Studies on Palatability in Varieties of Orchardgrass (Dactylis glomerata L.). : 6. Comparison of intake between varieties differed in palatability.

Abstract

Intake of fresh materials in two varieties of orchardgrass (Dactylis glomerata L.), Lude and Akimidori was measured by Holstein heifers for 3 days. The first, second and third trial was conducted in July 1993, November 1993 and June 1994, respectively. There were no significant differences between varieties in dry matter intake (DMI, g/kg BW^<0.75>), but the mean DMI of variety Lude was 1.0%, 2.4% and 2.9% higher than variety Akimidori in the first, second, and third trial, respectively. Dry matter digestibility (DMD) of each variety was predicted from the degradability by 1% cellulase solution. Relationship between DMI and DMD in each variety was investigated through the whole trial. According to the t-distribution, the regression coefficient of original equations which predict DMI from DMD in each variety can be pooled statistically (P>0.39). The pooled equations were as follows: DMI of Akimidori=-44.72+1.79 DMD, DMI of Lude=-41.23+1.79DMD. However, the intercept of regression line on these equations was significantly different (P<0.05). According to the difference in the values of intercept, the estimated increase of DMI value in Lude over Akimidori was 3.49 g/kg BW^<0.75> at the same DMD level. Palatability of Lude measured by the same heifers was 32.2%^<***>, 37.5%^<***> and 46.9%^<***> higher than Akimidori in the first, second, and third trial, respectively (P<0.001). Excellent palatability in Lude might have a positive effect on the DMI level and could make it higher than it was expected from the DMD level.