Stephanie Larson

A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef

Growing consumer interest in grass-fed beef products has raised a number of questions with regard to the perceived differences in nutritional quality between grass-fed and grain-fed cattle. Research spanning three decades suggests that grass-based diets can significantly improve the fatty acid (FA) composition and antioxidant content of beef, albeit with variable impacts on overall palatability. Grass-based diets have been shown to enhance total conjugated linoleic acid (CLA) (C18:2) isomers, trans vaccenic acid (TVA) (C18:1 t11), a precursor to CLA, and omega-3 (n-3) FAs on a g/g fat basis. While the overall concentration of total SFAs is not different between feeding regimens, grass-finished beef tends toward a higher proportion of cholesterol neutral stearic FA (C18:0), and less cholesterol-elevating SFAs such as myristic (C14:0) and palmitic (C16:0) FAs. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD) activity as compared to grain-fed contemporaries. Fat conscious consumers will also prefer the overall lower fat content of a grass-fed beef product. However, consumers should be aware that the differences in FA content will also give grass-fed beef a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef. In addition, the fat from grass-finished beef may have a yellowish appearance from the elevated carotenoid content (precursor to Vitamin A). It is also noted that grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through the consumption of higher fat grain-fed portions.

Comparison of Comparative Yield and Stubble Height for Estimating Herbage Standing Crop in Annual Rangelands

Abstract We compared calibration equations for estimating herbage standing crop (HSC) from comparative yield (CY) rank or stubble height (SH) to determine 1) if CY rank is a better estimator than SH of standing crop, 2) if addition of SH to CY rank will improve the estimation of standing crop, 3) if there is a seasonal effect on CY rank or SH, and 4) if botanical composition influences the prediction of HSC from CY. The results of this study indicate that CY is a slightly better predictor of HSC than is SH. Addition of SH to CY did not improve the prediction of HSC. Models that predict HSC from CY in summer were weaker than models for winter, early spring, and late spring. Thus the CY method can be used with confidence throughout the year. The presence of filaree (Erodium cicutarium L.) in winter and early spring resulted in steeper calibration equations than were present in nonfilaree quadrats.

Ranching Infrastructure: Tools for Healthy Grasslands, Livestock, and Ranchers

Author(s): Barry, Sheila; Larson, Stephanie; Bush, Lisa | Abstract: Part of the Understanding Working Rangelands series. Ranch roads, fencing, gates, water systems, corrals, and working scales play a key role in proper management of livestock and effective management of rangelands. Having the right infrastructure is crucial to maintain the health and safety of rancher as well as the environment.