High Levels of Grass Silage for Milk Production with No Grain, Medium, and High Grain Feeding. 1. Intake, Milk Production, and Body Weight Changes

Abstract

Summary A three-lactation study with 18 Holstein and six Guernsey cows compared roughage intake, milk production, and weight changes on three levels of grain feeding (no grain, medium grain—1:6, and high grain—1:3) with maximum molasses-grass silage intake in addition to 5lb. good alfalfa hay. Pasture was supplied during the summer. For each pound of grain fed, roughage dry matter intake decreased 0.23lb. Average hay equivalent intake was 2.15lb. over all groups. Average 245-day 4% FCM production for 12 cows with an estimated potential of 8,830lb. was 6,490, 7,690, and 8,910lb. on the three rations; for 12 cows with an estimated potential of 10,930lb., production on the three rations was 8,080, 10,100, and 12,960lb., respectively. There was no evidence of carry-over effects in the reversal phase or cumulative effects in the continuous phase. There was a close relationship between potential producing ability of the cows and response, measured as the ratio of extra milk produced per pound of grain fed, comparing production on high grain with that on no grain (r = 0.88). Cows which had a 245-day potential of 8,900lb. FCM gave 0.58lb. milk per pound grain fed; whereas, those with a 245-day potential of 11,700lb. FCM gave 1.35lb. milk per pound grain fed. There was no evidence of diminishing returns in the high-potential cows, and relatively little for the lower-potential cows. Differences in rate of decline in production during the lactation were not apparent after the first 11 wk. of lactation, with little change after 6 wk. Though cows receiving no grain lost considerable weight from the first to the fourth month (−106lb.), compared with the high-grain cows (+16lb.), they gained more in the latter part of lactation (190 vs. 142lb.) ; however, they still did not regain their precalving weight in 50 wk. High-grain feeding may be profitable for cows with the potential for high production, but not for cows with lower potential, when fed large amounts of good-quality molasses-grass silage.