In last week’s blog I wrote about the cooling needs of today’s genetics. I received quite a few calls and emails asking about a lower limit (either age or weight) for cooling strategies to be used.
I’m not sure if there is a ‘lower’ limit when conditions approach those of last Wednesday (heat indexes will about 100F across a large part of the central and upper US). With a skin temperature of approximately 95F, when it gets warmer than that in the pigs surroundings something must be done to assist the pig with heat loss.
I had the chance to demonstrate this on Thursday. I was in a swine nursery with pigs that weighed 30-35 lb. Air temperature in the nursery was 90-91F and pigs were crowded around the bowl drinker in each pen. Those that weren’t around the drinker were lying on their side with elevated respiration rates. At 2 pm in the afternoon there were no pigs at the feeders and no unnecessary pig movement in any pen.
The nursery manager, along with others from the production system, asked about cooling of pigs – were these pigs too young? To demonstrate the impact of a cooling regimen, we took a hose and wet the pigs in the pens nearest to us. Within minutes of becoming wet, pig activity increased. Some of the activity was due to the novelty of having a wet floor (plastic coated), but a lot of it was due to the immediate impact of heat relief. In all of the pens that we wet pigs in, pigs were observed with heads in feeders within 5 minutes of being wet and there was no crowding around the drinker in an attempt to get wet. In this nursery, while there were ventilation challenges there was sufficient air flow above the pigs to keep the room from becoming a steam bath.
For many years I have recommended that producers install drippers/misters in swine nurseries. These pigs get hot when the heat index gets above 100 and the addition of water to their skin is just as effective as it is for grow-finish pigs or sows. The length of time required to wet the pigs is shorter, and the off time for the pigs to dry may be longer, but with careful observation you can learn what will work in your facility.
Adequate ventilation is a key to making this work. If your nursery is short of ventilation, adding water to the air from the pigs drying off will make the heat index in the nursery even higher. Assuming you have respectable ventilation in place in your nursery, I recommend that you wet the pigs at 18-20F above the controller set point. Start with 1 minute of wetting (more or less depending on the nozzles you have and the distances involved) and 30-45 minutes of drying. Be sure the system shuts down every evening (midnight to 10 am?) so that you get everything thoroughly dry in the facility every day. The last thing we want to have happen is to cause a disease challenge such as Salmonella or Strep due a humid environment 24 hrs a day.
If you think I’m still crazy about this, I suggest you take a garden hose in your nursery and wet the pigs 3-4 times from 2-8pm when the heat is the greatest. I think you’ll be surprised how much more active the pigs are and how often they go to the feeder versus if you don’t assist them with heat relief.