Relative resistance of Menz and Washera sheep breeds to artificial infection with Haemonchus contortus in the highlands of Ethiopia
Relative resistance of Menz and Washera sheep breeds to artificial infection with Haemonchus contortus in the highlands of Ethiopia
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DOI：
10.1007/s11250-015-0815-6
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发表时间：
2015-06-01
影响因子：
1.7
通讯作者：
Notter, David Russell
中科院分区：
文献类型：
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作者：
Getachew, Tesfaye;Alemu, Biruk;Notter, David Russell
本研究的目的是评估孟茨和瓦谢拉绵羊品种对扭曲血吸虫人工感染的相对抵抗力。挑战审判是在埃塞俄比亚的Debre Berhan农业研究中心进行的。试验选用约6月龄羔羊39只(Menz=21只，Washera=18只)。所有羔羊最初都被用阿苯达唑和法西奈克斯治疗以对抗体内寄生虫，以释放它们的体内寄生虫，并将其饲养在室内。用Baerman法采集屠宰场采集的旋毛虫雌成虫，按标准程序制备三期幼虫(L3)。约5000只感染幼虫在驱虫后约5周接种给实验羔羊。记录激发后28、35和42天的粪卵计数(FEC)、红细胞压积(PCV)、Faffa Malan评分(FAMACHA)、羔羊体重和羔羊存活率。品种效应不显著(P>；0.05)，而测定时间、品种与时间互作对FEC和PCV有显著影响(P<；0.05)。在攻击后28天，孟兹羊的FEC低于Washera羊，而在35和42天，Washera绵羊的FEC低于Menz羔羊。在整个挑战后期间，PCV显著下降。尽管有寄生虫的负担，孟兹绵羊在42天的挑战中仍然能够保持活着的体重。对羔羊存活率的品种差异的卡方检验在任何时候(挑战后28天、35天和42天)都不显著。在感染孟兹羔羊后，28日龄的FEC降低和FEC的延迟上升将允许推迟驱虫治疗。除了在感染期间保持体重外，两个品种的绵羊在PCV和FEC上都表现出很大的变异性，这表明在选择计划中有机会考虑寄生虫抗性。
The aim of this study was to evaluate the relative resistance of Menz and Washera sheep breeds to artificial infection with Haemonchus contortus. The challenge trial was conducted at the Debre Berhan Agricultural Research Center in Ethiopia. A total of 39 (Menz = 21, Washera = 18) lambs of about 6 months old were used for the trial. All lambs were initially treated against internal parasite using albendazole and Fasinex to free them from internal parasites and kept indoors. H. contortus third-stage larvae (L3) were prepared according to standard procedure from adult female parasite collected from abattoirs and recovered using the Baerman technique. Approximately 5000 infective larvae were inoculated to the experimental lambs at about 5 weeks after deworming. Fecal egg count (FEC), packed cell volume (PCV), FAffa MAlan CHArt (FAMACHA) score, lamb body weight, and survival of lambs were recorded at 28, 35, and 42 days after challenge. Breed effect was not significant (P > 0.05), whereas time of measurement and the interaction of breed and time had significant (P < 0.05) effects on FEC and PCV. At 28 days after challenge, Menz sheep had lower FEC than Washera sheep, whereas at days 35 and 42, the Washera sheep had lower FEC than Menz lambs. The PCV decreased significantly throughout the post-challenge period. Despite their parasite burden, Menz sheep were able to maintain live weight during the 42 days of challenge. Chi-square tests for breed differences in lamb survival were not significant at any time (28, 35, and 42 days after challenge). Lower FEC at 28 days and delayed rise in FEC after infection in Menz lamb would allow in delaying anthelmintic treatment. In addition to maintain body weights during the infection period, sheep of both breeds exhibited substantial variability in PCV and FEC, suggesting opportunity to consider parasite resistance in selection program.