Tick control and tick-borne diseases in cattle

In most of sub-Saharan Africa, ticks are among the most important health problems in cattle. Heavy infestations cause blood loss, weight loss, damaged udders and teats, and hide damage. Worse, ticks carry diseases that can kill animals quickly, especially cattle brought in from areas where those diseases do not occur. Good tick control is not about killing every tick; it is about keeping disease and damage low in a way you can sustain.

The main ticks and what they carry

Recognising tick-borne diseases

Early signs are often vague: a high fever, going off feed, standing apart from the herd. Some typical signs are listed below, but many overlap, and a vet diagnosis, often with a blood smear, is the only reliable way to know which disease you are dealing with.

• Redwater: fever, red to dark brown urine, pale or yellow membranes, weakness.
• Gallsickness: fever, severe anaemia, yellow membranes, constipation with hard dung.
• Heartwater: fever, nervous signs such as high-stepping, chewing movements, circling and convulsions.
• East Coast fever: fever, swollen lymph nodes, especially below the ear, laboured breathing and frothing at the nose.

Endemic stability: why killing every tick can backfire

Calves infected with redwater or gallsickness while they are young, protected by their mother's antibodies and their natural resistance, usually develop only mild disease and then have long-lasting immunity. In herds where young calves are regularly exposed to a small number of infected ticks, most adults are immune. This balance is called endemic stability.

If a farmer dips so intensively that calves never meet ticks, the herd loses that immunity. Then, if tick control slips, for example during a drought or when an acaricide stops working, adult cattle meet the disease for the first time and severe outbreaks follow. This is why many vets now recommend strategic control rather than blanket, year-round intensive dipping, where the diseases are present.

Building a control plan

1. Know which ticks and diseases are present on your farm and in your area. Your vet or state veterinary office can advise.
2. Time treatments to tick seasons. Many ticks peak in the warm, wet months; strategic treatments at the start of the season reduce the number of ticks that breed later.
3. Set a threshold: treat when tick numbers reach a level that causes damage, rather than on a fixed calendar all year.
4. Pay special attention to animals at risk: newly bought cattle from tick-free areas, and exotic breeds with low tick resistance.
5. Vaccinate where vaccines are available and advised, such as redwater and gallsickness vaccines in parts of Southern Africa, or immunisation against East Coast fever in parts of East Africa. These must be given under veterinary guidance.

Using acaricides properly

Acaricides are the chemicals that kill ticks. They come as dips, sprays, pour-ons and injectables, and belong to several chemical groups, such as organophosphates, synthetic pyrethroids, amidines and macrocyclic lactones.

• Use only products registered for cattle and follow the label exactly for dilution, method, frequency and withdrawal periods for meat and milk.
• In plunge dips, keep the dip at the correct strength by measuring and replenishing it as the label directs. A weak dip lets ticks survive and speeds resistance.
• With sprays, wet the whole animal, including the ears, under the tail, between the legs and the udder, where ticks hide.
• Resistance is a serious and growing problem. Ask your vet about testing whether your ticks are still susceptible, and about rotating between chemical groups rather than changing between brands of the same group.
• Wear protective clothing and store chemicals safely away from children, feed and water.

Breeding and management help too

Indigenous breeds such as Nguni and many other local African cattle carry far fewer ticks than European breeds under the same conditions. Adding tick-resistant genetics to a herd, and culling animals that always carry heavy tick loads, reduces the need for chemicals over time. Good nutrition also helps, because well-fed animals cope better with ticks and disease. Rotational grazing, burning under expert guidance, and keeping grass around handling facilities short can also reduce tick numbers in some systems.

Key points

• Know the ticks and diseases on your farm; they differ by region.
• Call a vet early; tick-borne diseases can kill quickly.
• Aim for strategic control that preserves immunity where diseases are endemic.
• Follow the registered label for every acaricide, and manage resistance with your vet.
• Use tick-resistant breeds and good nutrition to reduce reliance on chemicals.