A Horse of a Different Hue, May 2022 – Part 3.1: Potential for Epigenetic Changes in the UK Suffolk Horse

Introduction

In reviewing the material for Part 3, it  became clear that there is an ever increasing range of information relating to the potential for epigenetic changes in the Suffolk Horse.   To reduce it down to a series of bullet points was to obscure the importance of this research based material.  For this reason,  Part 3 –  Potential for Epigenetic Change is now  divided in two:  Part 3.1 and Part 3.2

Nevertheless, despite attempts to prune the content, both Parts remain long.   

Throughout Parts 3.1 and 3.2 of A Horse of a Different Hue,  a series of Tables are used with Categories summarising effects of the use, husbandry, feeding, health/ill health, environmental factors,  and breeding.  These are areas which have implications for epigenetic mutations.  Each category is discussed – some more than others.

This icon indicates Further Reading for those readers who prefer to delve somewhat deeper for more information.

To review the earlier parts of this series of articles with the title A Horse of A Different Hue, please follow the links:  

Part 1: suffolkpunchaustralia.com/thirteen-articles-on-the-status-of-the-suffolk-horse/a-horse-of-a-different-hue-the-suffolk-horse-1880-2022-part-1-march-2022/

Part 2 – Epigenetics  explored  the concept of Nature + Nurture throughout life via the ‘switching’ on or off of genes –  without changing the DNA.  What we do with our horses results in consequences which may, or may not,  be of benefit to the overall health and wellbeing of the horse.       If breeding the horse,  for both stallion or mare, this has potential for epigenetic changes in subsequent progeny including transgenerational changes.   Use and Husbandry have a greater impact  in determining the subsequent  ongoing health (together with breeding success) in  Mare, Stallion and their Progeny.

Part 2: suffolkpunchaustralia.com/a-horse-of-a-different-hue-the-suffolk-horse-1880-2022-part-2-epigenetics/ 

Differences between 2022 – NOW, and  1922 – THEN  

When comparing several categories of influences on the Suffolk Horse, between 2022   and 1922, there  is  the possibility that  the different way of life, for both humans and horses, may have ameliorated or slowed epigenetic mutations/moderations 100 years ago.  Going back further to the breeding, husbandry and useage decisions made from the time of Crisp’s Horse of Ufford, it becomes evident  that epigentic mutations as well as genetic mutations played equal roles in what became the Phenotype of the  Suffolk Horse of 1922.

It was certainly a different world to what we have today.

Population and a few other statistics

At 25 June 2021 the combined human population of England and Wales was estimated to be 59,720,000 – an increase of 21,562,000 from just over 100 years ago.        (Office of National Statics, UK)

In 1922, the population of England  and Wales totalled  38,158,000 for males and females.                                                                 (UK Parliament  Hansard Commons: 28 July 1927, Written Answers Agriculture).

One hundred years ago, East Anglia was the heartland of the Suffolk Horse.   Apart from the larger towns, it might best described as a predominantly  rural environment, small villages and hamlets, with many farms and farmland.  The larger cities and towns had smaller populations.   Norwich in 1921 had a population of 120,700 (202,150  est. for 2022) , Ipswich 79,371, (633,000, 2020)  Felixstowe 11,677 (c. 29,000, 2020).  Colchester, just across the border from Suffolk is in Essex.    Population in 1921 was 43,393  and the estimated mid-year population in 2020 was 197,200.

The Suffolk Horse in 1922

The Suffolk Horse was still a major source of agricultural power, despite the presence of mechanical power in the cities and towns gradually increasing.     Fred Smith, steady on the reins and ever optimistic, reported in Volume 26 of The Suffolk Horse Stud Book:

“The number of entries recording in the present volume amount of 684 consisting of 102 Horse and 583 Mares as compared with 156 Horses and 568 Mares in the previous volume (725 total for 1921).   It will be seen that whilst the Mares show a slight increase in the number of entries made for the past year, the Horses have fallen by no less than 35% when compared with the previous volume  and transfers number 50 less.

“This at first sight might appear retrograde to the best interests of the breed but, in reality it is an encouraging feature indication the healthy and promising condition of the Suffolk for the horse trade of the future.

“… … … previous to the War we were exporting to our colonies and to foreign countries no less than one-third  of the Stallions  annually registered;  at the present time the export trade is practically at a standstill.   Breeders are realizing that although there is a substantial demand for Stallions at home compared with pre-war days, yet there is nothing like the outlook  for sires which it had been customary to cater for and to expect.

“Therefore breeders have turned their attention to the fast increasing demand  for the Suffolk Gelding.

“The motor and mechanically driven vehicles have for a time depressed the trade for town houses, both of the heavy and the light type.    It is a question, however, when running cost and depreciation are taken into account, if this will long continue;  in fact there are noticeable signs already that the call for horses will in a few years time be greater than the supply, and many firms admit after the experience of the last few years that the horse is the cheapest mode of transport for short journeys. ¹

“Numerous farmers of all the country over and in the midland countries in particular have been in the habit of augmenting their receipts from the farm by selling geldings for town work.   In catering for business of this description it must naturally follow that there are a number of misfits- animals that are particularly unsaleable.  None perhaps but those who have experience are aware of the motley crew of horses, which, to the great detriment of the holding, can be be left to carry on the  agricultural work after the selection of heavy draught horses for Town work has been practised for a few years. 

“With the depressed state of the market for the city horses farmers are asking themselves why they should be troubled with these undesirables – why should they not have a clean-legged horse of happy constitution that requires little aid from the veterinary or the physic experimenting horse keeper.    This is certainly in the back of the minds of many followers of the agricultural calling and consequently the demand for the ‘par excellence’ agricultural horse has been pronounced.  

“At the same time it must be borne in mind that the slump in horses suitable for Town work did not materially affect the Suffolks, as before the War the breeders were exporting in comparatively large numbers the horse colts annually bred as Stallions for crossing purposes in other countries.   The position of the Suffolk Horse breeders at the present time is therefore perfectly sound and when the Export trade does commence again, as it most certainly will ², there will no long string of stallions to draw on but a few first-class animals which will command remunerative prices.”

