37 2015 Talking Horses The newsletter with news, views and practical advice From the editor… In this issue... It was great to meet so many of you as readers of our newsletters at Equitana 2014. The Special Equitana Issue #36 was a preliminary guide to looking after horses in hot weather. You may wish to obtain a back copy by emailing newsletters@kohnkesown.com or logging onto www.kohnkesown.com to download a copy. We can email you a more detailed Seasonal Alert on Summer Heat Stress We also provided handy guidelines on keeping heavily pregnant mares cool during the hot weather in Talking Breeding #13 published on 12th January 2015. A heavily pregnant mare has a uterine arterial flow of 1,850 litres/minute, or 18.5 times that of a non-pregnant mare! No wonder they sweat more heavily under hot conditions. * Locking Stifles * Navicular Syndrome * Mould in feeds Plus handy hints and lots more! Use a Poly-woven Chaff Bag to Dampen Hay You can dampen hay by spraying it with clean water and placing it in a poly-woven chaff bag for 10-15 minutes. You can then carry the dampened hay to your horse in the bag to reduce leaf loss and mess on your clothes. Avoid using a hessian bag, as with repeated use, mould can buildup in the natural flax fibres and it can contaminate the hay if it is not consumed within a few hours. Turn the poly-woven bag inside out once a week to rinse off any leaves or plant debris to reduce the risk of mould growth. Handy Hint 1 In this issue, we discuss ‘locking stifles’ (also referred to as Upward Fixation of the Patella), as well as provide an updated review on navicular syndrome and a short note on moulds in feed. For those who have been caught up in bush fires, we have a new ‘Seasonal Alert’ available on managing horses and donkeys following Check for Mould in Hay a bushfire. Again, you may wish to obtain it as a handy guideline by emailing Wet conditions during harvest and baling of grass with a moisture newsletters@kohnkesown.com or download it from our website. A number content above 14% (stored hay should ideally contain 10-12% moisture of readers have put it up in their tack room. to prevent mould growth) increases the risk of mould growth which gives it a ‘musty’, ‘fumy’ odour and matted whitish internal appearance when the bale is opened to feed out. Mouldy hay can cause colic, infertility, abortion All the best, in pregnant mares, ‘hay fever’ and airway disease, as well as retard growth and lead to liver and brain damage. Here’s a simple way to check for mould in hay. Take a handful of suspect hay, lightly dampen it with cool, boiled water. BVSc. RDA Using boiled sterile water to dampen it is important to minimise mould contamination even in rain water and mould-inhibiting chlorine in tap water. Place the sample in a Did You Know That... new, clear plastic bag which has at least 3-4 times the sample in volume. Place in a well-lighted warm place in the stable. Check the hay morning and evening The horse has the largest eye of all land mammals. The eyeball size is for signs of dark discolouration or white mould filaments (hair-like projections) largest and most prominent in faster gaited horses. The eyes are positioned on the hay. Mould should develop within 12-36 hours if it is in a high enough towards the front on the sides of the head, giving a horse an approximately concentration to cause side effects when fed to horses. If you are concerned 350o field of vision. This is made up of a forward arc of vision of 65o about mould in a batch of hay or grain, contact Agrifood Feed Testing Laboratory binocular vision (using both eyes to the front) and 285o of monocular vision on 1800 801 312 in Werribee Victoria (www.agrifood.com.au) and arrange to to the sides and rear, with each eye viewing independently. The horse has send a sample for mould and harmful mycotoxin identification. For full details, a ‘blind spot’ extending 40-60cm in front of its nose and also a blind zone of email newsletters@kohnkesown.com for a free fact sheet or log onto vision behind its head and over the tail when it is looking forward or to the www.kohnkesown.com to download a fact sheet on ‘Mould in Feed’. side without moving its head. Horses have a ‘visual streak’ on their retina, which has concentrated receptors to sense movement, which is used to New First Aid Book detect approaching predators and determine the height of jumps etc. A new book ‘First Response’ by Australian Amanda Edwards, a Horses have ‘dichromic’ colour vision. Humans have’ trichromic’ or a near full professional emergency nurse and horse owner, was released at Equitana colour spectrum vision. Horses can detect blue and green colour, but not red, 2014. The 200 page book