Starch Source Evaluation in Calf Starter: II. Ruminal Parameters, Rumen Development, Nutrient Digestibilities, and Nitrogen Utilization in Holstein Calves

Abstract

Ruminal parameters, rumen development, nutrient digestibilities, and N utilization were estimated in Holstein calves fed starch from different sources. Ground corn, ground barley, ground wheat, and crimped oats were used to formulate 4 isostarch (25% of starter dry matter) pelleted diets. These diets were randomly allocated to calves (16 calves per treatment, 8 female and 8 male) and fed ad libitum along with mixed grass hay throughout the experiment. Ruminal contents and blood were sampled at d 35, 50, and 70 of age to estimate ruminal parameters and plasma beta-hydroxybutyrate, respectively. At d 70, twenty-four male calves (6/treatment) were randomly selected, euthanized, and forestomach weight, papillae length (PL), papillae width (PW), rumen wall thickness (RWT), and papillae concentration were measured. At d 63, twenty-four female calves (6/treatment) were randomly selected and moved to metabolism stalls to estimate total tract apparent nutrient digestibilities and N utilization. Female calves were given 2 wk for adaptation to experimental facilities and then total collections of feces and urine were made from d 77 to 84 of age. Ruminal pH at d 35 of age was higher in calves fed corn and oat diets than in those fed barley and wheat diets. Ruminal pH at d 50 and 70 of age was the lowest in calves on barley diets followed by those on oat and wheat diets and then by those on the corn diet. Ruminal total volatile fatty acid concentrations at d 35 of age were greatest in calves fed corn or wheat diets followed by those fed barley and oat diets. Calves on corn and wheat diets maintained greater ruminal volatile fatty acids concentrations at d 50 and 70 of age. Ruminal ammonia, acetate, propionate, butyrate, and blood beta-hydroxybutyrate concentrations were also greater in calves on the corn and wheat diets. Full and empty weights of forestomach, PL, PW, RWT, and papillae concentrations were greater in calves on corn and wheat diets. Daily average intake of nutrients (dry matter, crude protein, neutral detergent fiber, starch, Ca, and P) was greater in calves fed corn and wheat diets than in those fed barley and oat diets. Starch source did not influence the total tract apparent digestibilities of nutrients in calves. Daily N retention (g/d) was greatest on the corn diet followed by the wheat diet and then the barley and oat diets. In conclusion, calves on a corn diet have greater ruminal capacity to accommodate feed bulk. More physically and metabolically functional rumens in calves on corn and wheat diets probably resulted in greater feed consumption and N retention.

Performance, rumen development, and carcass traits of male calves fed starter concentrate with crude glycerin

“…The data show the positive effect of including crude glycerin in starter concentrate on rumen-reticulum development, which was probably due to the higher concentrate intake, which is considered the main stimulant to develop the rumen by the end product of its fermentation (Harrison et al, 1960;Coverdale et al, 2004;Khan et al, 2008;Boyd et al, 2013). The rumen-reticulum weight and volume increased ninefold in eight weeks in the animals fed concentrate with 240 g kg −1 crude glycerin, compared with the reference animals.…”

“…Regarding the increase in DMI as a function of age, its response is commonly observed in feeder calves in the unweaned phase, as reported in other studies (Bach et al, 2007;Khan et al, 2008;Lee et al, 2008;Bach et al, 2013), as a result of animal growth and because the intake of a fixed quantity of milk does not meet the entire maintenance and weight-gain requirements of the animals.…”

Effect of feeding ensiled maize grain on rumen development and calf rearing performance

“…Khan et al (2008), who used isostarch (25% DM) diets containing different starch sources, found statistically significant differences in the ruminal VFA concentration. The diet containing only dry maize grain as the major source of starch was characterized by the lowest ruminal starch degradation and the numerical value for total VFA in calves from group M D was lower (P>0.05) than in those fed ensiled maize grain diets.…”

“…The use of different sources of carbohydrates (Suarez et al, 2006a,b) and starch (Khan et al, 2008) in feed mixtures has different effects on the development of metabolic and absorptive functions of the rumen as well as calf rearing performance. Barley, oats and wheat are almost completely digested in the rumen, while ruminal degradation of dry maize grain is slower with much more starch passing to the small intestine (Huntington, 1997).…”

Nutritional strategies to control ruminal acidosis in feedlot cattle

“…Rumen wall characteristics related to papillae length are in agreement to those reported by Khan et al (2008), who reported that corn diets increased papillae length and width compared to wheat, although animals had similar papillae concentration and rumen mucosa colour, which was described as dark brown. Those authors performed their study on post-weaning calves at the early stages of rumen development.…”