What I've Learned About Quality Pasture- Part IX

In this installment, I'd like to spend some time relating some thoughts on shade. Through this new information, I am going to be faced with some decisions on how my rotation plan plays out.

Much research has gone into studying the effects of heat and stress on livestock. A cow, in the summer heat, will drink about 400% more water than in the cooler months. This increase is due to the animals desire to keep cool. The magic threshold temperature seems to be 86 F/27 C with a humidity level above 45%. Anything above this threshold is thought to double the stress levels of the animal. In other words, when it is hot, the cattle will eat less. This goes back to an earlier statement suggesting that cows will graze more in the cooler morning hours and cooler, later afternoon and rarely at night. Beeves will not gain as much in hot weather and dairy will not produce as much either. This is what is termed the "summer slump". Cows will rest and chew their cud in the heat of an afternoon, the prime grazing time is from the first light of dawn till around 10:00 am, and again in the later afternoon.

Everyone agrees that heat will stress your animals. The question is; what to do about it? On this point there seems to be little agreement. Conventional wisdom says to provide some shade for the animals. According to research, there has been no significant statistical increase in the production of animals when provided with shade. In fact, the air temperature under a tree is the same as the air temerature in the sun. (What?) The fact is that it only "feels" cooler in the shade because an animal is not recieving direct radiation from the sun while in the shade.

We farmers will get out there and work in the blazing sun wuthout batting an eyelash because the work needs to be done and we're simply doing our job. When we're actively involved in what we're doing, we hardly feel the heat. On the other hand, we don't sit down to rest in the hot sun. We find a shady area to sit in and ciesta.

In hot weather, most grazing is done before 10:00 am. The second is from sunset until dark. Very little grazing occurs in between these hours. I have observed our animals doin just that. Therefore we should allow our animals access to shade during the non-grazing hours. This is unlikely to hurt production.

Mr. Nation also suggests that going to one per day milking after dark in hot weather will help the animals make the most of their limited grazing time. In other words, we might not want to interrupt their morning or afternoon meals to come in for a milking. Let them graze when the need to and get the most out of it and milk afterwards. If we interrupt their grazing to be milked, they simply get less time to eat and, consequently, produce less. This is true for either beef or dairy.

There are acouple of spots on our small farm that would be of concern in reguard to shade. It may be wise for us to let the polywire down after 10 am so they can lie down and ruminate in the shade, then place them back in the paddock in the afternoon to top off their belllies, then milk. According to this information, that plan would maximize their production, thus, less milk to buy because she is producing the most for the conditions.

(For more information on the subject of Quality Pasture, please look for "Quality Pasture" by Alan Nation, or click on the link to the StockMan GrassFarmer found at the left.)