Varietal Differences in Palatability of Orchardgrass (Dactylis glomerata L.) and Breeding for Palatability and Quality
Palatability of 14 varieties of orchardgrass (Dactylis glomerata L.) was evaluated with Holstein heifers by using a trough cafeteria method for 4 years. Highly significant differences in the palatability of varieties were recognized throughout the growing seasons in each year. Multiple regression analysis was carried out in 15 cafeteria trials to identify the variables which could predict the palatability of varieties. Among 41 available variables, the best combinations of 2 variables were identified in each growing season. For all the seasons, the concentration of Ca, the concentration of P, and flexibility of leaf and stem were considered to be the best positive predictors for the palatability. In contrast, ADF and 3 kinds of diseases (Rhynchosporium scald, rust and total leaf diseases) were considered to be the best negative predictors for the palatability. Lude, a French variety, exhibited superior characteristics in quality compared with other varieties, namely, high palatability, resistance to rust and total leaf diseases, high flexibility of leaf and stem and the highest concentration of Ca among the tested varieties. Intake of fresh materials in 2 varieties, Lude and Akimidori was compared by using Holstein heifers, It was observed that the estimated increase of dry matter intake (DMI, g/kgBW0.75) of Lude over Akimidori was 3.49 g at the same DMD level, High palatability in Lude might have a positive effect on the DMI level and could increase it more than expected from the DMD level. A model for the improvement of both palatability and quality which includes digestibility and mineral-balances was proposed as a part of the forage breeding program in Japan.
|作成者||Kazuhiko MIZUNO Shigeru SHIOYA Fumihiro FUJIMOTO Shin-ichi SUGITA|