pain | Horse Racing Free Tips

Is Colic The Only Reason For Bacterial Changes In The Gut? Probably Not

It's long been known that the best way to prevent ulcers in horses is to make sure they have something to eat—preferably forage—nearly constantly. But what happens if feed and hay are withheld to not exacerbate a problem, like colic?

Drs. Jaclyn Willette, Dipti Pitta, Nagaraju Indugu, Bonnie Vecchiarelli, Meagan Hennessy, Tamara Dobbie and Louise Southwood found that the bacterial population of a horse's gut changes if he has been without food for at least 10 hours.

Chronic gastrointestinal disease leads to a decrease in variety of bacterial species in the gut of humans and cattle; the same is thought to be true for horses.

The bacteria in a colicking horse's gut is distinctly different from that in a healthy horse's gut. While this could be related to intestinal problems and inflammation that is leading to the colic epsiode, other factors could be at play, including withholding feed, which is an essential tool in managing a horse with colic.

The study team used eight mares for a crossover study that withheld nearly all feed for 24 hours and then allowed each horse free-choice timothy hay for 24 hours. The horses had access to water at all times.

The researchers found that bacteria richness and diversity were significantly lower 10 to 24 hours after the fast began. This limited bacterial population persisted for 2 to 12 hours after the horses were given access to hay. The horse's gut returned to normal 18 to 24 hours after the hay was reintroduced.

The team concluded that the effect of withholding feed should be considered when interpreting data on species and amount of gut bacteria in horses. Their findings may help locate markers that will lead to the development therapeutic interventions for horses that are colicking.

Read the study here.

Update: Mineralization Of Neck Ligament Not Related To Headshaking

Headshaking in horses remains a frustrating mystery for the most part, with little relief for the horses it affects. One recent hypothesis was that headshaking was caused by the mineralization of the longitudinal odontoid ligament, a fan-shaped ligament in the neck. In a study published in 2020, three headshaking horses showed mineralization of this ligament in CT scans.

Much remains unknown about headshaking other than it is assumed that trigeminal neuralgia is the underlying cause. Other veterinarians and scientists suggest that musculoskeletal pain may also cause head shaking.

Imaging a horse's cervical spine used to be difficult, but diagnostic equipment has improved to the point where imaging this portion of a horse's spine is now possible. Drs. Alison Talbot, Miguel Rodrigues and Thomas Maddox re-examined CT scans of 97 horses that came through the Philip Leverhulme Equine Hospital, a part of the University of Liverpool.

They looked for records to indicate any relationship between the mineralization of that ligament and the primary issue, as well as breed, age, sex and use. They also looked for any association with neck pain, head shaking or restricted range of motion in the neck.

They team found that 25 of the 96 horses (26 percent) had some mineralization of the ligament, but they found no association between mineralization and either idiopathic head shaking or any other clinical signs. They did discover that increasing mineralization was linked to age and sex: it primarily affected mares.

They determined that the mineralization of the ligament had nothing to do with head shaking or neck pain. They recommended that the significance of the mineralization be interpreted cautiously.

Reade the study here.

Foals Need Specific Pain Ethogram, Scientists Say

Equine researchers are encouraging the creation of a pain ethogram just for foals. Drs. Johannes van Loon, Nicole Verhaar, Els van den Berg, Sarah Ross and Janny de Grauw have found that foals express pain differently than their adult counterparts. They feel creating a pain-related facial expression scale unique to foals will assist with their welfare. It's important for people caring for foals to recognize when they are experiencing problems, as well as to assist them in managing pain and determining when pain-relieving drugs are working.

To test their theory, the scientists took 60-second videos of 20 foals that were between one day and six months old that had had diagnosed painful conditions like colic, post-operative pain or an injury. They also took video before and after pain medications were administered.

They showed the videos to three observers who didn't know which foals were healthy and which were not, or if they had received pain medication. The observers, a senior anesthetist and two of his vet students, had undergone a two-day training to identify equine facial expressions and what they mean.

It was discovered that though foals and adult horses shared some of the pain-related expressions, like holding their ears back and tightening their eyelids, major differences were also observed.

Painful foals did not:

Show the whites of their eyes when they are in acute pain, like adult horses do. This is most likely because foals show the whites of their eyes all the time as they look around.
Exhibit a flehmen response when in acute pain—it's actually healthy foals that were more likely to curl their lip as they explore their environment.
Grind their teeth, even when they have them.

However, foals in pain did smack their lips, which painful adult horses don't do, though it isn't understood why.

Each observer had similar findings when watching each video. This indicates that that with basic training, horse owners and caretakes can easily assess pain in foals in their care. The scientists suggest that more research is needed to confirm the pain-related behaviors of foals. The team hopes to develop ethograms specific to types of acute pain, like musculoskeletal or colic pain, as well as for chronic pan.

Read the study here.

Cellulitis: A Challenging Condition To Cure

Cellulitis is a sudden, painful skin infection that requires aggressive, immediate care. Most commonly affecting the hind legs, many horses recover readily, but complications are possible, and chronic flare-ups are a possibility.

Cellulitis occurs when bacteria penetrate the epidermis of the skin and multiplies in the subcutis, which is made up mainly of fatty and connective tissues. Primary cellulitis has no specific point of origin and exactly how it penetrates the skin is often unknown. Secondary cellulitis occurs when bacteria enter tissues through a known route, like a wound or surgical incision.

Cellulitis can be caused by a variety of bacteria and needs to be treated promptly. Left untreated, the infection can affect bone, tendon or synovial structures. Sepsis and laminitis can also occur.

Signs of cellulitis include:

Dramatic swelling that comes on rapidly and feels firm
Heat
Pain that tends to appear when the horse is asked to step forward rather than bear weight
Fever
Wetness: the swelling can progress rapidly to the point where fluid leaks from cracks in skin that is overstretched

A vet may take X-rays or do an ultrasound to rule out other possible issues like a joint infection or fracture. He or she may also culture the fluid weeping from the leg; this will help determine what bacteria is involved so that the proper antibiotic can be administered.

The primary treatment for cellulitis is intravenous antibiotics, as well as nonsteroidal anti-inflammatories to help with pain and swelling. Cold hosing or ice boots or bandaging can also help.

Horses with secondary cellulitis tend to recover more rapidly. Though some cases of cellulitis can be managed at home, severe cases may need to be referred to an equine hospital.

Horses that have had even one episode of cellulitis become susceptible to chronic cellulitis, specifically in the same limb, whether the skin was permanently damaged from the extreme swelling or because circulatory and lymphatics systems have been damaged to the point that they are unable to mount an immune response. Horses that have had cellulitis even once should be monitored carefully as even the tiniest wound may initiate a new round of cellulitis.

Tips to avoid cellulitis recurrence:

Turn out the horse as much as possible in dry condition
Use shampoo sparingly when bathing
Avoid sharing grooming tools and sterilize them regularly