Effect of Dietary Fiber Level on Lactating Dairy Cows in the Humid Tropics

Abstract

A single-reversal feeding trial involving 12 Holstein Friesian × Red Sindhi crossbred cows fed rations differing primarily in crude fiber content (12.5 vs. 18.5%, dry-matter basis) was conducted during January–April, 1966, to determine effects of fiber content of the ration on milk production and physiological responses of milking cows. Feeding of the low-fiber ration resulted in significant increases (P < .01) in the production of 4% fat corrected milk (FCM) and in per cent ruminal propionic acid; significant decreases (P < .01) in milk fat percentage, rectal temperature, pulse rate, respiration rate, and per cent ruminal acetic acid. In the humid tropics, fiber level should be considered in formulating rations for lactating cows. The significant rise in rectal temperature with increased fiber intake indicated an increased heat stress of the cows. © 1967, American Dairy Science Association. All rights reserved.