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From the Alfalfa & Forage News blog (April 29, 2022)
What is vetch? There are several species that are commonly grown as crops, cover crops or weeds (see list at the bottom). Vetch is a winter-hardy legume that's favored by early fall rains, which we had lots of last October (5.5-in in 24-hr in Sacramento). Vetch is also a nitrogen-fixing plant that works well as a cover crop in farming systems. It's also a good forage for bees and other pollinators and has extra floral nectaries (glands on stems that produce nectar) that attract beneficial insects like parasitoid wasps that prey on pests.
Is it a good livestock feed? Yes and no. As an annual leguminous vigorous herbaceous plant, vetch has high protein and relatively low fiber and reasonably high yields. It's vigorous growth and N fixing qualities is why it is so valuable as a cover crop, but it can also be grazed or fed as hay. Its quality is lower than that of alfalfa or clovers (protein levels from 15-20% depending upon stage of growth). It is commonly grown in mixes with small grains or grasses as a mix in different parts of the US. Vetch hay is difficult to handle due to the vine-like characteristics, and caution should be used due to anti-nutritional compounds and livestock palatability.
Anti-nutritional compounds. However, vetch hay can cause serious (and potentially fatal) animal health problems, so is not recommended as a primary forage for horses and cows. Most of the anti-nutritional compounds are concentrated in the seeds, so immature harvests are recommended. Vetch seeds are poisonous; they contain cyanogenic glycosides and a diglucoside that can cause a neurologic disease. Although hairy vetch (V. villosa) and purple vetch (V. benghalensis) seeds are the most toxic (being very closely related), other vetches have toxic seeds too, including common vetch (V. sativa). In addition, a toxin in vetch foliage is associated with a dermatitis or skin sensitivity disease, though this is extremely rare and not well understood. Most cases of vetch-induced dermatitis involve black cattle, such as Angus or Holstein, and horses can also be affected, so there may be specific susceptibility explained by a genetic predisposition. Lack of good information makes is difficult to assess vetch hay suitability for small ruminants like sheep, though there is anecdotal information that suggests it might be okay for goats.
How about rangelands? Vetch growing on grazing rangelands is actually a good, high-protein feed for livestock. In open range, cattle typically won't graze vetch until it dries down and seeds have shattered. On a hot day you can hear dry pods snap, crackle, and pop, like a bowl of Rice Krispies. Vetch is not favored by livestock when green due to low palatability (bitterness).
How about pastureland? Fenced pastures loaded with vetch going to seed could spell trouble for horses and cows, especially if there is little else to eat. Toxicity risk can be alleviated by ensuring other forage options are available and by stocking animals at very low densities and giving them the option to selectively consume non-toxic plants and avoid toxic plants. Again, once the plant has dried down and seeds have shattered (detached and fallen), it should be okay as grazing feed.
How big a problem is vetch toxicity? The California Animal Health and Food Safety Laboratory at UC Davis has had a few cases of vetch toxicity to cattle and horses over the years, but not many. It's still unclear if this means few cattle are exposed to vetch or few cattle actually develop disease. It's still kind of a mystery as to why vetch is sometimes a problem and other times not. It might be a matter of the degree of its presence in animal diets – low percentage is okay, high percentage more problematic. "Dose makes the poison" as a toxicologist would say.
How about croplands? Oats and vetch used to be a popular mix for feed, but not anymore and hay growers try to keep it out of their forage crops. If cereal grains are in a crop rotation, vetch seed is about the same size as wheat and barley kernels, making it hard and expensive to separate during seed cleaning. Vetch is also hard-seeded, meaning seed can lie in the ground dormant for years and germinate when not wanted, though the viability for most seed is about 5 years, allowing opportunities for management. For control, one can mow prior to pod and seed set or use broadleaf or pre-emergent herbicides if needed.
Vetch identification. To differentiate different species of vetch one needs to look at the flowers. Common vetch (V. sativa) has flowers with a short stalk (peduncle), meaning the flowers are attached close to the stem from where it originates (picture). Hairy vetch (V. villosa), purple vetch (V. benghalensis), and American vetch (V. americana) all have flowers with long stalks. Hairy and purple vetch flowers are aligned on one side of the flower axis (picture) whereas American vetch flowers are more upright (picture). Purple vetch will generally have flowers about the same size as the leaflets (picture), while the flowers on hairy vetch are generally larger or longer than the leaflet (picture).