Preface to  The Suffolk Stud-Book, Vol.26,  1922 pp.v & vi :                                                                                                                      Bold & Italics added by  suffolkpunchaustralia.com

Notes:  

1. Fred Smith was somewhat prescient in his predictions of the town dray horse being better value than the then mechanised vehicles as the 1920s was a time of economic instability,  with the Great Depression arriving in 1929.   In the revival period of the 1960s and ’70s there was also a campaign to reintroduce dray horses into towns and some cities, as cheaper for short ‘stop and start’ deliveries.    There was an initial  hopeful increase, which did not last.

2. The Export Trade in Suffolk Horses did regenerate, with exports to Canada, the USA, South America, South Africa, throughout the 1930s right up to the outbreak of WW2 in September 1939.

Changing times for the wider world, but not so much for the Suffolk Horse

Three years later, in 1926, Raymond Keer was Secretary and Editor of the Suffolk Stud-Book.    He details in the Preface of Volume 29:

“The great decline in horse breeding, according to the Official statistics and report published by the Mistry of Agriculture for the year  1924-1925, does not to any great extent apply to the Suffolk Horse.   The Ministry states that during the past four years horse-breeding has been reduced by 50%, but if the numbers (given below) of animals entered in the Suffolk Stud Books for the four years in question be studied it will be found that the drop in the case of the Suffolk Horses entered is approximately only 6%, which fact proves and justifies the great confidence placed in the Breed by Members of the Society even in these difficult times.”

NB:  for the four years 1922-1925 total Mares registered total 2250, with  total Horses registered  380.  Unlike 2022 when all foals born and viable are registered, even if they are later gelded,  Geldings in 1922 were  not registered per se.    If it is  assumed that there would be a equal gender ratio at birth, then using the total number of registered Mares for the years 1922-1925 of 2250, and subtracting the number of total registered Horses for those same four years, then there is a possibility that gelding numbers for the same period might total 1870 animals.  It is not surprising that Fred Smith in 1922 was looking for more diverse markets for the Suffolk geldings.

In 1922, heavy horses were still required for the agricultural crops and grass (hay) for the farms of East Anglia, and would be still until post WW2.     None the less, change was happening, albeit much slower in the rural areas.    

Then

“A 1923 census of traffic by the UK’s Department of Transport showed there were more bicycles on the road than any other vehicle. Within just a few years the situation was much different.

“In 1923 there were 383,525 cars on the roads of Great Britain. By 1930 the number topped a million. Within another eight years another million cars were added to the roads.

Now

“At the end of June 2021, there were 39.2 million licensed vehicles in Great Britain.” 

All three  quotes  above are from the website:   https://roadswerenotbuiltforcars.com/critical-mass-1923/

2022 – Standards for the Care and Protection of all Equines

Most owners and breeders are aware and as far as they are able, practice the Five Freedoms for Horses.  Many countries worldwide have signed up to these principles.  

Whilst reading the material in this article, keep these definitions and the delineated principles  in mind. 

In the UK:

“The Animal Welfare Act 2006 (“the Act”) requires you to ensure that any horse, pony, donkey or mule for which you are responsible, whether on a permanent or  a temporary basis:

Five Freedoms for Horses:

1. 1. 1. 1. has a suitable environment to live in;
         2. has a healthy diet (including fresh clean water);
         3. is able to behave normally;
         4. has appropriate company; and
         5. is protected from pain, suffering, injury and disease.”

First formulated in the 1960s,The Department for Environment, Food & Rural Affairs has published a 38 page booklet that amplifies the Five Freedoms in detailed,  clear and unambiguous language.  (See: http://horses-welfare-codes-of-practice-april2018.pdf)

Wikipedia gives a slightly more defined version, based on the Farm Animal Welfare Council/Farm Animal Welfare Committee. (See: https://en.wikipedia.org/wiki/Five_freedoms)

1. 1. 1. 1. Freedom from hunger or thirst by ready access to fresh water and a diet to maintain full health and vigour
         2. Freedom from discomfort by providing an appropriate environment including shelter and a comfortable resting area
         3. Freedom from pain, injury or disease by prevention or rapid diagnosis and treatment
         4. Freedom to express (most) normal behaviour by providing sufficient space, proper facilities and company of the animal’s own kind
         5. Freedom from fear and distress by ensuring conditions and treatment which avoid mental suffering.                                   (Emphasis with use of italics added by suffolkpunchaustralia.com)

Elsewhere in Europe

The 2015 EU publication Equine Report Removing the Blinkers also deals with the Five Freedoms for Horse and identifies ‘The most commonly perceived problems, as reported by respondents to a survey of European non-government organisations (NGOs) are:

• • • Problems with the environments and ways in which equidae are kept, including:
      • Environments with a lack of space;
      • Long periods of confinement without access to turnout, and environments which do not provide social interaction;
      • A lack of knowledge of proper equine care, among equid owners, and;
      • Neglect (failing to meet basic needs such as the need for food and water).
    • Training and handling methods, including welfare problems in sport.
    • The use of Equidae for meat. ¹
    • The treatment of working Equidae
    • A lack of access to professionals such as veterinarians, farriers to provide hoof-care and saddlers to provide well-fitting harness.’ ²

Removing the Blinkers:  the Health and Welfare of European Equidae in 2015, p.8 of 122 pages

Notes:

1. 1. Usually not a feature in the UK, where humans are concerned, but of considerable concern when horses are shipped overseas for human consumption and/or processing into animal feed.
   2. Not problem of a lack of actual access in the UK and other western European nations.

The USE of the UK Suffolk Horse:  Now  –  2022  and  Then  –  1922

Use in 2022

It is not clear when the vogue for using the ‘horse bred for the furrow’ as a riding horse began.   Nonetheless, in the last 20 or so  years it has become more and more popular.   So much so,  that along with other  breed societies, the Suffolk Horse Society began actively promoting this use, and encouraging ridden classes at shows.   Initially this may have been  as a means to  booster sales of youngstock to presumably help subsidise the production of actual working heavy horses.   For the Suffolk Horse in the UK, riding seems to have become the prominent use.   In 2022 there are more being ridden than worked as  draught horses.

