The Use of Dehydrated Forages in Dairy Cattle Rations. I. Grain Substitution with Finely Ground Material

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Abstract
20 high-producing dairy cows were divided into 4 exptl. groups consisting of 3 Holsteins, 1 Jersey and 1 Guernsey per group. Three rates of grain replacement (15, 30 and 45%) with a commercially dehydrated grass-legume mixture were studied a total of 28 weeks, using 6-week exptl. periods, and 1 week for transition for each group of cows for each ration. Cows, when fed the control ration, gained an avg. of 25.7 lbs. in body wt. per cow per period, as compared with 16.8, 18.6 and 8.5 lbs. when they had 15, 30 and 45%, respectively, of their grain replaced with dehydrated grass. The cows on the control ration also produced an avg. of 36.8 lbs. fat-corrected milk daily as compared to 35.5, 35.3 and 35.7 lbs. when they had 15, 30 and 45% of their grain ration replaced with dehydrated grass, respectively. This difference in production in favor of the control ration was statistically significant. The finely ground physical state of the dehydrated grass-legume mixture was undesirable, since cows having 30 and 45% of their grain replaced showed varying degrees of rumen atony and anorexia. This condition was not observed when the cows were on the control and 15% rations, Cows receiving no dehydrated grass required less total digestible nutrients for maintenance and production of 100 lbs. of 4% fat-corrected milk than when they received dehydrated grass. The rate of decline in milk yield was less rapid when the cows were fed the control ration, but these mean differences only approached significance.