The Link Between Girth Pain and Birth Trauma

Riders and owners will know this as girthiness, or something similar – a horse that braces against having the girth tightened, flinches or tries to bite or kick.  There are many levels of escalation of this behaviour. Oddly, it is considered the norm for many horses.

Girth Pain Syndrome is not a purely localized pain or discomfort, originating in one area only or confined to one body system; rather, it involves the entire forelimb balance and conformation, the ribcage, the whither, the back, the saddle shape and fit, and the girth shape and fit. This article will not dive deeply into the condition – to learn more about girth pain syndrome and how we can treat it, watch the webinar by Dr Lesley Goff.

There is one aspect of the condition, however, that I found fascinating and would like to discuss today: Birth trauma.

Birth Trauma

In 2005, Ian Bidstrup did some work that questioned the relationship between birth trauma and abnormal whither and ribcage sensitivity in horses, as well as the one-sidedness of horses.

He notes several observations that have been made over the years that relate to rib and girth sensitivity:

1. Abnormal pain and sensitivity occur in the girth and rib cage area in horses of all ages – from foal to geriatric, regardless of whether they are ridden or have ever been ridden, and in all breeds and types.
2. Girth Pain Syndrome occurs in up to 80% of his patients and is linked to restrictions in the mobility of the spinal column.
3. The area of the spine that is most often affected is the 4th and 6th thoracic vertebrae, which present the widest point of the foal during the birthing process.
4. This same area of the spine matches the rib fracture pattern that was found by Schambourg et al in 2003, who concluded that at least 20% of foals have thoracic trauma such as costochondral dislocation and fracture of the ribs after birth.

Bidstrup goes on to note a few aspects of one-sidedness in horses – something we as riders often assume to be normal.

1. In 80-90% of patients, the right side of the ribcage and girth area is more painful or sensitive than the left side.
2. 80-90% of patients struggle with a canter transition on the right rein or circle, which resolves after treatment of the painful girth area.
3. The affected horses tend to have a smaller hoof on the right side, with a higher heel.
4. An affected horse will lean away from the abnormal side – for example, a foal will place the normal limb forward and the abnormal limb backwards.
5. A change in shoulder conformation and angulation can commonly be seen, with the right shoulder generally presenting as smaller and flatter, or more sloped.

Never stop learning

Interesting observations, right? I do love learning from the experience of others. It is clear that Bidstrup would not have been able to make these observations if he had not been diligent in his assessment and record keeping, and had not done the work of retrospectively analysing these records to identify the patterns. This is something we can and should all be doing! In addition, if he had not shared this knowledge with the greater equine community, we would all be that much poorer. So let’s start cultivating a heart of sharing – our knowledge, questions and theories.

The occurrence of birth trauma in the foal

In humans, birth trauma is well recognized by professionals and regularly treated. However, there are major differences between equines and humans in this regard. In horses, the birth process is quick, with the second phase lasting from two to twenty minutes. If we accept that the occurrence of trauma to the rib cage, such as costochondral dislocations and fractures to one or multiple ribs is very common in foals, as illustrated by Jean et al (Watch the research refresh in the Onlinepethealth Equine member’s portal) what impact does this have on our adult horses? These conditions heal quickly in the foal, possibly within two to three weeks. The same holds true for any damage that might occur in the whither area and thoracic vertebrae. So how do we link this damage to what we see in our adult horses?

Neurological development in the first weeks of life

This brings us to the second difference between foals and infants – within a few hours of birth, a foal is standing, walking and running, and within a few weeks, has mastered basic gross motor functions, running, playing, bucking, jumping and turning with ease. So in those first weeks of life, when the foal is dealing with these injuries to the ribs and spine, he is also developing his neural movement patterns. Thus an abnormal movement pattern is learned, where muscles around the injured site are tightened to protect the area, and limb coordination is affected as the foal favours movement on one side or shortens a stride to limit the movement of a rib. These learned movement patterns become the foal’s norm, and are likely to continue once the injury has healed. They may well be affecting afferent neural feedback from muscles, nerves and joints, resulting in heightened sensitivity in one area, abnormal muscle tone and abnormal myofascial trigger points, and abnormal muscle recruitment patterns.

How does this relate to one-sidedness?

Bidstrup suggests that one-sidedness could be due to the distribution and anatomy of the abdominal contents of the mare during the birthing process, in particular the caecum that sits on the left side of the foal during the birth.  This could create a pressure gradient and increased forces that lead to damage on that side of the foal. Just a thought.

I think that there is enough here not only to get us questioning what is normal in horses, but also to start working towards answering the questions raised when we challenge our own perceptions of normal.

Question the norm

If it were any other body part or condition, we would immediately question whether the tightening of the eye or the lip, or a change in posture, or a nip, was a reaction to a painful stimulus. We should equally question why we get this response during the tightening of the girth – especially when all precautions have been taken to ensure that the process does not cause discomfort (such as slowly tightening from both sides, ensuring a good fit of girth and saddle, and possibly placing a sheepskin cover around or under the girth). When it comes to one-sidedness, how can the movement be normal for the horse if it improves immediately upon treatment of the vertebral column, ribcage and girth area?

It is time for us to start challenging the norms, for the sake of the welfare of our horses!