provides excellent and practical advice on First similar to a red-green colour blind human. Horses can see a 2 colour jumping Aid and Emergency Care of injured and sick horses. It is written to provide rail more clearly than a single colour white rail, preferably with white and clear and simple guidelines in case of emergency and complements your own black, blue or green bands. They cannot see red bands on a jumping rail, vet’s advice and attendance. Amanda also manages the Equine Care Clinic, so avoid jumping rails which are painted red as they appear black and may providing workshops, care of injured horses and first aid supplies. Her website blend into the arena surface colour or the distant background. Offer a green is www.equinecareclinic.com and email amandaequinecareclinic@gmail.com apple rather than a red apple, as to a horse, a red apple appears black. Cut This book is a very worthy addition to your horse book library and handy a red apple into pieces so that the horse can recognise the odour of the fruit. to have in the tack room or feed room in case of colic, severe lacerations, With domestication, horses usually become more ‘near’ sighted to enable laminitis or any of the problems that can happen to a horse! them to focus on close up objects, whilst in the wild, horses are usually more We pass on our best wishes for 2015. Handy Hint 2 Dr John Kohnke ‘far’ sighted to help them see approaching predators in the distance. Reference: en.wikipedia.org/wiki/Equine vision Free call: 1800 112 227 - Free fax: 1800 112 228 Website: www.kohnkesown.com Email: info@kohnkesown.com Address: PO Box 3234, Rouse Hill, NSW, 2155 © Copyright 2015 John Kohnke Products ‘Like’ our new Face book page to get full access to interesting articles, informative handy hints, fun competitions and horse care updates! www.facebook.com/johnkohnkeproducts Talking Horses Equestrian Issue 37 2015 Locking Stifles a multi-cause condition Handy Hint 3 Locking stifles (also known as upward fixation of the patella or patella luxation) Avoid Breeding Mares and is relatively common. The patella in the horse is equivalent to the kneecap in Stallions with Inherited Patella Luxation humans. The patella is held in a groove in front of the stifle joint to act as It has been observed, and confirmed by X-rays angled across the a ‘pulley’ for an extensor tendon which passes over the stifle on its way front border of the stifle to image the inner femoral condyle, that individual to the lower limb. It can become loose in the groove and slip over the horses or ponies may have less well formed and prominent femoral condyle ridges. As the condition appears to be a recessive gene in certain bloodlines, inside edge of the femur to become displaced on the inner border of the it is best not to breed a mare or stallion with a history of patella luxation. It stifle, virtually preventing the stifle from bending and it ‘locks’ into a fixed is recommended to have the femoral condyles X-rayed to confirm the position. The only way to ‘unlock’ the stifle is to push the animal to take one genetic abnormality. Stallions should be gelded to prevent backward step, which straightens the stifle and enables the tendon and patella them passing the weakness on to future to ‘pop back’ into its normal position. generations. The underlying causes There are 5 main causes of patella displacement in horses. Genetic Tendency It has been observed that certain bloodlines of horses have a higher incidence due to inherited reasons. Some bloodlines have smaller ‘condyle ridges’ on the inside (medial) edge of their femur bones - a structural development problem which can occur in some pony breeds and minis. This lower medial ridge allows the patella to ‘slip’ over the inside edge of its groove in front of the stifle as the animal slightly rotates its leg when getting up when the patella is held less taut in its femoral groove. Some lines of horses and ponies have a tendency towards upright conformation of the hind limbs and this predisposes the offspring to ‘locking patella’. Strain of the Stifle Joint Checking the Angle of the Hind Hooves The front angle of the hoof wall on the hind limbs should be more upright compared to the corresponding slope of the front hooves, with a shorter toe and higher heels. A long toe, low hind heel hoof shape increases the risk of stifle lock because the stifle joint is angled back in a more relaxed position when the horse is standing, allowing the patella to be ‘loose’ within the stifle joint. The slope of the coronary band can be checked by placing the end of a piece of string on the coronary band on the back of the heel and then running it parallel to the slope of the coronary