Variations between and within breeds of cattle in resistance to field infestations of the cattle tick (Boophilus microplus)

Abstract

Maturing female ticks were counted in herds of Brahman x British, Africander x British, and British breed (Shorthorn x Hereford) cattle run together. About 3000 counts were made on over 1000 cattle. The Zebu crossbreds on average carried two-fifths the number of ticks carried by the British cattle, though in some herds the difference was greater, and it tended to be greater in females than in males, in summer than in winter, and in F2 than in F3 animals. Brahman cross and Africander cross cattle did not differ significantly in resistance. Male cattle carried significantly more ticks than females, and the resistance of lactating British breed cows, but not Zebu crossbreds, was lower than that of dry cows. Repeatability of counts was higher in females than in males, and higher in Zebu crossbreds than in British cattle. Expression of inherent resistance in the British cattle was variable according to circumstances which are only partly defined. Heritability estimates were up to 48%, but in some cases much lower. In the Zebu crossbreds there was little heritable variation in F, cattle, but in subsequent generations heritability was estimated as 82%. The needs for selection for resistance, and the control of error and the prospects of success, are discussed.

Expression of immune response genes in peripheral blood of cattle infested with Rhipicephalus microplus

“…Typically, Bos indicus animals are more resistant to ticks than are Bos taurus, although some variation occurs among and within breeds (Seifert, 1971). Genetic variations in tick resistance result from differences in a variety of mechanisms that are not fully understood, although the involvement of genes related to the immune system appears to be undeniable (Regitano and Prayaga, 2010).…”

Immunological Profiles of Bos taurus and Bos indicus Cattle Infested with the Cattle Tick, Rhipicephalus ( Boophilus ) microplus

“…Bos indicus cattle breeds are more resistant to R. microplus than are Bos taurus breeds, although considerable variation in resistance occurs between and within breeds (37,45). Although innate immunity arising from genetic differences between B. indicus and B. taurus breeds forms the basis of whether an animal will be resistant to tick infestation, host resistance is considered to be predominantly an acquired trait because the higher level of resistance seen in B. indicus becomes apparent only following a period of initial susceptibility to primary infestation (15,44).…”

“…Although innate immunity arising from genetic differences between B. indicus and B. taurus breeds forms the basis of whether an animal will be resistant to tick infestation, host resistance is considered to be predominantly an acquired trait because the higher level of resistance seen in B. indicus becomes apparent only following a period of initial susceptibility to primary infestation (15,44). Host resistance to tick infestation is heritable, with a rate estimated to be between 39% and 49% for British breed animals (45) and as high as 82% in Africander and Brahman (B. indicus) crossbred animals (37). Since these initial studies, it has been shown that the resistance status of both B. taurus and B. indicus breeds can be improved by selection for increased tick resistance, as demonstrated by a breeding program that has resulted in a highly tick-resistant line of Hereford ϫ Shorthorn (B. taurus) cattle, now known as the Belmont Adaptaur (9,25).…”

The occurrence of pathogens in Rhipicephalus microplus ticks from cattle in Madagascar

“…Overall, we found a significant association between the number of ticks and the sex and mass of cattle, with more parasites found on males, whereas we detected no association between parasites and the age of cattle. In many cattle species, males have more ticks than females (Seifert 1971;Martinez et al 2006;Dudek et al 2016), likely because of differences in hormone levels. This may also simply be due to the weight of the animals; those that are bigger capture more ticks, and males are generally larger than females.…”