Friday, October 14, 2016

Estimating  Calf Weights

We all have looked at a calf and mentally estimated about how much she weighs. The true of the matter is that studies have confirmed that people are abysmal at estimating weights.

So, yesterday I am on a dairy. The calf manager pulls a dairy weight tape out of his pocket as says, "Take a minute and show me the right way to use this."

I took the rolled up tape, shook it out and after cornering a calf slipped the tape around her body just behind the front legs - technically the heart girth position.

I showed him how to pull the tape "just right." Tight enough to flatten the hair coat but not enough to begin to stretch the tape.  

After I took a reading he tried it and came up with almost the identical number. Good. Lesson learned. 

HOWEVER, I asking him, "Where is your Holstein calf weight tape?"

"Huh?" he said.

Then I explained that the mature animal weight tape was developed to be most accurate at  breeding size for Holstein heifers. It is pretty sloppy when we get under 440 pounds (200kg). That was the reason that the Penn State research team developed a tape that was specifically for calves (under 220 lbs, 100kg).

So, I mailed two Holstein calf weight tapes to the farm today and now they can get more reliable weights for the calves as they leave the hutches. 

I f you Google "Holstein calf weight tape" you will get a series of places to buy one as well as some background links to how the tape was developed. 


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