EQUINE NEWS And Trade Services Directory - Vol 12 Issue 3 - SUMMER 2020/21

Bedding

and the air that we breathe...

Dr Jennifer Stewart

CEO BVSc BSc PhD Dip BEP

DON’T BREATHE BEDDING

So many bedding materials available – each with advantages and limitations. Wood-based beddings have inferior fluid and ammonia binding capacity but produce less dust. Straw pellets reduce ammonia levels and paper bedding is more absorbent and has lower aerial ammonia levels than sawdust bedding. Paper-based and wood-shaving bedding have a lower level of microbial contamination than straw and less moisture/urine accumulation than sawdust. Sawdust is less absorbent with more urine pooling on the floor and higher stable ammonia levels. Stable mattresses reduce the amount of airborne moulds. Confusing!

Bedding material has been evaluated for properties such as dust production, moisture absorbency, impact upon equine behaviour and airborne contamination. Choice of bedding material is important especially for air quality and respiratory hygiene. Stables and stalls are bedded to absorb urine, moisture and gases and to increase the comfort, health and wellbeing of the horses. Good bedding creates a layer of insulation between the horse and a cold floor, pads the hard surface, prevents bruised and capped knees, elbows, hocks and hips, and helps keep horses clean. It also needs to be easy to handle and have good composting properties.

Factors to be considered when selecting bedding are availability, cost, cleanness (free from dust and foreign material), effect on stable air quality and on the health of horses and people – because bedding material has a major affect on air quality, dust, ammonia, bacteria and toxins in stables, stalls and arenas.

Air quality is affected by bacteria, fungi, viruses, mites, allergens and airborne particulate matter (APM) – the particles in air that can penetrate the respiratory system and cause harmful effects. The amount of APM in stable and arena air affects the amount of secretions in the windpipe and lungs. The aim of stable management is to keep APM as low as possible. The main sources of APM in horse stables are bedding, feed (forage and concentrated feed), hair, skin and manure – with bedding and feed the major sources. Rolling and crushing grains

increases small particles from 19 to 202% whereas cleaning and sieving reduces small particles. Pelleted and steam-flaked feeds produce very low amounts of small particles and adding oil, water or molasses reduces small particles by up to 90%.

Airflow is critical to reducing APM in stables. High, open airy stables reduce the amount of APM in the breathing zone of horses. Horses in enclosed stables with high walls separating the stalls, closed windows and little airflow have 4 x as much mucous in their windpipe. Weather also influences the amount of APM – hot, dry days increase APM and mucus production. High rates of APM and poor ventilation lead to an explosion of APM concentration in the stables. This increases further during sweeping, bringing in bedding and mucking-out. The composition of the APM also changes during mucking-out, with an increase in fungal spores and toxins. Sweeping leads to a 5-fold increase in toxins and APM in the breathing zone of stable workers and horses for several hours. Wearing a mask and taking horses out of the stables, moistening the corridors before sweeping and opening doors and windows, reduces APM.

Stable cleaning activities also affect air quality in the riding arena if the two are connected. Connecting doors left open while mucking out and refilling of bedding in horse stalls lead to rise in arena concentration of airborne moulds by 2753%

If a riding arena is connected to the stables, the doors should be closed while stables are mucked-out and swept.

Riding in arenas also produces large amounts of both small and large particulates. During the canter and gallop horses move up to 1200 litres of air per minute, compared to around 60 litres at rest. This increase in air intake = increased intake of airborne contaminants. Trotting and galloping disperse the highest APM concentrations in the air of the arena. Riding instructors too are affected by air quality and have a significantly higher rate of diagnosis for chronic bronchitis and asthma than the general population – up to 40% of instructors working indoors experience chronic bronchitis, compared to only 26% of outdoor instructors. Crumb rubber from recycled tyres can significantly reduce APM in indoor arenas when applied over the existing sand surface. The effect is the same whether the depth of rubber is 4 or 7.5cm. Rubber flooring, foam flooring, pure sands and moist or wet footing materials generate the lowest concentrations of APM.