There are, thankfully, those who use them in forestry work and in promotional work for various companies using their horses as traditional dray horses.   Increasingly, these appear to be in a minority.

Historically, development of the Suffolk Horse through selective breeding was for a working heavy horse.  This was the ‘tractor’ and ‘truck’ of its times, working six days out of seven per week.   It was not, as it is now, mainly a companion animal and occasional riding horse.

Showing the Suffolk Horse

Both in 1922 and 2022, one of the main reasons for showing the Suffolk Horse at the Agricultural Shows was to promote the breed.   In 1922 it was based on producing the Suffolk as a working horse.   In 2022,  it is promoted as a riding horse.

Hours worked per week

Feeding the UK Suffolk Horse:  Now  –  2022   and   Then  –  1922

The importance of what, when,  and how much? in understanding the feeding and food for horses, is crucial to their health and well being.   This has become more consequential in the recent past, as many diseases/disorders of the modern day horse have become manifest. 

A paper published in 2017,  Developmental programming in equine species: relevance for the horse industry, is a must-read for all owners and breeders.

“Epidemiological observations in the Belgian Ardennes showed that foals born to dams fed concentrated feed during pregnancy were eight times more likely to develop lesions of osteochondrosis compared with foals born to dams fed forage only (Figure 3; Van der Heyden et al., 2013).

“These data were confirmed in a controlled study using Saddlebred mares fed forage only or forage and concentrates although the difference in the incidence of osteochondrosis was not as large as in the epidemiological study, possibly because of the limited number of experimental animals (Peugnet et al., 2015). Foals born to dams fed forage only, however,  had thinner cannon bones, were less efficient in regulating their blood glucose, and had delayed testicular maturation compared with those born to dams fed forage and concentrates (Robles et al., 2017). “

A conclusion one might draw from the above study is it shows the two extremes of feeding the in-foal mare, and that somewhere along the spectrum there is a happy medium.  It is not that simple.  The article itself makes for concerning reading.    The reader should judge for themselves.                                                                    

 See:  https://academic.oup.com/af/article/7/3/48/4616838

A Definition

“Osteochondritis dissecans (OCD)is a relatively common developmental disease that affects the cartilage and bone in the joints of horses. It causes clinical signs of disease in 5-25% of all horses and can occur in all horse breeds.

“Cartilage in joints with OCD doesn’t form normally; this causes the cartilage and bone underneath it to become irregular in thickness and weaker than in normal joints. This can cause the development of cartilage and bone flaps that can either remain partially attached to the bone or break off and float around in the joint. These loose flaps and areas of abnormal cartilage and bone cause inflammation in the joint and over time may lead to the development of arthritis. OCD is usually caused by a combination of several factors acting together, including:

• • • • Rapid growth and large body size
      • Nutrition: Diets very high in energy or have an imbalance in trace minerals (low copper diets)
      • Genetics: Risk of OCD may be partially inherited
      • Hormonal imbalances:  Insulin and thyroid hormones
      • Trauma and exercise: Trauma (including routine exercise) is often involved in the formation and loosening of the OCD flap”.                                                                                                  

A definition of Osteochondritis dissecans (OCD) from The American College of Veterinary Surgeons https://www.acvs.org/large-animal/osteochondritis-dissecans-horses

A 2018 Editorial in Equine Veterinary Journal titled ‘Fifty years of osteochondrosis’ begins:

‘Although the term ‘osteochondritis dissecans’ was coined in the late 19^th century in human medicine, the real history of osteochondrosis (O) in the horses started…..  in 1968….   

“Osteochondrosis is a fascinating disorder, principally because of its complexity.

“A similar variety exists in the environmental factors that have been implicated in the aetiology of OC. These include nutritional factors that can grossly be divided into mineral imbalances and excessive energy intake. Copper has been investigated most extensively   it was once believed to be the decisive element in OC but is now regarded as more important in the repair process rather than lesion pathogenesis. 

“Excessive energy intake, especially in the form of easily digestible carbohydrates, has been related to osteochondrosis   and thought to act via disturbance of hormonal balance, or possibly through the accelerating effect of high energy intake on the animals’ growth rate. It is now recognised that rather than growth rate per se, the occurrence of growth spurts during certain windows of vulnerability in the development of joints is important. These vulnerability windows vary for each joint and most likely, also by site within a given joint.”

“… There is another reason to consider OC … … … Whereas OC is inherent to the horse (and some other species including humans), its clinical relevance is man-made.

“In a study conducted in feral horses, which had not known other than natural selection for a long time, OC was present indeed. However, prevalence in the talocrural joint did not exceed 2.5% and was nil in the femoropatellar joint   

“In the general equine population, the prevalence of osteochondrosis differs per breed of horse, but is much higher in virtually all populations   In pony breeds, which have never been selected for similar traits as racehorses and sport horses, OC was and still is virtually absent 

“These facts strongly suggest that OC has been inadvertently introduced by selecting for other, desired traits. One of these traits is without doubt height at the withers. Of the Dutch Warmblood, it is known that it has become taller at a rate of approximately 1 mm per year over the past decades. Although this seems very little, it is still an inch in 25 years.”

“Equine Veterinary Journal has published over 60 papers on osteochondrosis in the past 50 years. It has also published scores of papers on exercise-induced pulmonary haemorrhage (EIPH), pathogenesis and epidemiological features of distal metacarpal fractures and carpal chip fractures in racehorses, equine metabolic syndrome, laminitis and colic.

“These are all disorders to which the equine species is susceptible, but which have become clinical problems with substantial impact on welfare of substantial numbers of horses because of either the use humans make of these animals, or the way they keep them. From this viewpoint it can be stated that it is less the horse itself, but the man-made drivers in the equine industry that create the bulk of work for the equine veterinarian.