band to determine where it intersects on the front limb. Line A: Optimum hind limb coronary angle, with the string line intersecting at the back of the knee, or no higher than mid way between the knee and elbow on the front limb. C B It has been documented that sprains within the stifle joint Lines B & C: Lines intersect can stretch the internal stifle ligaments (cruciate ligaments) A too high, indicating that the or stretch the patella flexor tendon. These types of injuries coronary angle of the hind Front Hoof might be the result of slipping when getting up in a stable hooves is too high, because the Angle with a slippery wet floor, especially after being cast against toes are too long and the heels Back Hoof a wall, slipping over when galloping around in a wet, muddy are too low. Angle paddock or when falling down in a float during transport. This can result in the patella becoming ‘loose’ within its Long Hind Toes groove and if the tibia (our shin bone) is unstable due to cruciate ligament It is well known that excessive toe length on the hind legs, combined with low sprain, the patella may slip to the inside of the stifle and ‘lock’. heel conformation, is a common cause of locking patella. This is due to the Low Selenium Diets mechanical effect of the long toes and low heels, which results in the hock Investigation into an unusually high number of locking patella, both single being positioned more upright and the stifle joint is less angled, leaving the and both limbs locking, in northern Tasmania which affected growing pony patella unstable in the femoral groove of one or both stifle joints. Many owners breeds and minis, linked soil deficiencies of the trace element selenium with report that the incidence of patella locking is reduced following each time the regional incidence of the problem. Many areas of Australia where high the hind hooves are shortened, but that the problem returns as the toes grow rainfall or a sand-dune base is reclaimed land, have selenium deficient soils. longer towards the end of the regular 6 week hoof trim. Besides increasing the risk of locking patella in young growing horses and Poor Muscle Development ponies, low selenium levels in pasture, grain and hay grown on areas with a Many resting, grazing or show horses do not have strong hindquarter muscle soil deficiency, can increase the risk of poor muscle development and muscle development. Once a horse is in work, the muscles respond to exercise and weakness (referred to as ‘White Muscle Disease’ in severe cases) and abnormal the increased muscle tension and strength helps reduce the risk of a ‘locking’ joint cartilage and tendon development in growing horses or adult horses over patella. If a horse continues to suffer from a ‘locking’ patella after trimming an extended time on a low selenium diet. the hind toes and supplementing with selenium, then it is best to hand walk or trot on a loose lead up at 10° slope for 1 km twice weekly to stimulate hind Supplement with Selenium in limb muscle development which may help reduce patella locking. Young, Growing Horses Rapid Growth Spurts Supplementation with selenium may be helpful to avoid ‘locking’ patella in young horses and ponies. A supplement, such as Kohnke’s Own Cell-Grow® is especially formulated to meet the needs of growing horses and ponies, up to about 2 years of age. It contains selenium in organic yeast form, which is better absorbed compared to chemical forms of sodium selenite or sodium selenate in most prepared feeds and supplements. After 2 years of age, daily supplementation with Kohnke’s Own CellProvide® or Kohnke’s Own Cell-Vital, will help provide adequate selenium to correct low or inadequate intake from pasture and hay based diets. It is an important daily supplement which should be fed to horses and ponies grazing on areas known to have selenium deficient soils. It is not uncommon for young Warmbloods in particular, and Thoroughbred yearlings to develop ‘clicking’ and ‘locking’ patella if they have a growth spurt as a result of increased energy intake on good pasture or high energy hard feed, or ‘catch up’ growth after illness or an injury. If it is suspected, then cutting back the energy intake and providing a balanced calcium, trace-mineral and vitamin supplement for growing horses or ponies, such as Kohnke’s Own® Cell-Grow®, is recommended. Normally the growth plate enlargement of the stifle joint bones returns to normal dimensions within 4-6 weeks and the ‘clicking’ sound at the walk and the patella locking ceases. Handy Hint 4 Talking Horses Equestrian Issue 37 2015 Navicular Syndrome Navicular disease is a common bilateral lameness that has been recognised in athletic horses as