Dairy producers reminded to manage heat in their herds
Contact: Alvaro Garcia
Phone: (605) 688-5488
Tuesday, June 23, 2009
South Dakota high summer temperatures have arrived, and they can be stressful for lactating dairy cows.
The stress can lead to decreased milk production as well as impaired reproduction.
South Dakota Cooperative Extension Dairy Specialist Alvaro Garcia said producers can use several strategies to manage the heat.
Research in Florida, Kentucky, and Missouri has shown that providing shade and cooling by adding sprinklers and fans resulted in increases of 7.1 to 9.2 percent in dry matter intake and 7.1 to 15.8 percent increase in milk production. Reproductive performance was not reported in these trials although it was expected that the improvement in the net energy balance would result in more heats.
In another trial, cows that had been provided with shade reduced their respiration rate and their internal temperature. They also increased conception rate from 25.3 to 44.4 percent, and milk production by 3.5 pounds per day.
The body condition score (BCS) of close-up cows has also an effect on their response to post-calving cooling. Cows that were cooled consumed 3.5 additional pounds of feed dry matter per day. Cooled cows that had an initial low BCS (2.6) lost 0.5 units of condition during the first four weeks of lactation, compared to those with high BCS (3.8), which lost 1 unit.
Cooled cows reached higher levels of peak milk production, and cows with low BCS attained peak milk production earlier than cows with high BCS. Non-cooled cows with low BCS had the lowest milk and fat production.
"These results suggest that body condition score plays a very important role in the performance of cooled cows after calving," Garcia said.
SDSU Extension Extra 4024, "Dealing with heat stress in dairy cows," offers more information on this topic. It is available at this link: http://agbiopubs.sdstate.edu/articles/ExEx4024.pdf. Or ask for it at your county Extension office.
AgBio Communications Unit
South Dakota State University
ACC, Box 2231, Rm 200
Brookings, SD 57007
Telephone: (605) 688-4642
Jarett.Bies@sdstate.edu