Wood shavings produce 38% and straw pellets 63% less APM than wheat straw, making them well-suited for horses with allergies, respiratory infections or chronic respiratory disorders or conditions. Bedding material such as hemp or linen shives are often recommended as dust-reduced alternative beddings, but studies have found they produce significantly higher APM than wheat straw, wood shavings, straw pellets and shredded paper/cardboard.

PAPER Recycled paper has been investigated for stable bedding. Printed paper (eg newspapers and phone books – if you can find any!) had no effect on heavy metal or trace element toxicity. Paper bedding was also more absorbent and had a lower usage rate compared to straw and wood shavings. The phone book paper bedding was more absorbent, had a cleaner appearance and lower aerial ammonia levels

than the sawdust bedding. Horses housed on phone book paper had a dustier outward appearance, but skin health was not affected. Pelleted newspaper keeps the hair coat cleaner than shavings and is easier to compost. The main advantage of phone book/recycled paper is its high absorbency of urine which allows for easy removal of urine spots and reduced ammonia levels in the stable/stall air – it can however form clumps of ‘paper mache’ and pack into the hooves. WOOD PRODUCTS – wood pellets have several benefits with higher microbial purity and improved endoscopy results when compared to shavings, saw dust, pelleted and chopped wood. Dust-free, untreated pine shavings have some anti-bacterial effects and are resistant to several equine ‘germs’. Different bedding types have different levels of contamination by bacteria that can cause diseases in horses. One of the key aspects of disease control is reducing exposure to pathogens. In the stable this means ‘clean’ bedding. Hygiene and water holding capacity is of particular importance, as excess moisture from urine in the bedding can contribute to foot problems and ammonia. There are some studies dealing with the effects of bedding materials on the behaviour and wellbeing of the horse. Use of any bedding other than straw was associated with a higher incidence of stereotypic activities (wood chewing, weaving, wind-sucking). Time spent lying down doesn’t differ between straw, sawdust, husk or fibre, but re-using bedding reduces lying down and can impact welfare and hygiene. Damp bedding is an ideal medium for survival of several equine diseases – including strangles and fungi that infect the skin and hooves. Pine bedding presented with significantly less bacterial growth when compared to other commonly used equine bedding substrates, including hemp and straw. Pine shavings have the lowest bacterial growth and the highest moisture-holding capacity - absorbing and retaining more urine and for up to 24 hours compared to straw bedding which absorbed urine for only 8 hours. As well as affecting the horse’s

respiratory tract, allergens and other irritants can compromise the horse’s overall performance. Poor quality stable air may reduce exercise tolerance in horses that appear completely normal at rest.

We’re always looking for alternate bedding materials that will help to keep stable and stall surfaces dry, pathogen levels low and reduce ammonia levels – all in a cost-effective manner. High ammonia in horse stalls can be a predisposing cause of foal pneumonia, and certain natural defence mechanisms of the horse’ s respiratory system can be inhibited by exposure to ammonia. Foals and horses that spend a lot of time lying down are exposed to much higher levels of ammonia in their breathing zone as they are closer to the ammonia source (urine and manure). Choose the bedding for each horse especially if your horse has a clinical problem, is young or has a wound or skin problem. APM concentration varies widely in forage and bedding according to type and manufacturing process. Ask the manufacturer for details on hygiene, moisture holding capacity and whether it has been ‘treated’ with or contains any chemicals.

ABOUT THE AUTHOR – Dr Jennifer Stewart

CEO BVSc BSc PhD Dip BEP Equine Veterinarian and Consultant Nutritionist

Dr Jen Stewart has been an equine veterinarian for more than 40 years and an equine nutritionist for more than 10 years. Jen has been developing premium formulas for studs, trainers and feed companies in Australia and around the world and regularly consults to leading international studs and trainers in various countries.

Jen has spent a fair bit of time researching and being involved in nutritional management of developmental orthopaedic diseases, colic, tying-up, laminitis, performance problems, post-surgery and other conditions. And is currently the only practicing equine veterinarian and clinical nutritionist in Australia. Jen’s promise is to continue to BRING SCIENCE TO YOUR FEED BIN www.jenquine.com