Effects of different methods of wheat grain processing on skeletal growth, blood metabolites, feed consumption and digestion in neonatal Holstein calves

Fifty six neonatal Holstein calves (22 male and 34 female) were fed calf starters and post weaning diets containing 35 and 21.90% Popped (PW), steam flaked (SFW), dry-rolled (DRW) or ground (GW) to 12 weeks of age. Particle size distribution of processed wheat grains, skeletal growth measures, starter digestibility, starter intake, health status, and blood metabolites of neonatal calves were assessed in weeks 4, 8 and 12 to assess rumen development and find the optimum method of wheat processing for calves. The experiment started when calves were 3 ± 1 d old and studied for 90 days. Calves were weaned at the end of 9th week and a post weaning specific starter diets were fed for one month. PW and SFW dramatically decreased fine particles in comparison to GW or DRW. PW had the most proportion of larger particles (93.52% >3.38 mm) where GW had the finest texture (70.71% <2 mm). Health status parameters of calves did not affected by treatments, but respiratory index was affected by time. Skeletal growth measures including body length, body barrel, wither height and hip width did not affected by treatments, but these measures progressed by age. Calves received PW had the highest body weight and daily gain, but feed; gain ratio was not affected by treatments. These parameters were also affected by age. Although, calves received DRW had the lowest starter intake, but the highest digestibility coefficients for dry matter, organic matter, crude protein, NDF and energy. This higher digestibility was attributed to lower starter intake resulted in probably higher rumen retention time and thus the most rumen degradation of nutrients. Calves received PW, had the highest serum glucose, BHBA and insulin concentrations which may indicate that PW could cause a better rumen development and performance in comparison with other types of processed wheat.