Horses with Cushing’s disease (also known as pituitary pars intermedia dysfunction ; PPID) are more likely to have higher fecal egg counts than are healthy horses according to a recent study.
Dr Dianne McFarlane and colleagues compared the response to anthelmintic treatment on fecal egg counts in healthy horses and those with Cushing’s disease.
The researchers performed faecal egg counts at 2-
At 2 and 4 weeks after treatment with ivermectin all horses in the study had negative fecal egg counts.
Horses with PPID had higher egg counts than did healthy horses, both before and at 6 -
A fecal egg count greater than 200 epg is often taken as an indication that anthelmintic treatment is required. In this study 6 of the 13 horses with PPID reached the 200epg threshold by 10 weeks after ivermectin treatment. In contrast only 2 of 25 control horses had reached the threshold at the same time -
“Given similar environmental conditions, horses with PPID were more likely to have higher fecal egg counts than were healthy horses” Dr McFarlane reports.
The findings suggest that horses with PPID may pose a risk for pasture hygiene if not managed properly.
On the other hand, age alone does not appear to increase the horse’s susceptibility to parasitism. However, the researchers point out that only a small number of horses were involved in that analysis. More work is required to confirm that older horses do not need treating differently to younger horses when it comes to deworming.
For more details see:
Fecal egg counts after anthelmintic administration to aged horses and horses with pituitary pars intermedia dysfunction.
D.McFarlane, GM Hale, EM Johnson, LK Maxwell
J Am Vet Med Assoc (2010) 236, 330-