Tritschler J P, Giordano D J, Coles G C
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst 01003.
Cornell Vet. 1989 Oct;79(4):327-38.
Epidemiological control of nematodes in weaned lambs in New England was investigated over three grazing seasons (n = 58, n = 52 and n = 62 lambs, respectively). Spring prophylactic treatment, clean pasture and mid-summer treat-and-move to hayfield strategies were compared to traditional fall treatments (control). In these studies when lambs were weaned prior to grazing, the most abundant nematodes were Nematodirus sp. Under these conditions, where only low levels of Haemonchus contortus were present, no significant improvement in body weight gain was observed for the epidemiologic approaches compared to the traditional fall treatments. No untreated control was used, and fecal egg counts and pasture larval counts indicate low total worm burdens with a controllable fall rise in pasture infectivity. These results indicate the importance of hypobiosis for the survival of H. contortus and suggest that weaning lambs prior to grazing can be an effective epidemiological control practice.
在三个放牧季节对新英格兰地区断奶羔羊体内线虫的流行病学防控进行了调查（分别有58只、52只和62只羔羊）。将春季预防性治疗、清洁牧场以及仲夏治疗并转移至干草地的策略与传统秋季治疗（对照）进行了比较。在这些研究中，当羔羊在放牧前断奶时，最常见的线虫是捻转血矛线虫。在仅存在低水平捻转血矛线虫的这些条件下，与传统秋季治疗相比，未观察到所采用的流行病学方法在体重增加方面有显著改善。未设置未处理的对照，粪便虫卵计数和牧场幼虫计数表明蠕虫总负担较低，且牧场感染性在秋季有可控的上升。这些结果表明休眠对捻转血矛线虫生存的重要性，并表明在放牧前断奶羔羊可能是一种有效的流行病学防控措施。
