 22 days periods with the first 17 days as adaptation period and the last 5 days as sample collection period. The SFC was prepared by steam flaking of corn for 30 minutes in a stainless steel tank to increase the corn moisture up to 18-20%. The results show that DMI (P=0.53) as well as milk yield (P=0.078) were not differing between treatments (P>0.05). Corrected milk fat was tended to be greater for FGC compared to SFC (P=0.07), and energy corrected milk also was increased in SFC (P=0.02). Feeding ground corn caused to increase milk fat and steam flake corn feeding caused to increase milk protein percent (P<0.01). Although flaking increased blood glucose concentration, no other blood metabolites were differed between treatments. Insulin concentration as well as liver enzyme (ALT and AST) concentrations was similar between two treatments (P>0.05). In conclusion considering the cost of flaking and the base on present research results, corn grain flaking may not be recommendable for early lactation period.