What types of vetch are found around California on agricultural and rangelands? According to Dr. Alison Colwell, Curator, UC Davis Herbarium, the following are the rankings of vetch (Vicia) species abundance by county. This information comes from the Consortium of California Herbaria (https://cch2.org). The data are from all years that collections were made, which is basically the past 100 years. The take-home point of this analysis is that there are several similar vetch species that are all spottily dominant around California.
Yolo County (all ag)
- V. villosa (hairy; lana/woollypod subsp. varia)
- V. sativa (common)
- V. benghalensis (purple)
Mariposa County (mostly ranch/public land, central)
- V. americana (American vetch; native plant)
- V. sativa
- V. benghalensis
Butte County (part ag, part ranch, north)
- V. villosa
- V. sativa
- V. americana
Tulare County (ag, arid, south)
- V. americana
- (3-way tie) V. benghalensis, V. sativa and V. villosa
Stanislaus County (ag, central)
- V. villosa
- V. sativa
- V. americana
Original source: Alfalfa & Forage Newsblog (April 29, 2022)
- Author: Dan Macon
I invite you to travel back in time with me - clear back to late October 2021! We'd measured more than 10 inches of rain in Auburn, and we could see the first green shoots of grass emerging through the dry forage. While November was slightly disappointing from a precipitation perspective, we measured more than 12 inches of rain in December - capped off by a crazy, wet, and cold storm just before the first of the year. I'm sure most of us were celebrating what looked like a great feed year when we rang in 2022. But then the spigot shut off - here in Auburn, we've measured just 1.77 inches of rain since January 1 - the driest start to the calendar year in the 20+ years I've kept records. Combining this lack of moisture with warmer-than-normal temperatures and unusual (at least for winter) dry north wind, we are squarely back in drought conditions. In many ways, we seem to be experiencing a more severe drought than last year, at least on our foothill annual rangelands.
Ranchers know that drought is more than just a lack of precipitation. Low rainfall years, provided the storms come at the right time, can produce above-average forage. This year, however, the warm temperatures have brought oaks and other vegetation out of dormancy earlier than normal - this early onset of the growing season in our oak woodlands has increasedevapotranspiration (or soil-water demand). The north winds haven't helped. Before we received an inch of rain on March 14-15, I checked soil moisture in Auburn - and found it to be less than 20% (more like May than March). The rain gave us a short boost, but by the end of last week, soil moisture was back around 25%.
Ourrangeland vegetation reflects these poor growing conditions. Our annual grasses andforbs, by definition, must produce seed every year. In dry conditions, this means that they reproduce and turn brown early and at a shorter stature. Where our sheep are grazing just west of Auburn, I've seen soft chess and annualryegrass headed out this week - a good 30 days early. In a good year, the soft chess will be as much as 18 inches tall; this year, it's done growing at 6 inches. Many of our importantbroadleaf forage plants are maturing equally early - I'm seeing vetch dying back on our shallower soils, and thefilaree is already in the late bloom stage, as well.
These are all red flags from a forage quantity perspective - shorter feed this spring means less residual feed to return to next fall. But early maturity also compresses our forage quality window. Many of us expect a 45-60 day period when we have high quality forage on our annual rangelands - and we set our production calendars accordingly. As these grasses and forbs mature, they decline in quality - providing less protein and energy to our grazing animals. They also become less palatable - in other words, they don't taste as good and they don't provide as much nutrition. The graph below demonstrates that crude protein levels in annual grasses drop below cow maintenance levels between the late flowering and maintenance stages (which we're approaching). If we're trying to put weight on animals, protein levels are deficient by the time we reach the early flowering stage. For more information, check out this ANR Publication (Annual Rangeland Forage Quality).
We're still hopeful that the significant snow pack we built up in December will mean we'll have adequate irrigation water here in the foothills - other regions in the state aren't so fortunate. Given the exceptionally dry conditions, however, I expect we'll need to make at least 2 irrigation rotations over our irrigated pastures to rebuild soil moisture and start growing forage. For us, this means we won't start regrowing irrigated pasture forage following our first graze periods until the end of May.
