Heat Tolerance

[DOC HARRIS]

This subject of "What's Hot and what's NOT" can be debated until He!! freezes - but facts are facts, and here are a few more to make you sweat!

Internal FAT - not just the marbling within the muscling, but that fat which is deposited in the "Interstitial Cells" - which is that area BETWEEN the internal organs and connective tissues. This may seem to be a small and insignificant factor, but in an animal body (human's included), there are NO 'empty' spaces - therefore - FAT fills the so-called "unused spaces". FAT, being oily and greasy, is not easily eliminated from the body, (as you who are on diets can agree), as it is stored in these unused spaces, and as such, it has insulative characteristics and " holds in" or retains the body heat generated by the animal's physical activities and bodily functions.

The above itemized facts on fat, in conjunction with the other preciously-alluded-to reasonings, justifies all the efforts expended in protecting our cattle from any undue over-heating problems.

Concerning the bos indicus ear discussions, there are two physiological elements or constituents in which the ears are involved ( in cattle, that is! ), other than hearing! They are heat dissipation and the prevention of rain water entering the ear canal.

In any case - God Made NO Mistakes!

DOC HARRIS

 

[Santas and Duhram Reds]

Doc, Doc, Doc,

Your forgot that ears can also be used as flyswatters.

Fat can play a role as well certainly. But that doesn't take away the fact the Bos Indicus cattle are more heat tolerant. They can get fat too you know and I've seen some black cattle that if they had fat I don't know where they were hiding it. Come to think of it, I think they were hot too. Maybe that is why they were so thin.

All cattle get hot. All cattle will stand in the shade. All cattle will stand in a pond. The difference is for what length of time and how often.

 

[dun]

But that doesn't take away the fact the Bos Indicus cattle are more heat tolerant.

And just to prove that indicus isn;t necesarry for heat tolerance you have Senepol

 

[Santas and Duhram Reds]

never said it was necessary. You also have Longhorn and I believe Corriente.

Brown Swiss are supposed to be more heat tolerant than most dairy breeds I believe.

 

[backhoeboogie]

The responses keep coming, from different locales. How many responding actually see 110 degrees in the summer, regularly or go 30 plus days of 100 degrees? Thankfully we haven't this year. But when we do, the difference is obvious. Have you ever had panting cows stand and allow water to be poured on their backs?

 

[ALACOWMAN]

The responses keep coming, from different locales.

• How many responding actually see 110 degrees in the summer,

regularly or go 30 plus days of 100 degrees? Thankfully we haven't this year. But when we do, the difference is obvious. Have you ever had panting cows stand and allow water to be poured on their backs?

my gawd.. how do yuse guy's stand that intense heat? ;-)

 

[backhoeboogie]

my gawd.. how do yuse guy's stand that intense heat? ;-)

Enthalpy. Evaporative cooling. It works. If it didn't, no one's A/C would work. If it rains and gets the humidity up, it is indeed miserable.

Back to what dun said about other breeds being tolerant, there are many dairy cows in this proximity also. Holsteins seem to be tolerant of extreme heat. Of course, the dairy breed does not carry the bulk and fat that beef breeds do.

This whole thing is an age old issue. Before I was born ranches were figuring it out. I remember all the gerts and brindled cattle grandaddy ran back in the 60's when I was a youngster. He got in on the big Argentina import of Brahmans.

 

[Caustic Burno]

The responses keep coming, from different locales. How many responding actually see 110 degrees in the summer, regularly or go 30 plus days of 100 degrees? Thankfully we haven't this year. But when we do, the difference is obvious. Have you ever had panting cows stand and allow water to be poured on their backs?

Heck you are cooler than we are in this rainforest no breeze and 90%+ humidity every day. Get up in the morning and just walk to the barn and your wringing wet with sweat. You don't see a piece of equipment without a water jug hung on it.
Cattle just perform better here if they have some Brimmer in them.

 

[andybob]

But that doesn't take away the fact the Bos Indicus cattle are more heat tolerant.

