Heat Stress in Dayboro MDI my Cow knows it all

Heat Stress in Dayboro MDI my Cow knows it all

 Let me introduce you to ROBERTA.

Roberta is the name of one of my cows. She is my MDI’er telling me when it is too hot to play outside. There is no direct relationship with any of the Roberta’s in Dayboro town, or even in the Dayboro District. The name was purely chosen based on the random selection.

I do have a very rigorous name selection process. For example “Little Roy” is named after Roy (my neighbour). Currently, I am not sure which of the Roy’s is the little one. On the property we produce bulls predominantly, I figured we call the next one “Little Robby” (after Roys son-in-law) as it so happens it was a heifer. I blame a lack of copper in the diet, either way, Roberta it is.

Why call cattle after names in the neighbourhood? Simple, if I yell out the cow’s name, it confuses the “sh.t”s out of the neighbours.

Enough about that now. Let me introduce the chart that gives you information about Heat Stress in Dayboro. Something we should not underestimate. For emergency financial needs you can like heat stroke illness.


Heat stress in dayboro chart. It shows you the different warning icons.


What does Roberta do?

While you enjoy the comfort of your house, Roberta shows you how she feels. Here is why.

Dayboro is a town that is surrounded by mountain ranges. It is almost like it is a volcano, most likely it is just less sexy, being a giant sinkhole. The real issue is that the Heat Index is going up relatively fast due to it.

So let us have a look at MDI,  instead of Heat Index, both you can see as a “magic number” (Yes another one, FBRFI is also a magic number).

MDI (Modified Discomfort Index)

Let’s get complicated, for heat stress in Dayboro we use MDI. The MDI is calculated as MDI = 0.75*Tw + 0.3*Ta.  Where Tw = Wet Bulb Temperature and Ta = ambient Temperature, this will give us a magic number.

At Dayboro Weather I associate the MDI directly with the heat stress in cattle. It applies to any other animal (including people). I have a particular interest in the cattle side of things. I want them to be comfortable and looked after. It is called husbandry, I have no idea why, but it is what it is, I calculate the heat stress in dayboro by manipulating the original MDI formula and adjust it. Dayboro is a little bit different due to its location. Because of the “protected” Dayboro location,  I decided to change the formula a little bit; I think it is more accurate now.

Cows do not sweat very well.

Cattle are unable to dissipate their heat load efficiently. Their sweating mechanism is poor, and they rely on respiration to cool themselves. Not sweating cows, explains why you do not have any specific deodorant stick for cattle.

A further disadvantage for cattle is the fermentation process. The rumen generates additional heat that cattle need to disperse, which becomes harder as the temperatures rise. They cannot get rid of heat efficiently, they accumulate a heat load during the day and dissipate heat at night when it is cooler. You understand why there is an increased risk for heat stress in dayboro.

In Dayboro with insufficient environmental cooling, in particular in the summer weather conditions. Summer nights can be warm and cattle will accumulate heat that they cannot disperse off quickly. Making it a bit harder for them the next day, this can cause a heat stress chain reaction if you like.

We are lucky here in Avelon Downs. We have the Dayboro Doctor coming through in the afternoon. The Dayboro Doctor it is a cool(ish) breeze from the ocean funnelled through a gap in the mountain range. It cools the whole area off and makes the house temperature drop by 5C.

This breeze is also why we build the house the way it is, all major “house openings” are facing the Noth East. If you live in this area  and cut down on your cooling expenses.

Typical visible signs of Heat Stress in Dayboro.

Now we know all of that, how do we know if Roberta gets hot and flustered? There are some telltale signs.

