Influence of Crude Fiber in the Ration on Efficiency of Feed Utilization by Dairy Cows

Abstract

A feeding experiment has been carried out with different levels of crude fiber in the feed of dairy cows of Holstein-friesian breed. Except for fiber, other nutritive factors (digestible protein and T.D.N.) were kept alike in different rations. A sufficient supply of vitamins and minerals also was provided. Four different rations were tried, namely, A with 60 lb. Napier grass, B with 40 lb. Napier grass, C with 20 lb. Napier grass daily per cow and D with no Napier grass. The balance needed of protein and T.D.N. was made up of pineapple bran, soybean oil meal, meat meal, fish meal and molasses. The crude fiber content for different rations were in percentage of dry matter as follows: A, 22.7 per cent; B, 19.6 per cent; C, 16.1 per cent; and D, 12.0 per cent. The effect of the level of crude fiber in the feed upon milk production was highly significant. With increase over 16 per cent in crude fiber content of the feed, a drop in milk production occurred, regardless of the fact that equal amounts of T.D.N. and digestible protein were fed. The average daily yield of 4 per cent F.C.M. per cow for 12 wk. was 20.6 lb.on ration A, 21.7 lb. on ration B, 23.4 lb. on ration C, and 23.8 lb. on ration D. Pulse rates per minute for cows with no roughage were 62, and increased to 69 with roughage. The statistical significance of this influence of rations fell close to the 1 per cent point. For high milk production, the crude fiber level in the feed should not exceed 16 per cent when calculated on basis of dry matter content of the ration. This holds true for feeds such as mature Napier grass and pineapple bran as major constituents of the rations. © 1950, American Dairy Science Association. All rights reserved.