The Pasture Jitterbug
Last week we talked about the pasture recovery or rest period – the framework underlying a well-built irrigated grazing system. We likened it to the dance hall because it gives us some important boundaries in which to implement our grazing system. You don’t want to two step outside the dance hall. It’s dark out there and you may lose your partner!
Similarly, once you define your pasture rest period, don’t wander away from it! We spoke last time about all the good things that come with a 30 to 35-day rest period. Check them out now if you are just tuning in. Once you have elected a 30 to 35-day recovery period, by all means maintain it. That may mean an out pasture or feeding some supplemental hay for a day or two, but it’s worth it. Remember, don’t lose that partner; it always pays to stay inside the dance hall!
If the rest period is the dance hall, the paddock grazing period is the dance. The tempo of that dance – one day to four days – is up to you. How many days you choose to stay in a paddock portrays the gaiety out there. Never dance before? Maybe you’ll want to try paddock grazing periods of four days. Want the best experience? Give one day a go. Let’s take a look at what differing paddock grazing periods have to offer.
Stalking a Higher Stocking Rate
Paddock grazing periods give other pastures time to recover. Continuous grazing, on the other hand, permits no plant recovery unless the plant in question is the most horrible tasting thing in the pasture. Palatable species just keep getting chomped off before they have a chance to recover from the last toothy event. Excuse me, Kathy, the undesirables are what we commonly call weeds! Unless you train your cows to eat them, they won’t.
On the other hand, a grazing system that incorporates daily moves to a fresh paddock maximizes the number of days that plants have an opportunity to recovery over the growing season. Let’s say that here in Montana, at an elevation of 4,200 feet, we have a 120-day growing season. (That might be stretching things a little – we can see snow any month of the year!)
If we choose a 30-day rest period and a one-day grazing period, each paddock has 116 days of pasture rest (120 growing days – 4 paddock grazing days). If we choose a four-day grazing period and still maintain a 30-day rest period, we end up with 104 days of plant recovery (120 growing days – 16 paddock grazing days) for each paddock.
Plant recovery provides pasture. The difference in rest days in our example (116 days versus 104 days) translates into an 11% difference in the number of cows, sheep, goats, or horses that you can stock on those pasture acres during the growing season; shorter paddock grazing durations can increase stocking rate.
Helping Your Plants Dodge the Bullet
Plants love short grazing periods too – because they spread the grazing event out over more of the various species in the pasture. And that’s because as grazing periods are shortened, stocking density increases. Instead of 100 cows lounging (chilling out?) on perhaps six acres, you now concentrate them on 1.5 acres.
The quadrupling of stocking density forces the four-footers to compete for each mouthful and they aren’t as discriminating about what they graze. The more palatable plants are more apt to dodge a second grazing within the same grazing period. And when plants dodge that bullet, it helps in two ways.
First, so-called nonselective grazing lessens the chance that a plant will be grazed down below its growing point. Cows under competition grab grass and move on. They don’t bother with the small stuff – the part of the plant where there are no leaves. That is where the growing point, or the apical meristem, is located. Call this apical meristem the growth command headquarters. If you knock it out, you can figure on one week elapsing before that plant will start actively growing again. That is a big time loss by intensive grazing standards. Try hard to avoid it.
Okay, you say, so where exactly is the growing point of an irrigated grass? That’s the 64-million-dollar question, and there is no definite answer in terms of so many millimeters from the base of the plant. It depends, and, as a researcher friend of mine told me, no one has really figured out the growing points for various times in the growth cycle of all of the tame species. The stock answer you might hear is 2.6 inches. “Yeah, right,” my researcher bud says with a sardonic smile.
Suffice to say, most irrigated grass species have growing points at four inches or less. That’s a good rule of thumb, and it allows for some wiggle room. I add a few more wiggles, figure on five inches, and try my darndest not to graze below that height.
Legumes also appreciate the absence of a second grazing. Legumes are generally the highest protein plants out there, and the animals know it. They don’t miss a chance to take a bite out of legumes first. Higher stock densities and shorter grazing durations help to prevent the second and third nips that frequently trim the plant to the ground level.
Legumes won’t survive such rough treatment month after month, year after year. Their root reserves get depleted and then Ol’ Man Winter does them in. Short grazing periods exert control. They are the grazing tool that keeps the music in the dance hall playing.
The Parasite Connection
If you do it right, you and your pastured young stock can dodge another bullet: the parasite bullet. We’ve already talked about reducing the larval population in your grass by extending the rest periods out to 30 days. But there are one or two more weapons you can throw at them.
Barber pole worm infective larvae take four, maybe five, days to crawl out of the deposited fecal pellets and work their way up the grass stem. Don’t let them climb aboard the train; steam out of town before they even get a chance. You have just prevented the newest batch of the rascals from being ingested by your lambs.
The same scenario can be duplicated with young feeder cattle and the brown stomach worm. This infective larva is a bit slower, requiring 5 to 6 days to migrate to its boarding platform. Let them die out there before you get back in five weeks! Very effective control, and it didn’t cost you one red cent.
Incidentally, the majority of parasitic larvae are said to only crawl two to three inches up the grass stem. If you control the height of the grass left behind, you’ll have the upper hand. Keep the grass residual at five inches, get out of there in a day or two, let the dry Western skies take over, and you’ll have ‘em whipped. (For more about small ruminant parasite control, here’s a past article by contributor Bill Fosher.)
You Have to Dance
So grab your partner, build the dance hall, and – most important – do the dance. Even if you divide up your continuously grazed pasture with only one wire, you’ve made a start and you will reap the benefits. In fact, I bet that once you see all the great opportunities that Jitter and Bug open up, you will wonder why you waited so long. Time’s a wasting, hit the floor!
Next week, we will gather up the cows and design the system. If you want to take a peek, go to “Irrigated Pastures, Setting Up an Intensive System that Works” on the ATTRA website.
Here are the rest of the articles in this series:
Intensive Grazing on Irrigated Pastures
Setting Up an Intensive Grazing System That Works – Pasture Rest Periods