“We now live in an era in which the right of the human being to deal at will with animals is heavily challenged. In the veterinary world this is very clear in the increasing public opposition against certain dog breeds where excessive selection for certain desired traits has led to animals in which physiological frontiers have been crossed. We are not that far in the equine industry, but that industry is under increasing scrutiny too and some of the drivers in the industry will not stand the test of public opinion.”

https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.12821

Now – too little?

It still happens that cases of neglect appear on the local television news, in newspapers, and social media, where inadequate nutrition, poor to appalling husbandry over time, produces the pictures of  skeletal horses.

But inadvertently, undernutrition can happen due to other factors, including insufficient knowledge and understanding of how to feed a horse, how to recognise when a horse gradually is dropping condition and not knowing where to find accurate and detailed information. ¹ 

Notes:    1.  agriculture.vic.gov.au/livestock-and-animals/horses

 

Potential for Epigenetic change?   The Ubiquitous ‘Environmental Factors’

In humans, the 1989 publication of the ground breaking epidemiological work of Professor D.J.P.  Barker (1938-2013) Weight in Infancy and Death from Ischaemic Heart Disease  was published in The Lancet.    The Abstract begins:

“Environmental influences that impair growth and development in early life may be risk factors for ischaemic heart disease.   To test this hypothesis, 5654 men born during 1911-1930 were traced and their weights in infancy were recorded.   92.4% were breast fed.   Men with the lowest weights at birth and at one year had the highest death rates from ischaemic heart disease.”

This lead to an explosion of research and published papers, not just in human epidemiology, but also equine and other animal studies.

From the 2014 Study,  Enhanced or Reduced Foetal Growth Induced by Embryo Transfer into Smaller or Larger Breeds Alters Post-Natal Growth and Metabolism in Pre-Weaning Horses, P. Peugnet et al, the authors  begin their Abstract:

“In equids, placentation is diffuse and nutrient supply to the foetus is determined by uterine size.   This correlates with maternal size and affects intra-uterine development and subsequent post-natal growth, as well as insulin sensitivity in the newborn.   Long-term effects remain to be described.”

Their Introduction, after describing some of the epidemiological studies on humans, goes on to say:

“In production animals, the Developmental Origins of Health and Disease (DOHaD) are of interest for their role in programming characteristics linked to commercial benefits, such as offspring survival, growth rate, body composition, fleece, milk and meat qualities and reproductive function.

“Alterations in the foetal environment could also limit future health and athletic performance of the horse.

“IUGR (intra-uterine growth retardation) ¹ in equids has been reported to induce various detrimental effects in newborn foals and older horses, affecting –

• • • • • the pulmonary microstructure balance the respiratory function efficiency,
        • the development of neuropathies or hyperlipidaemia,
        • as well as muscle and skeleton development and function.

“Recently, an epidemiological study performed in Belgium underline the detrimental effect of feeding pregnant mares with concentrates on the post-natal development of osteochondrosis lesions in their offspring. “   (See above)

“… … … Early impacts on energy homeostasis in horses, although still unclear, are also of of strong interest, since insulin resistance is involved in various pathologies of the adult horse such as :-

• • • • • Cushing’s syndrome (now known in horses as PPID)
        • laminitis,
        • type II diabetes,
        • hyperlipidaemia,
        • endotoxemia
        • osteochondrosis,
        • equine metabolic syndrome

Note 1.  A recent Australian Study, Prematurity and Dysmaturity are Associated with Reduced Height & Shorter Distal Limb Length in Horses, J. Clothier, A Small, G. Hitch, & W. Brown, J. Equine Science 91 (2020)103129 states in the Introduction:

“The growing field of research into the Developmental Origins of Health and Disease (DOHaD), also know as foetal or development programming, considers the prenatal origins of adult disease.    In livestock species, the persistent effects of prenatal and neonatal stress associated with gestation stress in juvenile and mature sheep and pigs have been investigated……

“Researchers have also investigated the effects of equine maternal nutrition on foetal growth and development, foetal and neonatal outcomes after embryo transfer involving disparately sized breeds, and the effects of neonatal pony foals.

” … … … However, the one-term consequences of equine gestation immaturity associated with prematurity (frequently defined as parturition at < 320 days gestation) or dysmaturity (i.e. full term, but, undeveloped being weak and/or small for gestational age, have not been fully investigated.

” … … … the orthopaedic effects of gestational immaturity, including incomplete ossification and collapse of the carpal and tarsal bones and angular limb deformities, have been studied extensively in foals.

“Studies have indicated that such foals may fail to fulfil their athletic purpose:  of foals with tarsal values available for follow-up reporting at 18 months of age 15 of 22 (68.2%) and 10 of 21 (30.35%).   The persistent effects of gestational immaturity, including smaller stature have also been reported in other studies.

“We hypothesised that gestational immaturity in horses is associated with reduced height and different anatomical ratios at maturity, in comparison with unaffected closely related animals (i.e. sire, dam, siblings).

” DOHaD Studies in humans have established associations between prematurity and a shorter stature at maturity, and this has been linked to metabolic differences and changes in the timing of physeal closure in the long bones.    A shorter height at maturity has also correlated with decreasing gestational age, whereas a slower rate of postnatal and juvenile compensational growth and growth failure has been associated with very low birthweight.”

A Horse of a Different Hue: Part 3.2 examines the work of Dr Clothier and her colleagues on this and other research on endocrinological and metabolic dysfunction in horses, as well as considering equine gestation length and location.

Glucose – not too little, not too much, needs to be just right

“Glucose is central to energy consumption. Carbohydrates, lipids, and proteins all ultimately break down into glucose, which then serves as the primary metabolic fuel of mammals and the universal fuel of the foetus.”      from: Physiology, Glucose Metabolism, M.N. Nakrani, et al, 2021.                 

https://www.ncbi.nlm.nih.gov/books/NBK560599/                                                      

Dysregulation of normal physiology in the parent – Sire or Dam – may have profound egigenetic ramifications for their  subsequent progeny.

