Eucalyptus bark: A new source of fiber from the wood pulp industry for feeding to beef feedlot cattle

Abstract

Objective: Our objectives were to compare the effects of feeding eucalyptus bark or eucalyptus wood chips, both by-products from the pulp industry, on voluntary feed intake, animal performance, and physiological variables of heifers finished on high-concentrate diets. Materials and Methods: Forty-eight British-breed heifers (Angus, Hereford, and their crosses) that were 22 to 24 mo of age and had an initial BW of 355 ± 8 kg were used. Four heifers were allocated to each of the 12 pens (experimental units). The experiment was a randomized complete block design with 2 treatments and 6 replications each. The 2 different fiber sources (wood chips or bark) were included in the fattening diet in the same proportion (8.9% DM basis). The rest of the ingredients in the diet were the same. The final diet was offered 3 times per day, and heifers were fed for 84 d. Results and Discussion: Fiber source (wood chips vs. bark) did not affect ADG or G:F (P > 0.10). However, DMI (P < 0.01), DP (P = 0.04), and hot carcass weight (P = 0.06) were greater in heifers fed with bark compared with those fed with wood chips. Heifers from the bark treatment spent less time (P = 0.02) chewing than heifers from the wood chips treatment. Implications and Applications: In conclusion, bark could be used as a source of fiber for finishing cattle in high-concentrate diets at the same levels as wood chips. This finding is relevant for the feedlot industry because eucalyptus bark has no industrial uses and would represent a cheaper fiber source than wood chips.