Search the board there has been a lot of discussions on this of recent.
The following was recently noticed:
===============
"...'When' and 'why' to deworm cattle covered at Kollege of Knowledge
By MONETTE TAYLOR | South Central Texas Edition
Dr. "Buddy" Faires detailed deworming strategies for cattle. He also noted several misconceptions made by producers.
-Staff photo by Taylor
May 23, 2002 -- If you are a cattle producer and are deworming your animals for the wrong reasons, you're just wasting your money, according to Dr. "Buddy" Faries of the Texas Agriculture Extension Service, College of Veterinary Medicine.
Speaking to a large group at the Santa Gertrudis Roundup Kollege of Knowledge in Schulenburg, Faries explained the reasons why producers should and should not deworm their cattle.
According to Faries, the brown stomach worm is the major concern in Texas, and many producers are not fully aware of when or why to treat their cattle for this parasite.
Asking each producer to think about the reasons they deworm their cattle, Faries explained why they may be wasting money.
"One of the most common answers to (the 'when') question is 'When I've got them up.' When I ask if that's the right time, they say, 'I don't know, but I've got them up!'"
He said many producers deworm while vaccinating, but unless there is a reason to believe the cows have worms, there is no need for treatment.
"I'll tell you this: Just because you've got them up doesn't mean they have worms. Don't ever think about stomach worms being in the stomach of cattle year around. They're not," said Faries.
According to the veterinarian, stomach worms only occur at certain times, depending on your location in Texas or any other state.
In answer to the "why deworm?" question, Faries said he hears producers say they worm "because it's been a long time, and they think the worms have really built up." Not true.
"The life of these stomach worms would be about two months," said Faries. "For worms to be in a cow's stomach, they have to have come in there in the last two months."
Also, many producers have problems deciding if they should deworm the cows and/or calves, yet if they don't have worms, it just isn't "cost effective."
Another reason Faries gives for producers deciding to deworm is the way the cattle look. Many seem to equate a dry, rough hair coat, weight loss, bottle jaw, thinness, weakness and diarrhea with being "wormy." Not always true.
"Not in the state of Texas. ... That would be very very unusual symptoms of worms in grown cows. The most common cause of 'down and can't get up' would be malnutrition ... the symptoms are the same, but I wish they weren't," said Faries.
The problem is usually that the cows are not getting enough protein, vitamins and minerals, or a mixture of these things. The veterinarian also noted that cattle that have a diet that includes these are less likely to fall victim to worms.
"Every time I've diagnosed a worm problem with cows, it's always been the result of malnutrition," said Faries. "I graduated from vet school at A&M in 1965. That's 37 years ago, and I've never diagnosed stomach worms in grown cows causing those kinds of symptoms when they were on adequate nutrition."
Another reason producers give for deworming is "the grass is short and the cows eat more dirt." Another fallacy, according to Faries. He said it is more "likely" that the producer is not supplementing the lack of grass.
Faries said he knows many of the drug companies are "on the road pushing certain seasons to be worming cattle." Again, he disagrees.
Just because a cow hasn't been dewormed in six months does not mean the cow has worms.
According to Faries, there is only one, good time to deworm cattle.
"The right time to (de)worm for stomach worms is after three to six weeks of continuous rain, and when the soil temperature is between 55 to 85 degrees. If it's below 55 degrees, the worms are hibernating. If it's above 85 degrees, the worms come out of hibernation and become available for cows to swallow.
When temperatures stay above 85 degrees for longer periods of time, it's too hot and they start dying, he said.
While there is a definite cycle of worms on the ground and in cattle, Faries said the cycle can be broken by deworming or the weather.
"I'll tell you, every pasture in Texas will become sterilized every summer, because it's going to get above 85 degrees in Texas, and it's going to get there, for sure, by July ... maybe even June," said Faries.
Another misconception, according to Faries, is how cows get the worm in the first place.
The only way the worm larva can get out of manure is for rain to wash them out, he said. Worms cannot "crawl" out. If the grass is wet from rain, the worms can swim to the top of the grass to be eaten by the cows, if the temperature is between 55 and 85 degrees.
Faries touched on liver flukes, but said they are not common and won't live in acid soil. "You (de)worm for winter flukes five months after you've had three months of standing water on your pasture," he said. (That statement drew laughs from South Central producers who are in a drought area.)
"Since 1995, I have not recommended any cattlemen in Texas to (de)worm their cows ... because we haven't had three to six weeks of continuous rain," he added.
In closing, if producers must deworm the cattle, he advised them to "use the same drug all year long." Also, to change the drugs every three years before returning to the original dewormer."
=================
Most deworm two times yearly...but there seems to be some question as to whether that is essential. We too are beginning to question our long time applications. Suggest it be explored.