1. One of the major health problems with horses which has emerged  in today’s world – for both light and heavy horses (and all sizes inbetween) – is that of Equine Metabolic Syndrome.   

‘Equine metabolic syndrome (EMS) is a widely recognized collection of risk factors for endocrinopathic laminitis. The most important of these risk factors is insulin dysregulation (ID). Clinicians and horse owners must recognize the presence of these risk factors so that they can be targeted and controlled to reduce the risk of laminitis attacks.

‘Diagnosis of EMS is based partly on the horse’s history and clinical examination findings, and partly on laboratory testing. Several choices of test exist which examine different facets of ID and other related metabolic disturbances.

‘EMS is controlled mainly by dietary strategies and exercise programs that aim to improve insulin regulation and decrease obesity where present. In some cases, pharmacologic aids might be useful. Management of an EMS case is a long- term strategy requiring diligence and discipline by the horse’s carer and support and guidance from their veterinarians. ‘  

‘Durham AE, Frank N, McGowan CM, et al. ECEIM consensus statement on equine metabolic    syndrome. J Vet Intern Med. 2019;33:335–349. https://doi.org/ 10.1111/jvim.15423

In the Suffolk Horse Magazine some years ago,  an article by a veterinarian on this newly named condition in horses, summarised its aetiology as:

Overfed + Underworked = Metabolic Syndrome.

2. The second dysfunctional endocrine system disorder in horses is Pituitary Pars Media Dysfunction (PPID).   This occurs most often in elderly horses > 15 years, whereas EMS often manifest at 8-12 years.

PSSM Polysaccharide Storage Myopathy in the UK

In 2017, Type 1 PSSM was identified within the UK New Forest pony breed.  Is this new to the UK?    Vet. Tim Watson’s article PSSM in Horses:  Common but under-diagnosed condition? appeared in January 2013, in the Vet Times http://www.vettimes.co.uk.

“In the UK, it has been identified in a variety of horses including quarter horse, Appaloosa, warmblood, Connemaracross, cob, polo pony and Thoroughbred cross (Stanley et al, 2009). The mutation has not yet been found in Thoroughbreds, Connemaras or Welsh ponies (McCue et al, 2010).

“Genetic analysis has confirmed the GYS1 mutation is identical by descent, suggesting it was present before the establishment of diverse breeds (McCue et al, 2008). Frequency of the mutant R309H allele is high and this could be explained by breeding of affected, but asymptomatic, individuals, since signs of PSSM are suppressed by historical managements that include daily work and low starch diet. It is also possible the mutation conferred an evolutionary advantage by promoting storage of glycogen in muscle at times when food was scarce.”

“Clinical signs and diagnosis
Signs of PSSM are variable but typical of tying-up. Mild episodes are characterised by a stiff gait, anxiety and stretching out – as if trying to urinate – associated with muscle cramping. Owners may complain the horse is “lazy”, or appears to be affected by shifting limb lameness, sometimes with muscle atrophy and paresis. The abdomen may appear tense, with fine tremors visible over the flanks.”

The article goes on to say that:

“Symptoms are often precipitated by exercise, especially when horses begin training or return to work after a period of rest with little turnout. There may be a recurrent pattern, with a history of several episodes that correlates with training or work schedules.”

and:

“If the case is a quarter horse type, such as an Appaloosa, draught or warmblood, then it is advisable to check for the GYS1 mutation that is common in these breeds.”

Under the heading Prevention, the article emphasises:

“Careful attention to diet … … …

“…. … …interventions are focused on high fat/low starch diets, so metabolism shifts away from the defective glycolytic pathway to the oxidation of fats, with a significant portion of energy coming from fermentable fibre. This results in less glucose uptake into muscle cells, limiting substrate for polysaccharide synthesis, and provides free fatty acids for energy utilisation.

“… … … forages with greater than 12 per cent NSC have been shown to exaggerate
glycaemia and insulinaemic responses in quarter horses with PSSM, with potentially detrimental elevations in insulin concentrations (Borgia et al, 2011). Hay and haylage are generally appropriate in this respect, but lush grass should be avoided.” 

Exercise needs to be graduated cautiously but determinedly.

” … … … starting with no more than five minutes of uncollected walk/trot on a lunge
or under saddle, and increasing by two minutes each day up to 15 minutes.

” … … …then 15-minute intervals interspersed by a five minute break at walk. Canter work can be introduced after four weeks of walk/trot. Regular exercise is important and days off should be minimised, with turnout or exercise on a walker offered on rest days.”

The website: https://www.animalgenetics.eu/Equine/Genetic_Disease/PSSM.asp  shows which tests are involved and what the results of those test mean.

By 2022, just nine years later, horse feed suppliers in the UK have information on their websites about PSSM) and how to manage it.   Mention is also made of PSSM Type 2 ‘most often found in Quarter horses, Arabs and Thoroughbreds.   

https://en.wikipedia.org/wiki/Equine_polysaccharide_storage_myopathy

https://www.horsejournals.com/horse-care/illness-injury/diseases/understanding-pssm-horses

https://cvm.msu.edu/research/faculty-research/comparative-medical-genetics/valberg-laboratory/type-1-polysaccharide-storage-myopathy

https://cvm.msu.edu/research/faculty-research/comparative-medical-genetics/valberg-laboratory/type-1-polysaccharide-storage-myopathy#9.-what-breeds-are-affected-by-pssm1?

https://cvm.msu.edu/research/faculty-research/comparative-medical-genetics/valberg-laboratory/type-2-polysaccharide-storage-myopathy

Pre-packaged Feeds, Hay and Forage in 2022

 In modern times, the choice of feed for horses is ever expanding and extensive.     Many products are especially blended for different categories such as  Age – for weanlings, young stock, ageing horses.   For Conditioning, for weight gain and weight loss; for the Broodmare, for the Stallion.   Prepared feeds are available for the Performance Horse such as Endurance Mixes.  

In the UK, horse feed manufacturers abide by certain requirements, clearly and unambiguously detailed in the 32- page 2002 publication:  Code of Practice  for the Marketing of Equine Feeding Stuffs & Constitution and Rules of Procedure for the Code of Practice and Regulatory Committee. 

