Smutgrass (Sporobolus indicus) is a warm-season perennial grass native to the tropics. Since it is well-adapted to warm summer temperatures, we seem to be seeing more of it on foothill and Sacramento Valley irrigated pastures. With a combination of coarse leaves and spiky seedhead, smutgrass is largely unpalatable to livestock. Since livestock will generally graze the plants they prefer rather than smutgrass, it can dominate irrigated pasture and cause significant reductions in grazing capacity. For a comprehensive description of smutgrass biology and control measures, be sure to check out the UCANR publication, Managing Smutgrass on Irrigated Pasture (Davy et al. 2012).

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 dmacon@ucanr.edu.

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:

1. Some of the trees that the rancher said had leafed out normally in spring appeared to be entirely dead and devoid of leaves.
2. 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.
3. 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 dmacon@ucanr.edu if you have questions!

 

One of the questions I'm asked most frequently when it comes to livestock guardian dogs is, "How many dogs do I need to protect my sheep/goats/cows?"  As you might imagine, the short answer is, "It depends." The long answer is more complex. From an economic perspective, the answer is, "As many as it takes to hold predator losses in your operation at an acceptable level, but no more than that." From a production perspective, I've found that the answer depends on operational characteristics, the environment, and the abilities of the specific dog(s).

While it is tempting to try to develop a rule of thumb recommendation (like one dog per 100 ewes), reality is usually more complicated. Wearing my sheepherder economics hat for a moment, the fundamental question comes down to comparing the costs of a dog versus the benefits the dog provides. On the cost side of the ledger, I must account for the cost of dog food, veterinary care, and depreciation. In our operation, these annual expenses amount to roughly $600 per dog. On the benefit side of the ledger, I need to know how many sheep DON'T get killed by predators to determine if my $600 in expenses are justified. Obviously, this is not an easy number to estimate - how can I measure something that doesn't happen? How do I quantify the sheep that might have died had I not had a livestock guardian dog with them? I suspect we'd lose more sheep if we didn't use dogs, but I'm not willing to leave the sheep unprotected to find out!

Operational characteristics, in my experience, play a significant role in determining the optimal number of dogs. Birthing seasons (spring vs. fall), other livestock protection tools (like electric fence, on-site herders, night penning, etc.), grazing management (set stocking versus rotational grazing), and the number of individual herds or flocks all factor into determining the right number. Using our operation as an example:

• We lamb in the late winter and early spring, when there is not a significant natural prey base for the wild predators in our environment. Our lambing paddocks are 7 miles from our home. This argues for more dogs.
• We use electro-net fencing, which definitely deters canine predators (dogs, coyotes and foxes) as well as bobcats. This allows us to get by with fewer dogs.
• We move the sheep frequently - they move to fresh pasture every few days, and graze different properties in spring/summer versus fall/winter. I suspect all of this movement keeps the predators off balance. This allows us to get by with fewer dogs.
• We rarely (if ever) have all of our sheep in one mob. This time of year, the mature ewes are in one flock; the feeder lambs and replacement ewe lambs are in a second flock; the rams in a third location. During breeding season, we have two separate breeding groups plus a group of lambs. This argues for more dogs.

Based on these factors, we feel that we need at least three dogs for our small, part-time operation. With three dogs, we can protect three different groups of sheep or place two dogs together during our most vulnerable time of year (lambing). During some parts of the year, we have more dogs than necessary, which provides flexibility if we begin to have problems with predation.

The environment where we're grazing, and the predators it contains, is a second critical consideration. Here in the Sierra foothills (at least at the moment) our main predators (in order of potential threat) are domestic dogs, coyotes, mountain lions, black bears, bobcats, foxes, and birds of prey. I've spoken with ranchers on the north coast who would add crows, ravens, and magpies to that list. And ranchers in northeastern California would add gray wolves. Predator density and prey base also come in to play. Are there several established packs of wolves in the region? Is there sufficient native prey? Are these particular wolves (or coyotes, or mountain lions) known to prey on livestock? Each of these questions are important to consider when determining how many dogs a particular operation might need.

Finally, every livestock guardian dog is an individual. Some are athletic and want to patrol a wide area; others want to stay with their livestock. Some dogs are more canine aggressive than others (an important trait in wolf habitat); others will harass bears. And these traits will change over time - a dog that was aggressive and athletic in his younger days might be content to stay with lambs on irrigated pasture in his later years. In my experience, there is more variation between individuals than there is between livestock guardian dog breeds (a subject for a future blog post!).

Finally, I started a new phase of my livestock guardian dog behavior study this week. I'll be tracking the movements of four dogs (2 each in separate 1000-ewe bands of sheep) grazing on the Tahoe National Forest in Nevada and Sierra Counties (in an area that a collared Oregon wolf has been known to visit in the last 12 months). This is a long-time producer with experienced herders operating on open range with no fences. They typically use two dogs with one band and three dogs with the other, and experience less than one percent death loss while the sheep are on Forest Service allotments. They also have additional dogs they can add to each band if predator problems begin to escalate.

I think this illuminates the "it depends" answer in my first paragraph! They have 1 dog per 400 sheep; we have 1 dog per 51 sheep. They are grazing mature ewes in a relatively wild environment for only 75 days - and at a time when the natural prey base is plentiful. We need more dogs to protect ewes and lambs at an especially vulnerable time of year (and I should note - the large operation needs more dogs at lambing as well). The common thread for each of these operations, however, is that we are constantly evaluating our need for predator protection against the cost of providing it. If we could get by with fewer dogs, we would; similarly, if the large operation needs more dogs this summer, they'll add dogs. In other words, it depends!