EFFECTS OF STAGE OF MATURITY OF TIMOTHY HAY AND CONCENTRATE SUPPLEMENTATION ON PERFORMANCE OF LACTATING DAIRY COWS

Abstract

The effects of concentrate supplementation of timothy hay cut at the late-boot and early-bloom was tested with dairy cows during two feeding and two digestibility trials. The diets for each trial contained the following hay to concentrate ratios: 100:0, 85:15, 70:30 and 55:45. Daily dry matter intake and fat-corrected milk production, respectively, were 15.1, 16.8, 18.6, 19.4 kg; 16.7, 20.7, 23.1, 21.0 kg for the four diets containing early-cut timothy hay and 11.0, 14.7, 17.2, 19.8 kg; 8.4, 10.7, 13.3 and 15.9 kg for the late-cut timothy hay. Percent digestibilities of the four diets containing early-cut and late-cut timothy hay, respectively, were 65.6, 65.6, 66.9, 66.8 and 53.6, 53.6, 60.2, 62.9 for dry matter; 62.5, 63.7, 65.2, 65.3 and 24.0, 39.3, 53.3, 60.0 for nitrogen; 70.3, 70.3, 68.4, 67.8 and 53.7, 53.4, 60.1, 62.6 for gross energy; 66.4, 65.3, 67.1, 66.6 and 55.0, 54.5, 61.4, 63.5 for cell wall constituents; 68.2, 65.8, 64.9, 63.4 and 50.8, 48.2, 52.7, 52.1 for acid detergent fiber. Timothy hay cut at late-boot stage as sole source of feed supported a daily milk production of 16.7 kg compared to 15.9 kg for cows consuming timothy hay cut at late-bloom stage supplemented with 9 kg of concentrate.