Laboratory testing and post-mortem lesion recognition in goats

The UK goat population is estimated to be around 111 000 in total (APHA, 2022), thereby placing them in the category often referred to as a minor species. Although most of our day-to-day veterinary involvement with a goat may be by application of dairy cow and sheep knowledge, experience and technical approaches, there are a few important yet subtle differences for the reader to be aware of:

A knowledge of the apparent lack of age dependent resistance to nematode parasites in goats is key to investigating weight loss and diarrhoea in goats of all ages in which clinical parasitic gastroenteritis (PGE) can occur. It is for this reason that most of the large commercial dairy goat units are permanently housed. Conventional faecal worm egg counts (Figure 1) form the basis of any investigation, and the laboratory should give goat reference ranges, but there are many variables to consider when attempting to give guidelines on the significance of worm egg count results, and each case must be assessed with reference to the age of the goat and the clinical signs present. As a general guide however, egg counts in excess of 2000 eggs per gram (epg) are usually indicative of clinical disease. Counts of 500–2000 epg are suggestive of sub-clinical parasitism and subsequent reduced production, or reduced milk yield. Haemonchosis (Figure 2) is clinically similar to the condition in sheep, in which severe anaemia and sub-mandibular oedema are common features, significantly, however, diarrhoea is not a feature of this parasite unlike other nematode species. Haemonchus contortus has increased egg producing fecundity, and often results in very high faecal egg counts, which, with the clinical signs outlined above, should raise a suspicion.