Breathing frequency reveals heat stress of sows. Do you know the normal breathing frequency?
Until a certain level pigs are able to control their heat release. When the room temperature is too cold they huddle against other pigs, and pull their legs up under their body. When it is too warm they will try to keep away as far as possible from other pigs, lay down widely, and eventually increase their breathing frequency. The temperature range in between is called the thermal-neutral zone.
But how do you know whether a sow in the farrowing pen experiences heat stress? After all, judging her laying behaviour is useless, due to individual housing. An alternative would be to count the breathing frequency of some sows in the farrowing department. Is their frequency considerably higher than the normal value (see table), than the sows experience heat stress.
|Age of the pig||Breathing frequency|
|Mature pig (sow)||13-18|
It will be rewarding to not only look at sows but to look at other age groups as well, and count their breathing frequency.
If a sow in the farrowing pen experiences heat stress, there are two real risks.
- A longer parturition. A longer parturition can lead to more still born piglets, less vital piglets and a lower colostrum intake. The preferred parturition length depends on the total number of piglets but is preferably not longer than 3-4 hours. Furthermore, keep an eye on the piglet-to-piglet-interval. This should not last more than of 45 minutes, or that the last born piglet is not completely dried before the next one shows up. Use this as guidelines for your farrowing management.
- A reduced feed intake of the sow. A reduced feed intake of the sow during lactation leads to a higher body condition loss than preferred. During the farrowing phase (from farrowing to weaning) the sow’s body weight loss should not exceed 10 %. A higher body weight loss will have a negative effect on the number and quality of the follicles (eggs) during the next oestrus, and therefor also have a negative effect on the number of life born piglets of the next litter. The upper limit room temperature for sows in their third week of lactation is 18 degrees Celsius. Each degree more in room temperature causes a decrease in feed intake of 170 grams per day.
Cooling tips for hot days
- Provide sufficient and cool water; so check the drinking nipple flow!
- Cool the incoming air.
- Adjust the feeding time to a cooler period of the day.
- Watch out for large temperature changes between day and night, and adjust the ventilation level accordingly.