Warning: the video link in this blog post includes images of a sheep killed by a coyote.
This story begins several weeks back. We split our ewe flock into two breeding groups in late September, and kept a third group (of replacement ewe lambs, who won't be bred until next fall) separate. With three groups of sheep, we felt like we needed to put our youngest livestock guardian dog (10-month-old Dillon) with the lambs. He had been with a handful of lambs at our home place, and seemed to be fine - a bit exuberant (as puppies can be), but fine.
A week into this situation, we noticed that one of the lambs had a chewed ear. We've had young dogs that occasionally chewed on ears, so we weren't too worried. In the next several days, four more lambs were injured, several seriously. We decided to put Dillon with a group of older ewes and rams.
His inappropriate behavior continued - and escalated. He began chasing sheep, which culminated with a ewe that became tangled in the electronet and died. We brought Dillon home (and put a "dangle stick" on his collar to make chasing sheep uncomfortable). The older dog went back with the breeding group, and we left the ewe lambs protected only by electric fence.
Fast-forward to this week. On Wednesday, we moved the lambs to a new paddock partly enclosed by electro-net fencing, partly by hard-wire sheep fence. On Thursday morning, we found a dead lamb in the paddock.
The rancher part of me was upset - we would expect this ewe lamb to grow up to produce five or six sets of lambs. The farm advisor part of me decided that this was an educational opportunity - I wanted to learn how to tell what kind of predator had killed the lamb.
I made a quick call to our local wildlife specialist (in Placer County, these folks work for the county - in other areas, county trappers are employed by USDA Wildlife Services). He looked a a few photos and said, "That looks like a coyote." He also told me how to investigate the carcass to know for sure.
You might wonder, why would this matter? The lamb was dead. As a rancher, I wanted to know what I was dealing with! Coyotes can get through a 4x6 inch hole; mountain lions can go over most fences. Mountain lions are protected by the State of California; coyotes, at the moment, are not. As a scientist, I was inherently curious. I wanted to know the differences between coyotes and mountain lions in terms of predatory behaviors.
Our trapper told me, "A mountain lion will usually kill its prey by crushing the base of the skull from above and behind; a coyote will kill by crushing the trachea from below. A lion will not usually eat the digestive tract; a coyote will eat everything. A lion will bury what it doesn't eat; a coyote will eat in the open and leave the rest." He also told me that skinning the neck of the lamb would confirm the predator involved: "Hemmoraghing on the throat would indicate a coyote; wounds on the top of the neck at the base of the skull would suggest a mountain lion."
Fortunately, I had my hunting pack in the pack seat of my truck (including rubber gloves and a sharp knife). I skinned the neck and found lots of trauma around the trachea - and no wounds on the top of the neck. We were dealing with a coyote, as the video below indicates.
We resolved the issue (hopefully) by bringing Dillon back to guard the lambs. We left his dangle stick on with the hope that he wouldn't chase the sheep. We also moved the sheep to a new paddock that was more secure. Our landlords told me this morning that they'd heard coyotes - and Dillon barking - most of the night. And we did not lose any more lambs.
As a shepherd, the premature death of any animal feels like a failure. I hate to put a young dog in a position where we have to rely on him before he's ready; I also hate to subject our sheep to depredation. But I also recognize that there are economic considerations involved. Treating the lambs that Dillon injured earlier in the month has cost us money; losing a ewe lamb to a coyote cost us more. These kinds of trade-offs are part of ranching, I suppose; my job as a farm advisor is to help others evaluate these choices objectively.
In the next several weeks, I hope to offer a tool to help others compare the cost of using a livestock guardian dog against the benefits. Stay tuned!
Like any livestock management tool, livestock guardian dogs come with both costs and (hopefully) benefits. Some of these are easily calculated - for example, through today, we've spent $624.70 on dog food and veterinary costs related to our livestock guardian dogs this year. We currently have 3 dogs (Bodie, a 3-year-old I purchased as a pup for $350; Elko, a 2-year-old given to me as a pup; and Dillon, a 9-month-old pup purchased for $500). Some of the costs and benefits are less easily calculated, however; how do I know how many sheep didn't die because we had dogs with them? What is the value of my own peace of mind? A recent paper by Dr. Ellen Bruno (Cooperative Extension specialist in agriculture and resource economics at UC Berkeley) and Dr. Tina Saitone (CE specialist in agriculture and resource economics at UC Davis) sheds new light on these questions. Read the complete paper here.
Using data from the University of California's Hopland Research and Extension Center, Bruno and Saitone estimated that dogs reduced lambs lost to coyotes by 43% each year; ewe losses were reduced by 25%. The authors calculated the present value of these prevented deaths over the 7-year useful life of the dogs to be $16,200 (present value calculations were based on the market value of the lambs as well as the value of running-age ewes). Their model was based on using one dog per 100 ewes (more on this below).