In light of these impacts, what are some of the strategies we should consider going forward? The basic premise of most drought management strategies is to increase our forage supply (by buying hay or other feed, irrigated early, or leasing new pasture) or reducing our forage demand (by selling livestock or weaning early). Check out our Drought Decision Making Tool for Ranchers for information on how to analyze the economics of these options! This page also includes a new bulletin on early weaning.
As far along as our annual rangeland vegetation is today, another rain won't do us much good - other than perhaps grow some summer annual weeds that may have some grazing value. Rain wouldgive our irrigated pastures a boost, however - at least here in the foothills. We'll see what April brings!
- Posted by: Gale Perez
If you missed the Managing Weeds in Grasslands and Rangelands 2021 online event (Oct. 19, 2021 • 9 AM-12 noon PST), you're in luck. We have the recordings of each presentation here.
Managing Weeds in Grasslands and Rangelands (2021)
Moderator • Whitney Brim-DeForest, Sutter-Yuba County Director and Rice Advisor, UCCE Sutter-Yuba, Placer, and Sacramento Counties
UC Weed RIC YouTube channel
Grassland and rangeland weeds in California • Rebecca Ozeran, Livestock and Natural Resources Advisor, UCCE Fresno and Madera Counties
Dusting rangelands with compost: examining the potential benefits • Scott Oneto, Farm Advisor, UCCE Central Sierra (El Dorado, Amador, Calaveras, and, Tuolumne Counties)
Grazing for weed control—are weeds palatable and nutritious, or just a nuisance and poisonous? • Royce Larsen, Area Natural Resource/Watershed Advisor, UCCE San Luis Obispo, Monterey, and Santa Barbara Counties
Updates on recent weed control trials in north eastern California • Tom Getts, Weed Ecology and Cropping Systems Advisor, UCCE Lassen, Modoc, Plumas, and Sierra Counties
Managing weedy grasses in grasslands in southern California • Chris McDonald, San Bernardino County Co-Director and Inland and Desert Natural Resources Advisor, UCCE San Bernardino, Imperial, Riverside, and San Diego Counties
Key ecological principles to guide adaptive management of grassland weeds under variable conditions • Valerie Eviner, Professor and Ecologist, Dept. of Plant Sciences, UC Davis
The UCCE Central Sierra office is selling the Weed Control in Natural Areas in the Western United States book at a discounted price of $30 USD total (includes tax + shipping). The book regularly sells at $37 USD (does not include tax + shipping.) The discounted price is good until inventory is depleted. Get them while they are in stock!
To order, click this link (https://ucanr.edu/survey/survey.cfm?surveynumber=32523) or contact Erica Malaspino [firstname.lastname@example.org, (209) 223-6482.]
Thank you UCCE Central Sierra office!
This online event was sponsored by
UC Cooperative Extension • UC Davis Dept. of Plant Sciences • UC Weed Research & Information Center
- Posted by: Gale Perez
Tuesday, October 19, 2021
9:00 AM-12:00 PM (Pacific Time)
The latest information on weed control will be presented at the Managing Weeds in Grasslands and Rangelands online event.The lineup of UC Cooperative Extension (UCCE) and UC Davis experts will discuss basic ecology and biology of common weeds in California rangelands, potential benefits of dusting rangelands with compost, grazing for weed control (palatable and nutritious or a nuisance and poisonous), invasive weed control research projects in Northeastern California, weeds in grassland in Southern California, and key ecological principles to guide management of grassland weeds.
$20.00 if received by Oct. 15, 2021
$30.00 if received after Oct. 15, 2021
Last day to register is 5 PM (Pacific Time) on Oct. 18, 2021.
Click here for the AGENDA.
Click here TO REGISTER.
No refunds will be granted for this event.
CONTINUING EDUCATION CREDIT (for California)
This event is approved for the following continuing education credit:
- 2.5 "Other" DPR credit for PCAs, QALs, QACs, Private Applicators (PACs). To receive DPR credit, you must attend the entire event, answer all the poll questions, and receive a score of 70% or better on the FINAL EXAM. Instructions for the FINAL EXAM will be emailed to attendees after the event.
- CCAs >> pending approval
- Program: Whitney Brim-DeForest [email@example.com or (530) 822-7515]
- Logistics/registration: Gale Perez [firstname.lastname@example.org]
- Author: Travis Bean
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From the California Agriculture 75(2):83-89. https://doi.org/10.3733/ca.2021a0011
Link to full article: https://doi.org/10.3733/ca.2021a0011