10th February 2022

Most current control strategies against gut worms, lung worm and liver fluke rely on the use of wormers applied to entire groups of animals at pre-determined times of the year. On many farms the same products have been used at the same time every year, for more than a decade.

But cattle vet Rob Howe, who is also a member of the Control of Worms Sustainably (COWS) group, sees unrealised benefits for this to change. A new approach would see cattle immunity develop, allow beneficial organisms to help control worms and reduce farmers’ reliance on products saving them for when needed.

Currently doing a Nuffield Farming Scholarship on the role of vets within regenerative agriculture, his practice now has a pilot of 30 farms in Lancashire adopting an integrated approach for two years, supported by the vet and vet tech team.

The results already show savings in wormer cost, time and stress from cattle handling, while reducing the chances of parasite resistance to products and having better environmental outcomes.

“Parasitic disease is of huge importance in ruminant species,” Mr Howe admits. “However, blanket treatment of all animals regardless of whether they are infected or not, has knock-on implications that can be highly counter-productive.

“Resistance is a real issue in cattle as well as sheep now, and use of these products can unintentionally reduce other beneficial organisms like dung beetles.”

To start, Mr Howe sat down with all the farmers to find out how each was traditionally using wormers. In many cases testing was rarely carried out to see whether worms were present before treating.

“I am advocating a three-pronged approach. Firstly vaccinate against lung worm just before turnout. There is no way to predict easily when lungworm will hit and waiting until coughing starts is less than ideal. Using a preventative vaccine should allow farmers to relax about what is arguably the most serious risk at grazing to youngstock.

“Youngstock suffering from excessive gut worms can lose weight and scour but there is likely to be plenty of warning before things get too serious. During the grazing season, farmers should monitor gut worm levels by observing the stock and taking faecal egg counts, treating only if the results show high levels on the pasture.

“At housing, testing for liver fluke antigen in the dung can quickly and simply alert farmers to the risk level for their animals, as can antibody detection tests in blood or milk samples.

“Type II ostertagiosis, a late season complication of gut worms, can also be detected by worm egg counts and blood tests – although my colleagues and I have hardly ever seen a case, so the risk of this disease might be overblown.”

The LLM Farm Vets VetTech team collected the dung samples on some of the project farms and Mr Howe completed questionnaires at the start and end of the two years to measure outcomes.

Lungworm vaccine sales increased by 115% from the start of the programme as most farmers took Mr Howe’s advice. In the small number of farmers who did not vaccinate, half went on to see clinical instances of lungworm in their calves.

Before any interventions 89% of the farmers used macrocyclic lactone products during the grazing season to control gut worms. After Mr Howe’s input, only one farm used any wormer class during the grazing season because testing showed this was not needed.

“There were many benefits for the project farmers,” says Mr Howe. “Not least a saving on the cost of the products, as much as £1800 on one farm, and a saving in the time, effort and stress of bringing the animals in to treat them.

‘Reducing treatments also reduced the risk of encouraging resistance to the products which is important as there are no new wormers coming. And who knows, maybe we made life easier for many non-target species out there feeding on the cattle dung.

“It is my vision that in the not-too-distant future, this kind of worming programme will be the norm, with much reduced reliance on wormers and all the benefits for farming, livestock and the environment.”

John Dewhurst
Whittingham Hall, Preston, Lancashire

Farm Facts
180 dairy cows
All year-round calving
102 ha
Low yielders and youngstock go out in summer

Before parasite planning
• Lungworm vaccination
• Treat all summer with pour-on twice or three times
• Injectable treatment for worms one week post housing
• Flukicide one week post housing
• No testing

• Continue lungworm vaccination
• Monitor parasite burden via pooled faecal egg counts.
• Fluke testing in autumn
• Rotate products away from those used in the past

• All faecal egg counts were low/negative so no treatments needed at grazing
• Blood pepsinogen test taken to rule out risk of Type II ostertagiosis. Came back negative
• At housing all faecal tests negative for fluke antigen. This was unexpected so antibody tests were performed four weeks after housing. These were negative. No fluke treatment given

“My priority is animal health and performance and I thought I had devised a strategy that would see my youngstock thrive,” said Mr Dewhurst. “I was sceptical of Rob’s plans to start but he encouraged us to test.

“To start I couldn’t believe that the results kept coming back clear. You must have faith not to treat. But without testing we would never have known we were wasting time, money and stress to man and beast by treating so routinely.

“Animal health remains my number one priority, but it is also good to know by not treating we are doing our bit for the dung beetles and other soil life too.”

Neil Kidd
Booth Hall Farm, Ellel, Lancashire

Farm Facts
150 dairy cows
All year-round calving
Heifers graze for six to seven months

Before parasite planning
• No lungworm vaccination
• Treat in summer three times for gut worms
• Treat for fluke three weeks after housing and possibly later too
• No testing

• Lungworm vaccination
• Monitor parasite burden doing faecal egg counts
• Fluke testing in the autumn
• Rotate products away from those used in the past

• Vaccinated against lungworm for the first time in 20 years
• No treatments made against gut worms as testing showed low/no levels
• Tested for fluke mid-December – will treat only if results are positive

“Vaccinating all the youngstock against lungworm was much more successful than trying to control lungworm with pour-on wormer,” said Mr Kidd. “Pour-ons also tend to be the most expensive – so this was a significant saving over the year.

“With regards to gut worms – taking dung samples was quick and easy. I would rush out and collect it when a group of animals got up and stretched and mucked, and then give it to the guy in the medicines delivery van to take back to the vets to test.

“Not having to bring the animals in to treat saves a lot of time and hassle – particularly during busy times when we might be silage-making. Jobs like worming can easily get put off for more important tasks.

“The animals have performed much better with consistent growth rates, meaning they are more likely to be ready to serve to calve at two years of age.

“Soil health and the wellbeing of creatures like dung beetles is becoming increasingly important and we need to take care of them too. This approach is good for that.

“It’s time that farmers try to forget what they have traditionally done because it may no longer be appropriate. Times are changing and mindsets might need to change too.”

This article was first published in Farmers Guardian, 7 January 2022