Norval R A, Sutherst R W, Kurki J, Gibson J D, Kerr J D
Veterinary Research Laboratory, Causeway, Harare, Zimbabwe.
Vet Parasitol. 1988 Dec;30(2):149-64. doi: 10.1016/0304-4017(88)90162-8.
The effects of larvae, nymphs and adults of the brown ear-tick Rhipicephalus appendiculatus on the growth of Bos indicus X B. taurus (Sanga) steers and on B. taurus steers and heifers was measured by exposing groups, maintained in the same pastures, to different levels of tick challenge. Larvae and nymphs had no significant effect on liveweight gains, but adults had a large effect. Each engorging female tick counted was associated with a loss of 4 g. Their effect on the Sanga cattle was minimised by host resistance which severely limited the number of ticks feeding on them. The B. taurus animals were severely affected and suffered extensive ear damage. Both breeds were subjected to screw-worm fly (Chrysomya bezziana) strike in the lesions caused by heavy tick infestations, but the B. taurus animals were much more prone to attack. The results provide a basis for calculating losses in production caused by this species of tick which is widespread in Africa.
通过将饲养在同一牧场的牛群暴露于不同程度的蜱虫叮咬挑战，来测定褐耳蜱（Rhipicephalus appendiculatus）的幼虫、若虫和成虫对印度瘤牛×黄牛（桑加牛）阉牛以及黄牛阉牛和小母牛生长的影响。幼虫和若虫对体重增加没有显著影响，但成虫有很大影响。每只饱血雌蜱会导致4克的体重损失。宿主抗性使它们对桑加牛的影响最小化，因为宿主抗性严重限制了叮咬它们的蜱虫数量。黄牛受到的影响严重，耳部遭受广泛损伤。两个品种在重度蜱虫感染造成的伤口处都遭受了螺旋锥蝇（Chrysomya bezziana）的侵袭，但黄牛更容易受到攻击。这些结果为计算这种在非洲广泛分布的蜱虫造成的生产损失提供了依据。
