adjusted weaning weights

[milesvb]

Is there a simple formula for calculating a 205 day weaning weight? The only "knowns" are the calf's weight, the calf's age and the approximate age of the dam.

 

[jkwilson]

{(Current weight - birth weight)- divided by days of age} multiplied by 205.

You are figuring out how many pounds per day the calf has gained since birth, then multiplying that by 205.

 

[milesvb]

{(Current weight - birth weight)- divided by days of age} multiplied by 205.

You are figuring out how many pounds per day the calf has gained since birth, then multiplying that by 205.

The problem is that I don't have a birthweight.

 

[Muratic]

Same thing here:

weaning weight
minus birth weight
_________________ X 205 + BW + age adjustment of dam
divided by calf age




Age of Dam Adjustment Factors

609-1003 days = 4 pounds for both sexes
1004-1368 days = 2
1369-1733 days = 1
1734-3923 days = 0
10 years and older = 2



I don't figure the adjusted weights too often, but every once in a while someone will ask me for the numbers. This is the formula I use. The dam adjustment figures are from the canuk saler association and I figure factor in the cold.

 

[Muratic]

{(Current weight - birth weight)- divided by days of age} multiplied by 205.

You are figuring out how many pounds per day the calf has gained since birth, then multiplying that by 205.

The problem is that I don't have a birthweight.

Then I reckon that you don't need to adjust the weaning weight too badly if you can even get a BW.

 

[dun]

You'll have to SWAG the birth weights, but here's the BIF wieght adjustment site

http://www.beefimprovement.org/guidelines/App3-1.PDF

 

[milesvb]

{(Current weight - birth weight)- divided by days of age} multiplied by 205.

You are figuring out how many pounds per day the calf has gained since birth, then multiplying that by 205.

The problem is that I don't have a birthweight.

Then I reckon that you don't need to adjust the weaning weight too badly if you can even get a BW.

It's for my own use. I don't raise registered cattle.

What I'm trying to figure out is what would a calf theoretically weigh at 205 days if it had been weaned off and sold at say 175 days and weighed "X" amount at that time.

Are dam adjustment factors different for different breeds?

 

[milesvb]

You'll have to SWAG the birth weights, but here's the BIF wieght adjustment site

http://www.beefimprovement.org/guidelines/App3-1.PDF

Thanks Dun.

 

[certherfbeef]

Are dam adjustment factors different for different breeds?

Ya Miles. Each breed has their own figures for the adjustments.

 

[milesvb]

Thanks guys/gals. I think I'll quit chasing my tail now. ;-)

 

[MikeC]

WDA (Weight per Day of Age) is the calculation a lot of people use that do not have birthweights.

WDA=Total calf weight divided by number of days of age.

If it comes out over "3" you're in pretty good shape.

 

[Aero]

it seems like growth rate would be adjusted on a progressive scale.

a calf gains more per day from 210-215 days than 200-205 days old.

 

[El_Putzo]

WDA (Weight per Day of Age) is the calculation a lot of people use that do not have birthweights.

WDA=Total calf weight divided by number of days of age.

If it comes out over "3" you're in pretty good shape.

Mike,

Just curious here, but did you leave the subtraction of birthweight out of you equation for a reason? I would think you would be better off using an estimated BW than none at all and getting an inflated WDA.

 

[MikeC]

WDA (Weight per Day of Age) is the calculation a lot of people use that do not have birthweights.

WDA=Total calf weight divided by number of days of age.

If it comes out over "3" you're in pretty good shape.

Mike,

Just curious here, but did you leave the subtraction of birthweight out of you equation for a reason? I would think you would be better off using an estimated BW than none at all and getting an inflated WDA.

The birthweight is left out of the equation because the difference is so miniscule to many. Example:

A 10 lb. BW difference divided over 200 days would only amount to .05 lbs. per day.

Besides, when you sell a calf at market.......the GROSS weight is all that matters.

Calves still sell by the pound. Most want all they can get.

I use 205 Adjusted ADG, WDA, and PWG (YW) in my recordkeeping. Customers take what they want from my data.

 

[ollie']

I never have cashed a check from selling adjusted WW. Some cows milk better than others at the end of their lactation. Early weaning messes up the data etc. I pay attention to actual data myself. I can ask the breeder how they were developed as calves and know from that how much stock to put in the weights.

 

[El_Putzo]

I see where you are coming from about total lbs being the most important Mike, but lets say your avg BW is 90 lbs, if you don't subtract that out when you figure WDA, you end figure will end up .44 lbs heavier. That is a big difference. Theoretically then, my calves that avg 90 lbs BW and and WDA of 2.56, actually gained the same as your calves that avg 90 lb BW and had a 3.00 WDA. In reality, there would be no difference in the calves except that yours look better on paper to Joe Blow who doesn't know any better.

Maybe I'm doing it wrong, it would be easier to figure your way.

 

[MikeC]

I'm not following you.


WDA and 205 Adjusted ADG are two different things. One is without BW's and one with BW's.

ADG is usually a computation used for a period of time during a calf's life. (205 days, 90 day feed test, or from weaning to yearling)

WDA is usually for his entire life to the date of computation.

Philosphical differences on what is right and wrong are mute points.

Some people use both.

 

[El_Putzo]

I understand your statement now. I was confused as to which we were discussing.

 

[milesvb]

My purpose for the original question was to help evaluate cows in a herd by the weight of the calf they raised. Up until now we calved year round so in a group of calves sold there would be a variation of ages. I record weaning weights at the date each calf is sold and I know within a day or two when it was born. So if I can come up with a 205 day number that is reasonably accurate then I have another tool to use. My original plan was to do what Mike suggested but I didn't know how well it would work for my purposes.