Farmers and vets are being advised to keep an eye out for a teat condition which causes cattle to excessively lick and remove their own teats and can lead to 80 per cent of affected animals being culled.
Incidence of ischaemic teat necrosis (ITN) is increasing, with reports suggesting higher levels in heifers and in early lactation.
At present, little is understood about the cause or treatment for the disease which occurs in lactating animals.
However, vet Roger Blowey, who first recorded the disease in 2004, explains the condition appears to start as a small, dry scab on the inside of a teat at the point where it joins the udder. This then spreads downwards.
He says: “There is now evidence there is an occlusion [blocking] of blood vessels within the skin of the teat. My own theory is this creates a ‘pins and needles’ effect, leading to intense irritation so the animal licks and chews the teat to the extent the teat may be removed.”
The extent of the condition varies, with some severely affected animals removing all four teats as a result of the disease.
Over the last two years, Mr Blowey has been collecting data from vets and farmers to gain a greater understanding of ITN.
Survey results from about 50 farms suggest the condition could be more common than previously thought.
“I was quite surprised by how many farms were affected,” says Mr Blowey, who gathered data for use by Liverpool University via a paper survey or show of hands at lameness events.
This information has been collated with results from an additional survey carried out by Sussex herdsman Calvin Otto.
Results showed about 50 per cent of farms had seen one case of ITN in the last three years, with cases reported across the country from Devon to Cumbria and Scotland. Some farms had about 10-20 per cent of heifers affected in a year, with 80 per cent of animals needing culling in some situations.
Mr Blowey says: “In one Devon herd, with 20 per cent of heifers affected, 20 per cent of them needed to be culled. It is a very expensive condition and a significant factor for the industry.”
With this in mind, last year Mr Blowey began working with Simon Clegg and Nick Evans from Liverpool University to carry out a ‘scope project’ on ITN. This has involved sampling infected cases, initially from herds within Mr Blowey’s practice area in Gloucestershire.
Other farmers and vets have been encouraged to send in samples. So far, tissue samples for culture have been taken from 12 affected teats and PCR tests carried out on swabs from 22 affected teats. These have been compared to 20 samples from normal teats from fallen stock.
Results showed 85 per cent of ITN cases had evidence of digital dermatitis treponemes growing in samples.
Mr Blowey says: “I started off by thinking to myself ‘I wonder if this is digital dermatitis’.
“It has the same appearance as digital dermatitis on the back of the heel and both conditions are irritating and painful. We are not sure if digital dermatitis is the primary or secondary cause. It could have infected the skin after damage has been done, like digital dermatitis on the foot.”
The hope is to secure grant funding to repeat the work in more detail and create a greater understanding of risk factors such as age, body condition, yield, housing or perhaps a reaction to milking or milking equipment. At present, Mr Blowey says there are no anecdotal patterns of infection.
He says: “I thought silicone liners might prevent it [compared to rubber ones], but we are now aware of one case on a farm with silicone liners.”
There is currently no known treatment for ITN. Non-steroidal anti-inflammatories do not appear to have an effect. However, in a few cases, farmers have noted some success from treating cases early, removing the dry scab and applying topical antiseptic or antibiotic.
Mr Blowey says: “It is not confirmed picking up cases early helps, but it could. If you catch it when you see the first scab on the udder, scrape away the scab and apply antiseptic or antibiotic, then some herdsmen reported success. As soon as the teat becomes irritant, there appears to be no return.”
Mr Blowey is keen to gather more information on the disease and is asking farmers and vets to report cases to him.
“Clearly if ITN results in losses in first lactation heifers, there is an even greater cost to the industry. It is also an animal welfare issue and seems to be on the increase – we need to do something about it.”
Have you witnessed ischaemic teat necrosis in a herd? If so, let Roger Blowey know at firstname.lastname@example.org