On the cost side, the authors included initial purchase of pups, dog food (and labor associated with feeding the dogs), veterinary costs, and dog replacement costs. Labor costs, as they note, are largely dependent on the type of production system - Hopland's labor costs are probably much higher than the typical commercial operation. Using net present value analysis, Bruno and Saitone found that the costs of Hopland's livestock guardian dogs exceeded the benefits (in the value of lambs and ewes not killed by predators) by $13,412 over the seven-year analysis period. In other words, the dogs didn't pay their own way.
Bruno and Saitone offer several important caveats when interpreting these results. First, many ranchers report that dogs eliminate predation entirely (which has been our own experience). If this had been the case at Hopland, the benefits would have exceeded the costs of using dogs by over $12,000. Second, labor-related expenses associated with dogs can be difficult to quantify. In our operation, feeding the dogs is part of our daily check of fences and sheep - we see the sheep every day whether we have dogs with them or not. We charge about 5 minutes per day to feeding 3 dogs - even if I pay myself $20 per hour for this work, our "dog" labor amounts to $371 per dog annually. Hopland, on the other hand, reported labor costs of nearly $1,600 per dog per year. Finally, the authors note that lamb and ewe prices may (and usually do) change from one year to the next - and sometimes dramatically. Sheep values can alter the cost:benefit ratio.
Skeptics might wonder, "Even if you use dogs, if you're not experiencing any predator losses, maybe there aren't any predators around." My ongoing research into livestock guardian dog behavior suggests that there are ALWAYS predators around where small ruminants are grazing (whether on rangeland or irrigated pasture). Using trail cameras, we frequently "capture" coyotes, foxes, and bobcats within 10-15 feet of our sheep paddocks. Interviews with sheep- and goatherders working in the Sierra Nevada indicate that coyotes are heard - and often seen - every night near sheep and goat bed grounds. Though we see them less frequently, we know there are mountain lions and black bears in the vicinity of these operations. The predators are there - the dogs must be at least partly responsible for the lack of predator losses!
As I've written previously, the number of dogs used by producers can vary greatly - from one producer to the next, and from one season to the next on the same operation (see How Many Dogs?). One of the bands of sheep I'm observing near Truckee is guarded by a single dog (band is roughly 1,000 ewes - this scenario is significantly more cost effective than the 1 dog per 100 ewes ratio used in Bruno and Saitone's model). This ratio works because the band is comprised of mature ewes without lambs - and because the predators have plenty of other prey at this time of year. Once this band moves back to Los Banos to lamb on alfalfa stubble later this fall, the dog-to-sheep ratio will increase.
In my experience, peace of mind for the shepherd (or goatherd) can be a significant (if qualitative) benefit. My friends Brad Fowler and Nathan Medlar recently started a targeted grazing project at Squaw Valley Ski Resort north of Lake Tahoe (see Watching Other Dogs). They started the project without livestock guardian dogs (mostly to avoid conflicts with recreationists). They are herding the goats on the ski slopes during the day and penning them at night near their camp (a tent on the side of the mountain). Brad reported that neither they nor the goats slept at all on the first night - the coyotes kept the goats stirred up even though they were protected by electric fence. Brad and Nathan added two dogs on the second day - which relaxed the goats (and the goatherds). Brad reported both herders and livestock slept soundly on the second night.
Finally, research at the U.S. Sheep Center in Dubois, Idaho, found "that ewes grazing with accompanying LGD will travel greater daily distances compared with ewes grazing without LGD accompaniment. As a result of traveling greater distances, ewes may also be exposed to more and varied foraging opportunities." See Webber et al. 2015 for the complete study. To me, this suggests that dogs may make our grazing operations more efficient - allowing us to access forage that would otherwise not get grazed by unprotected livestock. This increased grazing efficiency can reduce our supplemental feed costs.
From my perspective, perhaps the most important part of Bruno and Saitone's work comes at the end of the paper:
"Sheep producers who are considering the purchase of LGDs, or those who already have LGDs and are interested in their return on investment, need a few pieces of data to make this determination. Market lamb and ewe prices are typically well known to producers and can be used, in conjunction with efficacy rates from this study, to estimate the benefits of LGDs.
"On the cost side, producers would need to make some logical forecasts about the time required to maintain LGDs, given their operation specifics.... Also, using guidance from the literature included herein, producers could calculate the likely dog cull and mortality costs of the LGD's useful life."
