Comparison of Low Alkaloid Tall Fescues and Orchardgrass for Lactating Jersey Cows

Abstract

Johnstone (prevarietal release) and Kenhy, new varieties of tall fescue (Festuca arundinacea Schreb), were compared with Boone orchardgrass (Dactylis glomerata) in 2 yr. Cultivars were maintained in a vegetative stage by removal of excess growth. Johnstone seed and the resulting cultivar were 6.7% infected with endophyte fungus (Acremonium coenophialum). Forage from each cultivar was chopped daily and fed individually to five lactating Jersey cows for 12 wk in 1983 and to eight cows for 9 wk in 1984. Cows were fed 6.8 and 4.5kg daily of a 16% crude protein concentrate in 1983 and in 1984, respectively. No evidence of fescue toxicosis was observed in 1983, but a trend toward depressed prolactin occurred in 1984 for Johnstone tall fescue. Daily dry matter intake, intake as percent body weight, and daily milk production were significantly higher on orchardgrass than on tall fescues. Intake as percent body weight, daily milk, milk protein, and fat-corrected milk were significantly higher on Johnstone than on Kenhy tall fescue. Although the experimental design did not allow direct comparison, performance appeared to be as good on Johnstone fescue as on orchardgrass. The inferior animal performance on fescue compared with orchardgrass seems to be due entirely to Kenhy.