Chewing activity by dairy cows in response to particle size of diets and intake of neutral detergent fiber and forage neutral detergent fiber
Advisor:Firkins, Jeffrey Lynn, 1958-
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. College of Food, Agricultural, and Environmental Sciences Honors Theses; 1998
Proper rumen function is necessary for maintaining overall health of dairy cows. Rumen function is dependent on rumen pH being in the range of 6.2 to 6.5, which is regulated by the amount of time spent chewing. Chewing activity is stimulated by intake of forages and to a lesser extent by particle size of the diet. Nonforage fiber sources, specifically soyhulls and whole cottonseed (WCS), were investigated for their ability to stimulate chewing when used to replace a portion of both forages and concentrates in the diets for lactating dairy cows. Forty-four lactating dairy cows were randomly assigned and fed one of the four following diets that were formulated to contain: 1) 21% forage NDF (FNDF) with corn, 2) 16% FNDF with corn, 3) 16% FNDF with a 1:1 ratio of corn and wheat, and 4) 11% FNDF with corn and whole cottonseed (WCS). The mean particle size (MPS) was measured for all of the diets. Total time spent chewing per kg of both FNDF and NDF was also determined. The MPS was decreased by the addition of soy hulls and WCS in place of a portion of forage and concentrate in the diets. Total time spent chewing was not significantly different between the diets. Results of the study indicate that the addition of soyhulls and WCS were able to effectively replace a portion of forages and concentrate in the diets of lactating dairy cows and still maintain total time spent chewing and therefore proper rumen function.