Yield, herbage composition, and tillering of timothy cultivars under grazing

Abstract

Timothy is widely grown for silage and hay in eastern Canada. The relative performance of timothy cultivars under grazing is not, however, well documented. This research determined dry matter production, herbage composition, and tiller characteristics of 34 timothy cultivars under two grazing schedules over 3 yr on the same plots. Several cultivars outyielded the standard cultivar, Farol (7.96 t ha-1), by up to 10% for the 3-yr mean. Richmond and Comtal were the highest-yielding cultivars (8.75 t ha-1) while AC Regal had the best relative yield persistence over the experimental period. Crude protein concentrations of cultivars ranged from 172 to 208 g kg-1 for early and 150 to 179 g kg-1 for late grazing. Neutral detergent fibre (NDF) concentrations ranged from 460 to 495 g kg-1 and concentration of acid detergent fibre (ADF) ranged from 241 to 270 g kg-1 among the cultivars in early grazing. Differences in NDF and ADF concentrations between early and late grazing schedules varied among the cultivars indicating a variable rate of change in fibre concentration. Farol, Timora, Promesse, and Comtal had greater tiller densities than most other cultivars while AC Alliance, Colt, and Winmor had below average tiller densities throughout the grazing season. The ratio between reproductive and vegetative tillers was higher early in the season, than later, but depended on the grazing schedule. The reproductive to vegetative tiller ratios covered a wide range in the third (2–54) and fourth (3–115) grazing periods. We conclude that yield and relative yield persistence of timothy cultivars under grazing varied greatly among cultivars. Tillering density of cultivars also varied but was not significantly related to cultivar performance under grazing. Key words: Timothy, Phleum pratense, grazing, composition, tiller