Blog: Managing hormonal mares

Any mare that is cycling normally can have hormonal behaviour and it may not be related to a clinical problem. Mares are seasonal breeders. Most of their cyclic behaviour and desire to breed occurs in spring. A mare’s cycle lasts 21 days and is influenced by a variety of hormones released by the brain and the ovaries. The cycle begins the day of ovulation; the first 16 days are mainly under the influence of the hormone progesterone. From day 17-21 the level of progesterone decreases and the hormone oestrogen increases. Oestrogen causes much of the ‘in-season’ or oestrus behaviour. This phase of the cycle should last approximately 5 days, however it can vary between mares, the time of the year, or if there is a clinical problem.

Clinical signs that are often attributed to hormonal mares include:

  • Lack of concentration during ridden work
  • Poor performance
  • Lethargy during ridden work
  • Aggression
  • Increased sensitivity to being groomed, tacking up or touched generally
  • Pain response to pressure in the lower back
  • Increased urination
  • Low grade colic.

If you notice your mare is showing any of the above signs then it is recommended that you keep a diary. This can be helpful to determine if they are following a pattern similar to her reproductive cycle. It is advised that any mare periodically misbehaving, unpredictable or performing poorly, should be examined by one of our vets.

Things that you can do

Sometimes you don’t have to do anything about your mare’s behaviour. Hormonal behaviour is a natural process related to breeding. You may be able to change her work load or just remember to be more patient when she is ‘in-season’. If her behaviour is unmanageable or is limiting her performance, then it is important to have her examined. Other causes of poor performance such as an orthopaedic problem or other medical problems such as gastric ulceration can then be ruled out. There can be many causes of low grade colic in mares that may or may not be a result of their reproductive cycle.

An initial veterinary examination will include an ultrasound scan of the mare’s reproductive tract. This is to ensure that there is no evidence of abnormalities and that the mare shows evidence of normal cycling activity.

Uterine infections are the most common cause or abnormal cycling and associated behaviour in mares. Those with a uterine infection will often cycle more frequently and have a vaginal discharge. A uterine infection in a non- breeding mare often results when their natural ‘barriers’ between the external environment and the uterus fail. This is more common in middle aged and older mares.

Ovarian tumours are reported as 5.6% of all tumours in the horse. Granulosa cell tumours (GCT) are the most common and have been reported in many breeds and all ages. They can often cause mares to be constantly in oestrus, no oestrus at all, or show stallion-like behaviour. GCT can be detected by a rectal examination and an ultrasound scan of the ovaries. GCTs are slow growing tumours. Mares will often have one very large tumour affected ovary, and an opposite very small firm, inactive ovary.

Anovulatory follicles

At the beginning of the breeding season in early spring, there can be fluctuations in the hormone levels as the mare begins to cycle. This is called the ‘transitional period’ and can be a time when some mares show hormonal behaviour more strongly. During the transition period, there may not be enough hormones to allow the follicles in the mare’s ovaries to develop and so ovulation fails. These structures are called anovulatory follicles. Although they fail to ovulate, they may still release oestrogen thus causing prolonged ‘hormonal’ behaviour. Often a single intramuscular injection of prostaglandin will cause the anovulatory follicles to regress and resume normal cycling.

Oestrus suppression

Oestrus suppression treatments are given to a mare to try and stop her from cycling so she does not exhibit oestrus behaviour.

Altrenogest is a progesterone hormone that prevents the mare from cycling. The hormone is very effective for the time that it is administered but it is not licensed and is expensive for long term use. Once Altrenogest is no longer given, the mare will return to normal cycling and her irritable behaviour will most likely return. Altrenogest is banned in horses in training by the British Horse Racing Authority (BHA) but is currently allowed in mares competing under Federation Equestre Internationale (FEI) rules.

Oxytocin can be given by intramuscular injection twice daily 1-2 weeks after the mare has ovulated and has been shown to prevent mares cycling for up to 2 months. Oxytocin can be given to horses in training and is a ‘controlled medication’ under FEI rules.

Marbles have been placed in the mare’s uterus for many years to varying success. It is believed that its movement within the uterus had the same stimulus effect of the embryo during early stages of pregnancy. The most recent development in intrauterine devices is the iUpod. This consists of 3 shatter-proof, polymer coated magnets placed in the uterus 2 days after she ovulates. The device self-assembles into a ring and it has been noted to suppress cycling behaviour for up to 74 days.