(See: https://www.beta-uk.org/media/trade/download/Feed%20Code.pdf )

Manufacturers’ websites offer well set out tables  detailing recommendations of the different pre-packaged foods by weight/total weight of feeds per day/by size and weight of the horse.

Their tables clearly define how much feed should be made to horses, based on the amount of work required of that horse.

• • • • • • • • Rest-Light Work,
              • Moderate Work,
              • Hard Work.

One question that needs to be asked, is:  do owners of leisure horses overestimate or underestimate the above three categories of work? 

The Authors of the paper Equine obesity:  current perspectives suggest that they do.

“Equine obesity is now so common that is has become accepted by many as the norm (Owers and Chubbock, 2012).

Rates of obesity may be as high as 70% in some populations and obesity is often associated with morbidities that may ultimately result in mortality.

Obesity is a common feature in animals diagnosed with equine metabolic syndrome, a conflation of metabolic disturbances including insulin dysregulation, which may lead to laminitis. Obesity is a risk factor for insulin dysregulation and is therefore implicated in laminitis risk. In addition to laminitis, adverse consequences of obesity include orthopaedic disease, hyperlipaemia, hyperthermia, infertility and poor performance.

Over time, perception of what constitutes a healthy body condition in horses has shifted, with the result that potentially harmful excess adiposity may not be recognised by owners or those working in the equine industry (Owers and Chubbock, 2012). In addition, increasing numbers of equines are kept as companions rather than athletes and live relatively inactive lifestyles favouring the development of obesity.

Finally, owners of leisure horses often think their horses are working hard when, in reality, their exertions have minimal impact on their energy requirements.                       Emphasis by italics added by suffolkpunchaustralia.com

UK-Vet Equine 2018 2:Sup5, 1-19

The above Paper is highly recommended reading and rereading, not just for owners and readers, but Breed Societies, especially of heavy and pony breeds.  

Recommendation 1.0/Part 3.1 

This particularly applies to horses deemed ‘Priority’, the recently introduced classification replacing the previous category ‘Rare & Critically Endangered’ by the UK Rare Breeds Society.   The Suffolk Horse is a ‘Priority’ Breed

This policy  has the potential to:

• • dramatically decrease the incidence of disorders and diseases whose aetiology is unequivocally linked to obesity;
  • influence the rates of success in breeding and resultant healthy progeny. Recall that epigenetic moderations work both ways.  See: Part 2,  Figure 2.2.0  Transgenerational Epigenetic Inheritance through Four Generations  https://suffolkpunchaustralia.com/a-horse-of-a-different-hue-the-suffolk-horse-1880-2022-part-2-epigenetics/

Obesity in horses … … …

“Equine obesity is considered to be one of the UK’s most serious equine welfare concerns, affecting somewhere between 31% and 54% of the UK horse population.”  begins the article Exploring horse owners’ understanding of obese body condition and weight management in UK leisure horses.                                                         

https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.13360

… and in Humans

 

According to figures from the World Health Organisation:

• • • The worldwide prevalence of obesity nearly tripled between 1975 and 2016 – just four decades
    • In 2016 more than 1.9 billion adults aged 18 years and older were overweight.  Of these over 650 million adults were obese.
    • In 2019, an estimated 38.2 million children under the age of 5 years were overweight or obese.
    •  In Africa the number of overweight children has increased by nearly 24% since 2000.
    • Almost half of the children under 5 who were overweight or obese in 2019 lived in Asia
    • Over 340 million children and adolescents aged 5-19 were overweight or obese in 2016 
    • Overweight and obesity are linked to more deaths world wide than underweight.   Globally there are more people who are obese than underweight – this occurs in every region except parts of sub-Saharan Africa and Asia.

https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight.

Overfed and Overfeeding

When using the term Overfed in horses, it has two senses:

1. 1. 1. Fed too much food -> Disorders of Plenty such as EMS, deposition of fat on the body and possibly internal organs.
      2. Fed too much high energy food -> behavioural problems.

It still comes down to the owner or carer of the horse making the right decision for their horse, or in this case, their horse who happens to be a heavy horse –  the Suffolk Horse, renowned always for being ‘a good do-er’.

In wondering how  to define a good do-er, Fred Smith In his Booklet The Suffolk Punch, published in 1925  describes how Suffolk Punches in Australia not only managed on short rations, but thrived:

“”….  was particularly mentioned by  Mr C.G. Tindall….. was largely engaged in heavy transport work in that country.   His teams often covered several hundred miles from one point to another, This breeder had considerable experience with Suffolks for he purchased his first animal for export at the Chelmsford Royal Show in 1856, and in alluding to his experience with the Suffolk-cross horses on this work said that more often than not  they came off the journey better than when they set out  This well known breeder…. often testified that the Suffolks’ great advantages – they stood the heat well;  secondly, they would live on the road and often come off a journey in better condition that when they started, by simply grazing on the way sides…..”

Hay and forage – Now – 2022

Potentially, for the UK Suffolk Horse’s owners, the range and cost of commercially grown hay, haylage, straw (wheat, barley and oats);  the costs associated with different sizes of bales, together with delivery costs and speed of delivery, offers extensive choices.   

Feeding the Suffolk Horse – Then – 1922

In 1922 pre-packaged foods for horses were not common, and most of the feeds for horses were prepared by the horsemen on the farm.    Fodder for horses was based on hay (both meadow hay and oaten hay) and grain, usually oats, sometimes maize, sometimes barley.    Depending on the  area of East Anglia, there might also be ground root vegetables.  Some areas used dried beans and peas

There was immense amounts of work  in itself just to prepare and store the foods prepared – ground grains, chaffed hay, perhaps ground beans and peas –  with a set amount for each horse for its six working days, and the seventh day of ‘rest’.  The term ‘corn’ was a collective term which included the grains – oats, barley, linseed cakes, dried beans and peas.  

