Dairy farmers share their stories on tackling Johne’s disease
© Tim Scrivener Dairy farmers are being forced by milk producers to tackle Johne’s disease in their herds, with some milk buyers delisting farmers who don’t engage with controlling the disease.
Four dairy farmers attending the Action Johne’s Conference in Worcester earlier this week spoke of their commitment to tackling Johne’s and detailed how they were going about doing it.
Case studies
John and Sally Banks, Wildon Grange Farm
Focusing on hygiene around calving and improving youngstock rearing is protecting high herd health status in an expanding dairy herd.
See also: Journey to eradicating Johne’s disease
At Wildon Grange Farm in Kilburn, Vale of York, John and Sally Banks are expanding their herd of 380 Holsteins, aiming for 600 cows by 2018, by breeding their own replacements.
They are controlling Johne’s by improving farm management.
A low-stress calving environment includes a dedicated clean area designed to always be dry.
Calves are immediately removed from the calving pens and cows milked with a mobile milking machine.
All colostrum and milk fed to calves is fully traceable to the cow that produced it.
Dedicated calf rearers have no contact with adult cows and calf accommodation is positioned away from cow housing.
Mr Banks said protecting the herd from Johne’s required a team approach. “We have regular herd health meetings; all staff need to be involved,” he said.
Cows suspected of having Johne’s are tested instead of fully screening the herd. “We are not being complacent.
“Targeted testing has been the approach because performance has been good, but we will be keeping our eyes firmly open through expansion,” said Mr Banks’ vet, Jonathan Statham, of the Bishopton Veterinary Group.
David Hiscock, West Hayes Farm
An aggressive policy of culling Johne’s infected animals is paying off at West Hayes Farm, Sherborne, which has seen a reduction in disease prevalence.
Until five years ago, Johne’s was the single biggest threat to the dairy enterprise David Hiscock runs with his father.
When he tested for Johne’s he discovered that the high cell count cows whose milk was harvested for feed replacements had high levels of infection. “Our cows were burning out, it was really bad,” said Mr Hiscock.
Cows are now tested before drying off and those that test positive are marked with a red tag and only bred to beef. “Unless she is your best cow, move her on,” advised Mr Hiscock.
He admitted a weakness of his system is buying-in replacements, but those animals are always treated as Johne’s positive.
His latest herd test confirmed just two Johne’s positive animals in the 220-cow herd.
Mr Hiscock’s vet, Rachel Hayton of Synergy Farm Health, said buying replacements was less of a risk when there was a high prevalence of Johne’s in a herd. “When prevalence comes down, it is a higher risk,” Ms Hayton said.
Kate Lywood, Marshalls Farm
Calving an average of 30 cows a day presents a challenge for controlling the spread of Johne’s for spring calver Kate Lywood, but every heifer replacement is treated as high risk and there is a control programme in place based on that assumption.
Ms Lywood and her father run a 650-cow herd at Marshalls Farm, West Sussex, and identified their first Johne’s positive cow in March 2014.
That year a strategic programme of milk testing got underway and a further 11 positives were confirmed.
“Our weaknesses were that pre-weaned calves were given pooled milk and the calving yard is a high usage area,” said Ms Lywood.
There has been a change of policy with calves now fed milk powder and the culling of all animals that test positive. “If you are not reducing prevalence of the disease, she needs to be on the lorry the next day,” said Ms Lywood.
The farm has a dedicated heifer rearer and there are strict cleanliness protocols around calving.
Cows must have had six clear tests and to have been clear of the disease for two lactations for their colostrum to be fed to calves.
Teat disinfection has been improved and cow tails trimmed.
Chris Gasson, Redland’s Farm
A vet who is also a milk producer may in future breed stock bulls from embryos to fully protect his herd from Johne’s.
There is no incidence of Johne’s in the herd of 450 cows at Redlands Farm, Banbury, and it’s a situation Chris Gasson and his farm manager, John Peck, want to protect.
Their ambition is to have a fully Johne’s accredited herd to put the business in a strong position to sell surplus stock at a premium.
“We are not quite a closed herd because we have bought in three stock bulls in the last five years, but buying bull embryos is an option to be fully closed,” said Mr Gasson.
The herd is screened annually and every member of staff is involved. “It is crucial to make staff aware of why we are doing it,” said Mr Gasson.
That test confirmed three Johne’s positive animals, but when the blood screens were repeated and faecal samples analysed the animals tested negative.
Mr Gasson said the National Johne’s Management Plan is vital. “The dairy industry needs to present a united front, a common approach. Time is running out.”
What is Johne’s disease?
- A chronic, debilitating and irreversible disease of ruminants caused by infection with Mycobacterium avium subspecies paratuberculosis (MAP).
How do animals become infected?
- Animals are usually infected as calves with approximately 80% of infections occurring within the first month of life.
- Infection is mainly, but not only, caused by ingesting faeces often from contaminated bedding, udders, teats or buckets or from colostrum or milk. Much less commonly the disease can be acquired in the womb or later in life.
- Johne’s infections are almost always introduced to a herd by purchasing infected replacement breeding stock – although there are other risks of introducing the disease including importing slurry from other farms and swapping colostrum between herds.
What are the symptoms?
- Johne’s test positive cows are twice as likely to have a cell count > 200,000 cells/ml and are twice as likely to have milk yields 25% below their adjusted herd average.
- Johne’s disease costs can rise to excess of 1-2p/ litre with higher disease incidences and these costs remain for a number of years until the disease is brought under control.
- With Johne’s, the major costs come from increased susceptibility to other conditions, increased forced culling and the retention of cows that should otherwise be culled. Clinical Johne’s cases are just the tip of the iceberg.
How do you test?
Testing will help determine a herd’s status. These include:
- Risk based (quarterly testing) – Suitable for herds of moderate to high prevalence who are not able to dedicate the resources or have the facilities required for Improved Farm Management on all cows calving
- Single test (Pre Dry off) – This is a less rigorous testing programme, with just a single test performed before drying off. This result is used to segregate test positive cows at drying off into a dedicated area away from the low risk cows.
- Double test (Pre Dry off and Pre Breeding) – This increased testing provides greater sensitivity than the single test and also provides a test result pre breeding to allow breeding decisions to be made.
Infected animals will test negative for a variable period of time, usually several years before the disease progresses and they become infectious to others, at which time they will usually test positive by one or more of the available diagnostic tests.
(Information provided by Action Johne’s UK)