Equine GnRH vaccines can be given to mares, consisting of an initial course of 2 vaccines administered 35 days apart. The mare then develops antibodies against the hormone GnRH which prevents her from cycling. Most mares cease cycling 4 weeks after the second vaccination. The length of suppression is variable between mares. There have been some reports suggesting that young mares administered with GnRH vaccines failed to cycle later in life and as such it is not advised that the vaccine be used in mares that will potentially breed. GnRH vaccines are prohibited in horses in training but are not currently controlled under FEI rules. It is advisable to begin the course before the mare begins cycling in Spring.

A more permanent option to oestrus suppression may be ovariectomy (removal of the ovaries). However if hormonal behaviour is ‘normal’ and not associated with a true medical problem then ovariectomy may not solve the problem. It is not only the ovaries that are responsible for oestrus behaviour and removing the ovaries may make the situation worse as oestrus behaviour may become more irregular post-surgery.

Herbal remedies

There are a variety of over-the-counter herbal supplements that are advertised for relieving hormonal behaviour in mares. There is little scientific evidence that such supplements work in horses. Most of the supplements contain chaste berry, camomile or St Johns wort, such herbal remedies are believed to help the mares relax. It is important to check the ingredients of herbal supplements in competition horses as some may contained FEI banned substances such as Valerenic acid.

Hormonal behaviour in mares should be approached in a sympathetic but methodical manner. Not all mares with hormonal behaviour will require treatment by a veterinary surgeon and may be managed at home with a change in workload around the time of oestrus. If you would like to discuss options available to your mare then please contact the clinic where we can discuss the best oestrus suppression technique that will suit your mare and her occupation. The overall aim is to help your mare to reduce her stress, anxiety and discomfort associated with her cycle, so that you and her can enjoy the spring and summer months throughout the year.

If you suspect that your mare may have a hormonal problem, please call us on 01904 788 840 to discuss your individual case with a veterinary surgeon and to discuss the best option for your mare.

This article was reviewed by Gemma Dransfield MA VetMB CertEP MRCVS

Spring 2023 Newsletter

In this edition you will find:

Our quarterly update – Changes to our office hours, new mobile weight scales, awards, special offers, and events to look forward to in 2023.

How to book us for your event – We can come out to your Pony Club or Riding Club event and give an educational talk.

Hat Hair Don’t Care – We’re promoting safety by wearing a hard hat when dealing with horses.

Equine dental health checks – Throughout March to May, we are creating awareness of the importance of equine dental health checks.

Tick bites – Symptoms, causes, diagnosis & treatment

Spring Equine Emergencies – Spring’s hidden dangers for your horse

Download the newsletter here:

Changes to our office opening hours

From Monday 3rd April 2023 our Poppleton branch opening hours will change. You can still speak to a member of our reception team by calling 01904 788 840 Monday – Friday 08.30 – 17.00; calls outside of these hours will go through to our out of hours service.

Our out of hours emergency service remains available 24 hours a day, 7 days a week, 365 days a year. Please contact us for further information.

Blog: Reducing the cost of your horse’s healthcare

With under a month to go until British Summer Time begins and the clocks go forward, we are all looking forward to more time spent with our horses and extra time for riding in the evenings. Some of us are already planning shows and events and setting goals for the season. However with the cost of living crisis, many of us that have previously competed over the summer are considering cutting back on the number of shows we attend.

With this in mind, this month’s blog is all about the ways in which we can save money by utilising preventative healthcare for our horses, so that we can prevent unexpected vet bills interrupting our season and maximise the time spent having fun with our horses over the summer months.

Preventative healthcare

Regular routine healthcare can save you money by preventing more serious disease from occuring in the first place. Many practices offer horse health plans so that you can spread the cost of routine preventative healthcare over the course of the year, making budgeting easier and reducing upfront cost.


The first thing to think about whether you are a competitive rider or not is vaccination for your horses. Vaccination for protection against Equine Influenza is mandatory in affiliated competition, but it’s not only competition horses that should be protected. Equine ‘flu is widespread within the UK, has a close to 100% infection rate in unvaccinated horses, and can spread up to 5km away. Signs are caused by an infection of the respiratory tract and typically include:

  • Dry, hacking cough
  • Nasal discharge
  • Fever
  • Lack of appetite
  • Lethargy

Treatment is often provided by supportive and nursing care, and horses usually need at least 6 weeks to recover. Treatment can be costly, especially if your horse develops secondary complications which can be serious.


