STRATEGIES TO DEAL WITH THE HEAT IN COMPETITION HORSES

Transcription

1 STRATEGIES TO DEAL WITH THE HEAT IN COMPETITION HORSES The Normal Horse Heart Rate: bpm Respiratory Rate: 8-16 bpm Dr Anushka Chaku BSc BVMS MANCVS Temperature: C Membrane colour: pink, moist, refill time <2s Helping Your Horse in the Heat Environment: Good Ventilation Avoid respiratory problems & airway stress Diet: Low Heat Feed Minimize hindgut fermentation Processed or micro-ionised grains Fats Wet feed Add Salts 40-60g during competition Helping Your Horse in the Heat CONDITIONING! Builds circulatory & respiratory systems Improved muscle circulation = Improved oxygenation Improved waste removal Interval training improves: Fitness Muscular endurance Handling of physical & mental stress

2 Conditioning Continued... Heat Generation in the Body Thorough warm up Improves muscle perfusion = Oxygenation & Waste Removal Acclimatise the horse to heat Graduated programs Reduce the intensity and duration Active cool down Movement facilitates evaporation Maintenance of blood supply to muscle How Does it All Connect? Muscles & Nerves require a balance of ions to function normally Sodium (Na + ) Chloride (Cl - ) Potassium (K + ) Calcium (Ca ++ ) Magnesium (Mg + ) Importance of Sweat Large ability to sweat 2x ability of humans Heat loss via sweat =65% Heat loss via airway = 25% Evaporative Cooling Like an air conditioner Heat transported away from core In humid conditions Reduced effectiveness of sweating respiratory effort

3 Importance of Sweat Horse sweat VERY SALTY Loss of important salts for muscle and & nerve function Na + Cl - Increase loss of salts with: body temperature intensity of exercise heat and humidity High volume body water loss 10-15L/h exercise = measurable loss ions Total fluid loss up to 8-25L With prolonged moderate exercise: Continued losses next morning (up to 3-12L) Electrolyte Loss oor Electrolyte management may lead to: Poor Tissue Perfusion Lactic acidosis Muscle spasm & Tying up Thumps Metabolic alkalosis Arrhythmias Gastrointestinal stasis Kidney dysfunction Effect of Body Type Larger horses: Reduced skin surface area : Body mass = Less evaporative capabilities Increased muscle mass = heat generation Fat = Insulation Colour Lighter horses reflect more heat Factors Affecting Heat Stress Outside temperature Relative humidity Hydration status Electrolyte depletion Fitness of the horse Movement Surface area : Body mass ratio History of Anhidrosis

4 What is Heat Stress? Signs of Heat Stress Profuse sweating No sweating (ANHIDROSIS) Skin dry and hot Suboptimal performance Rapid Respiratory Rate > 20bpm Rapid Heart Rate > 50bpm Rectal temp >39 C Poor membrane colour and refill Signs of Heat Stress Poor skin elasticity Diarrhoea Colic Fatigue Muscle tremors & Tying up Nervousness Kicking out with hind end Central nervous system very susceptible high body temperatures Convulsions & collapase Management Alternate: Sponging with cold water Scrape Walk airflow facilitates evaporation & dilation of skin capillaries Active cooling Keep horse walking between sponging Use fans to enhance evaporation Especially in humid environments Encourage horse to drink Offer plain H 2 O and electrolytes Shade

5 Examples Of Cooling Aggressive Cooling Vet Checking 4* CCI Temperature: C HR: bpm Evaluate horses for signs of distress Horses checked every 5 minutes Make sure heart rate & temp Horses released once: HR <60 bpm Temperature < 39 C Pass soundness check Strategies to Minimise Heat Stress Ensure the horse is well hydrated before work Administer and electrolyte solution before work Offer water at same time If hot and dry: Pre-cool before work Starts evaporation early Delays onset of sweating and body water loss Warm up in shade After work Aggressive cooling until body temperature down to 38 C

6 DONT S Do not believe: If the horse doesn t sweat that it is fit Do not restrict water intake Do not put cold sheets or towels on horses back Increase heat retention Do not force horse to remain stationary post effort Anhidrosis Also known as: Drycoat Non-sweating syndrome The puffs No age or sex breed predisposition Inherited component Horses exposed to: Constant humidity and high temperatures May lead to insensitivity of sweat glands Up to 25% horses in heat affected Anhidrosis Sweat patches only at mane and tail Hair loss around face Scurfy and inelastic skin Core temperature dramatically Marked in respiratory rate Respiratory alkalosis Physical confusion Burning sensation Loss of conciousness FEI Regulated Competition FEI standards: Provision of veterinarians Cooling facilities Unlimited ice Wash bays Misting fans Wet Bulb Globe Temperature Index used = COMFORT INDEX Composite temperature Temperature Humidity Wind speed Solar radiation Events discourage when WBGT over 33

7 Equestrian WA New policy submission for events during hot weather Change time of year of event or, Change time of day: Between 7am 11am & after 5pm Reduction of effort Distance or jumping efforts Increase education If event held between 11am 5pm when WBGT highest Provision of FEI standard cooling facilities Wash bays Free ice Shade Dr Anushka Chaku Bullsbrook Veterinary Clinic Phone: