Select Sires

Effective Cooling Systems
for Improving Fertility
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired Aug. 14, 2003
With Jim Spain, Associate Professor of Animal Science,
University of Missouri, Columbia

Jim, we’ve been talking about what we can do to help facilitate the heat loss that cows are generating, and an effective cooling system benefits milk production and feed intake during the period of heat stress, but it also has a very positive effect on fertility and conception rates. Tell us about it.

Fans and sprinklers are going to be the key component of the system. We need to look to see if we can’t strategically operate those to maximize the heat transfer. For one example, we certainly encourage producers in their holding pen, which is under cover and shaded so that we reduce the exposure of the cows to sun while they’re crowded in the holding pen before milking that we use sprinklers, that we use fans to try and minimize the effects of the crowding on thermal balance so that those cows don’t come into the parlor after having gained heat in the holding pen. But when they return to the barn, we need those fans strategically placed so that we’ve got maximum air movement over the skin of the cows. We like to see the fans over the free stalls because that’s where we want those cows spending their time laying down in clean, dry, comfortable free stalls. We like the sprinklers over the feed line if we can manage the water and we’re not having problems with the sprinkled water getting over into the feed or over into the bedding and into the stalls. Some folks use misters, some use sprinklers, some use foggers. That water needs to be used in a manner that’s best for the housing environment that each one of the producers is using on their individual farm. One of the places that we often overlook our opportunity is when it cools off at night. Many of our cooling systems have been designed to where they’re hooked into a thermostat. That when it cools off at night it turns those fans off, and that’s really we think as a missed opportunity, that we can use that cooler night air, turn the sprinklers off because we’re not going to be using evaporative cooling now, we’re going to use convective cooling, where we’re pushing cool night air across the skin of the cows and helping them lose the body heat. So instead of setting the thermostat at 70 or 72 degrees Fahrenheit, we’re dropping the thermostat on the fan control down to that 60 to 65 degree range, so that those fans run a little longer at night and cool those cows a little more and help those cows get back down to thermal balance. That costs us a little extra electricity, and we recognize that, but we think the benefit is that in keeping those cows cooler we can undo some of the adverse seasonal effects on fertility. That cow is going to eat a little better, and because she eats a little better, she is going to stay in a little better body condition. Because she stays in a little better body condition, we know that’s going to have a positive effect on fertility, especially for the cows that are calving in August, September, and in some parts of the country, October. Cooling cows in that early lactation is critical to their stand on a high plane of nutrition and their ability to achieve high fertility and high first service conception rates when we start breeding those cows back in late October through early November. An effective cooling system will have a benefit on the milk production and on feed intake during the period of heat stress. It’s also going to have a very positive effect on fertility and conception rates when those cows are reaching that end of that volunteer waiting period and entering into the breeding herd on the dairy.

Select Sires Inc., 11740 U.S. 42 North, Plain City, Ohio 43064 / Phone: (614) 873-4683 Fax: (614) 873-5751