Heat Stress Reduces Performance

By Kayt Johnson, BPEX Knowledge Transfer Manager - This report is part of a series of articles offering top tips for hot weather from BPEX's Knowledge Transfer.
calendar icon 11 September 2006
clock icon 4 minute read
  • If the boars are heat-stressed fertility will be reduced for up to 8 weeks
  • If number born is down by one pig per litter, you will lose £25/sow/year
  • If growth rate cut by 50 g/d, = +1 week to slaughter, you will lose £1/pig

You can reduce heat stress by applying the WWWS rules:

  1. WATER - Ensure adequate supply of cool water at all times to all pigs
    1. Are all drinkers working?
    2. Is flow rate adequate?
    3. If in doubt supply additional water in troughs, keep topped up
  2. WIND – Maximise air flow
    1. Check and clean existing fans,
    2. Add fans and open doors
  3. WETTING - Pigs can’t sweat but can keep cool if their skin is damp
    1. Allow older pigs access to wet concrete if possible
    2. or provide small amounts of water over neck and back, repeat every 1-2 h (particularly for boars, lactating sows and sows in late pregnancy)
    3. Wallows for outdoor animals
  4. SHADE - Provide shade

Breeding Herd – apply WWWS, plus:

  • Serve at either end of the day where possible
  • If AI is outdoors ensure that the holding areas are covered
  • Use young, virile ‘V’ boars in pairs or threes for maximum stimulation
  • Temperature control of AI doses is vital, they can overheat very quickly
  • Maintain hygiene of sows especially where they have been wallowing, ensure clean vulvas pre-insemination. Have hand washing facilities and / or gloves
  • Keep boars cool
    • Heat stressed boars have reduced fertility now and in 6 to 8 weeks time
    • Mark this period on your calendar and remember to check semen quality
  • If using a high level of natural service you might top up with AI don’t rely on NS.
  • If using DIY AI boars check semen quality carefully.

During Lactation– apply WWWS, plus:

  • Feed twice a day if not already
  • Feed the larger meal at night
  • Check the trough hygiene, feed can become stale rapidly.
  • Check water availability and flow rate at peak demand - 2 litres/minute for lactating sows.
  • Put water in feed trough.
  • Control supplementary heating in farrowing, use only where necessary for the young/small pigs according to the housing environment.
  • Use dimmers if you have them
  • Cover the creep areas to keep the sow as cool as possible.
  • Cool sows by wetting with small amount of water to neck but make sure piglets do not get chilled.

Dry sows – outdoors – apply WWWS, plus:

  • Dry sows are especially vulnerable up to 2 weeks post service
  • Check arc insulation – sows lying outside are a sure sign that the insulation has deteriorated.

Dry sows – Indoors – apply WWWS, plus:

  • Use less straw, make wet concrete area available if possible

Growers/finishers – apply WWWS, plus:

  • Check the water flow rate and quality 1 litre per minute for 30kg pig 1.5 for 70kgs.
  • Reduce the stocking density where possible so that pigs are able to lie away from each other.
  • Check thermostats
  • Use foggers or misters if necessary
  • Check that the food is fresh –feed will become stale very quickly, consider ordering less feed more frequently particularly if bulk bins are exposed to direct sunlight
September 2006

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