Keyvan Karkoodi - Department of Animal Science, Saveh Branch, Islamic Azad University, Saveh, Iran
Saeed Khalajzadeh - Department of Animal Science, Saveh Branch, Islamic Azad University, Saveh, Iran

Thirty neonatal male Holstein calves fed by starter diets containing ground wheat (GW) or dry-rolled wheat (DRW) to 12 weeks of age. Skeletal growth measures, starter digestibility, starter intake, blood metabolites and rumen metabolites of nursing calves were assessed in weeks 4, 8 and 12 to assess rumen development and find the optimum method of wheat processing for calves. Calves were weaned at the end of 9th week and a post weaning specific starter diets were fed for one month. Skeletal growth measures including body length, body barrel, wither height and hip width did not affected by treatments (p> 0.05). Calves received GW had higher (p< 0.05) body weight and daily gain. Although, calves received DRW had the lowest starter intake, but the highest digestibility coefficients for dry matter, organic matter, crude protein, NDF and energy. Calves received GW, had higher serum β-hydroxy butyrate BHBA and insulin (p< 0.05) concentrations which may indicate that GW could cause a better rumen development and performance in comparison with other type of processed wheat. Calves received GW had higher total VFA, acetate, propionate, butyrate, ammonia nitrogen, rumen wall thickness, papilla width and density (p< 0.05). Calves fed DRW experienced lower rumen pH (p< 0.05) throughout the experiment. Calves consuming GW apparently had higher starter intake, more functional rumen in terms of serum metabolites and rumen metabolites in comparison with the other group. It could be concluded that GW was appropriate to young calves in their starter diets.

Calves, Starter, Grinding, Dry-rolling, Rumen development