Faecal Egg count numbers in ruminants - question

Re: Faecal Egg count numbers in ruminants - question

Tim Cheyne — Wed, 19 Jan 2011 15:11:07 GMT

In my opinion the value of single sample faecal egg counts is questionable. The presence of any eggs simply indicates that mature females are present in the intestine. The production and excretion of eggs is cyclical and, of course, depends also upon the ratio of male/female parasites, all of which could be causing damage. To obtain any sort of viable count requires bulking of repeated samples or 24-hour samples and even then........? In such a case I take a positive sample as indicating that mature parasites are present and then make a clinical judgement on the condition of the animal(s) as to whether or not treatment is necessary. Sorry that this is not very helpful to you.

Tim.

Re: Faecal Egg count numbers in ruminants - question

Heather Toft — Wed, 19 Jan 2011 13:36:17 GMT

I've copied and pasted the general advice from a VLA lab report below. However, these figures probably aren't much use to you because Trichuris isn't a trichostrongyle, and goats aren't sheep (try telling that to the rest of my workplace who always allocate the goat calls to me). I always thought that Trichuris wasn't thought to be a primary cause of disease, though may contribute to PGE in mixed infestations, so it might be difficult to decide what is or isn't a significant burden. I'd recommend getting in touch with the VLA and the goat veterinary society for their advice.......

"Faecal egg counts can be influenced by a number of factors including the age and nutrition of the animal, faecal consistency, timing of sampling and species of parasites present. Therefore, to minimise these as much as possible, monitoring samples should be collected from a group of animals, approximately the same age and reproductive status, grazing the same pasture and having the same recent anthelmintic treatment history.

Trichostrongyle-type eggs may include Ostertagia, Teladorsagia, Haemonchus, Trichostrongylus spp. as well as Cooperia, Oesophagostomum, Chabertia and Bunostomum spp. Speciation of the egg count requires an extra test to culture the eggs to the L3 stage.

The following give broad guidelines for interpretation of worm egg counts in lambs, taking all of the above factors into account.

<200 epg low egg count, anthelmintic treatment probably not justified but monitoring should be continued.

200-500 epg. some clinical disease could be present and anthelmintic treatment should be beneficial in individuals.

500-1000 epg. clinical disease likely in a large number of the group

1000+ epg. clinical disease likely in the whole group with some animals heavily infested.

The relaxation in immunity that occurs in ewes around parturition, allows large numbers of eggs to be passed in their faeces. Anthelmintic treatment for all ewes may not be necessary at this time; however, young ewes, those carrying multiple lambs and those in poor condition should be treated.

More information on parasite control in sheep can be obtained from SCOPS, sustainable control of parasites in sheep. SCOPS guidelines are available on Defra and NSA websites."

Re: Faecal Egg count numbers in ruminants - question

Anonymous — Tue, 18 Jan 2011 22:12:03 GMT

Excellent question!

Someone more experienced here might be able to answer your question, but if not then try ringing your local VLA lab tomorrow to enquire. They should have a standardized comment for reporting such egg counts done at the lab to help vets in practice interpret the findings:

http://www.defra.gov.uk/vla/vla/vla_contacts.htm

If you ring the Scottish equivalent (SAC, http://www.sac.ac.uk/consulting/services/s-z/veterinary/contact/vetlocations/) then you might get a different answer, as I can't imagine there are any limits agreed based on meaningful studies...

Re: Faecal Egg count numbers in ruminants - question

Michael Woodhouse — Tue, 18 Jan 2011 22:06:42 GMT

In these cases I reach for the SCOPS manual

http://www.nationalsheep.org.uk/images/stories/pdf/scopstechmanthree.pdf

If the answer's not there ring your local VLA centre!