featured article - EQUINE GRASS SICKNESS
With it being spring we are now entering the high risk season for Equine Grass Sickness (EGS). EGS is a debilitating and often fatal disease affecting horses, ponies and donkeys, with a mortality rate in excess of 85%.
EGS was first described in eastern Scotland in the early 1900s, and Britain continues to have the highest incidence of EGS worldwide, affecting over 3% of the equine population in some areas.
Despite more than 100 years of research, the cause has not been definitively determined. However, research is currently underway into a vaccine which may provide a way to protect horses and ponies from this devastating disease in the future.
To read more about EGS, Click here.
Image courtesy of Dr Scott Pirie, University of Edinburgh.
Leading equestrian organisations are appealing to all horse owners and keepers in the UK to stand up for horse health between 18 – 25 May 2015 and participate in the National Equine health Survey (NEHS). It's a short, sharp snapshot survey of general horse health that is already helping to make an important difference to the future health and welfare of horses and ponies. To read more about the NEHS, click here.
There is a type of laminitis, known as ‘supporting limb laminitis’ which occurs after a period of prolonged weight- bearing in the limb, typically following a severe lameness of the opposite leg. This type of laminitis is thought to have a different pathogenesis to laminitis identified secondary to endocrinopathic disorders (such as pituitary pars intermedia dysfunction AKA Equine Cushing’s Disease or Equine Metabolic Syndrome), or inflammatory diseases (such as colic, diarrhoea or retention of the placenta following foaling). It is possible that supporting limb laminitis occurs when the lamellae fail to receive an adequate arterial blood supply in combination with constant loading of the deep digital flexor tendon which pulls at the back of the pedal bone, leading to separation from the hoof wall.
Whilst vets are aware that this could be a complication following severe limb lameness in one leg, there have been no studies in Great Britain to describe how common a problem this may be. Two members of the Care about Laminitis team – Claire Wylie, Margaret Giffen Resident in Equine Clinical Research at Rossdales Equine Hospital, and Richard Newton, Head of Epidemiology at the Animal Health Trust, worked with two of the equine surgeons, Richard Payne and Andy Bathe, at Rossdales Equine Hospital to investigate this problem. To read more about their findings, please click here.
The negative impact of being overweight is well recognised in humans, and obesity leads to chronic health conditions such as arthritis and diabetes (linked to insulin resistance). Obesity is an increasing problem in companion animals such as dogs, cats and horses, causing similar health problems, and develops for roughly the same reasons as in humans - a sedentary or inactive lifestyle combined with excessive food intake. While humans are mostly in charge of their own diets, animals are reliant on their owners to provide them with appropriate rations for their size, breed, age and levels of activity.
To read about equine studies on obesity in the UK, please click here.
CARE OF THE ELDERLY HORSE OR PONY
The life expectancy of horses and ponies is increasing and those aged 15 years or older represent between 25 – 29% of the UK equine population. Improvements in veterinary care, nutrition, dental care and wormers within the last century are likely to have contributed to the apparent increase in equine life expectancy. In the past, equine lifespans were limited by the requirement of most horses to have continued athletic or reproductive ability. However, these days many older horses and ponies are kept as companion animals, and while it is common for the level of exercise to decrease as they get older, the majority of veterans are still involved in some form of ridden exercise. In fact, between 10 – 26% of older horses, from age 15 onwards, are used for competition.
When assessing health and disease in older horses, it is important to recognise and distinguish between signs of normal ageing, physiological changes with age which may predispose to disease and clinical signs of disease associated with ageing.
This is not necessarily straightforward, as factors influencing the rate of development of both normal ageing and chronic diseases are often identical. Dr Jo Ireland (epidemiologist and Equine Grass Sickness research co-ordinator) of the Animal Health Trust tells us more about caring for the elderly horse or pony.
Click here to read more.
EQUINE ATYPICAL MYOPATHY
With it being autumn, we are now in the high risk season for this disease. Veterinary practices across the country are reporting cases, with unfortunately the majority being fatal. It is a disease that has been linked with the ingestion of seeds from the Maple tree family (sycamores and Box Elders) and preventing animals from eating the seeds at this time of year plays a large part in reducing the incidence of the disease. Therefore sharing what we currently know about this condition is very important.
Equine Atypical Myopathy is an acute, severe disease occurring in grazing horses, which results from rapid and extensive breakdown of skeletal muscles (“myopathy” is the term used to describe any disease affecting skeletal muscle). A frequently fatal myopathy of grazing horses has been reported sporadically in various parts of the world throughout the 20th century and was first recognised as a specific disease syndrome, “atypical myopathy”, in 1984 during an outbreak in horses in Scotland. In the past two decades, several outbreaks of atypical myopathy have been reported in Europe, and in the autumn of 2010 an outbreak involving several cases was reported in south-west England.
Sonia Gonzalez-Medina (veterinary surgeon at the Centre for Preventive Medicine) and Dr Jo Ireland (epidemiologist and Equine Grass Sickness research co-ordinator) of the Animal Health Trust discuss what we currently know about the disease. Click here to read more.
HOW TO MONITOR MY HORSE/PONY'S WEIGHT?
It is accepted that horses and ponies have evolved to undergo seasonal changes in their metabolism, gaining weight to build up reserves and fat stores during seasons of grass and forage abundance, which will be used to sustain them through periods when food is not readily available. Therefore seasonal fluctuations in weight are believed to be completely natural with variations between breeds.
However, as owners of domesticated equines in Britain, we often automatically increase feed and forage rations over winter (coupled with other energy conserving practices such as rugging, stabling, reduced exercise due to inclement weather), allowing those animals prone to weight gain to carry excess weight into the following spring, that is then exacerbated by the flush of spring grass. It is these extended and unnatural periods of excessive weight and subsequent weight gain that are so detrimental to our animal’s health. This has a knock-on effect on body-wide metabolism and is a risk factor for development of endocrine disorders and laminitis. For example, insulin resistance is a result of an accumulating loss of resistance to insulin over time – which means that the body produces increasing levels of the hormone to try to overcome this resistance and get the tissues to respond, further increasing the risk of health problems.
Can we differentiate between what a healthy weight for our equine is and what would be classed as overweight, or even obese…? For example, what may be considered as ‘good’ condition for a showing class may in fact be an overweight body condition. Unfortunately – due to the huge diversity of horse and pony breeds and sizes – there is no general Body Mass Index (BMI) available across all horse breeds as there is for humans. However, even the human BMI becomes unreliable at certain extremes (such as very fit, heavily muscled athletes being considered overweight based on BMI because muscle is denser than fat).
Recognising how to balance rations, so that our animals do not become overweight or underweight, may not always be an easy task but estimating weight is a good place to start! While being underweight is not healthy either, obesity has been identified as an existing problem in pleasure ridden and non-ridden animals and will be the main focus behind learning how to monitor the weight of our horse or pony. If you are interested in recent advances in equine obesity-related research, please visit the Equine Research page.
Part 1: How to estimate weight. Click here to read more.
Part 2: How to estimate body condition score (BCS) and cresty neck score (CNS). Click here to read more.