Ultimately, the success of any livestock protection tool (including lethal control) is highly variable depending on operator characteristics and environmental conditions. Dogs work in our operation because we see the sheep every day and because they are our only option for protecting lambing ewes (we lamb on pasture without access to a lambing shed). Dogs work for the range outfit on the Tahoe National Forest as well; human presence, the vigilance of the dogs, and the stage of production during their time in the mountains virtually eliminates predator losses. And dogs work for the targeted grazing outfits I work with in the foothills and mountains; peace of mind and lack of predator losses justify the costs of keeping dogs in these operations, too.
Smutgrass, in my experience, is a complicated, opportunistic weed, by which I mean there neither seems to be any single factor that contributes to its spread, nor any single management technique that leads to its eradication. Smutgrass seeds require bare ground, sunlight, and warm temperatures (68°F to 95°F) to germinate. Management practices (like pasture harrowing), or pests (like gophers) that lead to bare ground may provide a toehold for smutgrass establishment.
We have grazing exclosures established on several irrigated pastures on the eastern edge of the Sacramento Valley. The grazed portions of these pastures have significant smutgrass populations; the exclosures, where the forage grows all season without being removed, have little or none. To me, this suggests that getting the grazing right on our pastures may be part of the answer. If we can graze our pastures to 4-6" of stubble height, and then allow sufficient time for the desirable forage plants to regrow before we graze again, perhaps we can allow these "good" plants to outcompete smutgrass. On paper, this sounds easy; out in the pasture, it requires us to vary our graze periods and (more importantly) rest periods based on the growth rate of the pasture. Our rest period in June might be 25 days; in August it might be 40 days! Not every operation is set up to accommodate this variability.
We have noticed that dry ewes are more likely to graze smutgrass than lambs, particularly early in the season. Other producers have observed that goats will graze smutgrass. Davy et al. suggests that this may be related protein levels and digestibility. Clipping (or grazing) can maintain smutgrass in a more vegetative state, increasing palatability and nutritional value.
But even where we get the rest periods and graze periods right for the plants we want, we may still have smutgrass. Irrigation inefficiencies may favor smutgrass in some cases. Josh Davy and Betsy Karle found that smutgrass was significantly decreases on a pasture where irrigation was changed from a 14-day rotation to a 7-day rotation (with corresponding increases in more desirable grasses). I've noticed on the pastures that we irrigate for sheep that we seem to have more smutgrass in areas where shallower soils or lower water pressure results in less than optimal irrigation (in other words, we can't get enough water on these sites to maintain sufficient soil moisture in our 12-day irrigation rotation). And since our system is designed to run on 24-hour sets and 12-day rotations, we don't have a great deal of flexibility when in comes to addressing our smutgrass problem by adjusting our irrigation schedule.
Some producers in our region regularly clip their pastures to avoid eye problems and keep forage in a more vegetative condition. Research shows that repeated mowing can decrease the diameter of individual plants but increase the density of the stand. Mowing may also spread seed. On the other hand, mowing may maintain the nutritional quality of smutgrass further into the summer (which may improve its palatability for livestock).
Finally, glyphosate (RoundUp) may be a viable control option. A rotary wiper allows the operator to adjust the height of the wiper drum above the desirable pasture plants and "wipe" the herbicide directly on the smutgrass plants. This application should occur shortly after grazing (so that the desirable plants are lower than the smutgrass). According to Davy et al., "glyphosate should be applied after flowering when the plants are translocating sugars back to the roots or below-ground reproductive structures (generally late summer and early fall). Managing Smutgrass on Irrigated Pastures contains a helpful guide to using glyphosate with a rotary wiper. The Tahoe Cattlemen's Association has a wiper that is available for rent through Far West Rents and Ready Mix in Lincoln. If you'd like help learning to use the wiper, contact me at (530) 889-7385 or at email@example.com.
Weeds are often a symptom of a management problem, rather than the actual "disease" - if we don't address the underlying issue (in the case of smutgrass this may be grazing management, irrigation management, or other factors), the problem is likely to reoccur. And with a weed like smutgrass that seems to be so opportunistic, eradication may be especially difficult. Controlling it (rather than eradicating it) maybe the most cost-effective option.
As some readers of this blog may know, I'm currently working on a research project examining livestock guardian dog behavior. The back story is this: several years ago, I was invited to demonstrate electro-net and livestock guardian dogs at a workshop on livestock protection tools. The electro-net fencing was easy! However, since I was speaking at midday, the LGD demo was less than dynamic - the dog came over to the fence, barked half-heartedly at the people he didn't recognize, and resumed napping in the shade!
This experience got me thinking! How could I demonstrate the effectiveness of these dogs without dragging folks out to observe the sheep in the middle of the night (when the dogs are much more active)? Geographic positioning system (GPS) technology seemed like a possible answer - but commercial GPS collars were too expensive for my cooperative extension / sheepherder budget. While perusing Facebook one day, I ran across a post from Dr. Derrick Bailey at New Mexico State University. Dr. Bailey was using home-built GPS collars to track cattle distribution on New Mexico rangeland! At last, an affordable solution! Dr. Bailey was gracious enough to spend an hour on the phone with me talking about my project ideas - and he shared the technical details of the collars he was using.