  • Bunching (in the shade if it’s available, and ideally with a breeze, so the area is not heating up),
  • Slobbering,
  • High respiratory rates (panting),
  • Open mouth breathing,
  • Lack of coordination, and trembling.
  • Seek shade or align themselves with the sun if there is no shade.
  • Splash water if it is available.
  • Eat and ruminate less.
  • Become unresponsive, lie down and start to die when their body temperature reaches 41.5°C.
  • Increased thirst. Drinking water intake increases markedly, an indication a cow drinks 15 liters per 100kg approx on hot days.
  • Decreased activity is possibly one of the more prominent signs of animal heat stress in dayboro.
  • Agitation and restlessness.
  • Increased urination (with heavy electrolyte loss, this is a big big issue. It can cause a cow to go into distress. Recently in the area, a cow died because of it. Heat stress, a bit of bacteria infection (cocci) and massive loss of body fluids. If your cow is in that shape, only one thing you can do is give it Gatorade or some sports drink. To increase the electrolyte, unfortunately, most suburbians do no know that trick. Sheep farming is a bit different, still, nothing to gossip much about.)
  • Crowding, over the water troughs.
  • Refusal to lie down.
  • Slower growth rates.
  • When the relative humidity exceeds 50%, the dissipation of heat by evaporation cooling becomes much more difficult, and signs of heat stress develop sooner. High humidity is typical for our area, due to the high humidity, this is also why I decided to use MDI.

So for that reason, the “Heat stress in Dayboro warning” image shows a cow, simple right. With the hot summer months in full force, heat stress in cattle is a big concern. Heat stress can cause all kinds of problems, including reduced breeding efficiency, milk production, feed intake, weight gains and even death.

However, your cows don’t need to be victims of the heat. Here are five tips for minimising heat stress in cattle from Stephen Boyles, Ohio State University Extension beef specialist:

  • Have access to cool and clean drinking water
  • Rethink your grazing strategies
  • Understand the estrus cycle
  • Work with cattle in the morning
  • Review and establish an emergency plan for handling the heat.


1. Make sure cows have access to cool, clean drinking water.

It is thought that water temperature affects rumen temperature, and thus blood temperature, which affects brain centres that control feed consumption.  Above-ground water lines should be provided shade by having taller grass to cover them. Run lines in fields or under fences that are not being currently grazed. You should at least check the water temperature in water troughs throughout the summer. A jump in the outside temperature of just 5°C-15°C can increase total water requirements by 2.5 times. So keep an eye on that. If you do not have an automatic water system, you should keep evaporation into account as that will be high in the early morning.

2. Rethink your rotational grazing strategies.

Producers using management intensive grazing might consider several options. One option is to rotate through fields at a more rapid rate. Taller grass tends to be a cooler surface to maintain cattle on than pastures with shorter grass stands. Another option is to rotate cattle in the evening rather than the morning. The assumption is that eating the grass in the evening and the ‘heat of fermentation’ or digestion is mostly dissipated by mid-morning, thereby reducing the heat load produced by the animal. Another possible option is to graze paddocks that allow access to temporary shade or trees during the heat of the day. This will reduce the equal distribution of manure throughout the paddock but might be a suitable compromise during excessively hot weather.”

3. Know that hot weather lengthens the estrus cycle.

Hot weather can reduce the duration and intensity of the estrus (heat) period, and increase the interval between estrus periods (the estrous cycle). During the early stages of pregnancy (fertilisation to implantation of the egg into the uterine wall), the embryo is directly affected by maternal body temperature. High temperatures can cause the non-implanted egg to be expelled. Implantation is estimated to occur 11-40 days after breeding. Expulsion of the embryo due to heat stress does not affect the fertility of future estrous cycles but delays when she will calve again. This may be the reason we observe longer estrous cycles during hot weather.”

4. Handle cattle early in the morning.

Bulls and finished cattle are especially vulnerable to handling during the heat of the day. Handle animals quietly because once they get excited, it will take 20-30 minutes for their heart rates to return to normal. When hauling cattle, load early in the morning and don’t stop during the heat of the day.

5. Have an emergency plan in place for handling extreme heat.

“Emergency management generally involves wetting down the cattle and perhaps the roofs of buildings,” Boyles says. “Delivering large droplets of water (versus a mist) is preferred at 20- to 30-minute intervals. Water mist will allow for some cooling effect. The benefits of sprinkling may not work well if it increases the amount of mud and humidity in the feedlot.” In the midst of the many concerns that can plague over the summer months — flies, weeds, foot rot, pneumonia, sunburn, lumps, down fences, broken down balers, etc. — don’t forget to watch for heat stress in cattle.


Now you know all about heat stress in Dayboro, perhaps you will like UV in Dayboro.

Heat Stress in Dayboro, in particular cattle.
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Heat Stress in Dayboro, in particular cattle.
Dayboro is in a valley, call it a hole. For this reason, heat stress in dayboro is very likely. It does not only apply to cows, it applies to ALL animals.
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