1 Oct
Rosina Lillywhite
Job Title
Equine obesity is increasingly recognised as a significant welfare issue, with detrimental impacts on the health and longevity of horses and ponies.
Research indicates that up to 53% of horses in the UK are classified as overweight or obese, with even higher prevalence in some native breeds (varying ranges have been identified in different areas of the country and different horse populations; Furtado et al, 2020; Rendle et al, 2018; Akinniyi et al, 2023).
This article explores the critical role that REVNs can play in combating this pervasive issue, focusing on education, nutritional management, exercise planning and behavioural interventions.
Obesity in horses is not merely a cosmetic issue; it poses severe health risks that can lead to a variety of life-threatening conditions.
Obesity is a major risk factor for laminitis – a painful and potentially debilitating condition characterised by the inflammation of the laminae in the hoof.
Overweight horses are significantly more likely to develop laminitis due to insulin dysregulation and the increased mechanical stress on their limbs. Insulin dysregulation – commonly associated with obesity – disrupts glucose metabolism and is a key trigger for laminitis (Akinniyi et al, 2023; Furtado et al, 2020).
Research from the RVC has highlighted that weight gain in horses and ponies more than doubles the risk of developing laminitis, with the odds increasing dramatically as a horse’s body condition worsens. This underscores the importance of managing weight to prevent this serious condition, which can lead to long-term lameness or even necessitate euthanasia in severe cases (RVC, 2023). Therefore, managing obesity is crucial in preventing laminitis, and RVNs play an essential role by promoting awareness and preventive strategies (Avonvale Equine Vets, 2023; BEVA, 2023).
Equine metabolic syndrome (EMS) is analogous to type 2 diabetes in humans and is commonly seen in overweight horses.
EMS is characterised by insulin resistance, hyperinsulinaemia and an increased risk of laminitis. The condition is exacerbated by excessive adipose tissue, which produces hormones that impair insulin action. RVNs can assist in identifying at-risk horses and guide management strategies that include dietary and exercise adjustments to mitigate this risk (Akinniyi et al, 2023; Rendle et al, 2018).
The additional weight carried by obese horses places increased strain on their joints, leading to accelerated wear and tear, and increasing the risk of arthritis. This condition can cause chronic pain and reduced mobility, significantly impacting the horse’s quality of life.
RVNs are crucial in advising on weight management strategies that alleviate joint stress and slow the progression of arthritis (Furtado et al, 2020; BEVA, 2023).
Obesity also has serious implications for a horse’s cardiovascular and respiratory systems. The excess body mass requires the heart to work harder to pump blood – especially during physical exertion, increasing the risk of heart disease and respiratory problems. RVNs can help design safe exercise programmes to improve cardiovascular health while avoiding excessive strain on the horse (Akinniyi et al, 2023; Rendle et al, 2018).
Figure 1. Kentucky Equine Research’s version of the Henneke system.
REVNs are ideally positioned to take a proactive role in managing and preventing obesity in horses, contributing across several key areas.
REVNs are at the forefront of equine health education, playing a pivotal role in educating horse owners about the risks of obesity and the importance of maintaining an optimal body condition.
Body condition scoring (BCS) is a valuable tool that RVNs can use to help owners assess their horse’s weight status. BCS involves evaluating the horse’s fat deposits in specific areas and is essential for detecting obesity early (Akinniyi et al, 2023; Rendle et al, 2018).
Beyond simple awareness, RVNs can also educate owners on recognising early signs of obesity-related conditions such as EMS and laminitis. Early detection and intervention are crucial for effective management and prevention of these conditions (Furtado et al, 2020; Goldberg, 2017).
BCS is a critical tool REVNs and veterinarians can use to assess the fat deposits on a horse’s body – essential for managing weight and detecting obesity or malnutrition. Several different BCS systems have been developed – each with specific applications depending on the context and the specific characteristics of the horse being evaluated.
● The Henneke BCS system: a widely used system developed by Don Henneke (1983), it is a nine-point scale, where horses are scored from one (emaciated) to nine (obese) based on the amount of fat cover over six key areas of the horse’s body: neck, withers, shoulder, ribs, loin and tailhead.
■ Application:
Figure 1 shows Kentucky Equine Research’s version of the Henneke system. As an REVN, this system is useful for identifying early signs of obesity. As more points are evaluated, it can also be easier for clients to see subtle improvements and help them engage with a weight loss programme.
● Carroll and Huntington BCS system: this is a five-point system where horses are scored from zero (very poor) to five (very fat). The scoring is based on three specific body areas: the ribs and back, neck and pelvis. The overall score is an average of the scores for these areas, with the pelvis score being adjusted if it differs significantly from the other scores.
■ Application:
Panel 1 shows the British Horse Society (BHS) interpretation of this BCS. This system can be useful for use with owners as it is more simplified and can help with owners who are less aware of the horse’s anatomy.
