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Post by larso on Apr 19, 2015 4:06:52 GMT -6
When your weighing calves at weaning and your working out their weaning weight percentage to dam's weight how do you factor in the difference of the calf's age. eg (we work in kgs not lbs but that shouldn't make a difference to the point of the exercise) calf A weighed 373 kgs @ 216 days old, dams weight 692 kgs to calf B who weighs 317 kg @ 194 days old, dams weight 826 kgs. It's allowing for that 22 day age difference that I'm having trouble with when working out %'s. Appreciate the help.
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Post by strojanherefords on Apr 19, 2015 9:41:36 GMT -6
The point of percentage of cow weight weaned is to measure how efficient cows are. If the cows had the same opportunity to get bred, I would not make an allowance for calf age. But I would make an adjustment for body condition score to better reflect the cows true nutritional requirements. When using performance data it is important to not reward or adjust away bad characteristics.
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Post by elkwc on Apr 19, 2015 10:26:00 GMT -6
The point of percentage of cow weight weaned is to measure how efficient cows are. If the cows had the same opportunity to get bred, I would not make an allowance for calf age. But I would make an adjustment for body condition score to better reflect the cows true nutritional requirements. When using performance data it is important to not reward or adjust away bad characteristics. Bingo. This is what I see is wrong with the ratios and adjusted EPD's. Like weights. They have created ways to adjust away factual information that may not be favorable and make it more favorable.
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Post by larso on Apr 19, 2015 12:38:36 GMT -6
Cow B has a better condition score than Cow A but both are back in calf according to the vet 16-18 weeks so hopefully cow B has plenty of time to recover body condition before calving again. So from what you guys are saying don't factor in the age gap?
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Post by larso on Apr 19, 2015 12:40:17 GMT -6
Sorry I meant cow A has time to recover body condition.
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Post by hoekland on Apr 20, 2015 0:17:25 GMT -6
Weight X 205 / actual age in days = adjusted 205 day weight, but that is not factoring in the age of the dam like the official adjusted weights do. Cows under 5 and older than 10 usually get a positive adjustment, but the exact formulae would be considered intellectual property and would be very hard to come by.
WHen it comes to effeciency it's simply adjusted WW/actual cow weight at weaning X 100
All theoretical adjustments aside, the question you need to answer yourself is: does this cow make economical sense in a commercial setup? Or in other words can she realistically wean 50% calf without extra inputs under the conditions your commercial customers run their cows?
Back to your 2 cows, they're too big for my conditions, but cow A would make sense to own, but not cow B
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Post by larso on Apr 20, 2015 6:19:45 GMT -6
Cow B is only on her 3rd calf cow A is 9 years old. We have had a very dry Autumn and a lot of breeders have weaned at 4 mths but I've hung on to really put pressure on the herd to see which ones could perform as we have had pretty good seasons up until this year. I know some may say their to big but I believe it is easier to come down a bit in size and breed thickness into them than start with toads. Even though it has been very dry I still got 85% in calf on their 1st cycle with a 96% conception rate overall including heifers, so while I agree with your comments Harley I'm trying to let the environment dictate and cull accordingly.
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