For decades cattle producers have dealt with tall fescue toxicosis and hoped for a remedy. Often, promised fixes have led to unneeded expense and exasperation.
Fescue toxicosis is a constant thorn in producers' sides. The condition is caused when cattle forage on “infected” fescue containing ergot alkaloids produced by fungal endophytes (Neotyphodium coenophialum). The infected fescue negatively affects animals' blood circulation, causing problems for everything from weight gain to heat dissipation/retention to conception.
In recent years, novel endophyte fescues have come on the market. These don't contain the harmful qualities of their infected cousins. But seed is expensive and management is sometimes difficult.
Until an easy-to-use, sure-fire cure is found, might it be better to skip the magic bullets and concentrate on managing a herd on toxic tall fescue? Over the last three years, Arkansas cattle researchers have been looking for the wiser course.
“After collecting a lot of data, we're now asking, ‘How much benefit did we really get out of these improvements?’” said Ken Coffey, University of Arkansas professor of animal science, who spoke at the Livestock and Forestry Branch field day outside Batesville, Ark. “Sometimes, the best answer points to what was already available in the fields.”
Standing on a dirt road between two pastures, Coffey said both sides are in the second year of a study looking at novel endophyte fescue versus commonly planted “infected” Kentucky 31 fescue.
“They're fairly pure stands of fescue. In the first year we found about a 50-pound advantage in weaning weight with the novel endophyte fescues. As many know, though, at $4 a pound for seed, that's kind of expensive renovation for 50 extra pounds of weaning weight.”
Coffey and colleagues will continue the study this year and then switch to another approach. “We'll be looking to see if we can use just a little of it at strategic times and leave most of what we have — utilize the infected fescues and renovate just a bit and graze at the right times.”
Another three-year study was conducted on a nearby hilly area with fall calving cows. Most producers calve in the spring.
“We had different weaning dates. The calves were weaned early (mid-April) or late — just after the first of June.”
At the same time, researchers checked rotation schedules — either twice monthly or twice weekly — to try and keep more legumes in the pastures. Unfortunately, the legumes failed miserably.
“We seeded them twice and could get a little to come up in the spring. Then, when the summer drought hit, the legumes went bye-bye. We had very poor luck getting those established.”
One positive out of the study was when the pastures were overseeded with crabgrass. The cows took advantage of a continual increase in the proportion of crabgrass on the hills.
“That is much better than the straight fescue pastures in the summer. That was encouraging.”
Another encouragement: there was better than 92 percent conception rates on the pastures regardless of the treatment imposed.
Can all producers switch to fall calving cows? “Economically, probably not,” said Coffey. “But if you have some open cows in the spring and want to hang onto them and start a fall calving herd, we were able to get very good conception rates. The advantage to that is when we wean calves off, we're selling on the high market. Weaning weight on calves sold in mid-April is about 450 to 500 pounds. That's the top of the market.”
This approach allows some flexibility.
“If you want to leave the calves on their mamas until the first of June, that produced 600-pound calves. Most folks won't complain about selling off calves that big and the June market is still good — much better than in October.”
Coffey brought up a southern Illinois research project looking at spring versus fall calving on infected fescue. The study made use of two herds — one spring, one fall. Any open cows in one herd were moved to the other. After four years, some 80 percent of the cows were calving in the fall.
“If you're having reproductive problems with fescue pastures, this might be an option to consider.”
Most cattlemen in Arkansas hill country aren't going to have straight fescue pastures. “If you do, it probably won't be too hard to get some bermudagrass into that fescue. Can we manage that and get along all right? How much advantage would different forages provide?”
To answer the question, a study was set up in bermudagrass-based pastures. Overseeded into the test areas were orchardgrass, some with endophyte-free fescue. Also included in the test was infected fescue that had already been seeded.
Going in, the researchers knew the endophyte-free fescue and orchardgrass would likely need closer management. “We were certainly told that. So, we looked at twice-weekly and twice-monthly rotations on the endophyte-free forages and a simple twice-monthly rotation on the toxic forages.
“We found that at breeding the cows did weigh less on the infected fescue. But body condition scores stayed well above the cutoff level where they won't breed well. We were able to do this while feeding no concentrate to those cows.”
Researchers fertilized the fescue with 60 pounds of nitrogen in the spring. Then, around the first of June, they fertilized the bermudagrass with another 60 pounds. Come fall, another 60 pounds was applied to kick-start the fescue's fall re-growth.
By doing that and simply feeding the cows bermudagrass hay during the winter, “we kept those cows well. If anything, a lot of them were a little too fat — with no concentrate. If you look at the conception rates, they were a little lower than what we were getting with the fall-calving cows. However, we were looking at about 5 percentage units (88 percent verses 83 percent) lower conception rates on the endophyte-infected versus the endophyte-free or orchardgrass. When we had bermudagrass in the pastures, we didn't see a substantial reduction in conception rates.”
Looking at average birthdates there wasn't any difference. “So we're getting 80-plus percent of our cows bred and are keeping them on a yearly cycle because the endophyte-infected cows calve on the same date as the others.”
The researchers found actual weaning weights averaged about 510 pounds across four years on the infected fescue. “That's not bad. Can we live with that versus orchardgrass with a 50- to 60-pound differential? Doing the math, that 60 pounds may be worth around $30. How long is it taking you to pay for the orchardgrass overseeding versus what's already out there needing management?”
To Coffey, the extra 60 pounds isn't worth the cost to kill infected fescue “that's already going to contaminate those pastures.”
Producers in northwest Arkansas who have tried orchardgrass warned Coffey to watch it closely. “They said, ‘We get three or four years out of it and it's gone.’ And that's what we saw in this study. I felt really good three years into the study. We were walking these pastures measuring species composition. The next fall, we looked at it again and couldn't find the orchardgrass.”
If managed on a twice-weekly rotation, “we got the orchardgrass percentage up to about 50. But by the end of the fourth year of grazing, we were down to 36 percent. And it was just going to get worse from there.”
Managed in a twice-monthly rotation, the orchardgrass dropped to 22 percent. Based on the study results, “we're going to have to manage it hard and hope for the best. Or, we'll have to reseed it every four years.
“Can we do that? We thought, ‘We'll use the cows for weed control in the spring of the first year to give that orchardgrass a chance.’ The cows then went down the drill rows, clipping the orchardgrass at ground level. So that first year, it has to be babied.”
So how best to manage orchardgrass?
“It's very sensitive to grazing. Even in parts of the world where it's well-adapted, it's the same. On these pastures, we try to get cows off when it's about 4 inches tall. Flash graze it, leave them on for three or four days and move on. That keeps the proportion up somewhat, but bermudagrass will still compete heavily with it.”
There is research looking at summer dormant orchardgrass. If released, Coffey believes it will help producers. “If it'll go dormant, it doesn't matter — we can graze it harder. Problems occur when it doesn't go dormant during the summer and gets grazed too short and the sugar reserve is used up. Hopefully in five years, we'll have an orchardgrass that fits the bill.”
If infected fescue is combined with bermudagrass, the Batesville station research shows, producers lose about 50 pounds of weaning weight. Strangely, that's about what we're losing between infected and novel endophyte forage.
“When you put the dollars to it, you wind up with about 50 cents per pound as the value of the extra gain. That's $25. When you figure most operations run one cow per 2 acres, the cost is down to $12.50. How long will it take to make up that $12.50?
“When you check the finances, an infected fescue mix may be something to hold onto. You may not want to get too excited about going whole-hog with pasture improvements.”
e-mail: [email protected]