Score and points associated with the score
0 – Very unhealthy (emaciated)
1 – Unhealthy (thin)
2 – Moderate (lean)
3 – Healthy (good)
4 – Unhealthy (fat)
5 – Very unhealthy (obese)
Information sourced from www.bhs.org.uk/horse-care-and-welfare/health-care-management/horse-health/fat-scoring
● Cresty neck scoring: the cresty neck scoring (CNS) system specifically evaluates the fat deposition along the horse’s neck on a scale from zero (no visible crest) to five (very large crest that can droop to one side). This system was developed to assess the regional adiposity often linked to metabolic disorders such as EMS.
■ Application:
Panel 2 is adapted from the BHS’ version of the CNS, and this can be helpful as a visual aid to owners – especially those with horses that are not scoring highly in the overall BCS systems, but have large fat deposits on the neck.
Panel 2. Cresty neck scoring
Zero
The crest can’t be seen or felt.
One
The crest can’t be seen, but a small amount of fat can be felt.
Two
The crest can be seen, but the fat is spread evenly from the poll to the withers. The crest can be held easily in one hand and is flexible and easy to bend from side to side.
Three
The crest is thick with a larger amount of fat in the centre of the neck than in the poll or withers. The crest fills one hand and is not so easy to bend from side to side.
Four
The crest is large and thickened with hard fat, and can’t be held with one hand or bent easily from side to side. The crest may have creases along the top.
Five
The crest is extremely large and droops to one side.
Information sourced from the British Horse Society.
● Morphometric measurements: morphometric measurements involve taking specific measurements of the horse’s body – such as neck circumference, body mass index and girth – to estimate body fat content. These measurements are often used with other BCS systems to provide a more objective assessment.
■ Application:
Each of these BCS systems has its strengths and specific applications, making them valuable tools for RVNs in managing equine obesity.
By selecting the appropriate BCS method based on the context and specific needs of the horse, REVNs can provide more accurate assessments and tailor their interventions more effectively, thereby improving the overall health and welfare of the horses under their care.
Managing equine obesity requires a multifaceted approach to nutrition. The goal is not just to reduce caloric intake, but to ensure that the horse’s diet remains balanced and nutritionally complete.
This process involves several key steps, and REVNs play a critical role in developing and implementing dietary plans tailored to each horse’s specific needs.
The first step in managing equine obesity through nutrition is reducing overall caloric intake. However, simply cutting calories is insufficient; the diet must still meet the horse’s essential nutritional needs to maintain overall health.
● Hay selection: REVNs should recommend high-fibre, low-calorie forage, such as hay with a low non-structural carbohydrate (NSC) content. Hay is the staple of most equine diets, and selecting the appropriate type is crucial for controlling calorie intake. Ideally, the NSC content of the hay should be below 10% to help manage weight and prevent conditions such as laminitis – especially in horses prone to EMS (Rendle et al, 2018; Akinniyi et al, 2023).
● Soaking hay: in cases where low-NSC hay is unavailable, soaking hay in water for about an hour can help reduce its sugar content, making it safer for horses requiring strict calorie control. However, the effectiveness of this method can vary depending on the hay’s composition (Akinniyi et al, 2023), so it should not be 100% relied on to reduce calories.
● Feeding amounts: RVNs should calculate the appropriate amount of forage to feed, typically recommending 1.5% of the horse’s ideal bodyweight per day in dry matter. This amount can be adjusted based on the horse’s weight loss progress and specific health needs. It is essential to use a scale to measure hay accurately, as underfeeding can lead to health issues such as hyperlipaemia, while overfeeding can prevent weight loss (Akinniyi et al, 2023).
● Grazing management: to further control caloric intake, RVNs may recommend limiting access to pasture or using grazing muzzles, which can reduce grass intake by about 80%. Controlled grazing periods – especially when the grass is less nutrient-dense – can help manage weight without completely restricting access to pasture, which is important for the horse’s mental well-being (Goldberg, 2017; Rendle et al, 2018).
● Eliminating high-calorie feeds: horses with obesity or EMS often do not need the extra calories provided by grain-based concentrates. RVNs should advise against feeding high-calorie concentrates and instead focus on delivering a forage-based diet supplemented with vitamins and minerals to prevent deficiencies (Akinniyi et al, 2023).
● Low-NSC feeds: low-NSC feeds specifically designed for horses with metabolic issues should be selected for horses requiring additional supplementation. These feeds provide necessary nutrients without the high levels of sugar and starch that can exacerbate insulin resistance (Rendle et al, 2018).
Controlling the glycaemic index (GI) of horses’ diets is particularly important for horses with equine metabolic syndrome (EMS).
The GI measures how quickly foods raise blood sugar levels, with high-GI foods causing rapid spikes in glucose and insulin, which can be dangerous for horses with EMS.
