Murrell K D, Leighton E A, Boswell B A, Gasbarre L C
Helminthic Diseases Laboratory, Beltsville Agricultural Research Center, USDA, Maryland 20705.
J Parasitol. 1989 Jun;75(3):360-6.
Four- to 6-mo-old calves raised on clean pastures were allowed to graze for about 30 days on pastures naturally contaminated with Ostertagia ostertagi, Cooperia spp., Haemonchus placei, and Nematodirus helvetianus. The calves were then housed on concrete for 3 wk before slaughter. At necropsy the eggs per gram of feces (EPG) and the total worm burdens from the abomasum and small intestine were determined. Blood samples were also obtained for serum pepsinogen (PEP) assays. A total of 44 calves was sampled over 27 mo. Adult worm totals were distributed more normally after logarithmic transformation (LOGTOTAL), and EPG and PEP were distributed more normally after square root transformation (SQRT--EPG; SQRT--PEP). Correlation between LOGTOTAL and either SQRT--EPG or SQRT--PEP was about 0.7. These correlations were higher than those obtained with nontransformed data, suggesting that either EPG or PEP are easily measured variables that explain a significant amount of the variation observed in total worm burdens. Polynomial regression models of a cubic order using the SQRT--EPG accounted for 78% of the variation observed in the LOGTOTAL, whereas SQRT--PEP accounted for 58% of the variance. Within the range of worm burdens observed, these results indicate that EPG has value in estimating total worm burdens of naturally infected calves, and that pepsinogen levels are of less value for analysis of total worm burden in calves with a limited previous exposure to trichostrongyle nematodes.
在干净牧场饲养至4至6月龄的犊牛，被允许在自然感染了奥斯特他线虫、古柏线虫属、牛血矛线虫和瑞士细颈线虫的牧场上放牧约30天。然后将这些犊牛圈养在水泥地面上3周，之后进行屠宰。尸检时测定每克粪便中的虫卵数（EPG）以及真胃和小肠中的蠕虫总负荷。还采集血样进行血清胃蛋白酶原（PEP）检测。在27个月内共对44头犊牛进行了采样。经对数转换（LOGTOTAL）后，成虫总数的分布更接近正态分布，而经平方根转换（SQRT - EPG；SQRT - PEP）后，EPG和PEP的分布更接近正态分布。LOGTOTAL与SQRT - EPG或SQRT - PEP之间的相关性约为0.7。这些相关性高于未转换数据时的相关性，表明EPG或PEP是易于测量的变量，能够解释观察到的蠕虫总负荷中相当一部分的变异。使用SQRT - EPG的三次多项式回归模型解释了LOGTOTAL中观察到的78%的变异，而SQRT - PEP解释了58%的变异。在观察到的蠕虫负荷范围内，这些结果表明EPG在估计自然感染犊牛的蠕虫总负荷方面具有价值，而对于之前接触毛圆线虫有限的犊牛，胃蛋白酶原水平在分析蠕虫总负荷方面价值较小。