Tetanus is caused by a bacteria found in soil, therefore can affect all horses. However it is not contagious and can’t be spread between horses – the bacteria enters the body via a wound and produces toxins that affect the horse’s nervous system and cause disease.

Signs of equine tetanus include:

  • Muscle stiffness and a ‘rocking horse’ stance
  • The jaw will not open hence the old term for Tetanus ‘lock-jaw’
  • Difficulty moving and eating
  • Hypersensitivity to noise
  • Protrusion of the third eyelid
  • Seizures

Treatment for Tetanus infection is often expensive and labour intensive. Without vaccination, most horses infected with Tetanus die despite all treatment and efforts to save them. Vaccination against Tetanus is very effective and all horses, ponies and donkeys should be vaccinated.


Strangles is a highly contagious disease caused by a bacteria called Streptococcus equi equi. Strangles is not spread through the air but can be easily spread by direct contact between horses when they cough or through the sharing of equipment. Signs of a Strangles infection include:

  • A high temperature, normally above 38.5°C
  • Lethargy
  • Loss of appetite, difficulty swallowing
  • Thick and discoloured nasal discharge
  • A lowered head and neck
  • A cough
  • Swelling of the glands under the jaw (lymph nodes)
  • Swelling of the jaw which may develop into abscesses that can burst with infectious yellow pus

The incubation period is normally between 3-14 days, which is why it’s important to isolate any horses as soon as they show signs of a high temperature and to stop the movement of horses and ponies on or off the yard while an outbreak is ongoing. This can help to stop the spread of infection to more horses. Some horses do not show typical signs, so it’s important to know what’s normal for your horse and regularly check their temperature.

Treatment is often provided by supportive and nursing care, and horses normally recover in 3-4 weeks, however horses should still be isolated for at least 6 weeks after symptoms have gone. The only way to tell if your horse is no longer infectious is by testing provided by your vet.

Good yard management and biosecurity is essential to help stop the spread of Strangles. There is a vaccine for Strangles available in the UK and this should be discussed with your vet to see if it would be appropriate for your horse. Strangles Awareness week commences on 1st May 2023 – you can get involved and help spread the word not the disease! Get involved in the campaign to be in with a chance to win some amazing prizes.

Routine dental check-ups

Dental disorders can be painful and cause suffering, as well as affecting the horse’s performance under saddle. More often than not there are no outward signs of a dental problem as horses are stoic creatures and are highly adapted to disguising oral discomfort. Recent studies have shown that up to 70% of horses were found to have an undiagnosed dental problem.

Prevention is always better than cure and as such owners are encouraged to have their horse’s mouths examined on a regular basis (every 6 – 12 months, depending on advice from your vet). Treatment is often simple and possible to carry out at the time of the exam. Thorough and regular examination is key to maintaining dental health and avoiding potentially more expensive, more serious problems in the future.


Many of us will be familiar with the outdated practice of giving dewormers at set times throughout the year. This has resulted in worms becoming resistant to the drugs used to treat infestations in our horses. This is why it’s important to test your horse’s worm burden before using a dewormer. There are no new deworming drugs and so we must preserve the ones we have available to prevent unnecessary suffering for our horses in the future.

targeted worming plan is essential for monitoring and treating worm burden in your horse in a sustainable way that preserves deworming drugs for when they are really needed. If your horse’s worm burden is not managed effectively, serious issues such as colic, weight loss and anaemia can occur, which can be fatal. Regular worm egg counts are much more cost-effective than regular use of unnecessary and potentially ineffective dewormers.

The first worm egg count of the season is usually done around March, so now is the time to collect a poo sample and send it in for analysis!

Preventing illness and injury

Illness and injuries can mean unwelcome and unexpected vet bills for horse owners. The best way to avoid this type of expense is to always follow good stable management practices to reduce the risk where possible.