And just to prove that indicus isn;t necesarry for heat tolerance you have Senepol

Add Tuli to the list of heat tolerant Taurus breeds, from the heat and humidity of the Tuli circle to the intense dry heat of the Namib, they cope with the heat, parasites and diseases in the harshest of conditions.

 

[Santas and Duhram Reds]

In Missouri we have 5-10 days over 100/ yr I would guess. We also have Humidity that makes all those 90s seem like 100+.

None of that is relative however. Studies have shown 85 degrees and up is when optimum productivity is affected in most Bos Taurus cattle. We have plenty of those days.

 

[DOC HARRIS]

The responses keep coming, from different locales. How many responding actually see 110 degrees in the summer, regularly or go 30 plus days of 100 degrees? Thankfully we haven't this year. But when we do, the difference is obvious. Have you ever had panting cows stand and allow water to be poured on their backs?

Heck you are cooler than we are in this rainforest no breeze and 90%+ humidity every day. Get up in the morning and just walk to the barn and your wringing wet with sweat. You don't see a piece of equipment without a water jug hung on it.
Cattle just perform better here if they have some Brimmer in them.

CB- I feel for you. I have experienced this kind of heat in many places, South Mississippi, Deep South Texas, Ft. Worth, Kansas City, Phoenix (with all the irrigation there the humidity becomes HIGH). Now we are in Beautiful, Colorful Colorado with the Humidity at about 5% or less, and even when it is 100 during the day, we have a light blanket on us every night. It is difficult to tolerate - - but we try!

DOC HARRIS

 

[KNERSIE]

I've missed this thread, but there are things to consider, the haircoat and specifically the felting quality of the hair (the same process to make hats). Hair with a poor felting quality means the animal is more heat tolerant, good felting quality means less heat tolerant, but can tolerate cold climates better.

Bonsma has done several studies on this, I have some of the original text about adaptability to hot humid subtropical conditions. The conclusion to all his work on the subject is that although various factor plays a role, the hair's felting quality seemed to be the deciding factor. Various breeds and various felting qualities within the breeds was used and all cam back with the same results.

The Afrikaner turned out to be the most tolerant and also has the slickest shiniest red coat with the worse felting quality. Colour variations of the red afrikaner coat made very little difference. Shorthorns came out the worst, with the other british breeds in between, Sussex being the best of the British breeds.

It seems that the coat's ability to reflect heat instead of absorbing the heat was the deciding factor.

But generally bos indicus and bos taurus africanus cattle (afrikaner, tuli, boran) is more heat tolerant than straight bos taurus, however heat tolerance can greatly be manipulated through selection.

And, yes, we do get heats of 115F(46C), and we seldom get a day under 90F (32C) from december through till end of march.

 

[Caustic Burno]

The responses keep coming, from different locales. How many responding actually see 110 degrees in the summer, regularly or go 30 plus days of 100 degrees? Thankfully we haven't this year. But when we do, the difference is obvious. Have you ever had panting cows stand and allow water to be poured on their backs?

Heck you are cooler than we are in this rainforest no breeze and 90%+ humidity every day. Get up in the morning and just walk to the barn and your wringing wet with sweat. You don't see a piece of equipment without a water jug hung on it.
Cattle just perform better here if they have some Brimmer in them.

CB- I feel for you. I have experienced this kind of heat in many places, South Mississippi, Deep South Texas, Ft. Worth, Kansas City, Phoenix (with all the irrigation there the humidity becomes HIGH). Now we are in Beautiful, Colorful Colorado with the Humidity at about 5% or less, and even when it is 100 during the day, we have a light blanket on us every night. It is difficult to tolerate - - but we try!

DOC HARRIS

I know it must be tough Doc but someone has to do it.
When I go north to hunt pheasant with some friends that live in Mo. I dang near freeze to death. I draw the line at hunting anywhere you need white camo.

 

[certherfbeef]

I draw the line at hunting anywhere you need white camo.

We don't where white camp here, CB. Come on out!!!

