Abstract: This study was to evaluate the effects of maize silage particle size and feeding method on dry matter intake, ruminal fermentation, chewing activity and passage rate of lactating cows. Four multiparous Holstein cows fitted with ruminal cannulas, averaging 625 kg of body weight and 195 days in milk, were assigned to a 4x4 Latin square design. The geometric mean of particle length was calculated according to Penn State Particle Separator. Treatments consisted of Total Mixed Ration (TMR) with 100% short maize silage (SS, 6.3 mm), TMR with 50% short maize silage +50% long maize silage (SL, 10.7 mm), TMR with 100% long maize silage (LL, 16.4 mm) and Separate Ingredients (SI) feeding compared with TMR. With the increasing of maize silage particle size, ruminating (p = 0.05) and chewing time (p = 0.03) responded quadratically. There was a significant linear increment (p = 0.01) of ruminal pH from 6.20-6.39 with increased particle size. Significant linear effects of diets were detected on the total Volatile Fatty Acids (VFA) (p = 0.01) and propionate (p = 0.02) concentrations of which the greatest value appeared in the diet-LL. However, concentrations of acetate (p = 0.01) and butyate (p = 0.01) were linearly decreased with increasing particle size. Cows fed diet-SI spent more time ruminating (p = 0.05) and consumed less acid detergent fibre (p = 0.04) than cows fed diet-SS. Feeding method did not affect ruminal pH and total VFA concentration.
Zhijun Cao, Mei Ma, Peng Ji and Shengli Li, 2010. Effects of Maize Silage Particle Size and Feeding Method on Ruminal Fermentation, Chewing Activity and Passage Rate of Lactation Cows. Journal of Animal and Veterinary Advances, 9: 374-383.