the effect of alfalfa hay particle size and soy hull on physically effective fiber content in diet, chewing activity and milk production in holstein dairy cows

this study was conducted to evaluate the effects of alfalfa hay (ah) particle size and soybean hull (sh) on physical effective fibre (pendf), particle size distribution in diets, chewing activity as well as milk composition and production in early lactating dairy cows. eight lactating holstein cows averaging 590±33 kg of bw and 47±13 days in milk were assigned in a 4×4 latin square design to a 2×2 factorial arrangement of the treatments: alfalfa hay particle size (fine vs. coarse) combined with soy hull (zero or as a substitute for 50% of ah). the pendf and physically effective factor (pef) values of diets increased by increase in ah particle size and inclusion of sh in diets (p