Influence of high-oil algae biomass as a feed intake and growth-performance enhancer in feedlot cattle during period of high ambient temperature

Abstract

Sixty calf-fed Holstein steers (290 +/- 2 kg) were used in a 90-d trial to evaluate the influence of fresh high-oil algae biomass as a feed intake and growth-performance enhancer in feedlot cattle. Steers were grouped into 5 weight blocks, and randomly assigned within blocks to 15 pens (4 steers per pen, 4 pens per treatment). All steers were fed the same steam-flaked corn-based basal growing-finishing diet. Three treatments were evaluated (1) basal diet, (2) basal diet plus 60 g/head water or (3) basal diet plus 60 g/head high-oil algae biomass. On an as-fed basis, the algae biomass contained: 78.4\% moisture, 2.15\% ash, 0.21\% N, 0.07\% starch, 0.50\% neutral detergent fiber and 17.2\% ether extract. Steers were fed once daily. Water and algae biomass treatments were top-dressed onto the basal diet at time of feeding. On a dry matter basis, algae biomass application accounted for 0.14\% of average daily feed intake. Top-dressing the basal diet with water did not affect (P > 0.20) cattle growth performance or dietary net energy (NE). In contrast, top-dressing feed with algae biomass increased average daily gain (7.8\%, P = 0.02), and tended to increase gain efficiency (5.7\%, P = 0.08) and estimated dietary NE (3.7\%, P = 0.09). We conclude that application of low levels of high-oil algae biomass may enhance daily weight gain of feedlot cattle during period of high ambient temperature. This effect is due in part to an apparent increase in efficiency utilization and in part to an increased dry matter intake.