Effect of Alfalfa Ash and Valeric Acids on Growth of Dairy Heifers

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Abstract
Recent work by the Ohio workers (2~ 5) indicates that a combination of rumen factors including valeric acids improved cellulose digestion in the artificial rumen and improved the growth rate of beef cattle in three of four trials. It has been shown that the addition of eitlier alfalfa ash or alfalfa meal to rations contMning low-quality roughages will improve the utilization of such rations when fed to beef cattle or sheep (1,3, 4). It seemed desirable to evaluate these two factors in growing dairy heifer ra*-ions. Twenty-four yearling dairy heifers (15 Hob stein and nine Brown Swiss) were divided into three groups and used in a 150-day feeding trial to study the effect of alfalfa ash and the fatty acids, valeric and isovaleric, upon growth. All heifers were fed ground corn cobs free choice once per day as the sole roughage. In addition, Group 1 heifers were fed a 32% protein soybean oil meal grain mix in sufficient quantities to meet the heifers' need for digestible protein (6); Groups 2 and 3 were fed the same grain mix supplemented with either 25.7 g. of alfalfa ash or 1.0 g. of valeric and 0.27 g. of iso-valeric ~cids per pound of grain mix, respectively. The influence of the supplements on the feed consmnption, growth rate, and feed efficiency of the heifers is shown (Table 1). Neither the alfalfa ash nor the combination of fatty acids appeared to affect the consumption of corn cobs significantly. The supplementation of the control ration with either alfalfa ash or the combination of fatty acids increased the growth rate of the heifers significantly. Both supplements appeared to exert their greatest effect during the Published with the approval of the Director of the Michigan Agricultural Experiment Station as Journal Article No. 2115. first 30-day period. The average daily gains of the heifers were 1.71, 2.30, and 2.03 lb. for Groups 1, 2, and 3, respectively, for the first 30-day period. Average daily gains of the heifers were 1.14, 1.26, and 1.32 lb. per day for Groups 1, 2, and 3, respectively, for the last 120 days of the experiment. These latter differences in growth rate were approaching significance (5% level). The results of this experiment indicate that both alfalfa ash and the combination of fatty acids exerted a beneficial effect upon the growth rate of dairy heifers fed corn cobs as a roughage. Growth and feed consumption data collected in this experiment would indicate that both alfalfa ash and the fatty acids improved the growth rate of the heifers through some mechanism other than increased appetite.