In addition to using traditional cooling methods, have you ever given thought to how your cows’ diets could play a role in tackling heat? Recent research suggests certain nutritional strategies can actually help lessen the effects of heat stress.

Dry cows are the up-and-coming milk-makers in your herd – yet when it comes to cooling, they are often overlooked. A study conducted by the National Animal Health Monitoring System (NAHMS) revealed that 74.3 percent of all dairy operations provided fans for their lactating herd, while only 36 percent offered fans for dry cows. The milking herd on 20.3 percent of all operations was also cooled by sprinklers, yet only 4.6 percent of dry cows had access to this cooling method.

Environmental factors such as temperature and light influence dairy cow productivity and health. Heat stress during lactation accounts for 10 to 25 percent of milk production loss on average. If you were milking cows this past summer, you can probably agree with that. In the upper Midwest, we faced a 4-pound to as much as a 30-pound drop in milk production. It’s easy to quantify the effect of heat stress on milking cows, but how can we really know its effect on dry cows? Does it even have an effect? During the dry period, the udder cells are recovering from the previous lactation and preparing for the next. This is the time to replace the old milk secretory cells and grow new cells that will support milk production in the next lactation. Heat stress during this important time of cell turnover can dramatically impact transition into the subsequent lactation.