Last night, a storm blew through our ranch, and even though it wasn’t much, we were grateful to receive a quarter-inch of precipitation. Much of the area is experiencing drought-like conditions already this summer, and as producers run short of pasture and available forages, more pairs are headed to the sale barn.
Needless to say, every drop of rain counts, and anything green on the range could be potential cattle feed.
I recently visited with a local rancher who told me that weeds pop up for a reason, and if they’re growing, find a way to improve your management and utilize the ones that are there. Over the years, he has used molasses to train his cattle to eat Canada thistles, and it’s been an effective way to manage the spread of these pesky plants while also utilizing another forage in his pastures.
Will cattle really eat weeds though? And are they nutritious? Here are four things you need to know about weeds before expecting your herd to munch on these plants:
1. Palatability is more than taste
Kathy Voth, owner of Livestock For Landscapes and the author of “Cows Eat Weeds,” says, “The first thing I learned is that palatability is more than a matter of taste, so just ignore anything you ever read or heard that said something like ‘livestock don’t eat that because it’s bitter.’ Palatability is the result of nutrients and toxins in a food and how they meet the needs of the creature eating them.
“When I started training cows to eat weeds, the research told me that if the weeds had good nutrition and were low in toxins, then animals would eat it. I figured that if I could get her to try something just once, the cow would get the good feedback from the nutrients in the plant and then would continue eating it in pasture.
“So at first, I always tried to find out the protein content for the plants I was going to teach my trainees to eat. After looking up lots and lots of plants and having many sent off for analysis, I’ve learned that if it’s green and growing, it’s probably very nutritious. In addition, I know that the more leaf to stem a plant has, the more digestible it is, so a Canada thistle is much more digestible than a mouthful of grass because of its greater leaf mass.”
2. Know your plants
In a study titled, “The nutritive value of common pasture weeds and their relation to livestock nutrient requirements,” researchers looked at the potential quality of individual weed species and the nutritional values of weeds commonly found in pastures.
According to the study findings, which were published by Virginia State University’s Cooperative Extension Service, “Protein is essential in all livestock diets, but protein requirement varies with each type of animal. In the study, all of the winter/summer annual weeds and the cultivated forages at all three maturity stages evaluated had sufficient crude protein (CP) – except for Virginia Wildrye (Elymus virginicus L.) to meet the requirements for mature beef cows (10.5% CP); first-calf beef heifers (10.5% CP); and pregnant, replacement beef heifers (8.8% CP) at all reproductive stages.”
Click here to view the CP and dry matter digestibility of weeds and forages at various stages of maturity.
3. Consider low-intensity/high-frequency grazing
According to researchers, when grazing pastures containing weeds, management is very important to achieve successful weed utilization and suppression. Researchers tested the effects of different grazing systems and different animal types on weed suppression and animal utilization. Researchers looked at Canada thistle management in temperate pastures using three different cattle-grazing systems, including season-long, low-intensity, high-frequency rotational grazing, and high-intensity, low-frequency rotational grazing.
Season-long grazing sustained the amount of Canada thistle in the pastures and even increased the thistle in some cases, which resulted in a lower forage yield. High-intensity, low-frequency rotational grazing resulted in the greatest suppression of Canada thistle, with lower thistle-shoot density and biomass.
Most Canada thistle shoots were eliminated with two intense defoliations over two to three years with the high-intensity/low-frequency rotational grazing, due to cattle defoliation and trampling. The remaining Canada thistle shoots were mostly vegetative and of high quality, with greater nitrogen and moisture and lower ADF. The high-intensity, low-frequency rotational grazing pastures still had the lowest Canada thistle density a year after grazing ended, with the season-long grazing pastures having the lowest grass production.
4. How weeds impact hay quality
According to a summary of the research, “Weeds can often make up a large percentage of a hay crop, especially in early spring when winter annual weeds are thriving. At the first hay cutting, many winter annual weeds such as curly dock, Virginia pepperweed, and cutleaf evening primrose may be mature, which may cause hay quality to decline.
“If some of the higher quality but less palatable summer annual weeds – sicklepod, coffee senna, hemp sesbania, prickly sida, and jimsonweed – were included in hay, they could still provide a nutritious food source. Conversely, the incorporation of unpalatable species like Canada thistle, hoary asylum, Jerusalem artichoke, curly dock, perennial sowthistle or swamp smartweed into pastures or hayfields may cause forage intake to decrease.
“The amount of weeds contained in hay is an important factor to consider when determining hay quality. Researchers examined the quality of weedy and weed-free hay and the effects of individual weed species on hay quality. The weedy hay in one experiment contained 15% weeds – dandelion, yellow rocket and white cockle – with the remaining 85% consisting of grass and alfalfa. There were no differences in animal intake or digestibility between the weedy and weed-free hay, but crude protein was slightly decreased in the weedy hay.”
In a dry year, every blade of grass and any green plant matters. Consider these tips to get the most out of your pastures this year and perhaps even enjoy reduced costs and man hours trying to kill the same weeds your herd could learn to enjoy.
The opinions of Amanda Radke are not necessarily those of beefmagazine.com or Penton Agriculture.