Submitted to: Animal Feed Science And Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2010
Publication Date: 8/1/2010
Publication URL: http://hdl.handle.net/10113/45876
Citation: Krueger, W.K., Gutierrez-Banuelos, H., Carstens, G.E., Min, B.R., Pinchak, W.E., Gomez, R.R., Anderson, R.C., Krueger, N.A., Forbes, T.D.A. 2010. Effects of dietary tannin source on performance, feed efficiency, ruminal fermentation, and carcass and non-carcass traits in steers fed a high-grain diet. Animal Feed Science and Technology. 159:1-9. Interpretive Summary: Tannins are a complex group of compounds that have been shown to decrease bacterial pathogens from the mammary tissues of milking cows and have a protein-sparing effect in cattle. However, tannins can have a negative effect on animal intake and produce gastric lesions if fed at high concentrations of the diet. An experiment was conducted to evaluate the effect of tannin source on animal performance and feed efficiency, ruminal fermentation, and carcass traits in calves fed a high-grain diet. This project was part of a parent project evaluating the effect of tannin supplementation as a pre-harvest strategy to reduce native food-borne pathogens. None of the tannins had a negative impact on animal performance, feed efficiency, or ruminal fermentation. Additionally, there was no detrimental effect of tannin source on carcass and non-carcass traits, except for empty rumen mass and dressing percent. Calves fed hydrolysable tannin had greater rumen mass than calves fed condensed tannin, with rumen mass of control calves being intermediate. Calves fed condensed tannin had lower dressing percent than control steers, with dressing percent being intermediate for calves fed hydrolysable tannin. Neither tannin source affected the animal’s consumption of the diet or the animal’s growth. Additionally, the tannin sources did not affect the meat or by-product tissues, making tannin supplementation a viable option in finishing beef cattle.
Technical Abstract: Tannins are polyphenolic secondary plant compounds that have been shown to affect microbial activity to impact fermentation, protein degradation, methane production, and potential to mitigate foodborne pathogens. This study was conducted to examine the effects of source of tannin (condensed, CT, vs. hydrolysable, HT) on performance, feed efficiency, ruminal fermentation parameters, and carcass and non-carcass traits in finishing beef steers. Thirty-six crossbred steers averaging 414 ± 40 kg body weight (BW) were stratified by initial BW and randomly assigned to one of three treatments (n = 12): control, mimosa tannin, or chestnut tannin. Commercially available tannin extracts were added to a high-grain diet (ME = 11.93 MJ/kg DM) at 15 g/kg DM. Mimosa and chestnut extracts provided hydrolysable tannin and condensed tannin, respectively. Steers were individually fed the experimental diets using Calan gate feeders for 42 d. Rumen fluid was collected on d 0, 21, and 42 via stomach tube and sample analyzed for volatile fatty acid (VFA) and in vitro methane producing activity. Cattle were harvested at the end of the study and carcass data collected 24-h post-harvest. There was no effect (P > 0.05) of tannin supplementation on animal performance, ruminal fermentation parameters, in vitro methane producing activity, or carcass and non-carcass traits, except for empty rumen mass (P = 0.03) and dressing percent (P = 0.01). Calves fed HT had greater rumen mass than calves fed CT, with rumen mass of control steers being intermediate. Steers fed CT had lower dressing percent than control steers, with dressing percent intermediate for HT steers. There was a treatment*day interaction for butyrate concentration. For steers fed CT, there was a linear increase in butyrate while the HT steers remained relatively stable, and the control steers had numerically lower butyrate. Despite the significant interaction, treatment means on d 42 were not significantly different. Results indicate that neither source of dietary tannin affected performance, feed efficiency, or composition of growth in carcass or non-carcass tissues in cattle fed high-grain diets, making tannin supplementation a viable option in finishing beef cattle if bactericidal efficacy is established. More research is needed to further our understanding of how tannin supplementation may fit into real-life feedlot situations.