Tannins as antinutritive chemicals in Red cedar

TitleTannins as antinutritive chemicals in Red cedar
Publication TypeJournal Article
Year of Publication2019
AuthorsLourencon, RC, Hart, SP, Gipson, TA, Muir, JP
JournalJournal of Animal Science
Volume97
IssueSupplement 1
AbstractIn studies using goats to control red cedar (Juniperus virginiana) it has been observed that in some locations goats readily consume red cedar while in other locations, they consume relatively little, but consume more during the winter months. It was hypothesized that differences in red cedar intake may be caused by tannins acting as an antinutritive chemical. The purpose of this study was to characterize the levels and types of tannins in red cedar from different locations and season of the year. Thirty-seven samples of red cedar needles were obtained from four locations (LOC; Langston, OK, Midwest City, OK Mannford, OK and Neosho, MO) at monthly intervals over a one-year period. Samples were obtained by manually stripping the needles from branches at approximately 1.5 M high from at least 25 plants at each location. Samples were refrigerated until analyzed for extractable condensed tannin (ECT), protein bound tannin (PBT) fiber bound tannin (FBT) and total tannin (TOT; sum of the three) by procedure of Terrill et al., 1992. Data was analyzed by SAS GLM with main effects of LOC and SEA. FBT averaged less than .1% and PBT averaged 1.3% and both were not significantly affected by LOC or SEA. ECT was significantly lower for Neosho (1.53%) than for Mannford (2.69%), OKC (2.79%) and Langston (2.37%) which were similar. ECT was lowest for summer (1.76%), similar to Fall (1.85%) and both were significantly lower than for winter (3.32%) and spring (2.39%) which were similar. TOT followed a similar pattern being highly correlated to ECT (R=.955; P<0.001) and was significantly lower for Neosho (2.61%) than for Langston (3.79%), Mannford (3.81%) or OKC (4.15%) which were similar. Total tannins were significantly higher in the winter (4.71%) than for the other seasons Spring (3.64%, Fall, 3.18% and Summer 2.87%. Tannins were lowest for Neosho where goats browsed red cedar most aggressively, killing >85% of the trees whereas goats killed <10% cedars at other locations which had greater levels of tannins. Tannins may be a significant antinutritive factor in red cedar, affecting consumption and degree of control.