Select Sires

Managing Transition Cows
in Hot Weather
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired Aug. 7, 2003
With Jim Spain, Associate Professor of Animal Science,
University of Missouri, Columbia

Jim today you have strategies on what to look for in transition cows.

Bill, one of the things that producers often overlook is what we are doing to cool that cow in the close-up pen; the cow that is three to four weeks before she is due to calve. Let’s think about that cow, she is on a high fiber diet; she has a calf that is growing by leaps and bounds. That cow is beginning to synthesize colostrums to provide that calf with a good sound start and that cow is generating a significant amount of internal heat. The question is, what are we doing to help those cows lose their body heat, or what are we doing to protect those cows from the radiant solar heat load. We are finding that if we cool our close-up dry cows twice a day, in the morning and in the evening, we are adding three to four pounds of milk produced per-cow per-day after they calved. Those cows that are cooled maintain higher blood glucose; and lower blood ketone levels which means those cows are going to be less susceptible to some of the metabolic diseases associated around calving. So, when we look at trying to help these transition cows, especially during the pre-calving, that last three to four weeks of gestation, we are looking at two things.

Step one: Try to do everything we can to reduce the solar radiant heat load, do we have shades up, do we have those cows where they have good accessibility to shade. Do they have to travel a long distance through sun to get to feed or to water, or can we put together a system or modify our current system so we minimize how much heat that cow is going to have to balance coming from the sun. That is step one and a step that we often overlook with these close-up dry cows.

Step two: Can we identify a way that we can cool these cows with fans or sprinklers for a couple of hours every day to help them loose that heat that they are gaining. We like to accomplish that late afternoon or early evening so that the cow can get back down to a thermal balance. We are going to expect that to help her maintain a better feed intake and a better energy balance. As a result of that, to have fewer metabolic problems that can be associated with calving difficulties. Also, because of fewer metabolic problems, to lead into higher levels of milk production in that lactation. Let’s start with looking at managing heat stress with a cow herd with that cow that we often overlook. That cow that is in the close-up pen three to four weeks before calving, and let’s take care of that cow that is going to be dealing with the stress of calving by trying to reduce and minimize the stress of hot summer days.

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