Table 1.

Stud farm data and prevalence of Parascaris spp. egg excretion before and after ivermectin (IVM) treatment

Farm	Herd size	Foals	Sex F/M	Age [3/4/5/6 months]	FEC-positive foals		EPG (min–max)		IVM efficacya
					Pre/with EPG ≥ 150	Post	Pre	Post	Observed FECR
1	≥ 100	49	34/15	6/14/10/19	23/22	20	471 (50–1050)	400 (50–900)	57.0 [36.9–74.2]
2	≥ 100	40	26/14	7/10/9/14	28/24	20	2134 (50–13,750)	1355 (100–5150)	56.8 [20.3–80.3]
3	≥ 100	51	35/16	4/11/17/19	16/15	16	572 (50–1400)	341 (50–2050)	44.0 [6.8–74.5]
4	50–100	24	14/10	4/5/6/9	7/3	2	850 (50–5300)	200 (50-350)	–
5	≤ 50	16	9/7	3/0/7/6	12/8	4	833 (50–5550)	325 (100-650)	86.6 [44.8–96.4]
6	50–100	34	0/34	0/10/6/18	6/4	1	167 (100–250)	50	–
7	≤ 50	11	7/4	1/3/5/2	7/6	1	471 (50–1050)	50	96.9 [92.9–100.0]
Total		225	125/100		99/82	64

F female, M male, FEC faecal egg count, EPG eggs per gram faeces

^aObserved faecal egg count reduction (Observed FECR) with 95% confidence intervals given in square brackets