Githigia S M, Thamsborg S M, Larsen M
Danish Centre for Experimental Parasitology, The Royal Veterinary and Agricultural University, Ridebanesvej 3, DK-1870 C., Frederiksberg, Denmark.
Vet Parasitol. 2001 Jul 31;99(1):15-27. doi: 10.1016/s0304-4017(01)00448-4.
A dose and move to clean pasture strategy for nematode control in weaner sheep was compared to a move only strategy. Sixteen ewes with twin lambs (2-3 weeks old) were turned out on infected pasture on 4 May 1999. On 1 July, the lambs were allocated to four groups of eight and weaned on to clean pasture. Two groups (DM1+2) were treated with anthelmintics, while the other two (M1+2) were not treated. Each group was allocated to a separate paddock and set stocked until 27 September when all the animals were slaughtered to perform worm counts. Moving the weaned lambs to clean pasture reduced the faecal egg counts to less than one third within 4 weeks while the treatment reduced it to zero for 4 weeks. Faecal egg counts of the dose and move groups remained significantly lower for 6 weeks (P<0.0001) after moving to the clean pasture. After this period the differences were not significant as the dose and move groups started shedding eggs in faeces. The pasture infectivity was lower in the paddocks grazed by groups (DM1+2). The weight gains and the serum albumin levels were comparable in all four groups. O. circumcinta and Trichostrongylus vitrinus were the major species recovered. The total worm counts were significantly lower in (DM1+2) compared to M1+2, particularly the mean counts in the small intestines (T. vitrinus) (P<0.01). It was concluded that weaning lambs at the beginning of July and moving them before the expected mid-summer rise in herbage infection to a clean pasture will prevent parasitic gastroenteritis and achieve good production whether the move is accompanied by anthelmintic treatment or not. The effects will be subject to prevailing nematode species, local climatic conditions and length of the grazing season.
将断奶羔羊的线虫控制策略——“给药并转移至清洁牧场”策略与“仅转移”策略进行了比较。1999年5月4日，16只带双羔（2 - 3周龄）的母羊被放到受感染的牧场上。7月1日，羔羊被分成四组，每组8只，并断奶转移至清洁牧场。两组（DM1 + 2）用驱虫药治疗，另外两组（M1 + 2）未治疗。每组被分配到一个单独的围场并固定放牧，直到9月27日所有动物被屠宰以进行蠕虫计数。将断奶羔羊转移至清洁牧场可使粪便虫卵计数在4周内降至不到三分之一，而治疗可使其在4周内降至零。转移至清洁牧场后，给药并转移组的粪便虫卵计数在6周内仍显著较低（P < 0.0001）。在此之后，差异不再显著，因为给药并转移组开始在粪便中排虫卵。（DM1 + 2）组放牧的围场中牧场感染性较低。所有四组的体重增加和血清白蛋白水平相当。回收的主要虫种为环纹奥斯特线虫和透明毛圆线虫。（DM1 + 2）组的总蠕虫计数显著低于M1 + 2组，特别是小肠中的平均计数（透明毛圆线虫）（P < 0.01）。得出的结论是，7月初断奶羔羊，并在预期的仲夏牧草感染率上升之前将它们转移至清洁牧场，无论转移是否伴有驱虫药治疗，都将预防寄生性胃肠炎并实现良好的生产性能。效果将取决于当地流行的线虫种类、当地气候条件和放牧季节的长度。
