In search of a new tool for phenotyping tick resistance in cattle

Ticks and tick-borne diseases cause significant loss in livestock production, with about 80% of the world’s cattle at risk.

Tick control is normally carried out through the use of chemicals (acaricides). However, the cost of chemical control is high and there is an ever growing risk of the ticks becoming resistant to the acaricides, rendering the treatment ineffective.

Genetic selection of tick resistance in cattle as an alternative long-term control strategy is constrained by laborious phenotyping of this trait using tick counts or scores.

A recent study, published as part of the proceedings of the 12th World Congress on Genetics Applied to Livestock Production, explored the use of cattle volatile compounds that may be attractants or repellents to ticks as a potential proxy for tick resistance in cattle breeding and selection programs.

About a 100 young cattle composed of Bos indicus and Bos taurus were artificially infested with 2,500 larvae of the Rhipicephalus decoloratus tick, with daily counts of female ticks (4.5 mm in size) taken from the 20th day after infection. Volatile compounds were sampled before and after tick infestation.

The study identified three volatile compounds that were associated with tick resistance before infestation and one after infestation, using 6-day repeated measure analysis.

The high correlation between repeated records and all volatile compounds supports the potential of volatile compounds as a new, low-cost tool for phenotyping cattle resistance to ticks.

The tool could be useful in selection and cattle breeding programs in both smallholder and commercial animal production systems.

Citation
Matika, O., Foster, S., Githaka, N., Mwendia, C., Brown, H., Watson, K., Djikeng, A. and Birkett, M. 2023. In search of a new tool for phenotyping tick resistance in cattle. IN: Veerkamp, R.F. and Haas, Y. de. (eds), Proceedings of the 12th World Congress on Genetics Applied to Livestock Production (WCGALP): Technical and species orientated innovations in animal breeding, and contribution of genetics to solving societal challenges. Wageningen, the Netherlands: Wageningen Academic Publishers. pp. 410-413.

Photo: Cattle at a drying river in Isiolo County, Kenya (credit: ILRI/Geoffrey Njenga)