a cause of progressive lameness, primarily in the front of hooves, for over 300 years. It is caused by the slow internal degeneration and decalcification of the navicular bone, also referred to as the distal sesamoid bone. The navicular bone is a small bone about the size of a human small finger bone which acts as a pulley embedded in the Deep Digital Flexor Tendon (DDFT) as it traverses the coffin joint in the rear of a horse’s hoof. It is a bone which supports weight and is subjected to concussion in its role as a pulley to protect the (DDFT). Navicular degeneration is not a disease as such, but rather a progressive change to the navicular apparatus, which is now referred to as ‘navicular syndrome’ or more correctly ‘caudal hoof pain’. Diagnosis of Navicular Syndrome Symptoms include a progressive heel lameness, ‘proppy or choppy’ gait, toe stumbling, ‘tied-up in the shoulder’ type movement, excess wearing of the toes and upright heels with deep frog grooves (sulci) due to contracted heels as a horse lands on its toes with minimal heel ground contact as a result of caudal hoof pain. Nerve blocks to localise the area of pain, X-rays and the newer technologies of nuclear scintigraphy, MRI and CECT under general anaesthesia provide a more accurate diagnosis and assessment of the structural damage within the DDFT and navicular flexor surface compared to previous diagnostic techniques, which relied mostly on nerve blocks and X-rays. Treatment and Management Position of the Navicular Bone in the Foot It is important to evaluate the horse’s breed, history, exercise demand, age, conformation and any overweight condition which adds extra weight loading. These factors will be considered together as important criteria in managing caudal hoof pain. A number of shoeing techniques, including rolled toes to increase break-over, wedging to elevate the heels and egg bar shoes, may be used to give relief and restore normal movement. Vasodilating drugs, such as isoxoprine, have been shown to be of benefit in early cases. Barefoot trimming has been widely advocated to balance the hooves with many reports of success in early cases. Short pastern bone Coffin joint Pedal bone Deep flexor tendon New drugs in the bisphosphonate class have been shown to be of benefit in re-mineralising bone and reducing navicular lameness after a single injection. The product Tildren® (CEVA) is now available in Australia for use in horses with navicular syndrome and bone spavin. In the USA, a similar bisphosphonate, marketed as Osphos®, has shown a 74.7% reduction in lameness scores in navicular affected horses at 56 days after a single injection. Consult your vet for advice. Navicular bone (encased in deep flexor tendon, which results in a naturally poor blood supply and a large amount of concussion during exercise) De-nerving the rear of the hoof in chronic cases is not permitted in competition horses and surgically cutting the distal sesamoid ligaments or check ligaments has been carried out with mixed success. Consult your vet for advice. Reference: D Rodgerson DVM (2013) Aust. Equ. Veterinarian 32(4). 41-44. Underlying Causes The exact underlying cause is unknown, but various theories have been proposed. The original theory developed in the USA was related to concussion and resulting bursitis in horses working on hard ground, police horses on paved roads or reining and jumping horses, combined with upright conformation, heavy shoulders, ‘pinched heels’ and long term poor farriery techniques. It is considered to be an inherited problem in small-footed horses, especially Quarter Horses. Researchers in Denmark have proposed that increased pressure between the DDFT and the navicular surface of the coffin joint is the cause of degenerative cartilage damage (osteoarthritis), which leads to coffin joint lameness and caudal hoof pain. Over 30 years ago, navicular degeneration was linked to clotting of blood within the small vessels originating in the DDFT, causing poor blood supply and demineralisation, consistent with internal ‘lolly-popping’ of the vascular channels on the back border of the navicular bone. These can be seen on an X-ray and were thought to be the bony degeneration associated with ‘ischaemia’ or poor blood supply to the rear border of the small bone. Recent studies using Magnetic Resonance Imaging (MRI) and Contrast Enhanced Computer Tomography (CECT) have localised vascular and other degenerative changes to soft tissue structures in the heel of the hoof. These are considered to lead to internal fluid swelling (oedema) within the navicular bone and continued concussion results in tears within the embedding fibres of the DDFT. This is now considered to be the