Here's a quick photo guide to building the collars I'm using on LGDs (and on sheep). The materials include:
- LGD collars from Premier 1 Supplies (I like these extra-wide collars - I think they're comfortable for the dogs, and they seem to hold up in rangeland conditions). https://www.premier1supplies.com/p/guard-dog-collars?cat_id=164
- 3-1/2" x 2" threaded nipples and threaded caps (for the case)
- 1/2" x 5/32" pop rivets and #8 SAE flat washers (to attach the case to the collar)
- i-gotU GT-600 travel and sports logger (available on Amazon - https://www.amazon.com/i-gotU-USB-Travel-Sports-Logger/dp/B0035VESMC/ref=sr_1_2?crid=2OO21VMYVPBN2&keywords=i+got+u+tracker&qid=1564451973&s=gateway&sprefix=I+got+U%2Caps%2C194&sr=8-2
The collars take about 5 minutes to build. The i-gotU trackers can be programmed to collect GPS coordinates from every 5 seconds up to every 5 minutes. Set at 5 minute intervals, the batteries in the unit will last 10 days. Dr. Bailey also sent me plans for an auxiliary battery system - that will be my next project!
I've also experimented with an Optimus 2.0 tracker (https://www.amazon.com/Optimus-Tracker-6543857646-GPS-2-0/dp/B01C31X50K/ref=sr_1_4?crid=UR8F2VQBBT8M&keywords=optimus+tracker&qid=1564452200&s=gateway&sprefix=optimus+t%2Caps%2C199&sr=8-4) which sends a real-time signal to my cell phone with the position and speed of travel of the unit. These trackers don't record positions, but they are useful from a practical standpoint - they will send an alarm to my phone if a guard dog is out of my pasture.
I'm hoping that we'll have some data to share from my project on the Tahoe National Forest north of Truckee in the next couple of weeks. Working with Talbott Sheep Company, I've collared 2 dogs in each of 2 bands of sheep. So far, the collars seem to be working great!
And on a humorous note, as you can see from the photos, I put UCCE (for University of California Cooperative Extension), along with my phone number, on the collars. I received a text yesterday that said:
"Hello, we found Ucce at the upper little truckee campground this morning. He still has his tracker around his neck and is just hanging out at the campsites."
I explained that we were doing a research project with the dogs and that someone would come by to get the dog soon.
That said, I think Ewecie (or maybe Ewechie) would be a great name for a guard dog, don't you!?
Here are some photos to walk you through building a collar.
In the space of several days in early June, I received phone calls from two foothill cattle producers about an unusual number of dead and dying blue oaks on their annual rangelands. The first rancher's observations were limited to his home place; the second rancher was noticing the blue oaks dying on leased grazing land from Auburn to Nevada City. In mid June, I visited one of these operations and noted several things:
- Some of the trees that the rancher said had leafed out normally in spring appeared to be entirely dead and devoid of leaves.
- Several trees appeared to be dying from the top down or on individual branches. Many of the leaves on these trees also appeared to be scorched.
- These trees did not appear to have any lesions on their trunks - no wounds or noticeable fungal growth.
Several weeks later, I published my summer newsletter and included a short blurb asking readers to contact me if they were noticing anything unusual in their blue oaks. Within an hour of sending the newsletter electronically, I had emails from several landowners noting similar conditions. The issue, it seems, is more widespread than just a couple of random trees!
While I'm no expert on the diseases of blue oaks (or any other tree, for that matter), I'm fortunate to have colleagues within the University of California who are! I contacted Dr. Matteo Garbelotto, a Cooperative Extension Specialist in Forest Pathology at UC Berkeley. Dr. Garbelotto has studied a variety of tree diseases, and he immediately suggested collecting samples from some of our foothill trees to try to figure out what is happening.
This week, Dr. Doug Schmidt from Dr. Garbelotto's Forest Pathology and Mycology Lab joined me in collecting samples. We collected leaves with evidence of scorching, soil samples from the base of infected trees, and tissue samples from the trunks at eight sites from Placer to Yuba County. The lab will test these samples over the coming weeks to try to isolate the pathogen(s) or other factors that may be causing blue oaks to die. We hope to have some preliminary answers in about six weeks.
In the meantime, you can help us understand the extent of the problem. Take note of any recently dead or currently dying blue oaks on your property. Take photos of the entire tree, a close up of the leaves, and any other unusual features. And complete our Blue Oak Mortality survey to help us build a database of impacted areas.
Contact me at firstname.lastname@example.org if you have questions!