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In the last few years the pressure has been increasing on farmers to reduce antibiotic use. That pressure has come from government and from wider society, given the growing threat of antibiotic resistance in human medicine. If current trends continue, it is expected to overtake cancer as the largest killer of the world’s population by 2050.
The reason for this increased problem of antibiotic resistance is the overuse of some vital drugs in human medicine. The same trends are happening in agriculture, where antibiotic resistance is also a growing problem.
Given that most scientists believe that unnecessary use of drugs on animals is of concern to human health, farmers have a vital role to play, even if it is mainly just to reassure the public about the safety of the food we produce.
The vast majority still blanket-treat cows with antibiotic tubes at drying off, so this is a key target area when it comes to reducing antibiotic usage on farms
Over the last few weeks, CAFRE, in association with Animal Health and Welfare NI (AHWNI), has been running a series of workshops on the responsible use of antibiotics in the dairy herd.
Best estimates suggest that NI dairy farmers routinely treat around 10-20% of animals in their herd each year with antibiotics for problems related to scour, pneumonia, lameness, mastitis and withheld cleanings.
However, the vast majority still blanket-treat cows with antibiotic tubes at drying off, so this is a key target area when it comes to reducing antibiotic usage on farms.
Speaking at the workshop held in Fivemiletown last week, Dr Sam Strain from AHWNI suggested that selective dry cow therapy potentially has a role on many farms.
“The purpose of a dry cow tube is to clear any infection and prevent new infection. But if there is no infection a teat sealant is a viable alternative,” he said.
In general, when a herd has a somatic cell count (SCC) below 200,000, then selective dry cow therapy becomes an option – to be used on cows that have had low cell counts at the last three milk recordings.
“But where you draw the line in the sand (SCC below 200,000) is specific to your farm. Dip your toe in the water cautiously. Milk recording is a critical component. Cleanliness when using teat sealer is also crucial,” said Strain.
He recommended using gloves and alcohol-soaked cotton wool to properly disinfect a teat (rather than teat wipes), when inserting the sealant into a teat.
Target
The industry target is to reduce the amount of dry cow tubes used in UK dairy production by 20% by 2020 (from a 2015 baseline). The figures for 2017 suggest that the use of dry cow tubes is down 8%.
However, the equivalent figure for mastitis tubes shows usage was up 1% in 2017 when compared with 2015, despite a target to reduce usage by 10% by 2020.
“It will be the most difficult target to achieve in my opinion. Across everything, we are roughly speaking halfway there. There is still room for improvement,” noted Strain.
The other main target area is to reduce the amount of High Priority Critically Important Antimicrobials (HP-CIA) in dairy farming. This list is made up of three core groups, generally seen as “go-to” antibiotics in human medicine. Perhaps the best known in agriculture are Fluoroquinolones, which includes Marbofloxacin (Marbocyl).
“These should only be used as a last option, not a first option,” said Strain.
The target is to reduce HP-CIA products used in cattle farming by 50% by 2020. The most recent figures for 2017 show that usage is down 29% when compared with 2015 levels.
Total
But as a whole, the total amount of antibiotics used in UK cattle production has changed little in recent years. Compare that with the intensive pig and poultry sectors, where usage is now under half of what it was in 2013.
“The amount of antibiotics used in cattle is still lower than the intensive sectors, but they are catching up,” said Strain.
He suggested that the lesson from pigs and poultry is that improved animal health is key to reducing drug use. That means providing a better environment for livestock, plus strategic use of vaccines.
He also emphasised the importance of only using antibiotics when they are likely to be effective.
For example, viruses such as rotavirus or coronavirus cause calf scour, but neither will respond to antibiotics – where a calf is otherwise bright and healthy, it should receive rehydration therapy.
Treated
Where a lactating cow has been treated with antibiotic and the milk kept out of the food chain, Strain advised farmers to dump the milk, not feed it to calves.
“In effect you are giving the calf an under-dose of antibiotics. Johne’s disease is also behind a lot of cow illnesses. By feeding this milk, you are potentially storing up problems for the future,” he suggested.
Finally, he reminded farmers to be careful around withdrawal periods and to make sure that a product is licensed for use in a particular animal. He referred to the likes of Ivomec Super, which is not licensed for use within 60 days of calving. Nuflor is not licensed for use in a milking cow, while Closantel in flukicides cannot be used in dairy cows, or dairy heifers in the second half of pregnancy.
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