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Minimizing the impact of hot weather on pigs

peet on pigs Ensuring that watering and ventilation 
systems are working properly is important

Reading Time: 3 minutes

The onset of hot weather after a long period of wet and cool conditions means that it’s time to think about the comfort of pigs during the summer. Two aspects of management are the most vital to consider if the impact of hot weather on performance is to be minimized — environment and water availability.

In summer, ventilation systems should move the maximum amount of air with the minimum resistance or pressure. Any deficiencies in the design of the system will be exposed in hot weather, especially sub-optimal fan capacity and air flow restrictions. If there is any doubt about these aspects, it is worth bringing in a ventilation engineer to check not only whether the capacity is correct, but also to check inlet sizes, system operating pressure and the control staging.

Assuming the system has been correctly designed and installed, a hot-weather check should include ensuring that all inlets open fully and adjusting them as necessary. Also, check that there are no restrictions to air movement between the outside of the barn and the inlets, for example at the eaves openings where air enters the loft, or where air from the loft enters an alleyway between rooms in the barn.

If misting nozzles or drippers are installed in grow-finish rooms, check that they are coming on at the correct temperature and also that they are working correctly and producing a fine mist. Too coarse a mist will reduce the amount of evaporative cooling that takes place in the room.

Water intake

The pig’s water intake increases considerably during hot weather, up to double the intake compared to less hot conditions. Therefore it is very important to check daily that drinkers are working correctly for all the pens in the barn. It is good practice to check drinker flow rates at this time of year and rectify any situations where flow rate is less than optimum. Grow-finish pigs and lactating sows are the most vulnerable to poor flow rates and reduced water availability will lead to lower feed intake and worse performance. Table 1 shows likely water consumption and recommended flow rates for different classes of pig in winter and summer.

Pigs need to ingest more water to keep cool in hot conditions because their primary means of getting rid of excess heat is panting, which expels warm, moist air from their lungs. Part of the reason that water consumption, or more correctly water disappearance, goes up in summer is that, when they are able, pigs will use the drinkers to wet themselves to increase evaporative cooling. They will also choose to lie where the air speed in the pen is the highest, usually in the dunging area, to increase their body heat loss.

Feed intake

Lactating sows are the most vulnerable to hot conditions and reduced feed intake typically leads to lower weaning weights over the summer, combined with increased weaning-to-service intervals. One approach to minimizing the impact of hot weather is by changes to the diet. As the sow eats less, the intake of lysine and other amino acids can be maintained by increasing their content in the diet. For example, a typical lactation diet with 1.0 per cent total lysine could be replaced with one containing 1.2 per cent.

Another approach to consider is to replace some of the dietary energy provided by starch with fats or oils. These produce less heat as a byproduct of metabolism than starch, reducing the excess heat produced by the sow. However, the practical evidence for this being a successful strategy is not at all conclusive and the cost per unit of energy for oils is higher than that for starch.

Feed tends to deteriorate quickly in hot weather, so careful trough management in the farrowing barn will help to maintain feed intake. Increasing the number of feeds per day is a simple strategy to both keeping feed fresh and also increasing feed intake. Feeding 4-5 times per day has been shown to result in higher intake. Also, as lactating sows will eat during the night when the room cools down, an evening feed can provide the biggest meal of the day.

Reduced appetite due to hot weather has a huge impact on production. While some of this is unavoidable, careful attention to ventilation, water supply and feed management of the lactating sow will help to minimize the loss of performance.

water     requirements and drinker flow rates

  1. Nursery, 6 – 15kg
  2. Nursery, 15 – 30 kg
  3. Finishers, 50 – 70 kg
  4. Finishers, 101 – 120 kg
  5. Gestating sows/boars
  6. Lactating sows
  7. 0.5 – 1
  8. 2.5 – 3
  9. 4 – 5
  10. 6 – 7
  11. 6 – 10
  12. 15 – 25
  13. 1 – 2
  14. 3.5 – 4.5
  15. 6 – 8
  16. 7 – 9
  17. 10 – 15
  18. 20 – 35
  19. 0.7 – 1
  20. 0.8 – 1.2
  21. 1.5
  22. 1.5
  23. 1.5 – 2
  24. 2 – 3

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