One of the most common conditions to affect horses is colic. There are many ways in which you can prevent your horse from getting colic, and although not all cases are preventable, good healthcare and stable management is the most effective preventative measure. Risk factors that may increase your horse’s risk of colic include:

  • Dental problems
  • Worm burdens
  • Lack of good quality fibre in the diet
  • Lack of water
  • A sudden change in diet/feeding regime, e.g. turning out to lush summer pasture after the winter, or a sudden flush of new grass growth
  • External stressors such as a sudden change in routine or environment
  • Poor pasture management
  • Lack of turnout time
  • Inappropriate exercise for the horse’s level of fitness
  • To reduce your horse’s risk of colic, make sure you follow these golden rules:
  • Always provide a constant supply of clean, fresh water for your horse. If your horse has trouble drinking at competitions, there are many hydrating feeds and supplements available to encourage them to drink while away from home.
  • Provide a diet that is fibre based, consisting of good quality hay and grazing
  • If a concentrated feed is necessary for your horse, ensure that small quantities are fed frequently alongside a fibre based diet
  • Ensure that all hay and feed is of good quality, free from mould and other hazards that may have been picked up when baling
  • Turn your horse out as much as possible, but ration lush grass or new growth. Access to fresh grass should be treated in the same way you would a change of feed, introducing it gradually over a longer period of time.
  • Avoid grazing on overgrazed paddocks or sandy soil to reduce the risk of sand colic
  • Ensure your horse is fit enough for the work you ask them to do, and do not suddenly overexert them without proper training and conditioning beforehand. Make any changes to their exercise routine gradually.
  • Make sure your horse’s teeth are checked regularly to ensure that they are able to properly chew their food and avoid impaction colic.
  • Ensure you have a targeted worming programme in place to monitor your horse’s worm burden and treat them only if necessary.
  • Make any changes to their routine gradually.

Body condition

Making sure your horse has a good body condition score is extremely important for their health and the prevention of illness. There are many detrimental health conditions exacerbated by obesity, and it is something that is completely avoidable. Overweight horses are susceptible to:

It is important to understand how dangerous obesity is to our horses so that the appropriate effort is made to rectify this issue. If you’d like more information on equine obesity and how you can help your horse lose weight, see our blog on equine obesity or find out about our free equine weight management support programme.

Ground conditions and fitness

Making sure your horse is fit and conditioned for their intended workload means that injury is less likely to occur. Building up fitness over a number of weeks is the best way to achieve a fit and sound horse with the ability to do the task at hand with least risk of injury.

Consider the ground conditions when riding no matter what the time of year. Hard ground conditions can cause concussion to the horse’s limbs, bruised soles, splints and tendon injuries. Soft ground or deep going can increase the horse’s risk of tendon and ligament injury and muscle soreness while uneven ground or suddenly going from hard to soft or vice versa increases the probability of injury from a mis-step. It’s important to always be mindful of the ground conditions underfoot and adjust the horse’s workload accordingly to avoid a potentially costly injury and avoid a long period of recovery time. If you need help or advice on a fitness plan for your horse, contact us to speak with one of our experienced vets.


Having a good insurance policy that covers veterinary fees in place can really help to save you money should your horse become unexpectedly ill or injured. Having insurance in place means that your horse can have access to the best healthcare available and the best chance of recovery in the shortest possible time for that condition, and you are not left with a difficult decision to make about how much treatment your horse receives, or worried about how to pay for it. When you take out an insurance policy, it’s really important to read the small print about what your policy covers and for what scenarios. Some policies have an ‘excess’ payment that you’ll need to budget for before they pay out the full amount of the claim, and some will only cover a percentage of the total cost rather than the full amount. Check your individual policy in detail before commencing any treatment so that you are fully prepared for any costs involved in treating your horse.

Reducing the cost of healthcare

Some of the initiatives we offer at Minster Equine Vets include discounted ‘clinics’ and zone visits to save money on routine healthcare. We offer discounted gastroscopy clinics every month for all horses, no matter if they have been treated for gastric ulcers before or not, and Equine Performance Packages to monitor all of the essentials your horse needs to be prepared for success under saddle. Gastroscopy clinics and Performance packages offer a huge discount on the usual cost of these procedures, and take place at the Poppleton clinic, which means there will be no visit fee payable.

On zone visit days we undertake routine and preventative healthcare procedures that can be planned in advance. Having a set day where we visit your area and flexibility from you on the time of our arrival means that we can offer these visits for a heavily discounted visit fee of £25. Zone visits work really well for those with horses on our horse health plan – everything included on our standard horse health plan can be done on a zone visit.

This article was reviewed by Gemma Dransfield MA VetMB CertEP MRCVS Clinical Director and Veterinary Surgeon at the Minster Equine Veterinary Practice

Is your horse ready for the competition season?

Equine Performance Packages – just £150

Maintaining and monitoring your horse’s health and movement is crucial to a happy and harmonious ridden career, for both leisure and competition horses. Our new ‘Equine Performance Package’ aims to provide all of the essentials your horse needs to be prepared for success under saddle, in one convenient appointment at our Poppleton clinic.

