Cattle Ticks and Your Farm

Ticks have been present in Nelson for many years, sporadically found in pockets throughout the area. In more recent years, the occurrence of infestations affecting all species seems to have increased. Changes in local climate and stock movements are the most likely causes.

Awareness has further been heightened by the emergence of the tick borne protozoan disease, Theilerea. (read more here)

Ticks are blood sucking external parasites. The common cattle tick Haemaphysalis longicornis favours cattle but they are not completely host specific and can infest deer, sheep, goats, humans, horses, rabbits, hares and domestic pets.

This type of tick, is the only one found in New Zealand. It is called a three host tick, with each of its growing stages- larvae, nymph, and adult feeding off separate hosts, not necessarily of the same species.

The adult female tick, which when fully engorged with blood can grow to approximately 9mm long by 7mm wide, lays hundreds of eggs from which the larvae will hatch on nearby vegetation. The larvae attach to a suitable host and feed before falling to the pasture where they develop to a nymph stage. Nymphs will also attach to a host to feed before detaching and developing into an adult. The time taken for the completion of the life cycle varies considerably from days to months depending on factors such as temperature and the host’s immunity developed from previous exposure.

The larvae and nymphal stages of the life cycle position themselves at the tips of long grass or vegetation and attach to the skin of grazing animals or hosts walking through the paddocks.

Ticks are obvious on clinical observation and are commonly found on the head, ears, udder and lower body extremities.

PASTURE MANAGEMENT

Ticks can live without a blood meal for over a year, so leaving pasture un-grazed and hoping the ticks will die from lack of food isn’t a very practical option.
If you have poorly-drained pasture, your animals are more at risk from picking up ticks, as this is a good habitat for them. It may be best to fence off those areas.
Even on well-drained pasture, ticks can hide in the long grass, so topping can help remove their preferred habitat of damp pasture and moist soil. However, it won’t affect the eggs.
Heavy grazing by adult cattle and sheep, pugging up the ground, can help destroy eggs but can’t be used farm-wide all at once unless you then destock for a time to allow regrowth.

TICK REMOVAL
For single animals, you can pick ticks off your animals, but it’s messy and often when you pull a tick off, its mouthparts are left inside the skin of the animal, which may cause irritation or even an infection.

You can daub them with methylated spirits or tea-tree oil and they will eventually release, but they may still scatter their eggs when they hit the ground.
Chemical products include insecticides like Ripcord and Permoxin for horses, and specialist pour-ons and dips for sheep, deer and cattle (Bayticol pour-on). In cats and dogs, Frontline will kill ticks.

Bayticol pour-on is a well known and reliably performing chemical and should be applied from August on to eliminate the early infestations and reduce the build up that will occur with delaying your first application. Interval between applications is 8 weeks and should be combined with good husbandry as mentioned below.

GOOD ANIMAL HUSBANDRY
Ticks are most noticeable and most prevalent from October to December, but early applications will have a significant reduction in summer populations. While chemical products will remove ticks to bring the population down, other extra effort will be required.

Large-scale farmers sometimes use ‘vacuum cleaning’ to reduce numbers. This is where older stock are grazed on known infested areas for up to three days to give adult ticks a chance to attach but not enough time to feed and then drop off. The stock are then treated in a dip and put back onto the same pasture, this time with animals that are undipped. By doing this several times in the same paddock, tick numbers will be depleted. The paddock is then left for up to a month before ‘clean’ animals are put on it to see what tick numbers remain.

Hares, rabbits and wild goats and deer are all implicated in the spread of ticks, so if they are a problem in a known tick-area, they will help continue the spread.

VETERINARY RECOMMENDED PRODUCTS FOR MANAGEMENT

At The Vet Centre we recommend using Bayticol for Prevention and Treatment on your livestock.  We also recommend a tick treatment for your working dogs and pets to ensure the tick management program is complete. We have a variety of treatments available from Seresto Collars providing 8 months tick and flea treatment, to chewables like Nexgard which is a monthly chewable treatment providing tick, mite and flea control.