THE EFFECT OF HAEMONCHUS-CONTORTUS ON LIVEWEIGHT GAIN AND WOOL GROWTH IN YOUNG MERINO SHEEP
THE EFFECT OF HAEMONCHUS-CONTORTUS ON LIVEWEIGHT GAIN AND WOOL GROWTH IN YOUNG MERINO SHEEP
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DOI：
10.1071/ar9890419
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发表时间：
1989-01-01
影响因子：
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通讯作者：
BARKER, JSF
中科院分区：
文献类型：
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作者：
ALBERS, GAA;GRAY, GD;BARKER, JSF
采用三个交叉试验的结果，共1078只美利奴羔羊，估计了11,000只捻转血矛线虫幼虫的单次感染对活重增加、净毛生长和羊毛细度的影响。估计数是通过直接比较6组感染和匹配的未感染羔羊在现场条件下。5周后感染终止，此时出现了一些死亡率，六分之五的病例的血细胞压积下降至低于24%。在8-9周的时间内，从感染开始，感染羔羊的增重平均减少1.29 kg（范围0.83-1.71 kg），相当于未感染对照组增重的38%（12-64%）。感染的有害影响在感染期结束时最为严重。在幼虫给药和羊毛生长抑制发作之间有3-6周的滞后期。羊毛生长的减少持续至少14周后终止感染。这一削减的规模差异很大。在感染后的4个月内，减少范围从11至97克干净的羊毛（平均46克）或1.4至15.7%（平均6.8%）的干净的羊毛生长的未感染的羔羊。估计在同一时期纤维直径的减小范围为0.39至0.79 μ m（平均0.57 μ m）。
Results of three crossover experiments on a total of 1078 Merino lambs were used to estimate the effect of a single infection of 11,000 Haemonchus contortus larvae on liveweight gain, clean wool growth and wool fineness. Estimates were obtained by direct comparison of six groups of infected and matched uninfected lambs under field conditions. Infections were terminated after 5 weeks, at which stage some mortality had occurred and haematocrits had in five out of six cases declined to less than 24%. Over an 8-9 week period, beginning at the time of infection, liveweight gains of infected lambs were reduced by on average 1.29 kg (range 0.83-1.71 kg) amounting to 38% (12-64%) of liveweight gain in uninfected controls. The detrimental effect of infection was most severe towards the end of the infection period. There was a lag phase of 3-6 weeks between larval administration and the onset of wool growth depression. The reduction of wool growth persisted for at least 14 weeks after termination of infection. The size of this reduction was very variable. Over a 4 month post-infection period, reductions ranged from 11 to 97 g clean wool (mean 46 g) or 1.4 to 15.7% (mean 6.8%) of clean wool grown by uninfected lambs. Estimates of reduction of fibre diameter over the same period ranged from 0.39 to 0.79 .mu.m (mean 0.57 .mu.m).