The Dynamics, Prevalence and Impact of Nematode Infections in Organically Raised Sheep in Sweden

Table 1 Prevalence and seasonal abundance of trichostrongylid eggs (excl.Nematodirus spp) in faecal samples from ewes and lambs in organic sheep flocks in Sweden. Ewes were sampled in spring (April – May) and autumn (September – October) and lambs were sampled in summer (June) and autumn (September – October).

Year & season	Flock prevalence (%)	Mean EPG		Genera prevalence
		AM	GM*	H.contortus	Teladorsagia	Trichostrongylus	Cooperia
EWES
Spring				%	%	%	%
1997 (72) 21^•	93	652	393^a	24	93	74	3
1998 (101) 15	95	244	107^b	15	92	89	0
1999 (93) 18	98	373	195^c	18	85	83	5
Autumn
1997 (60)	40	32	3^a	5	27	22	2
1998 (74)	78	53	8^b	4	31	37	0
1999 (66)	77	46	7^b	8	33	61	6
LAMBS
Summer
1997 (66) 7^⊗	88	180	85^a	2	88	55	3
1998 (81) 17	89	186	87^a	5	69	69	4
1999 (74) 9	80	122	66^b	9	52	39	0
Autumn
1997 (60)	70	269	119^a	7	68	53	0
1998 (73)	93	384	189^a	11	63	77	18
1999 (66)	97	287	140^a	17	45	74	14

AM = Arithmetic mean; GM = Geometric Mean
* Comparisons between years. Means with the same superscript, within each subset, were not significantly different (p > 0.05)
^• Number of ewe flocks that were dosed with an anthelmintic, following the detection of H. contortus
^⊗ Number of flocks where lambs were dosed with an anthelmintic

ISSN: 1751-0147