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CATTLE TODAY

PARASITES ARE AN ONGOING EVIL THAT MUST BE CONTROLLED

by: Clifford Mitchell

With all the new information available in the beef business, it is easy for cattlemen to get lost in the fog and overlook the importance of general animal husbandry. The industry is preaching many things, depending on which congregation breeders choose to attend. DNA markers, carcass traits, cloning, embryo transfer and other techniques to help improve the bottom line are being discussed randomly.

Without sound animal husbandry, progress will not be made in any area of genetic improvement. Letting cows fend for themselves will only prove Darwin's theory of “survival of the fittest”; because only the tough ones that can brave all the elements will be left. If this was the most profitable scenario, managing beef cattle would not have evolved into what it is today.

It's about time the beef industry started embracing some futuristic ideas, but to be successful, the basic fundamentals of sound animal husbandry must be followed. Some regions of the country present a unique set of challenges when it comes to managing livestock. Different areas afford various limiting factors that affect overall performance. Parasites are an ongoing evil and must be strategically dealt with for cattlemen to make the most of their efforts when dealing with this profit-robbing vermin.

“The amount of treatment is going to be related to the geographic area you're in. Strategic de-worming gives producers the most “bang for their buck”. Keep track of the life cycles of the worm eggs and larvae. If possible de-worm before you move cattle to a clean pasture,” says Dr. Mel Pence, University of Georgia College of Veterinary Medicine, Tifton, Georgia.

“We're facing a unique challenge as we repopulate our beef herd. We're always going to have problems with brown worms and liver flukes, but external parasites like horn flies and mosquitoes could spread anaplasmosis,” says Gary Wicke, Livestock Specialist, LSU Ag Center, Cameron, Louisiana. Cattlemen in Cameron Parish are still trying to repopulate the beef herd after Hurricane Rita caused much devastation.

Tools for fighting parasites have been available to cattlemen for a long time. As with most pharmaceuticals, improvements have been made to make these products more effective and easier to use. Continued use of some products has decreased affectiveness because internal parasites have built immunity to the active ingredients.

“Basically we have three types of de-wormers: White paste, the Levasol and Tramissol products and avermectins (Ivermectin and Dextomax). The avermectins are the only products parasites have not built some immunity to,” Pence explains. “Continued treatment will only build a resistance problem. Once the parasites become resistant to that treatment, it is difficult to reverse. The goal should be to minimize pasture contamination and use de-wormers on a limited basis.”

Weather and pasture conditions have an impact on the breeding ground for parasite populations. Certain times of year are more receptive environments for eggs and larvae.

“I religiously de-worm cattle twice a year using a broad based de-wormer. When I de-worm I do all my vaccinations, but timing varies so I can get the best kill on the worms,” says Robbie Hamilton, H & M Cattle Co., Wharton, Texas.

“To control horn fly populations most producers are using a combination of tags, fly mineral and spray. Another option would be to use a de-wormer with some fly control,” Wicke says. “In the spring, we have to take care of the lice and worms. Mud and moisture provide a good environment for both. In the fall, we have to use a combination de-wormer that will also kill liver flukes.”

“Depending on the time of year, it only takes a worm egg a short time to hatch into infective larvae,” Pence says. “Once the eggs hatch into infective larvae, the only place for them to get more energy is when they are consumed by the cow. Cool and moist weather allow parasites to thrive.”

As with many preventative measures, the decisions made with parasite control must be teamed with other management practices to achieve best results. Timing is critical when parasite control is administered to the herd. Making applications during the proper time frame is a challenge for some producers.

“When conditions are right for parasites to survive, the money a producer would spend on de-worming could be better spent in other areas of the operation. Parasite loads decrease when the egg becomes dormant in summer and winter months. When parasite loads on the pasture decrease, this is the best time to de-worm,” Pence says. “Unfortunately for most producers, the best time to de-worm is when the cow is in the chute. Timely treatment when the worm eggs are dormant and cattle are going to clean ground is ideal. This could be in July when a producer grazes some hay ground or during the winter months grazing annual rye on peanut or cotton ground.”

“The best time to de-worm is probably in mid summer, but most of our producers don't do it because it's too hot. There are a lot of different philosophies,” Wicke says. “I recommend de-worming cattle before they go to clean ground. In our area, that could be rye grass or rice ground used for winter grazing. When cattle are getting better groceries, they should be de-wormed, there's no sense feeding the worms.”

