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

Abstract

A feeding expt. was carried out with different levels of crude fiber in the feed of dairy cows of Holstein-Friesian breed. Except for fiber, other nutritive factors were kept alike in different rations, that is, digestible protein and T. D. N. A sufficient supply of vitamins and minerals was provided. Four different rations were tried: namely, A, with 60 lbs. Napier grass; B, with 40 lbs. Napier grass; C, with 20 lbs. 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. Crude fiber content for different rations was in percentage of dry matter as follows: A, 22.7%; B, 19.6%; C, 16.1%; and D, 12%. Effect of the level of crude fiber in the feed upon milk production was highly significant. With an increase over 16% 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 avg. daily yield of 4% F. C. M. per cow for 12 weeks was: Ration A, 20.6 lbs.; ration B, 21.7 lbs.; ration C, 23.4 lbs.; ration D, 23.8 lbs. The pulse rate, respiration rate and body temp. of the cows were recorded during the expt. The rations influenced the pulse rate in such a way that this rate was lower when no roughage was fed. Pulse rates per min. for cows with no roughage were 62, and increased to 69 with roughage. The statistical significance of this influence of rations falls close to the 1% point. In conclusion it may be stated that for high milk production, the crude fiber level in the feed should not exceed 16% 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.