How ticks affect sheep and ways to keep your livestock safe

Ticks may be small, but they can cause serious problems for both livestock and the people working with them. In Ireland, tick activity typically peaks from April through to July, with a secondary period of activity in autumn as temperatures drop.

As the weather warms each spring, staying tick-aware becomes an important part of managing a healthy flock.

Awareness of ticks has grown significantly in Ireland in recent years and for good reason. Tick populations are expanding across the country, driven by milder winters, changes in land use, and a decline in sheep dipping practices.

Understanding the risks, knowing what to look for, and having a plan in place is the best defence.

Are there ticks in Ireland?

Yes, ticks are present throughout Ireland, and their range and numbers are increasing. There are several tick species found in Ireland, but the most significant for livestock farmers is Ixodes ricinus, commonly known as the sheep tick or castor bean tick.

This species is responsible for transmitting the main tick-borne diseases affecting sheep in Ireland, and it is also the primary vector of Lyme disease in humans.

Tick hotspots in Ireland include upland and hill areas with dense vegetation: the Wicklow Hills, the Kerry Mountains, the Connemara region of Galway, the Mayo uplands, and the Donegal highlands are all areas where tick burdens on sheep can be significant.

However, ticks are not confined to hill ground, they can also be found in rough grazing, forestry edges, and even lowland fields with dense grass or bracken cover.

Understanding the sheep tick

Ixodes ricinus is a three-host tick, meaning it feeds on a different host animal at each stage of its lifecycle, as a larva, a nymph, and an adult. Larvae and nymphs tend to favour smaller mammals and birds, while adult ticks prefer larger hosts such as sheep, deer, and cattle.

The tick feeds by attaching to the host’s skin and drawing blood over several days. It is during this feeding process that disease can be transmitted to the host animal or to a person or animal that later picks up an infected tick.

As Teagasc and the Department of Agriculture, Food and the Marine (DAFM) have noted, tick control is an important part of integrated sheep health management, particularly in higher-risk areas of Ireland.

Diseases spread by ticks in Ireland

Louping ill

Louping ill is a viral disease spread by the sheep tick that affects the central nervous system. Infected sheep develop a fever, followed by incoordination, trembling, and in severe cases paralysis and death.

Sheep that survive are often left permanently affected. Louping ill is present in Ireland, particularly in areas with established tick populations, and a vaccine is available.

Vaccination of at-risk sheep before tick season is strongly recommended where the disease has been confirmed.

Tickborne fever

Tickborne fever is caused by the bacterium Anaplasma phagocytophilum, transmitted through tick bites. It suppresses the immune system, causing fever, loss of appetite, and a drop in milk yield in ewes.

Critically, tickborne fever leaves infected animals more vulnerable to secondary infections, including tick pyaemia in young lambs which is often where the real damage is done.

Tick pyaemia

Tick pyaemia is a bacterial condition affecting young lambs, typically occurring in the first few weeks of life. It follows tickborne fever and causes abscesses to develop in joints, tendons, muscles, and in some cases the brain. Affected lambs become lame, and severe cases can lead to paralysis or death. Tick pyaemia is a significant cause of lamb losses in Ireland’s upland sheep-farming regions.

Lyme disease in humans

All life stages of Ixodes ricinus have the potential to transmit Borrelia burgdorferi, the bacterium that causes Lyme disease in humans.

The Health Service Executive (HSE) has highlighted Lyme disease as a growing public health concern in Ireland, with tick activity in rural and upland areas posing the greatest risk.

Farmers, farm workers, and anyone spending time in tick habitat should be aware of the risk, check themselves regularly for ticks, and seek medical advice promptly if they develop a rash or flu-like symptoms after a tick bite.

Control measures for Irish sheep farmers

Effective tick control on Irish farms requires a combination of prevention, treatment, and farm management. There is no single approach that works for every farm as the right strategy depends on your location, the tick burden in your area, the breeds you run, and how sheep are managed.

Acaricide treatments

The most widely used method of tick control in Ireland is the application of acaricide products to sheep. Pour-on products such as Crovect are commonly used on Irish farms and are effective when applied at the right time, typically just before the main tick season begins in spring.

Your vet or animal health adviser can help you choose the most appropriate product and timing for your situation.

Vaccination for louping ill

Where louping ill has been confirmed on a farm or in the local area, vaccination of sheep before tick season is the most effective way to protect the flock. Discuss this with your vet, particularly if you are farming in the Wicklow Hills, Kerry uplands, or other high-risk areas.

Protecting newly introduced sheep

Adult sheep from tick-free farms are just as susceptible to tick-borne disease as naive animals. When introducing sheep to tick-infested ground, for example, moving lowland ewes to hill grazing, treat them with an appropriate acaricide product well before exposure and ideally before the breeding season.

This gives them the best chance of building some immunity gradually rather than facing a sudden high challenge.

Pasture and habitat management

Ticks thrive in dense, humid vegetation as long grass, bracken, and scrub provide ideal conditions. Where practical, grazing management that keeps grass covers lower and reduces the amount of rough, overgrown habitat can help to reduce tick burdens over time.

This is a longer-term strategy rather than a quick fix, but it can make a meaningful difference on farms with persistent tick problems.

How Herdwatch helps you stay on top of tick treatment records

Keeping accurate medicine records is a legal requirement for all Irish livestock farmers and tick treatments are no exception. With Herdwatch, recording acaricide applications takes only a few seconds and gives you a complete, searchable record of every treatment applied to your flock.

The app automatically calculates withdrawal periods based on the product and dosage entered, so you always know when treated animals are safe to go to market.

Reminders and records are all stored in one place, making it straightforward to show compliance during a DAFM inspection or a Bord Bia farm assurance audit.

You can also use Herdwatch to log field notes about tick-risk areas on your farm, flagging pastures or boundary areas where tick activity is consistently higher.

Over time, these records help you build a clearer picture of where on the farm tick pressure is greatest, and plan treatments and grazing accordingly.

Stay tick-aware this season

Ticks are a manageable risk for Irish sheep farmers, but they require consistent attention, especially as the spring season gets underway. Knowing your farm’s risk level, planning treatments in advance, talking to your vet about louping ill vaccination where relevant, and keeping accurate records of what has been done and when are the most important steps you can take.

Herdwatch makes the record-keeping side of that straightforward. Request a quote to find out how it can help simplify your livestock health records this season.