Moran M C, Nigarura G, Pegram R G
FAO/DANIDA Tick and Tick-borne Disease Control Programme, Bujumbura, Burundi.
Med Vet Entomol. 1996 Jan;10(1):12-8. doi: 10.1111/j.1365-2915.1996.tb00076.x.
Groups of cattle of four different cross-breeds (Ankole x Friesian, Ankole x Brown-Swiss, Ankole x Guernsey, Ankole x Sahiwal) plus a group of pure Ankole cattle were immunized against tick-borne diseases: East Coast Fever, using a Theileria parva trivalent vaccine, and anaplasmosis, babesiosis and, subsequently, heartwater. With the exception of two small subgroups of Ankole and Ankole x Sahiwal which were treated by weekly spraying using Delnav, all the groups were exposed to natural field challenge of ticks to quantify the development of host resistance to ticks. The results indicate resistance to the most abundant species, Rhipicephalus appendiculatus, as follows: Ankole > Ankole x Sahiwal > Ankole x Brown Swiss > Ankole x Friesian > Ankole x Guernsey. In both Amblyomma variegatum and Rhipicephalus evertsi evertsi, the manifestation of different levels of resistance between breeds is inapparent. Correlations between total ticks and standard female ticks were good for R.appendiculatus (r = 0.73) and R.evertsi (r = 0.51) but poor for A.variegatum (r = 0.31). Correlations between species were reasonably consistent (r = 0.43-0.59). There was no significant correlation between tick burdens and daily liveweight gain (DLWG) over the whole period of the study. Of the cross-bred groups, Ankole x Sahiwal, which had the highest level of resistance, had the highest DLWG. In contrast, the Ankole x Guernsey which developed the lowest level of resistance had only marginally lower DLWG, the difference being only 8 g/day. During the first period of exposure to ticks, however, the untreated Ankole x Sahiwal group had markedly lower DLWG, which may indicate that the development and manifestation of resistance is at the expense of productivity.
选取了四组不同杂交品种的牛（安科勒牛×弗里斯兰牛、安科勒牛×瑞士褐牛、安科勒牛×根西牛、安科勒牛×萨希瓦尔牛），外加一组纯种安科勒牛，针对蜱传疾病进行免疫接种：使用泰勒虫三价疫苗预防东海岸热，同时预防无形体病、巴贝斯虫病以及随后的牛心水病。除了安科勒牛和安科勒牛×萨希瓦尔牛的两个小亚组每周使用地尔硫磷进行喷洒处理外，所有组均暴露于蜱的自然田间攻击之下，以量化宿主对蜱的抗性发展情况。结果表明，对最常见的种类——微小扇头蜱的抗性如下：安科勒牛＞安科勒牛×萨希瓦尔牛＞安科勒牛×瑞士褐牛＞安科勒牛×弗里斯兰牛＞安科勒牛×根西牛。在变异革蜱和埃氏扇头蜱中，不同品种间抗性水平的差异并不明显。总蜱数与标准雌蜱数之间的相关性，对于微小扇头蜱（r = 0.73）和埃氏扇头蜱（r = 0.51）良好，但对于变异革蜱（r = 0.31）较差。不同种类之间的相关性较为一致（r = 0.43 - 0.59）。在整个研究期间，蜱负荷与日增重（DLWG）之间没有显著相关性。在杂交组中，抗性水平最高的安科勒牛×萨希瓦尔牛的日增重最高。相比之下，抗性水平最低的安科勒牛×根西牛的日增重仅略低，差异仅为8克/天。然而，在首次暴露于蜱的期间，未处理的安科勒牛×萨希瓦尔牛组的日增重明显较低，这可能表明抗性的发展和表现是以生产力为代价的。