● Forage: as mentioned, choosing hay with a low NSC content is crucial. For EMS horses, even the type of pasture can make a difference; certain grasses have higher sugar content – especially during spring and autumn – and should be avoided or managed carefully (Rendle et al, 2018).
● Avoiding high-GI grains: RVNs should recommend avoiding grains and other high-GI feeds. Instead, feeds formulated specifically for insulin-sensitive horses – which are high in fibre and low in starch and sugar – should be used. These feeds are designed to provide the necessary nutrients without causing harmful spikes in blood sugar (Goldberg, 2017).
● Regular assessments: RVNs should regularly monitor the horse’s body condition and blood parameters to ensure that the dietary changes are effective. This includes measuring insulin and glucose levels, which can help determine if the diet is appropriately managing the horse’s metabolic condition (Akinniyi et al, 2023).
● Adjusting based on seasonal changes: because the sugar content in grass can vary with the season, RVNs should be vigilant in adjusting the horse’s diet accordingly. For example, during periods of rapid grass growth, it might be necessary to restrict grazing or increase the time hay is soaked to mitigate the higher sugar content in the forage (Rendle et al, 2018).
Image © Alexia Khruscheva / Adobe Stock
Effective nutritional management of equine obesity – particularly in horses with complex metabolic issues such as EMS – often requires a team approach. RVNs should collaborate closely with vets and possibly equine nutritionists to develop and implement safe and effective dietary plans.
● Veterinarian input: vets can provide critical insights into the horse’s overall health, including any underlying conditions that may influence dietary needs. For example, if a horse has concurrent liver or kidney disease, the diet may need to be adjusted to avoid exacerbating these conditions while promoting weight loss (Rendle et al, 2018).
● Nutritionist expertise: equine nutritionists can help ensure the diet is balanced and meets all of the horse’s nutritional requirements while controlling calories and managing the glycaemic index. They can also assist in selecting the best types of forage and supplements, and in developing strategies to overcome challenges such as weight loss resistance (Akinniyi et al, 2023).
● Regular check-ins: collaboration should not end with creating the diet plan. Regular check-ins among the REVN, veterinarian and nutritionist are crucial to assess the horse’s progress, and make necessary adjustments. This might involve re-evaluating the horse’s condition, testing for insulin sensitivity or making seasonal changes to the diet (Rendle et al, 2018).
● Education and owner support: the team should work together to educate the horse’s owner about the importance of adhering to the diet and exercise plan. This includes guiding how to implement the plan at home, recognising signs of potential issues, and understanding the long-term benefits of proper nutrition (Goldberg, 2017).
Regular physical activity is essential for weight management, but exercise regimens must be tailored to the horse’s condition. For overweight horses, REVNs can design low-impact exercise plans that gradually increase in intensity as the horse becomes fitter. For severe cases, rehabilitation modalities such as manual therapies and electrotherapy can be incorporated to safely promote weight loss, and improve overall fitness (Akinniyi et al, 2023; Furtado et al, 2020).
Exercise not only aids in weight loss, but also improves insulin sensitivity, which is crucial for managing EMS. REVNs can recommend specific exercises, such as controlled grazing and riding, to balance physical exertion and safety – particularly for horses recovering from laminitis (BEVA, 2023; Goldberg, 2017).
Successful weight management often requires changes in both the horse’s environment and the owner’s behaviour. REVNs can implement behavioural change strategies, such as regular follow-ups, progress tracking and motivational tools. For example, the traffic light sticker system can prompt conversations about weight management and encourage owners to take action (Rendle et al, 2018).
Behavioural change science, successfully applied in human health care, can be adapted to equine care. REVNs can use this approach to understand owners’ psychological barriers when managing their horse’s weight and develop interventions that address these challenges (Mair, 2020).
Continuous monitoring is essential for managing equine obesity. REVNs should establish weight monitoring clinics where horses can be regularly weighed and their body condition assessed. These clinics provide a structured environment for tracking progress and making necessary adjustments to diet and exercise plans. Regular check-ins offer RVNs an opportunity to provide ongoing support and encouragement, helping to maintain owner commitment to weight management strategies (Akinniyi et al, 2023; Furtado et al, 2020).
The use of digital tools and online resources can further enhance the support provided. By offering access to educational materials, forums for owner support and tools for tracking progress, RVNs can ensure that owners are well-equipped to manage their horse’s weight effectively. These resources can be particularly valuable for owners who may not have easy access to veterinary services or who need additional guidance between visits (Avonvale Equine Vets, 2023; Goldberg, 2017).
REVNs play a critical role in managing and preventing equine obesity. Through education, nutritional guidance, exercise planning and behavioural interventions, they help reduce the prevalence of obesity and improve the overall health and welfare of horses.
As equine obesity becomes an increasingly widespread issue, the expertise and proactive involvement of REVNs are more crucial than ever in ensuring the well-being of horses.
