Effects of Expanding or Pelleting upon Feed Digestibility and Heifer Growth

Abstract

The effects of processing feed by expanding or pelleting were evaluated. Ration digestibilities and growth of 12 eight-month-old Guernsey heifers when fed rations so processed were compared with the response to a control ration containing nonexpanded grain (50% yellow corn and 50% raw soybeans) and long hay. Digestibilities of nutrients in the complete rations were determined by the chromic oxide method. Digestion coefficients were highest in the expanded and lowest in the pelleted ration. Mineral matter was retained to the greatest extent in the pelleted ration. The effects on growth were studied over an 8-wk. period using a randomized block design. Ab libitum daily total dry matter consumption in pounds was: 9.17 of the expanded 8.66 of the control, and 6.51 of the pelleted ration. Daily weight gain in pounds was: 1.68, 1.47, and 1.19 respectively. Increase in heart girth was greatest in the group fed expanded grain. Chronic bloating and a significantly lower rumen pH were associated with the feeding of the completely pelleted ration.