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Mastitis — To Treat Or Not To Treat?

When it comes to deciding whether or not to treat mastitis in a beef cow, safety may just trump both economics and cow comfort. Convincing a cranky cow that you’re there to help her can be risky and might be more trouble than it’s worth.

That advice applies only if you’re seeing a straightforward case of mastitis in one quarter with a cow that is otherwise doing OK. If she’s depressed or not eating, with her ears down and not wanting to walk too much, then the infection may be systemic and she probably requires treatment.

Rob Swackhammer has seen lots of mastitis working as a farm service veterinarian for the Ontario Veterinary College for over 10 years prior to establishing his private practice near Rockwood, Ont. The typical mastitis call he would get describes a cow with an enlarged quarter, sometimes showing signs of depression, with her calf bawling because he’s not getting enough milk. Sometimes with a chronic case there may be an abscess burst out the side of the udder but that, he says, is fairly rare.

When he’s presented with these symptoms, Swackhammer will examine the cow to make sure nothing else is going on. If he determines that the mastitis has gone systemic he’ll advise injectable non-steroidal anti-inflammatory drug (NSAID) treatment to reduce inflammation and fever along with a course of broad-spectrum antibiotics for three to five days that will have some penetration into the udder.

In severe cases the cow may need fluids as well, with a total treatment cost ending up between $100 and $200, but he still feels it’s economical to treat depending on the cow, her age and her value to the herd. “There’s a good enough success rate that people would be happy with the outcome,” he says.

Swackhammer sees some with what he calls “pet cows” that will have the patience and time to spend on poulticing and treatment, with cows that are quiet enough to be safe to work around. He gives those people a lot of credit but realizes that 90 per cent of beef producers “won’t go there.”

Treatments such as mastitis tubes that are inserted into the teat opening can be risky to administer to the typical beef cow. For that reason, if it’s only one quarter that’s affected and the infection hasn’t become systemic, he’s not likely to treat her at all. Dry cow and lactating cow teat treatments are inexpensive and readily available, with a 30-day meat withdrawal period that must be observed.

Often a quarter affected with mastitis will not produce milk in the next lactation but the cow should compensate quite well with the other three quarters. “The growth rate of the calf should be as good on three quarters as four,” says Swackhammer, and what little research there is into the subject backs him up. Newman et al. (1991)1 reported that beef cows infected with Staphylococcus aureus, one of the organisms that may be responsible for mastitis, weaned calves that were only 9.6 kilograms lighter than non-infected cows.

Organisms that are present in the environment, bacteria such asE. coli, Staphylococcus aureus and Streptococcus agalactiae, cause most mastitis infections. Occasionally mastitis may follow an injury to a quarter. Sometimes a calf that cross suckles will spread the infection but as a rule, in beef cattle mastitis is not considered a contagious issue.

In humans, mastitis is quite common and symptoms develop quickly. Most cases are thought to be caused by milk not being expressed regularly and result in flu-like symptoms, fever and swelling. About 15 per cent of inflammations develop into infections, usually caused by S. aureus that may be introduced through the nipple opening or lesions, either from the environment or the baby’s mouth.

As for the calf, the milk from a mastitic dam will not likely have any adverse effect provided he’s healthy in all other respects because he’s not likely to consume too much of it anyway. The infected milk will likely have an abnormal taste that will deter him from drinking it, and the cow won’t likely let the calf drink from the swollen and sore quarter.

Dairy farmers operate under different circumstances where the incidence of mastitis may be an issue of public health. Mastitis is a very common problem in the dairy industry and it’s not unusual for dairy farmers to have a supply of intramammary antibiotics on hand, a treatment that’s much less risky to administer to a dairy cow that has her udder handled on a regular basis.

Dairy cows are more prone to mastitis for several reasons: they risk transmission of infectious organisms through milking equipment, and their udder sphincters may be under greater stress than a beef cow who has a calf nursing at regular short intervals, allowing bacteria an easier entrance into the teat. Dairy cows can get systemically sick with mastitis as well.

There are vaccines available to stimulate the cow’s immune system toE. coli,another organism that may be responsible for mastitis. Some dairy farmers use the vaccine routinely but Swackhammer sees them as a band-aid for a bad year; instead, “what you really want to do is clean up the environment,” he advises.

The same mastitis prevention advice holds true for beef and dairy: keeping the udders clean is the key. For beef, that means calving on grass when possible and avoiding muddy situations. The incidence of mastitis will increase during wet weather when teats — especially those on older cows or those with larger, low-slung udders — may be in more contact with bacteria in the mud. There is also a greater risk of mastitis in cows that calve indoors in the winter, simply due to greater exposure to bacteria in confinement housing.

To treat or not to treat? “I’m a beef farmer too,” says Swackhammer. “As long as the calf is not bawling and the cow’s not sick she’ll handle it.”

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