“In the spring and fall, timing of the treatment depends on the life cycle of the worms I am trying to kill. I try to do multiple management practices every time I run the cows through the chute,” Hamilton says. “We can have problems with liver flukes and some years it's worse than others depending on how wet we are. I have to take the proper measures to control parasites before they become a problem.”

Liver flukes are common in some areas and not a problem for other producers. Not controlling this problem could impact profits, directly for the producer or down the line for another segment of the industry.

“Liver flukes have a complicated life cycle where it has to mature through a certain small snail. Cows consume the snail drinking water,” Pence says. “Soil type and conditions have to be just right for liver flukes to multiply. They have problems with flukes in many Gulf states so far they aren't a problem in Georgia.”

“Liver flukes like moisture and unfortunately we have to deal with them in our country. It is important to treat them because of the liver deductions (price) cattle can receive without prevention,” Wicke says. “There's a possibility we'll get a little break from liver fluke contamination. It depends on how well the snail species can deal with salinity in the water after the storm.”

Others factor may influence worm populations and parasite loads on pastures. Some producers could be limited due to acreage size or if there is clean ground available. More numbers or higher animal concentration could put increased pressure on managers to have a fool proof parasite control program.

“We increased parasite problems with overgrazing and overstocking after the storm,” Wicke says. “We had some drought stressed pastures and when we overgrazed them there were more eggs on that ground. Anytime grazing is short and cattle don't have access to unlimited forages parasite load will increase.”

“With the cost of feed, I can't afford to feed many worms. It doesn't take much feed to offset the cost of my de-worming program,” Hamilton says. “I have to have a good program to control parasites. I am limited in the number of acres I can graze and with the cost of land in my area that isn't going to change. My cattle are grouped pretty close and the ground is concentrated with a lot of cattle, without good prevention I would have a problem.”

“Some grazing systems like rotational grazing will actually increase parasite load. High animal concentration and grubbing the grass down will increase worm population,” Pence says. “Stockpiling forages or staying out of certain pastures for three to six months will decrease parasite burden.”

For adequate parasite control, no matter what geographic location, certain classes of cattle need more attention than others. De-worming strategies, most will concede, are directed solely at weight gaining strategies; however, a diligent effort enhances many areas of production.

“Younger animals are more susceptible to parasites. Parasites detract nutritionally and affect an animal's immune system,” Pence says. “Properly de-wormed cattle show increased weight gain, greater ability to respond to timely vaccinations and enhanced reproduction, especially in young cows because it takes time for them to build some immunity to internal parasites. Bulls are highly susceptible to parasite loads.”

“I don' think we worm young cattle enough. It helps a lot if producers will de-worm light calves as soon as they start grazing,” Wicke says. “Young cattle are nutritionally challenged without passing a worm load onto them. Bulls coming into our environment from low moisture climates will take a while to adjust. I would suggest de-worming them at least three times the first year. For what those bulls cost, three times in a year is cheap to get him acclimated.”

“Young cattle have no immunity to parasites and will get wormy quicker than anything on the place,” Hamilton says. “Older cattle will build a little immunity, but they still need treatment.”

To improve management, cattlemen fight many adverse conditions. However, the strongest influence may be tradition. Good cattlemen, for the most part, take care of the land and the herd equally. This passion for the industry also leads to management theories that are set in stone, rather than something pliable.

This rigid form of husbandry would be well served to take another shape when armed with new information based on sound science. Grandpa may have been the best Cowboy and steward there was. The only disadvantage might have been the lack of knowledge.

Sifting through the “smoke and mirrors” could be the toughest job faced by producers in the 21st Century beef industry. Cattlemen, trying to answer too many questions, should step back and blend a little of what Grandpa would do with new policy to form a complete husbandry program.

“More accurately managing parasite load on the pastures will allow producers to decrease the use of de-wormers,” Pence says. “If you are only going to de-worm one time of year, do it July 1 and go to clean ground. Typically, the parasite load is 90 percent on the pasture and 10 percent in the cows. These ratios do not change, but in the summer months the eggs are dormant in the pasture. Use a product that will kill worms in the inhibited larval stage. Some of the pour-on products are convenient and effective against the inhibited stage in cattle.”

“I encourage producers to take care of business from a parasite management standpoint,” Wicke says. “De-worming products have become more economical over the years. De-worm twice a year, especially when you are going to new pastures with more abundant forage supplies. In our area for fall treatment, we need to make sure the product is labeled for liver flukes.”

“In my area and the way I manage my cows, I have to de-worm twice a year. I have high concentrations. Improved performance is necessary because of the product I market,” Hamilton says. “A good de-worming program is pretty cheap when you figure how much it costs to take care of a cow.”

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