Targeted grazing by sheep to control weeds, like our Vines

and Ovines project is becoming more popular, but did you know that cattle are also useful in targeted grazing? Researchers at Oregon State University have discovered that cattle, through targeted grazing benefit forest seedlings. Their work done on conifer plantations of Douglas fir and ponderosa pine used cattle to graze the competing understory. On those plantations the understory of predominately grasses compete with the seedling trees, retarding their growth.

In their study the researchers wanted to find out if by grazing cattle to reduce the common grass orchardgrass, that more soil moisture would be available to the trees.  They found that seedling water stress levels during spring and summer were similar in a cattle-grazed vs. ungrazed area, but in summer, water stress was reduced significantly in the grazed area. Soil water content was higher in the grazed area, especially at the 10-20 cm soil depth. End of season (July) orchardgrass root growth was reduced 18% and 15% with grazing. They concluded that repeated cattle grazing of orchardgrass reduced transpirational surface area and root growth sufficiently to increase soil water availability to seedlings. Thus, prescribed cattle grazing on conifer plantations can enhance seedling physiological status by acting as a regulator of above- and belowground competition.

Additional Reading

Karl, Michael G. and Paul S. Doescher. 1993. Regulating Competition on Conifer Plantations with Prescribed Cattle Grazing. Forestry Sci. 39(3):405-418.

Goats are historically used for brush control, but a recent Oregon State University study by Ph.D. candidate Claudia Ingham looked specifically at the effectiveness of high intensity-short duration goat browsing for the control of Himalayan blackberry and English ivy.

Blackberry control is a common issue for many ranches in both Mendocino and Lake Counties and so I thought it would be interesting to hear about Claudia’s research and results. She compared the effects of goat browsing on blackberry vigor by quantifying the densities of different age class stems, comparing it to mowing alone, and goat browsing followed by mowing over a three-year period.

Her results showed that total stem density declined, but the primocane density actually increased after all three treatments, which means that the blackberry population was still vigorous. All three treatments, however, resulted in a decline in blackberry cover and a favorable increase in both perennial grass and forb cover.

She could not detect any significant differences between the three treatments, which mean that goat grazing alone controlled the blackberries as well as mowing or grazing plus mowing. Given the fossil fuel costs of mowing, goats as targeted grazers are a better option.

The American Meat Institute (AMI) Foundation has just recently released their 2010 Recommended Animal Handling Guidelines & Audit Guide. The guide, written by Temple Grandin, while focused on humane animal handling at the processing level, still has valuable information for all those involved in the livestock industry. The sections on animal transport, temperature, and handling facilities are especially useful at the ranch level. I’ve attached the pdf file but you may also download it from AMI’s web site, animalhandling.org, under their guidelines and auditing section. I’d suggest checking out the other information and links on their web site too.

In the March issue of the Nutrition Journal, researchers from both CSU-Chico and UCCE, have published their findings on the nutritional qualities of grass-fed beef vs. grain-fed beef. To read the entire article go to: http://www.nutritionj.com/content/9/1/10. For those that want a quick overview I've provided a copy of their abstract below.

Abstract:

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.