Alfalfa with and without Concentrates for Milk Production

Abstract

Milk and butterfat production results are reported for 17 mid-lactation periods of 28 days each when alfalfa hay supplemented only with salt and P was fed and 25 periods during which part of the alfalfa hay was replaced with a calculated equal amt. of total digestible nutrients in various concentrates. The study showed that the total digestible nutrient system of feed evaluation considerably overrates the production value of good alfalfa hay when fed in large amts. to good cows as the only source of digestible nutrients. The net energy system of feed evaluation more nearly gives a sole alfalfa hay ration its proper production value. Each of 12 different concentrates fed alone or with starch or sugar at a 13 to 25% alfalfa hay replacement level allowed cows to produce normally. Ground soybeans stimulated milk production to the greatest extent of any concentrate used possibly due to increasing the % of ether extract in the dry matter from 2.23% to 3.98%. There was no indication that the better milk production with concentrate feeding was due to improvement in the quality of protein. No consistent measurable effect of the concentrates fed on the % of butterfat in the milk or on the body wt. of the cows was noted.