Performance of Lactating Dairy Cows Fed Varieties of Endophyte-Free Tall Fescue

Abstract

A 3-yr study was conducted to determine the performance of midlactation multiparous and primiparous Holstein cows (Bos taurus) fed 3 endophyte-free varieties of tall fescue (Festuca arundinacea Schreb) soilage. Cultivars were maintained in a vegetative stage by removal of excess growth. Forages were ‘Johnstone’, ‘Kenhy’, and ‘Kentucky-31’ (Ky-31) tall fescues. Means for the forage content of crude protein were 14.1, 13.3, and 12.8% for Johnstone, Kenhy, and Ky-31, respectively. Concentrations of forage acid detergent and neutral detergent fibers were 30.4 and 60.1, 31.2 and 59.9, and 30.9 and 60.4% for Johnstone, Kenhy, and Ky-31 tall fescue varieties, respectively. Soilage from each cultivar was chopped daily and fed individually to 12 cows (average weight of 1128 lb) in 1986 and 15 cows (average weight of 1242 and 1365 lb) in 1987 and 1988 for 6 wk. In addition, cows were fed 20 lb of a 19% crude protein concentrate daily. No differences were detected in daily forage intake (21.4, 22.0, 20.7 lb/d), milk production (56.4, 59.1, 56.7 lb/d), milk fat percentage (3.38, 3.40, 3.39%), respiration rate (75.1, 71.8, 71.7 counts of breaths per minute), rectal temperature (101.8, 101.8, 101.9° F), or serum prolactin (Prl) concentration among cows fed Johnstone, Kenhy, or Ky-31 forage, respectively. Endophyte-free varieties of Johnstone, Kenhy, and Ky-31 appeared to be equal in their ability to support milk production in lactating dairy cattle.