Feeding Value of Low-Moisture Alfalfa Silage from Conventional Silos

Abstract

Summary The feeding value of low-moisture alfalfa silage from conventional tower silos was compared to the same crop preserved as high-quality hay. Silage or hay was fed ad lib as the only forage to dairy cattle or heifers in four feeding trials. Average daily forage dry matter intakes by dairy cows were 24.3 vs. 23.0 and 24.6 vs. 25.1lb for low-moisture silage and hay, respectively. The corresponding values for FCM production were 23.4 vs. 22.5 and 33.5 vs. 32.8lb. Heifers consumed similar amounts of low-moisture silage and hay dry matter per day (16.5 vs. 17.1 and 21.3 vs. 21.5lb, respectively) and made similar liveweight gains (.93 vs. .71 and 1.71 vs. 1.62lb). Analysis of variance indicated no significant differences in these means at a 5% probability level. Proximate composition of the two forage types showed a consistent tendency for higher crude protein and lower crude fiber in the low-moisture silages compared to the matched hays. These silages were characterized by low contents of ammoniacal nitrogen and total acid, with a predominance of lactic acid and more than 2% reducing sugars. This indicated excellent preservation and limited fermentation. Higher digestibility of silage was observed in one of the two years. It was concluded that replacement of field curing with low-moisture ensiling would be advantageous in many instances, since this would permit greater independence from weather and full automation of harvesting and feeding, with no sacrifice in feeding value.