Breeding strategies for tick resistance in tropical cattle: a sustainable approach for tick control

Abstract

About 80 % of world cattle population is under the risk of ticks and tick borne diseases (TTBDs). Losses caused by bovine tick burdens in tropical countries have a tremendous economic impact on production systems. Chemical control of disease has been found to be ineffective and also involving large cost. To reduce our reliance on these chemical products, it is necessary to embark on programs that include habitat management, genetic selection of hosts, and development of a strain capable of inducing host resistance to ticks. Selection for disease resistance provide alternate method for sustainable control of TTBDs. Domestic livestock manifests tick-resistance by skin thickness, coat type, coat color, hair density and skin secretions etc. Zebu cattle have, on average, greater tick resistance than either European cattle or African cattle. Heritability for tick burden in cattle has been shown to range about 0.30, which is sufficient to result in the success of some programs of selection for tick resistance in cattle. To select animals at younger age, to reduce generation interval and to increase genetic gain, marker assisted selection is an important tool. There are also various MHC molecules which are associated with resistance to TTBDs.