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Effects of inclusion of graded amounts of soya bean hulls on feed intake, chewing activity and nutrient digestibility in dairy cows
Author(s) -
Mohammadzadeh H.,
Rezayazdi K.,
Nikkhah A.
Publication year - 2014
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1111/jpn.12094
Subject(s) - soya bean , nutrient , agronomy , food science , biology , zoology , ecology
Summary Twelve multiparous H olstein dairy cows were used in a replicated 4 × 4 L atin square changeover design to evaluate the effects of graded inclusion of soya bean hulls ( SH s) in replacement of diet forages at 0%, 10%, 20% and 30% of dietary dry matter ( DM ) basis on pe NDF > 8 and pe NDF > 1.18 contents of diets and their resulting effects on chewing activity, nutrient digestibility and milk production of dairy cattle. The control diet contained 50% forage, 50% concentrate and no SH. In the other three diets, SH was substituted for alfalfa hay, corn silage and wheat bran to supply 10%, 20% and 30% of the dietary DM . Increasing SH concentration in the diets resulted in decreasing concentrations of forage neutral detergent fibre ( NDF ), physically effective NDF (pe NDF ) and mean particle size (p < 0.01). Chewing activity per kilogram of daily dry matter intake ( DMI ) was not affected by the different diets tested. However, chewing activity significantly decreased for kilogram intake of NDF , but increased for pe NDF > 1.18 when SH was included in the diets (p < 0.01). Total tract apparent digestibility of nutrients significantly increased for DM , organic matter (p < 0.05) and NDF (p < 0.01) but decreased for crude protein (p < 0.05) as the proportion of SH was increased in the diets. Rumen pH value of cattle was not influenced by the diets. Including medium and high amounts of SH in the diets decreased DMI of the animals (p < 0.05) without any significant effect on their daily milk or 4% fat‐corrected milk production. In conclusion, the results of this study showed that the NDF from a non‐forage fibre source like SH had a lower potential for stimulating chewing activity than did forage NDF . Despite this, the small size of dietary particles increased not only the chewing activity per kilogram of pe NDF intake but also saliva secretion as well as the potential for rumen to neutralize acids. The findings of this study demonstrate the greater differences in pe NDF > 8 among the diets and that these differences are better reflected in terms of DMI , chewing activity and nutrient digestibility, but not in rumen pH .