cause of ‘caudal hoof pain’ (pain in the rear of the hoof), with typical symptoms of navicular syndrome. an up-to-date review Please Note: A detailed fact sheet on ‘Navicular Syndrome’ is available from newsletters@kohnkesown.com Handy Hint 5 Managing Navicular Syndrome Recent reports suggest that the combination of corrective barefoot trimming or shoeing with rolled toes and egg-bar shoes (with or without raised heels), combined with daily supplementation of a joint preparation containing glucosamine, manganese, vitamin C and other cartilage ‘foods’, such as Kohnke’s Own® Nutricart®, is successful in relieving the progressive deterioration caused by navicular overloading and developing fibro-cartilage collapse in ageing equestrian horses. Success of Corrective Trimming and Shoeing Corrective barefoot trimming alone is successful in about 50% of hacks and lightly worked horses. Using an egg-bar shoe to extend, expand and support the forelimb heels, is effective in about 33% of early navicular cases. However, ensure that the hind toes are kept short and squared off to prevent ‘forging’ and risk of ‘heel chop’ during workouts if egg-bar shoes are fitted. Handy Hint 6 Benefits of Barefoot Trimming (BFT) Did You Know That... A hereditary predisposition to navicular syndrome, related to the shape of the navicular bone and thickness of the fibro-cartilage layer at its articulation within the coffin joint, has been identified in Warmbloods. Offspring of stallions with a concave navicular lower border and a thin cartilage covering had a higher risk of developing navicular syndrome. Earlier studies suggested a 35% risk of inherited navicular syndrome from affected stallions, compared to 5% for sound stallions. Barefoot trimming is now widely advocated to restore proper symmetry and balance to the front hooves of horses with navicular syndrome. It may help to improve the internal blood flow and reduce compression loading on the heels and navicular structures. It has proven to be effective for early navicular problems, and it is worthwhile to carry out regular barefoot trimming by a trained BFT professional on a regular monthly program. Handy Hint 7 Talking Horses Equestrian Issue 37 2015 Moulds in Feed A Growing Problem Grains and hays can be contaminated with fungal organisms or moulds during harvest, storage and processing under damp or humid conditions which are Minimising the Risk of Mould Contamination favourable to their growth. Perennial Ryegrass pasture can contain You can adopt a number of measures to minimise mould in feeds. an endotoxin produced by endophyte fungi in late summer and Maintain grain and hay moisture content below 12% to limit mould growth. Some 1. autumn, triggering ‘ryegrass staggers’ in horses, sheep and molasses sweet feeds contain 15-18% moisture in sealed bags which may facilitate mould cattle. Moulds present in hay and hard feed can affect the health and performance of breeding, growing and working horses in a variety of ways. Fungal organisms can be inhaled from mouldy or ‘musty’ hay, triggering an allergic asthma-like effect on the lower airways, with inflammation and constriction of airway capacity. This can have a direct effect on airway function, reducing oxygen uptake and ultimate performance. growth and the in-built anti-mould agents may not be effective. Always check bagged feeds for a mouldy odour, especially those nearing their expiry date, as well as mould in the bottom of the bag or on the underside of bales of hay stored on damp ground, especially following wet, humid weather. 2. Test any suspect feed, particularly darkened or black tipped grains or ‘fumy’ hay for presence of mycotoxins. These tests can be carried out by the Agrifood Feed Test Laboratory at Werribee, Victoria. <www.feedtest.com.au> Phone: 1300 655 474. 3. Generally, properly extruded and dried grains have less risk of mould growth if stored under dry, aerated conditions. 4. Use buffered mould inhibitors based on natural propionic acid to resist mould growth during storage of grain. These can be obtained from your feed or produce store (eg Mold-Zap®). Mould toxins, called mycotoxins, can have adverse effects on the appetite or the immune system, and in a breeding mare, reduce fertility, cause abortion and early embryonic death, as well as retarded growth in young horses. 