You’ll have the option to leave your horse with us for the day while we undertake a clinical examination of the eyes, heart and lungs, an orthopaedic examination with gait analysis on the hard and soft lunge surfaces, teeth rasping under sedation using an oral video endoscope to take an in-depth, detailed look at your horse’s mouth and teeth, and a worm egg count with tapeworm saliva test to check for any internal parasites. Your horse will go home with a report on our findings and any recommendations, all for the special offer price of just £150.

In conjunction with the Equine Performance Packages, we will be offering optional extras aimed at perfecting your horse’s performance at a discounted price. You will be entitled to the following offers if the procedure is undertaken on the same day as the performance package:

10% off a flu / flu and tetanus vaccination £150 gastroscopy including sedation to look for gastric ulceration Haematology and Biochemistry blood sample for £105.38 £100 endoscopy including sedation to evaluate the upper airway

To book your horse in for our Equine Performance Package, please give us a call on 01904 788 840, or request an appointment. Please note that our special offers require a deposit of £50 upon booking and full payment will be required at the time of the appointment. We can offer stabling on-site at an additional charge if you would like to drop your horse off with us the night before and collect at a convenient time after the examination is complete – please contact us for further information.

Sarcoid laser clinic dates announced

Does your horse suffer from sarcoids or other skin tumours?

Laser surgery has many advantages over conventional surgery, and it’s use has been increasing over the past few years, particularly for the removal of sarcoids and other skin tumours such as melanoma. There are many advantages of laser surgery:

  • Minimizes the risk of spreading tumour cells during tumour removal
  • Less Bleeding: the laser seals small blood vessels during surgery
  • Less Swelling: decreased bleeding and no crushing of tissues decreases postoperative swelling
  • Many procedures can be done with standing sedation and therefore the horse does not require general anesthesia. This reduces the risk of complications as well as hospitalization time.
  • Precision: the laser can be controlled precisely to remove thin layers of tissue
  • Less Pain: the laser seals nerve endings as it cuts therefore, the patient experiences less pain
  • Sterilization: the laser sterilizes the surgical site (kills bacteria) as it cuts
  • Faster Recovery: a decreased amount of bleeding and swelling will result in faster healing of tissue. This will lead to a faster return to activity and use.

We are having a sarcoid removal laser surgery clinic from 13th – 17th March 2023 at the Poppleton clinic (YO26 6QF). The cost to have a sarcoid lasered during the clinic will be £400.00, to include the procedure and sedation. This price is for a small sarcoid or sarcoids localised in a single area.

If your horse has any lesions that you feel may benefit from laser surgery, please contact the clinic on 01904 788840, or email photos to to discuss suitability.

Blog: Equine Skin Conditions

During the winter months many of us will become familiar with the various skin conditions that horses can suffer from. The main issue at this time of year tends to be mud-fever, with many owners spending hours agonising over whether to wash legs, not wash legs, and which products to use to treat and prevent occurrence. In this article we discuss the most commonly seen skin-conditions in horses, signs and symptoms, and how to manage the conditions.

Mud fever (AKA Pastern dermatitis)

Mud fever is a non-contagious skin condition that causes scabs, heat and pain in the horse’s lower legs. It is often caused by opportunistic skin bacteria penetrating the breached skin barrier as a consequence of standing in muddy or wet conditions for long periods, standing in dirty bedding, regularly washing the legs without drying them afterwards or having a pre-existing broken or damaged skin due to a wound. Infection can develop underneath the scabs, and you may see swelling of the leg in severe cases. Further more serious complications such as cellulitis and lymphangitis can occur if it is left untreated. 

You can help prevent your horse getting mud fever by:

  • Avoiding leaving your horse standing in wet and muddy conditions for long periods of time
  • Rotating fields to reduce poaching and putting hardcore in places where horses gather
  • Avoiding washing your horse’s legs when you bring them in from the field and instead brushing the mud off when it is dry. 
  • Using barrier creams to create a protective layer between the skin and the mud.
  • Treating any underlying conditions such as mites, fungal infections or wounds.

If you think your horse is suffering from mud fever, it is important to contact your vet to get appropriate advice. In some rare cases horses can develop signs of mud fever despite their environment being clean and dry. These horses will need investigating by your vet.