It was hard, hot and dusty work to work the hopper grinding the composite feed stuffs, to load the resulting ‘corn’ into sacks, and potentially backbreaking work to carry those sacks into the storage area.

One of the early prepared stock foods

In the 1907  Pauls’ Agriculture registered the name Kositos for a prepared stock feed for horses, cattle, pigs and sheep.   The product was made from cooked and flaked maize.  The maize was imported from the USA.    It was widely advertised, often with the slogan “Kositos, Cooked, Easily Digested”.

And, that most important Nutrient of all – Water

That indispensable classic book, Veterinary Notes for Horse Owners by Captain M. Horace Hayes FRCVS, says:

“This is the nutrient required in largest amounts.   It comprises about 70 per cent of the body.   It has many important functions, being involved in digestion, body-temperature regulation, lubrication and metabolism.   Water, however is often neglected.  For example it is thought that the incidence of impactive colic, increases during winter because owners neglect to provide water for their horses or because horses will not drink extremely cold water.    Automatic water bowls are often neglected and become fouled.

“The requirement for water depends on many factors:  environmental temperature, amount of work performed (i.e. sweat production), level of milk production, rate of body weight gain, and faecal and urinary loss. … … … If possible, the best policy is to allow the individual to drink all it wants, it can regulate its own intake.”

p.583, from Chapter 43 , The Nutrition & Feeding of Horses, Seventeenth  Edition, 1987

  The 18th Edition (2018) of Captain Hayes’ Veterinary Notes for Horse Owners‘ is available in hardback, soft back, and for the modern electronic age as an e-book. 

And from the chapter, Farm Management of the Heavy Horse, in Heavy Horses:  Breeds and Management, p169

“Another important point, second only in importance to the food, is the water. Domestic animals of all kinds, and more particularly horses, thrive best, and are more uniform in health, when they have access to running streams. This, in many cases, is impracticable on some geological formations where there are only two sources of supply.

“One is obtained by conserving the rain water which, under the most favourable conditions is erratic, and frequently fails for long periods. The other source of supply is obtained from deep wells ; this is usually highly charged with chemical impurities derived from the rocks through which it passes. Water of this character is utterly unfitted for young horses, but by being pumped into tanks or reservoirs and exposed to the sun and air it be comes oxydised (sic), softened and increased in temperature ; and hence is better fitted to assist in promoting the animal functions.

“Ponds or storage reservoirs are of much value on a farm ; these insure a more uniform quality. Every animal should have free access to water at all times, as when this is the case no unfavourable results are likely to follow.”

Feeding to keep a heavy horse fit in 1922

The Horse in Furrow by George Ewart Evans, first published in 1960, details the feeding of the agricultural working Suffolk Horse, through the differing areas of Suffolk.  Certainly these horses had to be maintained to an appropriate level of fitness, given the length of their working day, and working week.

Eight to ten years before, however, fitness was essential as draughts horses including Suffolks were requisitioned and purchased for what became known aa The Great War.

World War 1:  1914 – 1918

From the website of the National Army Museum:  

“By 1917, the Army employed over 368,000 horses on the Western Front. The vast majority of these were draught or pack animals rather than cavalry horses.

“The Army’s Remount Department spent £67.5 million (about £3 billion in today’s money) purchasing, training and delivering horses and mules to the front. There were not enough horses in Britain that were fit for Army service, so large numbers had to be brought from abroad. Canada, for example, sent about 130,000 horses.”

https://www.nam.ac.uk/explore/horse-power-first-world-war

The Army approached  the care, maintenance and sustenance of its horses and mules seriously.    In the Army Manual of Horsemanship, Equitation and Driving ¹  the first chapter deals with General Considerations, then Watering, then Feed.     Most, if not all,  of the principles espoused, have the same relevance today, perhaps even more so.

“1. Horsemastership is the science of the care of the horse under all conditions, whether hunted or dismounted, in the field or in barracks.   It aims at continuously keeping the largest possible number of horses fit for work, and reducing inefficiency to a minimum by prevention of accident and illness.

“2. The importance of being a good horsemaster should be impressed upon every mounted soldier.   He should be taught to look upon his horses as his best friend to study it, to take a pride in its appearance and to look after its wants before his own.

“3. He should receive instructions in : –

1. 1. 1. 1. 1. Watering
            2. Feeding
            3. Bedding
            4. Grooming
            5. Shoeing
            6. Care of the horse when at a work in the field or on the march
            7. The prevention and cure of minor ailments
            8. Fitting and care of saddlery and harness

“4. The main secret of success is to study the temperament and constitution of each horse individually.  It is only by doing so that work and food can be properly regulated, and horse and rider correctly suited to each other.”

More on Watering the Horse in Part 3.2, except for just these further two small excerpts:

“A horse requires from five to six minutes to water.   It must not be thought that he has finished drinking merely because he lifts his head.”

“The three guiding rules of feeding are : –

1. 1. 1. 1. 1. 1. 1. 1. Feed after and not before water
                     2. Feed in small quantities and often
                     3. Do not work horses immediately after a full feed

 

Note:   1. Assorted copies from 1908, 129, 1937 stress the importance of the absolute care of the horse.

It is moving to read the little booklet ‘The Drivers’ and Gunners’ Handbook to Management and Care of Horse and Harness, issued by Our Dumb Friends League, 1915‘.    On p.1 under “General Remarks” it states:

 “It is absolutely essential that the horses of every Unit should be hard and fit and free from galls, cracked heels, sore withers and backs, etc., and this book is issued in order that all Drivers may have simple knowledge which will assist them to keep the horses under their charge thoroughly fit and ready for Active Service.   Every driver should take the greatest interest in his two horses ; if he does so they will know him and look to him for their daily care.”                                                             emphasis added in italics  by  suffolkpunchaustralia.com

Fred Smith in his 1925 publication wrote of the Suffolk at war:

“The Suffolk was, as was to be expected, a decided success in the Great War.   Numerous letters appear in the press amplifying the powers of endurance possessed by the Suffolks.   Of these spontaneous testimonials from men in the fighting line, one was very much to the point.    After remarking he had come across many different breeds amongst the lines, he says – ‘before I came to France I was continually being told that it was the feet and legs of a horse of which you must take particular notice;  these carry the body and therefore are most important, the carcase being of little account, but now I am a Tommy and have to look after horses myself I am not the least particular about feet and legs, they will not break, but what I want to see is a good constitution, an easy feeder and a roomy cupboard wherein to stow the food away;  no short-ribbed herring-stomached animal in my lines if I can prevent it.’ 

