Increasing temperatures and a move to farming less intensively are favouring tick populations.  Molecare Farm Vets Alice Coppin-Harris and Steph Patel outline the risks ticks pose to cattle and sheep.

Tick populations are increasing and migrating into previously unaffected areas, as the UK climate becomes warmer and wetter.  Vet Steph Patel said a less-defined period, when tick-borne diseases occur due to the change in weather patterns, means prevention should be established earlier in the season.  Speaking on the latest Mole Valley Farmers podcast on tick-borne diseases, she said: “Last year, we saw the tick population migrating due to the hot weather, with farms reporting cases of tick-borne diseases that had never had any issues previously.

“We were called out to several cases of babesiosis, otherwise known as redwater fever in cattle and cases of tick-borne fever in both sheep and cattle.” 

The main tick species of concern is the sheep tick, ixodes ricinus, which becomes active in warmer weather. 

Ms Coppin-Harris added: “This region has lots of good tick habitat and a warm and wet climate, so we see high volumes of ticks here. I came back with 15-20 ticks on me after just one run last year,” she added.

Favoured tick habitats include:

• Moist areas with lots of plant life such as woodland, heathland and rough ground 

• Areas with a high deer population

• Areas with a warm and wet climate

Due to their blood-sucking tendencies, ticks act as effective vectors for various pathogens. They can transmit protozoal, viral and bacterial diseases to their host through saliva.

Ms Coppin-Harris added: “All of these diseases can cause production losses and mortality, as well as the obvious welfare concerns.”

The conditions of most concern for livestock are:

Babesiosis, also known as redwater fever

 What is it?

• Caused by a protozoan parasite Babesia divergens, it is passed between cattle by ticks

• Mostly affects animals older than two years of age as immunity from the colostrum usually protects calves for about two months

Clinical Signs:

• Blood in the urine

• Anaemia

• High temperature

• Severe diarrhoea that then becomes constipation

• Weakness

• High heart rate and respiratory rate

Treatment

• Generally, it involves an injection of Imidocarb. However, this has a 213 day meat withdrawal period

• If the animal is severely anaemic, a blood transfusion will be needed

 Prevention

• Strategic grazing to expose youngstock under nine months old to the disease to protect them in later life

• Good tick control

Tick-borne Fever

What is it?

• Affects both cattle and sheep and is also spread by the sheep tick

• It is caused by the bacterium anaplasma phagocytophilum, which targets the white blood cells affecting the animals’ immune system

• Incubation period is 5-14 days after being bitten by a tick

• Immunity is only acquired through exposure, putting youngstock most at risk 

Symptoms

• Cattle: dull, depressed, loss of appetite and drop in milk yield, coughing and respiratory distress.

• Sheep: Sudden fever (>40.5oC) for 5-10 days, dullness and lethargy, lameness and weight loss. Respiratory signs are common.

• Abortions can also occur in animals infected late in pregnancy. Ram and bull fertility can be affected, so tick treatment is essential in the lead-up to mating.

Treatment

• Injectable oxytetracyclines are effective and can be used preventatively in naïve animals. However, antibiotics must be used responsibly, so it’s important to try and manage tick populations through effective land management and prevention.

Prevention

• Graze ewes and lambs in tick-free pastures until six weeks old, enabling their immunity to build up

Tick pyaemia

What is it?

This disease is caused by the bacteria staphylococcus aureus entering the bloodstream of young lambs already infected with tick-borne fever. It can enter through tick bites or other routes, such as wounds and the umbilicus.

Symptoms

• Crippling lameness and paralysis, with abscesses found throughout the body.

• In some outbreaks >30% of lambs with tick-borne fever can go on to develop tick pyaemia.

• Up to 50% mortality and slow recovery with huge growth checks.

Louping ill

Although rare, louping ill is another viral disease to look out for, causing rigid neck and head muscles, incoordination and sometimes death. Lambs are usually protected in the first year if they receive sufficient colostrum.