Mites (Chorioptes equi) often affect feathered horses, causing itching, stamping and chewing of the legs. The damage to the skin can leave the skin open to infections such as mud fever and skin conditions like ‘mallenders and sallenders’, also known as hyperkeratosis. Hyperkeratosis can be identified as thick, scaly scabs on the back of the horse’s knees or the front of the hocks. The splitting and cracking of the skin of horses affected by hyperkeratosis is extremely painful and horses are often very reactive to touch. If you think that your horse may be suffering from mites or hyperkeratosis, please contact us for further advice and a treatment plan. There are several treatment options to eradicate the mites from the horse, and to prevent recurrence the horse’s environment and equipment should be disinfected. Once the mites are treated, it is important to keep the skin around the creases of the legs well moisturised to prevent dryness and painful cracking. 

Chronic Progressive Lymphedema (CPL)

CPL is a condition that primarily affects horses with heavy feathering on the legs, such as Shires, Clydesdales, Traditional cobs and other draft breeds. The disease is progressive, which means that it gets worse as the horse ages. CPL is a disease of the lymphatic system, which is responsible for protecting the horse from disease and infection, and allowing drainage of fluid from the body’s tissues into the blood. It is believed that the condition may be an inherited disease, with the condition causing excessive thickening of the skin on the lower limbs, ulceration and skin lesions.

The thickened skin and heavy feather is an ideal environment for Chorioptes equi mites, which often means that the first signs of CPL (thickening of the skin of the lower limbs) are not noticed until the legs are clipped to treat the mite infestation. In early stages, the condition may look similar to mud fever, however the treatment does not resolve the condition and as it progresses, swelling increases to form folds in the skin and firm nodules form.

There is no treatment for CPL, and careful management is required to minimise discomfort for the horse, including clipping feathers, regular exercise to improve lymphatic drainage, and prompt treatment of mite infestation and skin infections.

Sweet itch

Sweet itch as it is commonly known is caused by an allergy to the bites of midges. Horses will scratch themselves excessively, mostly around their manes and tails. You may see thickened skin, patches of rubbed out hair and bleeding in severe cases. We have already started to see the midges emerging this year and so now is the time to start planning preventative measures if your horse suffers from sweet itch.

The following measures may all be useful to prevent midges from biting:

  • Injections – there are injections available to help prevent and treat sweet itch (please contact the practice for further details – the course is best begun in February before the midges emerge)
  • Application of insect repellents and spraying stables with insecticides
  • Stabling especially around dawn and dusk
  • Installation of fans within stables (midges are very weak fliers)
  • Stabling/turn-out more than half a mile away from static water where midges breed
  • Stabling/turn-out away from woods, trees and high hedges where midges congregate
  • Stabling/turn-out in wind-swept, open locations

The use of fly hoods and body sheets are necessary in conjunction with these measures to have the best results.

If you think that your horse is suffering from a skin condition, we are here to help. Our experienced equine vets may be able to advise you on the best plan of action over the phone or you can book an appointment for your horse to be examined. We’re here for you every step of the way to help you keep your horse, sound, happy and healthy. 


This article was reviewed by Pol Abril-Casellas LV CertAVP(ESO) MRCVS on 17/01/2023

Blog: Poor Performance in horses

Poor performance in horses can often be interpreted as saddle fit, tack or bitting issues; however there is often an underlying health condition causing resistance or behavioural problems. Horses that are described as ‘fresh’ often exhibit behavioural signs of poor performance under saddle, including:

  • Resistance to the aids and contact, tense
  • Head tossing, tilting of the head
  • Reluctance to bend, hanging on one rein
  • Tail swishing or clamping, carrying the tail to one side
  • Bucking
  • Rearing
  • Spooking
  • A rushed gait, ‘motorbiking’ corners
  • Frequent changes of lead in canter, disunited canter or a ‘bunny hopping’ canter
  • Mouth opening and closing, tongue protruding from the mouth


It’s not only ‘fresh’ horses that suffer from performance related issues. Other signs that something could be amiss include:

  • Reluctance to move forward, or ‘laziness’
  • Toe dragging, not tracking up
  • Stumbling
  • Refusal to jump
  • Stiffness, reluctance to bend, hanging on one rein


Chronic musculoskeletal or orthopaedic problems are some of the most common reasons for poor performance. Underlying low-grade or bilateral lameness is often very difficult to detect, and so a vet’s input is needed here to pinpoint the issue, achieve a diagnosis, and create a treatment plan. Low grade, bilateral or compensatory lameness can cause muscle pain and issues with saddle fit, so it’s important that you, your vet, saddle fitter and physiotherapist work together as a team to get your horse performing at his best again.