5. Products, such as Kohnke’s Own® Activ-8™, contain a special mycotoxin binding yeast to help support the immune system. Other feed mould toxins (eg aflatoxins) can be ingested in contaminated feed, leading to increased risk of harmful damage to the liver and kidneys and suppression of the immune system. Handy Hint 8 Store Grains and Hay under Dry Conditions Wet, cold weather can lead to moisture condensation on the inside of the It has been estimated that up to 25% of the world’s grain supply is walls of metal silos, steel 200 litre feed drums and metal feed storage bins in the now contaminated with mycotoxins. Although some moulds stable feed room and facilitate mould growth. Always check for dampness, blackening and a ‘musty’ odour within the layers of grains and chaff touching the metal sides. Store can be used to produce bread, cheese and antibiotics, recent bulk grains in poly-woven bags or inner plastic containers/buckets and place them, along with changes in global weather patterns, with flooding, droughts bags of chaff, inside the bins to minimise contact with the walls to help avoid the risk of mould or unseasonal frosts, have increased contamination of animal contamination. Do not store dampened feed mixes for more than 24 hours. Check the centre feeds with a variety of harmful mycotoxins. section of round bales for mould by checking and feeding out the hay in portions rather than The moisture content during harvest of grains and hays, and allowing horses to waste hay and risking mould growth in wet weather by especially in baled hay and stored grain, exceeding 14%, combined providing hay as ‘self-serve’ in a yard or paddock. Do not store small hay bales under plastic or metal sheeting as the hay is with drought stress during the growing period and broken kernels likely to develop mould on the outer surfaces. of grains, can all increase the risk of mould growth and mycotoxin Handy Hint 9 production. Recent research has highlighted the widespread effects that moulds and their mycotoxins can have on athletic and breeding performance, with a growing realisation that mould contamination of hay or grain must be considered as a cause of poor performance in racing and equestrian horses. When you need a product to assist joint health and function in horses, supplement with Kohnke’s Own Nutricart Please Note: Separate detailed Fact Sheets on ‘Moulds in Feeds’ #M10 and ‘Ryegrass Staggers’ #S7 are available by emailing newsletters@kohnkesown. com or by downloading from www.kohnkesown.com Control Aspergillus spp Mould in Stables Handy Hint 10 Inhalation of Aspergillus spp mould in molassified feed (sweet feeds), hays, shavings and straw bedding may produce allergic airway disease, which under humid conditions, can increase the incidence of airway damage and lung bleeding in racing and eventing horses. It appears that the allergic response to microscopic mould particles, less than 5-10 microns in diameter, triggers airway inflammation, rather than a mycotoxin type reaction in the lower airways and lung air sacs. Keep feed bins and water vessels clean and remove molasses residues which harbour mould, on a regular weekly basis. Steam clean or wash down all the feed buckets and walls of stables with soapy water where molasses is used to sweeten feeds at regular 10-14 day intervals to control its Aspergillus spp mould, especially prior to introducing a new horse to the stable. Remove all cobwebs which can harbour fine dust and mould and dissipate them into the stable air space. • The Nutricart formulation has proven its effectiveness throughout extensive field trials in both Australia and Overseas. • Nutricart contains glucosamine hydrochloride as the major joint cartilage component. • Nutricart is complemented with other nutrients which have a role in cartilage health and function which may be low or inadequate in common grain, chaff and hay mixes. • Low Dose - 20g maintenance dose delivering glucosamine and complementary joint nutrients. • Highly palatable natural fenugreek flavouring, low dust formulation with no ‘fishy’ odour. • Highly economical and effective! Pack Sizes: 1.2kg (60 x 20g doses) or 4kg (200 x 20g doses) Disclaimer: The information and recommendations in this newsletter have been presented as a guideline based on the veterinary experience and knowledge of the author, Dr John Kohnke BVSc RDA. Whilst all care, diligence and years of practical experience have been combined to produce this information, the author/editor, Dr John Kohnke, accepts no responsibility or liability for unforeseen consequences resulting from the hints and advice given in this newsletter. The information in this newsletter, or part thereof is copyright. We encourage its use in newsletters and other horse/pony club or association bulletins, provided that the source of the newsletter is acknowledged as courtesy of the author, Dr. John Kohnke BVSc RDA. The information cannot be used for magazine publication unless permission is sought from the author by email info@kohnkesown.com prior to publication. ©Copyright 2015