All modern cattle breeds descend from two ancient lines, Bos taurus and Bos indicus, which humans domesticated more than 10,000 years ago.
Bos indicus or Zebu breeds:
Bos taurus breeds:
Tropically adapted taurine breeds:
Breeds adapted to tropical environments perform better than temperate breeds under a wide range of tropical environmental stressors including resistance to cattle tick. Bos indicus breeds show the greatest resistance to ticks followed by tropically adapted taurine breeds then the European Bos taurus breeds.
In temperate environments there are substantial productivity differences (growth, milking ability, reproduction, product quality) between different cattle breeds. However in cattle grazed on pasture in tropical environments, the differences in performance are generally masked by the effects of environmental stressors on those productive attributes.
In the tropics, comparisons of performance should be made across general breed types or groupings (Bos taurus – British and European; Bos indicus; and tropically adapted taurine) rather than across specific breeds.
Any breeding program designed for cattle grazed at pasture in tropical environments should consider the impacts of both productive traits (growth, fertility, meat quality) and adaptive attributes (resistance to environmental stressors such as heat, drought and parasites), even though these traits are generally difficult to measure.
Unless there are contrary economic reasons, it is strongly recommended that breeders in tropical and sub-tropical regions should make their selection of preferred breed (or breed type or composite breed) from amongst the wide range of tropically adapted breeds simply because it is much simpler and less expensive to use cattle breeds that are suited to the environments in which they are expected to perform, than to modify the environments to enable poorly adapted animals to perform to their potential. Contrary economic reasons to this recommendation could include for example the availability of significant price premiums for products such as meat or milk that have special attributes (e.g. high levels of marbling in Bos taurus beef breeds or higher milk production from Bos taurus dairy breeds). Even if those contrary economic reasons exist, economic modelling should be undertaken to determine whether it would be more cost-effective to re-locate the farm business to a more suitable environment, rather than modifying a tropical or sub-tropical environment, or incur the expense of a tick management program, to accommodate poorly adapted cattle.
There are a number of additional animal and environmental factors which impact on resistance of cattle to ticks that should be considered during the design of any cattle breeding program that measures cattle tick resistance. These factors are briefly summarised under ‘Susceptibility to ticks’.