Another common issue causing signs of poor performance that is often secondary to musculoskeletal or orthopaedic pain is gastric ulcers. The only way to diagnose gastric ulcers is by gastroscopy, a process where a 3m long endoscope is passed through the nasal passage, down the oesophagus to the stomach. The endoscope is used to visualise the stomach to look for ulceration or bleeding. The horse is sedated for this procedure, and it takes approximately 15 minutes to carry out. Treatment for equine gastric ulcer syndrome (EGUS) is often quick and effective, and with treatment of any underlying issues alongside management changes recurrence can be prevented.

Often mares are labelled as hormonal or difficult when they in fact have an underlying pain issue, which is why it is important to have her examined before assuming that hormones are the cause. At the beginning of the breeding season in early spring, there can be fluctuations in the hormone levels as she begins to cycle – this is called the ‘transitional period’ and this can be a time when some mares show hormonal behaviour more strongly. During the transitional period, there may not be enough hormones to allow the follicles in the mare’s ovaries to develop, and so ovulation fails. These structures are called ‘anovulatory follicles’ and although they fail to ovulate, they may still release oestrogen thus causing prolonged ‘hormonal’ behaviour. Often a single intramuscular injection of prostaglandin will cause the anovulatory follicles to regress and resume normal cycling.

It is important to remember that some causes of poor performance can be avoided by maintaining your horse’s preventative healthcare schedule. Dental problems can cause issues with rein contact, head tossing, tilting and mouth opening. However, horses are stoic animals and some horses will not show any outward signs of discomfort, therefore regular dental examinations are important to ensure any issues are treated promptly. We recommend dental checks every 6-12 months for the average horse; older horses or those with a previous history of dental disease may need more frequent checks.

Respiratory, cardiovascular and metabolic issues are other potential causes of reduced performance in horses. If you notice that your horse shows any of the signs listed above or displays a change in behaviour to what’s normal for them, then it is a good idea to investigate further.

If you think that your horse is suffering from poor performance or is showing behavioural signs of discomfort, we are here to help. Our experienced equine vets can advise you on the best plan of action over the phone or you can book an appointment for your horse to be examined. We’re here for you every step of the way to help you keep your horse, sound, happy and healthy.


This article was reviewed by Pol Abril-Casellas LV CertAVP(ESO) MRCVS on 09/01/2023

Minster Equine Achieves Investors in the Environment Award

We are delighted to announce that we have achieved Bronze accreditation following our recent audit with Investors in the Environment!

To become accredited, we had to measure and take steps to reduce our resource use (water, waste, electricity, paper and transport), as well as undertaking environmental projects. We achieved an ‘outstanding’ score for our Environmental Projects – these focused on Resource Efficiency, Biodiversity and Conservation, and Social Wellbeing and Community at the practice. To read more about the projects we worked on, take a look at our sustainability newsletter published in Spring 2022 here.

Look out for the next edition coming very soon with more updates and ideas for how you can reduce, re-use and recycle at your own yard.

You can find out more information on our sustainability efforts and the Investors in the Environment scheme on our sustainability page here.

Everyone in the practice team played a huge part in achieving Bronze accreditation, but did you know that you can also help? Our aim is to go paperless, so if you are a client of ours and able to receive your invoices and statements via email instead of post, please let us know!

Blog: Obesity in horses

The showing season is now well underway and I am very much looking forward to being part of the veterinary team at the Great Yorkshire Show with my long standing colleague Julian Rishworth MRCVS. The Great Yorkshire Show has been working with the Horse Trust for a number of years trying to raise awareness of obesity in showing and I offered to assist them by handing out rosettes to any horses in in-hand classes that had ideal body condition score 3/5. I have since passed this important role to my fellow Minster vet Katherine Hall MRCVS who will be again in the Ridings Ring and White Rose Ring next week presenting The Horse Trust Body Condition Award rosettes. It is commonly thought that horses should be fatter if they are used for showing than for other disciplines but the Great Yorkshire Show has always tried to lead the way in Equine Welfare and ensure that it remains paramount at their event by encouraging horses to be presented at their correct weight.

Obesity in horses is now considered to be one of the biggest welfare concerns in the UK and I feel it is our responsibility as vets to try to help owners learn about the health risks associated with weight gain and how it can be best managed at home. Rates of obesity are likely to be 30-50% in the general horse population and as high as 70% in native pony breeds. This silent illness is now so commonplace that it is seen by many as ‘normal’ despite the poor welfare implications.

