UNL Extension Educator,
Webster County
July 22, 2011 Edition I remember now why I prefer the Fall of the year. Cool weather! I guess you could throw in football for good measure. There is nothing like a cool fall night and football to make you feel alive. This incessant heat and humidity has a tendency to make you feel the opposite. I really believed that we would get a reprieve after the brutal climate that was bestowed upon us during our county fair. We did have a couple of nice days, but those other days were enough to make you look for a watering hole. I can’t seriously remember when we had a spell like this. I know I heard my parents and grandparents talk about the 30’s and 40’s and I remember the hot and dry spell of the early 50’s and even in the mid 70’s and during most of that time there was little or no air conditioning in homes or vehicles. We at least can get some release in today’s world.
We, in South Central Nebraska, of course, remember the 7 year drought that we experienced between 2000 and 2007, but I don’t recall the heat and humidity both being so brutal for so long. It can get somewhat depressing, but if you look around, we actually don’t look too bad – so far. Yes, I know, looks can be deceiving. The pastures are starting to show the effects, as are some of our dryland crops. You do see some “pineappling” of corn and milo leaves, soybeans are cupped in some fields and there is a blue look to a lot of the crops, alfalfa and pastures. Some stressed areas from too much moisture early on are turning white. But as a whole, things are holding on. One only has to look to our neighbors to the south and southwest to feel pretty good about our state of affairs.
One thing is for sure, this environment has not been so kind to livestock. I have met the “dead wagon” much more often than I would like to. It of course brings my thoughts to the animals who suffer through this worse than any other organism. With a long range forecast of more of this “brutality”, I thought we may want to look at some effects and tools for dealing with heat stress this week. We sometimes become rather impervious to what is going on around us when we experience these little acts of nature. I don’t know if you really get used to it, but perhaps tolerate it a little better and then we may get a little complacent. We may not see that things that are happening around us and actions may be too late.
There isn’t much we can do concerning the crops, especially if we don’t have irrigation. No-till operations have done wonders for water conservation and management of our crops. If a producer still does conventional till he may want to rethink that as every time you make a pass through the field with a cultivator or disk you make the soil even hotter and moisture is compromised, as are the plants. I have been watching fields these past couple of weeks and have noticed that everything seems to be pollinating. You could probably get verification from people who suffer from allergies. I have also heard people complain of headaches which they blame on corn pollination. I am not a doctor, but I suppose that is possible.
What is the big deal about pollination? While it is common knowledge that corn and even other crops like heat, it is not conducive to the plant at pollination. For corn, the ultimate temperature for pollination is 86 degrees. We have been over that by quite a bit over that last couple of weeks. Pollination is a critical period for corn development and yield. Pollen shed occurs over a two-week period. For kernels to develop, silks must emerge and be fertilized by viable pollen. Silks grow about 1 to 1.5 inches a day and will continue to elongate until fertilized. Temperatures greater than 95° F with low relative humidity will desiccate exposed silks, but not impact silk elongation rates greatly. Pollen is no longer viable once temperatures reach the mid 90's or greater, especially with low relative humidity. Fortunately, pollen shed usually occurs from early to mid-morning when temperatures are lower. If the corn markets have been a little unstable the last couple of weeks, concern about heat stress could be the reason.
While we can’t really have much effect on the crops, we can however have an effect on our animals. The best thing we can do is keep an eye on them and look for the signs of stress and then do something about it. Temperatures like we are experiencing coupled with high humidity can cause heat stress. This stress causes general discomfort, decline in animal performance and even death. Heat stress is defined as any combination of temperature, humidity, radiation and wind producing conditions higher than the animal’s thermal neutral zone. Beef cattle cool themselves primarily through breathing. They sweat only about 10 percent of what humans do. Light colored animals can experience sunburn and Angus and other black animals can be easily overheated by radiant heat because the black absorbs more of the sun's radiant heat.
Either open-sided sheds, trees, or other shade can reduce the radiant heat by as much as 40 percent. I might even suggest rigging a shade for livestock that don’t have access to it in open pastures or lots. Corn cribbing stretched over quick built pole frames works wonderfully well. Clean, fresh and preferably cool drinking water in good supply is vital to beef cattle in hot humid weather. Beef cattle cool themselves by panting and some sweating. In panting, there is water loss from the lungs. Since beef animals do not sweat, in extreme heat, they may need to be sprayed with water to keep them cool. Whatever you do make sure that they be given plenty of fresh water, shade and ventilation. If a four-legged farm animal refuses to eat, is salivating excessively, exhibits labored breathing or has convulsions the vet should be called and the animal bathed in cool water starting at the ribs and working the way down the legs. Don’t forget about your pets, and don’t forget to take care of yourself – It can sneak up on you. Keep hydrated and ----keep cool!
The preceding information comes from the research and personal observations of the writer which may or may not reflect the views of UNL or UNL Extension. For more further information on these or other topics contact D. A. Lienemann, UNL Extension Educator for Webster County in Red Cloud, (402) 746-3417 or email to: dlienemann2@unl.edu or go to the website at: http://www.webster.unl.edu/home
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