Labor-saving grazing management of a Kentucky bluegrass (Poa pratensis L.) dominant pasture in Hokkaido. 1. Comparison of animal performance under fixed grazing versus put-and-take grazing.

摘要

In order to establish the labor-saving grazing management of Kentucky bluegrass (Poa pratensis L.) and white clover (Trifolium repens L.) mixed sward in Hokkaido, animal performance in a fixed grazing system was compared with that under put-and-take grazing by Holstein steers (mean initial age; 6 months, body weight; 214 kg). To reduce surplus herbage in fixed grazing, grazing was started at the plant length elongated to 5 cm and the annual fertilization rate was decreased to one-third. As a result, grazing capacity of 504 cow-day/ha and 769 kg body weight gain/ha were obtained under fixed grazing, and these were equivalent to about 80% under put-and-take grazing. Furthermore, body weight gain/head in the grazing season was comparable to that under put-and-take grazing (0.89 kg/head). Therefore, a Kentucky bluegrass and white clover mixed sward may be of practical use under fixed grazing in Hokkaido.