Sustained release products developed for cattle are revolutionizing the way we treat pneumonic calves in Canadian feedlots.
Draxxin, developed by Pfizer, is a play on “duration of action.”
There was a need to develop a long-acting product because multiple doses of long duration products like Nuflor or Micotil were given in feedlots.
The active ingredient is Tulathromycin. It has an extremely long half-life, the time it takes for half the product to remain in the animal’s system.
The half life is 184 hours in the lungs, allowing it to remain active against specific bacteria 10 days or longer when used at recommended doses of 1.25 cc per 50 kilograms or 1.1 cc per 100 pounds.
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The compound in Draxxin has qualities particularly helpful in our Canadian climate. It has the consistency of water yet is stable and will not freeze until below –15 C and so is easy to use in a syringe. Ultraviolet light does not affect it so it comes in a clear bottle.
It has an affinity for lung tissue and so concentrates there, making it effective on pneumonias. It is absorbed quickly, within 30 minutes, with only minor swelling evident occasionally. It is given subcutaneously and has been proven safe. When tested in rats after 60 days there was no significant effect on reproductive rate.
It is totally safe when given to pigs, and pigs are test models for humans.
If given intravenously, there are no deleterious effects.
Accidental injections should be safe in humans but that is no excuse for being careless. In most cases, dirty needles and the size of the needle cause the problem in accidental human injections.
We should be careful with any product we handle or inject and use the one-handed technique to inject.
The withdrawal for slaughter is 44 days.
That amount of the drug in the meat is calculated back to a 60 kg human eating 500 grams of muscle meat daily.
In the U.S., the calculations are based on eating 300 grams of muscle and the detectable levels are slightly higher. That is why the same product in the U.S., at the same dosage and delivery, has a withdrawal of only 18 days.
Baytril, a potent drug for pneumonia, must be given only as the second drug of choice, such as in a relapse situation.
Draxxin can be given in a group situation when a diagnosis of pneumonia has been made or the calves are highly stressed and likely to contract pneumonia.
We call this giving it metaphylactically, just before an outbreak of respiratory disease is suspected.
More susceptible
With all these superior drugs on the market, why do morbidity and mortality not seem to change much?
Today’s genetics have increased growth rates in cattle, causing greater physiological stress and immune suppression. Some calves are now gaining more than five lb. daily.
To maximize these genetics, we have created diets that have more concentrated nutrients that can increase acidity and lead to digestive upsets and more pneumonia.
With larger feeding operations, labour is more scarce and staff look after more animals.
There is also bound to be a greater concentration of organisms in larger feedlots and calves are obtained from further away. There is often no opportunity to delay purchases because of weather or to secure pre-conditioned cattle. Feedlot cattle often come from multiple sources.
In our practice, I am sure we will use this drug on stressed, long-haul, lightweight groups of cattle and clinically sick individuals. We’ll still use other drugs but if there are problems with facilities, cold weather or getting adequate labour for retreatment, this drug will be used.
The results look promising and the product will add to veterinarians’ ability to keep your dead pile and chronic pen smaller.
As always, get your veterinarian’s opinion on drugs. They will be able to fine tune a program specifically for each group of calves. Different situations warrant different methods.
