Solving summer reproductive problems

439

Heat stress is caused when a pig’s body temperature rises above certain limits, this can have a negative impact on reproductive performance. In these circumstances the pig will first increase its respiration rate in an attempt to keep cool, then search for environmental opportunities for cooling eg wallowing, soiling pen and lying in urine. As we move into summer and periods of higher temperatures make sure you take action as appropriate to minimise heat stress in your pigs. A handy guide to the problems you might encounter, and how to address them, can be found below.

Issue

Why is it a problem?

Where to look for advice
Staff holidays Problems associated with continuity of work. Reduction in productivity if cover staff are not fully trained and standard procedures are not be fully followed. If cover staff are not available the remaining team can become stretched and similar problems may occur resulting in poorer performance. Work Instruction 1: How to write a work instruction
Boar libido In hot weather boars become lethargic and uninterested in working. Action for Productivity 39: Heat stress in boars
Semen quality Prolonged raised temperatures can reduce sperm quality for up to eight weeks following the hot period. Action for Productivity sheets:
30: Semen storage and handling
39: Heat stress in boars
Semen storage Temperature controlled units can struggle to maintain temperatures when the outside temperatures are excessively high. Action for Productivity 30: Semen storage and handling
Water intake & quality Sows will drink more during hot weather, this can mean that they spend more time at drinkers, resulting in submissive sows not getting sufficient water.
Water quality can be reduced when the flow rates are poor and microbial growth can increase in warm water.
Action for Productivity 16: Water supply
Feed intake Sows’ appetites will be reduced in hot weather, however it is essential to maintain sow condition and therefore nutrient intake.

Sows in good condition should return to oestrus within 4-5 days.

Action for Productivity sheets:
3: Heat stress (indoors)

4: Heat stress (outdoors)
39: Heat stress in boars
High temperatures The ‘normal’ thermoneutral zone can range between 7-21 degrees celcius. Outside of this zone sows will have to make changes to try and return to thermal comfort.

In hot weather blood is sent to the surface of the skin to maximise cooling. If sows are in pig, this would mean that less blood is available for the piglets and their development and the piglets born in autumn may be smaller than usual.

Action for Productivity sheets:
3: Heat stress (indoors)

4: Heat stress (outdoors)
39: Heat stress in boars
Sunburn Prolonged exposure to sunlight can result in sunburn, with gilts being particularly susceptible when they first move outdoors or into sow accommodation with an outdoor run. Action for Productivity sheets:
3: Heat stress (indoors)

4: Heat stress (outdoors)
39: Heat stress in boars
Fluctuating wean to oestrus interval & reproductive failure High temperatures can disrupt the hormones involved in pregnancy and interfere with the oestrus cycle, leading to variable standing heat lengths, reduced ovulation rates and increased embryo mortality. Sows can be particularly susceptible to disruption durng the first 15 days post-mating when temperatures rise above 23 degrees celcius. Action for Productivity sheets:
29: Effective heat detection

31: Optimising timing of service