Eenvoudige metode vir die beraming van bosluisbestandheid by beeste

Author: M.M. Scholtz, P.E. Lombard, D.S. de Bruin, C.B. Enslin & A.M. Spickett
Year: 1989
Issue: 3
Volume: 19
Page: 121 - 124

A simplified method, whereby tick resistance in cattle is assessed by counting all ticks under the tail and on the scrotum or udder only, was compared to the Australian method, where tick resistance is assessed by counting successful females on the entire body. A correlation of 0,85 (n = 14) was found between the values of the two methods. Therefore, the simplified method seems to be adequate for practical application and for screening of large numbers of animals. The repeatability between counts of the simplified method was found to be 0,73 (n = 73). It is also illustrated that tick counts should be transformed to the In scale (e-x) to obtain a more normal distribution of the data on which meaningful performance indices can be calculated. Significant differences were also demonstrated between the progeny of six Nguni bulls using this method. This indicates possibilities regarding successful selection for tick resistance.

 

 

Keywords: Cattle, Nguni, resistance, selection, tick
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