In my opinion it requires a collective effort from vets, owners, feed companies, breed societies and showing societies to ensure that horses are fed the correct amount in the correct way relative to the amount of exercise they are getting. I believe owners try to do their best for their horses but as obesity remains so prevalent we must all change what we are all doing to try to overcome this important issue.

I would welcome feedback and discussion from owners to determine how vets can best help them to manage their horse’s weight without judgement. We have historically provided free events aiming to educate horse owners about obesity related topics, including laminitisCushing’s disease and Equine Metabolic Syndrome (EMS). We very rarely discuss the practicalities of owning horses of native breeds, some of which seem to have a genetic predisposition for weight gain. In such breeds it can be very difficult to maintain them at body condition score 3/5 without help from friends or vets. We don’t discuss other common problems associated with obesity often enough. These include:

  • Orthopaedic disease including arthritis or suspensory ligament desmitis due to the excess weight and force being placed on these structures.
  • Infertility and altered breeding cycles
  • Orthopaedic disease in foals born to obese mares
  • Poor performance including respiratory compromise
  • Susceptibility to certain types of colic due to increased internal body fat.


It is important to understand how dangerous obesity is to our horses so that the appropriate effort is made to rectify this issue. The following is a few simple tips that I advise owners on how to reduce weight in horses:

  • Do not excessively feed your horse. They should be fed relative to their body condition; if they are overweight feed less, if they are too slim feed more.
  • Horses should be fed a low calorie balancer to make sure that they are obtaining all protein, vitamins and minerals required for normal body function. This is particularly important when they are dieting and fed soaked hay.
  • An overweight horse should receive 1.5% of its body weight in hay in 24 hours. This is 7.5KG (16.5lbs) of hay within a 24 hours period for a 500kg horse.
  • Soak hay with warm water especially in winter as it is more efficient at reducing sugar content in hay.
  • Treats such as apples and carrots should be completely removed from the diet of an overweight horse.
  • In the spring/summer sugar accumulates in the grass during the day and is gradually reduced overnight. Sugar levels in grass are therefore lowest at the end of the night and early morning. Therefore it is best to graze overweight horses from late evening to early morning.
  • Strip grazing or grazing muzzles may be an alternative solution to reducing intake in your horse during summer.
  • Horses should not be rugged in winter. Many native breeds are genetically designed to live in harsh winter conditions.
  • Horses should ‘live out’ as much as possible during the winter and not be stabled.
  • A horse should be exercised to increase its heart rate for 30 minutes five times weekly; this can include lunging if you do not have time to ride. Alternatively 5 minutes walking either side of 15 minutes trot work may also be adequate. Exercise must always be done in association with diet restriction.
  • Measure your horse’s ‘belly girth’. This is the easiest and most accurate method of measuring weight loss after management changes have taken place.
  • If all the above do not work then there are medications available to help your horse lose weight, including metformin and levothyroxine. Both medications are ‘off label’ medications (meaning that they are not licensed for use in horses for weight loss), are expensive and are not a long term solution.


Fighting the fat is certainly a difficult but not impossible task. It is as a long term investment that cannot be done without a high level of effort from all of us to improve horse welfare. Tackling obesity at home requires a strict programme that is constantly monitored throughout the horse’s life. Tackling obesity on a greater scale requires horse owners and the showing industry to make a stand. The obese horse has been commonplace in showing for many years and this has misled competitors as to how a horse should look. It is difficult to change perception about obesity if we are accepting this as the norm and judges continue to place obese horses as winners. We should all remember that the social licence we hold for using horses in sport and leisure should not be taken for granted. It remains our collective responsibility to help protect horse welfare so that we can continue to enjoy working with them, in whatever form, for many more years to come.

Written by Gemma Dransfield MA VetMB CertEP MRCVS, Clinical Director and Veterinary Surgeon at The Minster Equine Veterinary Practice.


Furtado T, Perkins E, Pinchbeck G, McGowan C, Watkins F, Christley R. Exploring horse owners’ understanding of obese body condition and weight management in UK leisure horses. Equine Vet J. 2020;00:1– 11

Rendle D, McGregor A, Bowen M, Carslake H, German A, Harris P, Knowles E, Menzies-Gow N, Morgan R. Equine Obesity Current Perspective Roundtable. UK-Vet Equine 2018; 2 (suppl 5).