The effect of grain processing and grain source on performance, rumen fermentation and selected blood metabolites of Holstein calves

The aim of the study was to determine the effects of type of grain processing and grain source on growth performance of calves. Thirty-two male Holstein calves were randomly assigned to 1 of 4 treatments differing in type of grain processing and grain source: CON - ground maize + ground barley, DMGB - dry-rolled maize + ground barley, GMDB - ground maize + dry-rolled barley, and DMDB - dry-rolled maize + dry-rolled barley. All calves were fed for 14 days (starting from day 4 of experiment) and weaned on 60 day of age and remained in the study until day 74. It was obtained that final and weaning body weights were higher in DMGB and DMDB groups in comparison to CON group. The total dry matter intake was greater in calves fed DMGB diet than in those fed CON diet. Averaged daily gain (ADG) was greater in calves fed DMDB diet than in those fed CON diet during the pre-weaning and overall periods, whereas during post-weaning period the ADG was greater in DMGB group in comparison to CON treatment. Ruminal pH was greater in DMGB and DMDB groups as compared to other groups on days 46 and 60, while ruminal NH3-N content was decreased in DMGB and GMDB groups. On day 46 glucose level was decreased in blood of animals fed all examined treatments. Blood beta-hydrogbutyrate level was greater (P = 0.01) in group fed DMGB diet in comparison to CON and GMDB groups at weaning. In conclusion, starter diets containing dry-rolling maize and barley can better improve calf performance than diets containing ground maize/ground barley.