Although we may not have the same degree of heat stress as some other areas of the country, the research indicates that cooling dry cows is good for milk production and profitability. The research also shows that the developing fetus benefits and these benefits may last at least through their first lactation.
Figure 1. Milk production response of cows cooled during the dry period. Source: Tao, et al., J. Dairy Sci., 2011.
The same approach used to cool lactating cows should be used for dry cows. First make sure that they have access to shade. Consider fans and sprinklers during the hottest part of the day. It is advantageous to cool cows during the entire dry period; however, the research showed that there was still a milk production response in cows only cooled during the close up period.
With summer coming, now is the time to evaluate your farm's cooling strategy. Just don't forget about the dry cows. This will pay dividends in more milk production, less disease after calving and healthier more productive calves.