Utilization of Co-Products from the Biofuels Industry As Alternative Protein Sources in Growing Dairy Heifer Diets.

Feeding co-products of the biofuels industry as alternative protein sources to growing dairy heifers can improve or maintain performance as well as reduce costs. Over the last five years we have conducted several studies evaluating the utilization of distillers grains and developing oilseed meals. All the studies were randomized complete block design experiments in which heifers were individually fed using Calan gates. Two 16-wk studies were conducted to evaluate the effects of limit-feeding dairy heifers distillers dried grains with solubles (DDGS) with varying forage to concentrate ratios. The first study had 48 heifers and treatments were 1) 30% DDGS, with diet fed at 2.65% of body weight (BW), 2) 40% DDGS, with the diet fed at 2.50% of BW, and 3) 50% DDGS, with the diet fed at 2.35% of BW. The remainder of the diets were grass hay and 1.5% mineral mix. The second study had 24 heifers and treatments were a corn and soybean product concentrate mix compared to DDGS. Both concentrate mixes were limit-fed at 0.8% of BW and grass hay was fed ad libitum. Results demonstrated that DDGS can be included at 30, 40 or 50% of dietary DM in replacement of hay in limit-fed diets or can be fed in replacement of corn and soybean meal with ad libitum grass hay and maintain growth performance. Gain to feed also increased as DDGS was increased in the diet. Research has also been conducted on camelina and carinata, which are promising sources of oil for biodiesel. The meals have high quality protein, but contain glucosinolates which can affect taste, growth, thyroid function, and limit dietary inclusion rates. A 12-wk study was conducted using 42 heifers with treatments including 10% of the diet as camelina meal, linseed meal, or DDGS. Feeding camelina meal maintained frame growth and average daily gain but decreased gain:feed compared to the other diets. Two 16-wk studies were also conducted on feeding carinata meal, one with 24 heifers and a second with 36 heifers. The first compared cold-pressed carinata meal with DDGS. The second compared solvent-extracted carinata meal with canola meal or a control diet containing soy products. Both studies demonstrated that carinata meal can be fed at 10% of the diet and maintain growth performance compared to commonly used protein sources. Overall, feeding alternative proteins can offer viable and economical options for growing dairy heifer diets.