Susceptibility to ticks

Certain cattle breeds are more resistant to cattle tick infestation than others. Typically, Bos indicus (tropical breeds) are more resistant than Bos taurus cattle (European breeds). Selecting a resistant cattle breed for tick infected areas will naturally reduce tick populations and is a low cost, permanent solution to control ticks.

Breed for tick resistance

Figure 1: Hereford x Shorthorn animal which is very susceptible to ticks. Image source: CSIRO Rockhampton
Figure 1: Hereford x Shorthorn animal which is very susceptible to ticks. Image source: CSIRO Rockhampton

Both animal and environmental factors can impact on an individual animals susceptibility to cattle tick, see Table 1. Within breed variability also exists at a genetic level (heritable traits), however, measuring a resistance score for a single animal is difficult. This constraint applies in both beef and dairy cattle. As described in the Within breed selection’ and EBVs sections, research is underway to find simpler, more cost-effective measures to identify cattle that are resistant to ticks, with the aim of genetically improving cattle breeds grazed in tick-endemic regions of the world.

Table 1. Animal and environmental factors (excluding breed) that can impact on resistance to cattle ticks.

Animal factor

Impact on cattle tick resistance

Sex

Male calves more susceptible than females.

Age

Takes 6-9 months to develop tick immunity.

Lactation status

Lower resistance in lactating dairy cows.

Tick counts significantly higher in first-lactation animals.

Coat type (very sleek to very woolly)

Heavier coats increase resistance.

Licking and social grooming

Grooming reduces female tick survival.

Environmental factor

Impact on cattle tick resistance

Time of year (season)

Heat stress and higher tick burdens in summer lowers resistance.

Other parasites: External (flies and lice) and or internal (worms)

Lowers resistance.

Seasonally poor nutrition

Lowers resistance.

High heat and humidity

Lowers resistance.