ANAPLASMOSIS, THREAT TO CATTLE, PROFITS

Disease causes oxygen depletion by destroying red blood cells.

By Katrina Huffstutler

Suffocation causes cattle to do crazy things. Things like plowing into the side of the friendly feed truck or putting a cowboy up a tree, says Dr. Dave Sparks, Oklahoma
State University Extension veterinarian.

Suffocation may sound like a far-fetched cause of aggression and eventual death in cattle, but that's exactly what happens when a cow has anaplasmosis. Sparks says
the disease, which is caused by the organism anaplasma marginale, destroys the animals' red blood cells, leaving them unable to properly transport oxygen throughout their body.

Another common symptom of anaplasmosis is orange or yellowish tissue when the animal's skin would normally be white.

"Around the eyes, lips, vulva — anywhere there's no hair coverage," Sparks explains, "that's pretty much a dead giveaway."

What causes anaplasmosis?
Once considered a summertime disease, Sparks says veterinarians are no longer surprised to see anaplasmosis any time of year.

"We still see most of it in the warmer months, but it's definitely become a year-round thing," he says.

"Anaplasmosis is transmitted by vectors," Sparks says, adding that those vectors can be insects (primarily biting flies, horse flies and ticks) or of a mechanical nature, meaning items that transfer blood from one animal to another (such as hypodermic needles, ear taggers or castration instruments).

But how do you know what type of vector is to blame so you can take steps to prevent outbreaks?

"You may not always know what caused an anaplasmosis outbreak on your place, but a lot of times you can get a pretty good indication," Sparks says.

"[In] an outbreak caused by insect vectors, typically you will have an animal that becomes sick, and then about 3 to 5 weeks later you'll have multiple other animals become sick. That's because the insects have spread it from that 1 sick animal to the other animals.

"But, in what I think of as a man-made outbreak, rather than seeing [a single animal] followed by multiple cases, you will probably see multiple cases all at once. Because it spread to all of them when we worked them," he says.

How can I treat it?
Sparks cites tetracycline as the drug of choice when anaplasmosis breaks out.

"If the animal isn't too far gone," he says, "it will usually respond very nicely to injectable tetracycline."

Sparks says, due to the animal's temperament change and the fact that it cannot carry oxygen properly, treatment isn't always the best option.

"If the animal has it very bad, sometimes treatment will do more harm than good. You could even kill them just trying to help get them well," Sparks says. "So I don't always recommend getting the cow to the pen and doing whatever it takes to get her treatment. Sometimes it's just going to be too tough to get her gathered up and she may just lie down and quit."

He says isolation is of utmost importance, especially during an outbreak.

"While an animal with anaplasmosis will always be a carrier of the disease and can continue to shed the organisms, [the animal] going through an active outbreak is many, many times more contagious than a carrier. So we need to isolate that sick animal to protect the rest of the herd," Sparks says.

He adds that, as with treatment, due to the animal's affliction it may make more sense to separate the herd from the sick animal instead of the opposite.

"Sometimes if she's down in the brush struggling to stay alive, if we just leave her alone and don't get her stirred up, some of those animals will recover spontaneously. So it might be easier sometimes to move the rest of the animals to a different pasture and leave her alone," Sparks says.

He says while there are treatment options available to eliminate the carrier state altogether — such as long-term use of antibiotics — it's usually not a practical method for most commercial cattle operations.

How can I keep anaplasmosis out of my herd?
With good management, the number of cases of anaplasmosis can be dramatically reduced. Sparks offers 4 tips for keeping outbreaks at bay — 2 specific to the type of vector causing the outbreak, and 2 catch-all methods.

He says one of the easiest and most effective methods is to change hypodermic needles frequently when working cattle.

"To tell you the truth, if I've got a lot of cattle to put through the chute, I don't change needles between every cow," Sparks admits. "But I do try to keep the risk down where it's a little more acceptable."

A good rule of thumb for producers using multiple-dose syringes like the popular 50-cc pistol grip is to change needles each time you refill the syringe, he says.

"That way I may spread it to a few of them, but it's not going to be significant and it's a little more practical. Those needles are getting dull at that point, anyway," Sparks explains.

He adds that any items that can spread a drop of one animal's blood to another, such as ear taggers, should be rinsed between applications.

As far as insect vectors are concerned, Sparks says "anything we can do to control them helps."

"Fly control is tough, because we're looking at biting flies like deer flies and horse flies, which are pretty hard to control. We can, however, do a lot to help control the ticks," he says, citing both chemical and mechanical means.

Not only can the ticks be controlled via the animal, Sparks says environmental improvements can also help keep the insects at bay.

"Weeds and brush make a good environment for ticks — and all insects — so by minimizing under brush, we can also minimize ticks," he says.

Another preventive measure Sparks recommends is providing cattle with a mineral supplement that includes chlortetracycline.

"Keeping cattle on a consistent dose of chlortetracycline will pretty much stop anaplasmosis in its tracks," he says, though he admits it's not a sure thing. "The problem we run into is there are always a few animals in every herd that don't eat mineral. Then there are bulls, the most valuable animals on the ranch, that often don't eat enough based on body weight. They're usually a lot bigger animals and yet they don't eat enough to get the protective dose."

He says some producers opt to give injectable tetracycline on a periodic basis to prevent the disease, but it's not always practical. Not only is it labor-intensive, but it can be stressful on the animals to get them up and run them through the chute so many times. (Not to mention the more times you get them up the harder — and therefore more stressful — it becomes.)

Alternately, an anaplasmosis vaccine is available in some states (Sparks says Texas, Oklahoma and most of the top cattle-producing states are among those included). The drug, which was developed by Louisiana State University in partnership with a major drug company, is distributed by the university and available by prescription only.

Sparks says while it's cost-prohibitive for some, the vaccine is gaining momentum in Eastern Oklahoma.

"I've talked to several people who are not quite ready to do their whole herd, but are at least vaccinating their bulls, which are not only more valuable, but may also not be getting enough protection from mineral alone," he says.

Sparks adds that there's no measure better than just keeping an eye on your herd. He says one reason some people will see more anaplasmosis in the summer is because a typical cowman sees his cattle less often then.

"In the winter, he's out there every day or every other day on the feed route. If there's a problem, he's all over it pretty quick," he says. "But, in the summertime, the cattle are out on pasture and have everything they need. The operator and all available hands may be spending most of their time in the hay field or working ground getting ready to plant. By the time you get out there to check cattle, you find you've got 10 or 15 down. It's really important that somebody stays on top of them year-round."