Title: Milk Production Response of Dairy Cows Fed High-Moisture Grass Silage. I. Effect of Varying Levels of Hay and Concentrate
Abstract: Varying levels of bay and concentrate were fed in conjunction with high-moisture grass silage ad tibitum to 16 lactating cows, to determine the effects of these ration variables on milk production and composition.Feeding the higher level of concentrate (0.6 kg/kg 4% FCM over 8.16 kg) resulted in the production of more 4% FCM (P < 0.01), as well as higher percentages of milk protein (P < 0.01) and solids-notfat (P < 0.01) than produced when the lower level of concentrate (0.3 kg/kg 4% FCM over 8.16 kg) was fed.Varying the level of hay fed between 0.5 and 1.0 kg/100 kg body weight had no significant effect on the amount of milk produced or its composition.Likewise, no significant effects on the per cent of milk fat were observed by varying levels of either hay or concentrate within the limits fed in this study.Increasing the level of concentrate fed was more effective than increasing the level of hay for maintaining high dry-matter intake and in meeting the estimated TDN requirements of the cows.The TDN system of feed evaluation provided a reliable estimate of the relative nutritive value of these rations.Grass silage is the principal winter forage fed dairy cattle on many farms.The bulk of the silage made on farms in the north Pacific coastal area is harvested by direct-cut methods, in spite of research evidence that partial wilting of immature, succulent forages before ensiling reduces dry-matter losses in storage (7,13,17) and increases silage dry matter intake when fed (10,14,16).Cool, damp weather prevailing during first-cutting harvest makes wilting a questionable practice on most farms in this area.