Yikes! My Horse Has No Tail! Are Pinworms The Culprit?


Nikki Alvin-Smith


This Summer I was aghast to discover one of my broodmares had rubbed her tail into a matted mess of hairs. She had been in her stall just a few hours, enjoying a respite from the heat of the sun. When I had brought her in from the pasture her tail looked perfectly groomed. I was staggered at the amount of damage she had done in such a short space of time to her tail head.


This particular horse has an unusually beautiful sorrel and chestnut mane and tail with bright frosted tips, a color blend that any hairdresser would love to emulate in their hair coloring endeavors. I had diligently conditioned her tail all season long, picked through tangles with my fingers to avoid the harshness of a comb or brush to carefully preserve the bountiful beautiful tail hairs. Students have dubbed this horse, ‘Tina’, after the singer Tina Turner, for her matching hair color. Her mane and tail truly are a crowning glory to a home produced horse that we bred from a chestnut mare and a notable black stallion.


Most of us have experienced that moment when our horse turns around in his stall and we see that its tail has become a tangled mess at the head of the tail. The skirt hairs are missing, or scrunched into a new backcomb style.


Water buckets or mangers are squished out of shape, bits of horse tail hair caught on their handles and your horse just looks at you like, “What?”


Eggs obtained by scrapping the the rectal area

A horse can itch for many reasons but a common cause is the dastardly pinworm. This issue is most prevalent in young horses. On close examination of the horse’s rectum you may even see a worm dangling halfway out. Disgusting I know! This is the female pinworm laying her eggs around the exterior of the rectal ring with a glue like material. The female pinworm will die after laying her eggs and the glue will dry and cause intense itching. The horse will consequently itch its tail head on any available surface. Whitish, light green, yellowish or gray patches of eggs may be seen and these patches can contain as many as several x 100,000 microscopic eggs in this egg-white consistency film.

As these worms will not be seen in a FECT (fecal egg count test) the best way to ascertain whether your horse is harboring pinworms is with a special test that is akin to placing a piece of sticky tape across the horse’s rectum, aptly called the ‘Scotch Tape Technique” then removing it and looking at the results under a microscope. Alternatively a lubricated wooden tongue depressor can be used to scrape the skin surrounding the anus to collect a sample of the material and place on it on a slide, or popsicle sticks can be utilized to collect the material and sent to the laboratory for testing. It is important that when collecting this sample the person responsible does not take for granted their risk for injury from a kick or adverse reaction to the procedure from the horse. A firm but gentle scraping of the rectal ring is required and although a horse may be generally quiet and easy to work around be aware the procedure may provoke a defensive response. It is wise to follow the directions of how to take the test and be extremely careful when working behind the horse.


The presence of pinworms in a sample can be hard to detect so it does require a professional eye. If you purchase an FECT sample kit here at Horsemen’s Laboratory  the pinworm test is offered for free, so just ask for it at the time you place your order. Dr. John Byrd or his assistant Ivy Lewis will be sure to educate you as to the suitability and safety of administering this test on your horse yourself. As we all know, safety around horses is paramount whatever we are doing. This test can certainly provoke an unexpected and unwanted reaction.


While pinworm infection was most commonly seen in young horses, recent studies suggest there is an upward trend in the pinworm population being hosted in adult horses. There are also indications that the pinworm may be resistant to treatment with Ivermectin. The recommended treatment at this time is a benzimidazole dewormer.


If your horse is in significant discomfort and you have ascertained this itching is caused by pinworms, you can bathe the perianal region to help relieve the itching. Sometimes although the glue like material has dried and been cleaned the horse may still have soreness and dry or cracked tissue around at the tail head that causes the horse to continue to rub its tail. Something I hadn’t thought to do but which made perfect sense the minute that Dr. Byrd explained it to me, was his suggestion to apply a cortisone cream or other steroidal salve mixed with an antibiotic to the dorsal (outside) of the tail head to improve the comfort of the horse and relieve the need to itch.

Picture of an Adult Female Pinworm taken at Horsemen’s Laboratory

It is also important to clean all surfaces where the horse has rubbed his tail, to prevent other horses from ingesting the sticky film that may be left behind and becoming infected.


In the case of our mare ‘Tina’, I dewormed her as recommended above and the problem disappeared. I also dewormed my entire herd at the same time with the same type of dewormer, to help mitigate the possibility that they shared the pinworm infection. Her stall and water buckets and manger were all thoroughly washed, and I am pleased to report her tail has recovered and the hairs have grown back.


So if your horse shows any signs of tail rubbing, it may be wise to explore the notion that pinworms may be the culprit. If you have any questions reach out to Dr. John Byrd for answers at 217 586 2004. He provides a wealth of information on all matters ‘equine parasitology’.