Fred Smith goes on to say:

“An Artillery Officer in Brigadier-General Holtham’s Division, referring to the Suffolk, says :- “He was a big-barrelled, strong necked , low-bodied horse, with terrific pulling power, and what was more to the point, had the knowledge of how to make the best use of it.   One could well describe him as a sort of beefy chestnut Goliath, which pulled anything and everything without much effort, and even replaced a team of mules on some occasions.”

Feeding the Horses on the Western Front

In his book, Farming & Forestry on the Western Front 1915-1919, author Murray Maclean described the daily rations of the Army horses.  Feeding took place three times daily, with water available four times during the day.

(NB. the oats would have been mixed thoroughly with half a pound  of chaff to each pound in weight of oats bringing the oats/chaff mixture to 15lbs./day.)

Murray Maclean commented: “These quantities give an indication of the scale of fodder requirements to supply every horse working along the Western Front each and every day”. p.29 

On page 10 of his book,  there is a Table summarizing “Estimated weekly tonnage to be discharged at ports in France for the Offensive of 1917” and points out that Forage, at almost 36,000 tons, was second in importance to ammunition.     Murray Maclean goes on to say, ‘This would consist of bulky consignments of hay, straw and oats, for the feeding of army horses and mules. 

On the Home Front in the UK, the greatest yearly increase in production of all crops over the five years of war (1914-1918) was oats.    In 1914 it was 20.66 million qtrs:  in 1918, 31.51 million qtrs.  (MacClean, op. cit. page 7,)   Note:  A quarter of oats weighted approximately 330 lbs, or 149.685 kilos.

The peak of hay production in the UK during the 1914-1918 was in 1916 at 15.20 million tons.  For 1918 it was actually less than that produced in 1914:   12.33 million tons (1918) compared to 12.40 million tons in 1914.

On the Western Front by the summer of 1917, the Army “was making use of locally harvested forage and harvesting their own hay in areas near the front which had been abandoned by the local farmers.

Note:  Farming & Forestry on the Western Front 1915-1919 by Murray Maclean,  2004, published by Old Pond Publishing, UK, is an extraordinarily detailed and compelling book.  

On reviewing the quantities quoted about from the SmallHolder’s Horse suggested rations, one hopes it was for at least a pair of horses (preferably Suffolks), not just one.

Fred Smith was in favour of using the Suffolk Horse on small holdings:

“As an agricultural horse the Suffolk has for many years been admitted hard to beat.   As a horse for horticultural work and market growing, now so much on the increase, he has additional qualifications.   

Suffolk breeders have never aimed at producing a horse with a massive spread hoof, but have rather devoted their attention to breeding an animal with a sound, medium sized hoof, of the best quality.   Engaged in such cultivation the Suffolk has the advantage, for he can pass to and fro on a plot of land without doing the damage a heavier-footed animal must inevitably cause.  

The same also applies to the working amongst fruit trees, where the Suffolk, especially the lighter class has been found to render valuable service under the spreading branches of standards and also amongst bushes, where a heavy massive animal is at a disadvantage.”                                                                                              F. Smith, The Suffolk Horse, 1925

 

And Still Required by The Army

Volume 29 of The Suffolk Horse Society stud book was published in 1926.   Raymond Keep, himself a veteran of The Great War, was now Secretary and Editor.    He wrote in the Preface:

“The Army Authorities have, as in former years, been large purchasers of both mares and geldings.   That they have a very high appreciation of the Suffolk Horse for Artillery and Transport Work will be seen from the following report received from Headquarters, Royal Artillery, 3rd Division, Bulford.  

“The Officers consider these Suffolk Punches  are certainly, as regards haulage powers, the equal, and in some respects the superiors of other Breeds of heavy horses of which they have had experience.  They have performed satisfactorily the normal Artillery work of peace time on Salisbury Plain.   They are ‘good do-ers’ and keep their condition on their Government ration, are active, show great perseverance and maintain a good walking speed.   They are easy to train and are particularly docile, especially in stables.   Their clean legs mean less work that with the rough legged Breeds, and the leg diseases most prevalent with the latter are absent.”                                                      Emphasis addd by suffolkpunchaustralia.com

Some concluding thoughts on Part 3.1 A Horse of A Different Hue

When the phrase ‘Overfed + Underworked = Metabolic Syndrome’ emerged to a wider audience in 2010 – only some twelve years ago, it was hoped that with balanced nutrition and increased work/exercise, this condition would be manageable, if not always easily managed.  Evidently this has not been achieved, nor is it likely to be in the foreseeable future unless there is major changes in understanding the dangers to their horses by all owners and carers.

What has emerged is that Equine Metabolic Syndrome is a potent driver of other equine disorders:  if not the train driver, then certainly the fireman.

Some questions to consider:

• • • Potentially, what other conditions are lurking just around the corner that will add to the threats of ill health to the Suffolk Horse?
    • What else is needed to convince owners and carers of those overweight/obese horses that they are not adhering to:

1. 1. 1. Freedom from hunger or thirst by ready access to fresh water and a diet to maintain full health and vigour
      2. Freedom from discomfort by providing an appropriate environment including shelter and a comfortable resting area
      3. Freedom from pain, injury or disease by prevention or rapid diagnosis and treatment
      4. Freedom to express (most) normal behaviour by providing sufficient space, proper facilities and company of the animal’s own kind
      5. Freedom from fear and distress by ensuring conditions and treatment which avoid mental suffering.  

_____________________________

Part 3.2  A Horse of a Different Hue coming very shortly

 

© Eleanor Yvonne Hatch, Suffolk Punch Australia 2022