Dog Days of Summer
As I sit to write this article, the actual temperature is 110 degrees Fahrenheit. It is down right uncomfortable for anybody or anything that has to be outside during the heat of the day. Definitely, the “Dog Days of Summer.”
If you read this article regularly, you know that I am a dog enthusiast. Border collies and livestock guardian dogs of varying breeds are what I have personally and most of what we work with at the Research and Extension center. Neither of these breed types were originally selected to endure this type of heat. Black coat color absorbs the most heat and long dense coats are the hardest to thermoregulate in these extreme conditions.
Growing up I always thought that “Dog Days of Summer” was a pun on how these animals in particular had to endure the hottest months of the year. But in preparation for this article I did a little research and learned it has nothing to do with Border Collies or big white dogs at all.
According to the farmers almanac, the hottest part of the summer coincides with the time of the year that the star “Sirius” rises and sets with the Sun. Sirius is part of the constellation Canis Major, the Greater Dog. Ancient Romans believed that Sirius was responsible for the added heat, when in reality it has to with the length of time the Earth is exposed to direct sunlight.
Heat stress can have a big effect on the health and productivity of sheep and goats. I conducted a heat stress research project during my masters program in New Mexico. During the summer it routinely reached 110 degrees throughout July and August. We tried to measure the impact of embryonic survival when sheep were bred during these hot periods. Unfortunately, the research project failed to identify any measurable difference in embryonic loss compared to traditional fall breeding. This was countrary to other published literature.
As we tried to decipher why this difference occurred, we concluded that our research project only exposed sheep to heat during the day and not at night. The sheep were able to maintain normal body heat, as long as they limited activity to the cooler nights, which are common in the Chihuahua desert. As the saying goes, I learned more from this failure than had we been successful. This learning has stuck with me for nearly two decades.
When people ask me how to help animals deal with heat stress. My initial question is always “What temperatures does it drop down to at night?” and “Can the animals relax in the shade during the day?” These are important aspects to determine if heat stress is evident or not. Adding multiple water sources could also potentially help utilize more pasture, as livestock typically don’t travel far from water when experiencing constant extreme temperatures. It is also critical to reduce as many other “stressors” that your sheep and goats may be experiencing as well, e.g. monitor them closely for internal parasite burden and if livestock must be worked, try to contain the activities to just the early morning hours.
One thing that further worries me about this year in particular in the San Angelo area is the lack of quality forage in the pasture. I am routinely observing whitetail deer up and foraging during the heat of the day. Why would they be doing this instead of seeking shade? I suspect, it is the lack of quality forage in the pasture for them to find at night and they are forced to search for nutrition during the day. Basically, adding insult to injury.
For our livestock, I would encourage you to supplement sheep and goats that are exhibiting this same type of behavior to help them get through the dog days of summer without losses in productivity.
And, of course, pray for rain!
To provide feedback on this article or request topics for future articles, contact me at firstname.lastname@example.org or 325-657-7324. For general questions about sheep and goats, contact your local Texas A&M AgriLife Extension Service county office. If they can’t answer your question, they have access to someone who can.