 

[Caustic Burno]

I draw the line at hunting anywhere you need white camo.

We don't where white camp here, CB. Come on out!!!

I'm skeerd and admit it I have seen how you folks melt in our mild climate. I am afraid they would find me like that hunter they found in that glacier from 5000 years ago over in Europe.

 

[dun]

I draw the line at hunting anywhere you need white camo.

We don't where white camp here, CB. Come on out!!!

I'm skeerd and admit it I have seen how you folks melt in our mild climate. I am afraid they would find me like that hunter they found in that glacier from 5000 years ago over in Europe.

I have a hard time changing from winter to summer temps anymore. Can;t handle the high heat and humidiy and can;t hanlde the cold either.

 

[MikeC]

Submitted to: Livestock Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 25, 2006
Publication Date: October 16, 2006
Citation: Brown Brandl, T.M., Eigenberg, R.A., Nienaber, J.A. 2006. Heat stress risk factors of feedlot heifers. Livestock Science 105:57-68. doi:10.1016/j.livsci.2006.04.025

Interpretive Summary: The impacts of hot weather on cattle production are varied, ranging from little to no effect in a brief exposure, to death of vulnerable animals during an extreme heat event. Vulnerable animals have been described as ones afflicted with multiple stress factors. It was known that cattle with dark hides were more prone to heat stress. Other factors have been difficult to quantify. This report documents that fatness, hide color, health history, and temperament (calm or highly excitable) are important factors. Stress level was measured by breathing frequency of each animal. Above 25 deg/C, stress levels were increased in animals with darker hides and those previously diagnosed with pneumonia. Animals with more body fat, and those that were highly excitable were also more susceptible to stress. Each of these factors appeared to be independent, so if more factors were present, the risk was higher.
Technical Abstract: Heat stress in cattle results in millions of dollars in lost revenue each year due to production losses, and in extreme cases, death. Death losses are more likely to result from the animals vulnerable to heat stress. A study was conducted to determine risk factors for heat stress in feedlot heifers. Over two consecutive summers, a total of 256 feedlot heifers (32/genotype/year) of four genotypes were observed. As a measure of stress, respiration rates and panting scores were taken twice daily (morning and afternoon) on a random sample of 10 heifers/genotype. Weights, condition scores, and temperament scores were taken on a 28-day interval during the experiment. Health history from birth to slaughter was available for every animal used in this study. It was found that at temperatures above 25 deg/C, dark-hided animals were 25% more stressed than light-colored; a history of respiratory pneumonia increased stress level by 10.5%; each level of fatness increased stress level by approximately 10%; and highly excitable animals had a 3.2% higher stress level than calm animals. These effects appear to be additive.




Project Team

Nienaber, John - Jack
Brown Brandl, Tami
Eigenberg, Roger



Last Modified: 07/23/2007

 

[milesvb]

I draw the line at hunting anywhere you need white camo.

We don't where white camp here, CB. Come on out!!!

I'm skeerd and admit it I have seen how you folks melt in our mild climate. I am afraid they would find me like that hunter they found in that glacier from 5000 years ago over in Europe.

I have a hard time changing from winter to summer temps anymore. Can;t handle the high heat and humidiy and can;t hanlde the cold either.

That statement could have come straight from my dad. He spent most of his life outdoors and could work most teenagers to death but the extremes bother him now. He turned 68 this year.

 

[dun]

That statement could have come straight from my dad. He spent most of his life outdoors and could work most teenagers to death but the extremes bother him now. He turned 68 this year.

Maybe it comes with age. Or it could be the heat stroke I suffered some years ago. More likely I just like to whine and find an excuse not to have to put in 12 plus hour days anymore.

 

[BAGTIC]

When comparing bulls with cows allowance must be made for the fact that bulls are much larger. Because of that their surface area per volumn is much lower than for cows so it is harder for them to stay cool.

Northern whitetails are genetically larger than southern whitetails. In cold climates size has an adaptive advantage. In hot, especially humid climates, it is a disadvantage.