The objective of this study was the evaluation of the inclusion of calcium propionate, sodium butyrate and sodium monensin in the starter concentrate on ruminal parameters and forestomach development in dairy calves. Fifteen newborn Holstein calves were rumen cannulated and housed in individual stalls until ten weeks old, with free access to water, fed 4 liters of milk per day, split in two meals, and starter concentrate ad libitum containing sodium butyrate (0.15%), sodium monensin (30 ppm) or calcium propionate (0.15%). Starting at the fourth week of life, before and 2 hours after the morning feeding, ruminal fluid samples were taken weekly to determine the pH, short-chain fatty acids and ammonia-N. After 10 weeks, the animals were slaughtered to assess the forestomach growth. The rumen pH was affected by sampling time and the additives used in the starter concentrate. The total short-chain fatty acids concentration and each fatty acid concentration, were was not affected by the additives. However, except for molar concentration of acetic acid, all rumen fermentation parameters were affected by sampling time. The total forestomach weight and the average weight of each compartment and the maximum reticulum-rumen capacity were not affected by additives supplied in the starter concentrate. No significant effects of the additives were observed on the height, width and number of papillae of the ruminal epithelium. The inclusion of these additives in starter concentrate had no effect on most of the ruminal parameters and forestomach development in suckling calves.
additives; early weaning; ionophores; reticulum-rumen; ruminal development; ruminal papillae
