Kicking antibiotics out of the dairy barn

Contrary to popular belief, reducing antibiotic use has not resulted in lower returns to producers

It has been 68 months — and counting — since a cow in the milking herd at Rosy-Lane Holsteins LLC near Watertown, WI, was treated with antibiotics.

The owners are now taking a hard look at whether they can reduce or eliminate antimicrobial use in dry cows and calves.

While the 1,000-cow Wisconsin dairy Lloyd Holterman operates with his wife Daphne and two younger non-family partners, is a go-to example for the reduction of antimicrobial use in North America, their experience is far from unique.

In the Netherlands, where the government mandated a 10-year long series of reductions, antimicrobial use is now down 70 per cent. Not only that, herd efficiency is up. Some are now questioning how antibiotic use became so widespread in the first place.

Why it matters: Although many fear pressure to reduce antibiotic use in animal industry will lead to lost production and efficiency, some dairy operators are finding the opposite is true — because it has made them better managers.

At one time Holterman’s farm was a high user of bovine somatotropin, the growth hormone given to cows that resulted in higher milk production, along with antimicrobials. The decision to move away from BST use was based on market demand and a hard look at the cost of medicines during the most-recent economic downturn in the global price of milk.

Lloyd Holterman’s cows produce 1.7 litres of energy corrected milk for every kilogram of dry matter. That compares to a Wisconsin average of 1.4 litres per kg of feed.
photo: John Greig

Antibiotics are a subset of the larger umbrella term antimicrobials, which can also include some antifungals, but the terms are used almost synonymously.

Now that he has partners to help with the workload, Holterman’s job is financial management and his goal is to know the farm’s economic metrics, especially feed efficiency. The farm’s cows produce 1.7 litres of energy corrected milk for every kilogram of dry matter. That compares to a Wisconsin average of 1.4 litres per kg of feed.

The reduction in antibiotics has actually helped with feed efficiency improvement because no milk from cows being treated with antibiotics is being removed from the milk line. Treated cows contribute zero to the milk volume, but they consume feed and are drains on feed efficiency.

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“Cows have to go into the tank. They have to be healthy,” he said.

They still have a way to go in completely eliminating antimicrobial use, because the drugs are still used in dry cow treatment and for sick calves.

Dry cow treatments were found in the Netherlands to be the largest use of antimicrobials on a dairy farm. Farmers place antimicrobials into a cow’s teat canal when they are finished their lactation to prevent mastitis during their dry period. Farmers diagnose mastitis in lactation cows fairly easily because they are being milked multiple times each day. When a cow is dry, there is little interaction between farmers and a cow’s udder, so if they contract mastitis it can be severely damaging to the cow.

There are alternatives such as teat canal barriers. However, Holterman said they are an expensive option relative to antibiotics.

Combining milking cow and dry cow treatment for mastitis meant 67 per cent of antibiotics used in dairy were going into the mammary gland, said Tine van Werven, of Utrecht University from the Netherlands, at the recent Progressive Dairy Operators triennial conference in Mississauga. The mammary system is the “main consumer organ of the cow.”

However, government regulation forced massive reductions in the use of antimicrobials in the Netherlands, said Tine. An industry task force was created to deal with the issue in 2008, but the government wasn’t convinced any sort of voluntary program would work, so by 2011, it mandated a 20 per cent reduction. It went well, so it increased it to 50 per cent, from 2011 levels and then 70 per cent in 2015.

“Government regulation forced massive reductions in the use of antimicrobials in the Netherlands.” – Tine van Werven
photo: John Greig

The industry was able to make the reduction in four years, she said, and that meant some questions from the government about why there was such heavy use of antibiotics before the mandated reductions.

Indeed, researchers are now wondering the same thing.

There was no good monitoring of the use of antibiotics on farms in the Netherlands and after the Netherlands Veterinary Medical Authority was created, there were some interesting findings.

Veterinarians like van Werven have to provide data on all medicines to a national database every two weeks now. Each farm has its use calculated and compared to a benchmark.

Farms that are higher users will be questioned.

The researchers found there was no relationship between level of antimicrobial use and milk production.

The expectation was that high producing herds would require more antimicrobials because they were more physically demanding of their cows. But that theory was dashed.

A higher level of management resulted in better milk production without more antimicrobial use.

Dairy in or out of regulations?

There was originally a suggestion that dairy farms could be exempted from the antimicrobial regulations in the Netherlands, because they use much lower levels of antimicrobials than poultry and swine producers. But the government included all livestock in the regulations, said van Werven.

Farmers are required to follow specific treatment protocols for using antimicrobials. Deviating from that treatment protocol can mean punishments.

The decline in use is coming from education, tighter management and catching the large-user outliers.

One 80-cow herd was found to have 120 vials of penicillin, so those operators were questioned. The farmer said he had been told by a neighbour to use 10 millilitres of penicillin for 10 days to really make sure that umbilical cord infections were cured. That’s enough to treat 10 calves, said van Werven.

“Not one had checked that routine,” she said.

The program has been a success, she said, including the fact that antimicrobial resistant bacteria appear to be decreasing in dairy cattle. It had been thought that once a level of resistance arrived in a population it would continue.


Managing with fewer antimicrobials

There are several areas identified in the Netherlands where much lower volumes of antimicrobials are necessary, says Tine van Werven of the Utrecht University from the Netherlands.

Lloyd Holterman, a dairy farmer in Wisconsin who has not treated a milking cow in five years, also had some tips.

  • Calves that have diarrhea have almost no bacterial infection, said van Werven. It is almost always a nutritional issue.
  • Use a thermometer to monitor cow status.
  • Not all mastitis needs to be treated. Establish a treatment protocol and test for type of mastitis before treating.
  • Preventive treatment using antibiotics is no longer allowed in the Netherlands. As a result, dry cow treatment has to be selective. A standard in the Netherlands now involves treating cows with more than 50,000 somatic cell count (SCC) and heifers with more than 150,000 SCC. Part of dry cow treatment is to keep cows protected if there’s environmental risk during the dry period. That means more individual cow management including making sure milk production at dry off is low enough. If a cow is still milking 40 litres per day, her ration will have to be changed to encourage dry off. Producers must also see if cows have cracked teat ends. Making sure that milking machines are working effectively can reduce hyperkeratosis.
  • Level of exposure of bacteria (cleanliness of living conditions of the cow) is also a factor. Farmers who have a hygiene score completed on their farm, even once, show a reduced need for mastitis treatment. Holterman calves all his cows in a small area. It is cleaned and disinfected regularly. Dry cow pens are scraped daily and bedded twice per week. Waterers are also steam cleaned with disinfectants.
  • When calves are separated from cows at Holterman’s farm, they are moved into a disinfected calf box and their bedding is a quilt that can be removed, laundered and disinfected.
  • Cows with higher immune response can help reduce the need for mastitis treatment. Managing immune response can be done through vaccination or through proper nutrition.
  • Train people working on the farm well, said Holterman. They need to know protocols.
  • A focus on calving ease to reduce the stress on cows at calving has helped Holterman.
  • Don’t move around dry cows. Limit their stress as much as possible.
  • Select for mastitis resistance and livability measures when breeding cows.

About the author

Editor

John Greig has spent his career in agriculture journalism and communications. He lives on a farm near Ailsa Craig, Ontario. Contact John at [email protected] or follow him on Twitter @jgreig

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