A good read on birth weights

ROAD WARRIOR said:

-XBAR- said:

Revenue per cow tells us very very little about profitability as it completely disregards the other side of the equation, the cost of production!  I'd bet the farm that the cows in your herd that generate the most revenue are not even close to being the most profitable ie revenue less expenses.  Weaning weight % is the only economically relevant trait as it is the only metric that accounts for ALL indicator traits. Females with narrow pelvic have dead calves and thus wean 0%. Same with cows w/ excessive Bw's. Poor milkers wean poor WW%.  Heavy milkers don't breed back and wean 0%.  High maintenance cows don't breed back and wean 0%. Poor udders? Poor ww%.  Bad legs/feet => cant travel, loses body condition, either weans poor % or fails to breed back altogether.  No matter the flaw, it will be exposed in the WW%.

Revenue generated per cow is huge for me. The cow that consistently produces progeny that sell for $3,500 to $10,000+ will more than pay for herself and her upkeep as well as make the payments on other things. Compare her to the cow that consistently puts one in the cull pen to be sold as a feeder calf for $800 to $1,000, the choice is pretty easy for me to make on which cow that I will be feeding the next year. Our most prolific money generating cows will average 1450 lbs. They will all consistently wean off calves that will weigh 700 to 850 lbs without creep and on endophyte infected fescue. I do not have a 4 frame score animal on the place anymore simply because they could not produce the performance that would make them keepers. The last of the 1100 lb cows that were here struggled to wean off 500 lb calves in the same conditions as the other cows. We weigh our cows twice a year so I have a pretty good handle on their weights as well as what they produce.

Rather than putting direct selection pressure on indicator traits such as frame or weight, or even birweight or calving ease!, start selecting for weaning weight % and you'll have a new found love for those 4 frame 1100lbers.  If you have 1500lb cows that are weaning half their body weight without supplementation then that's great! But for most environments, selecting for a 50% weaning weight % will self regulate cow size to 11-1200lbs,, and even smaller in many locations. 

I do not select for B.W. when I select a herd bull or AI sire. I select for a bull that has good feet and legs first and foremost, how the bull is made, cow families and actual performance next. I pay very little attention to EPD's as there is far too much corrupt data involved in their formulation to be even remotely accurate.


Now I don't know anyone who thinks 85lb calves are too big for COWS but MANY quality commercial heifers will need assistance calving 85lb calves as that is over 10% of their body weight.  And this is where this topic just becomes circular.  No matter the metric, weight without context is arbitrary! Cow or heifer size has to be taken into consideration when talking about 'ideal birthweights.' 

Truthfully, BW has a fairly limited effect on calving ease. It's the square peg in the round hole concept. Typically our heifer will have 78 to 85 lb calves unassisted, but that is due a large part to the fact that the calves are made to come out easily. Long, smooth shouldered with a nice sized head. I have pulled 75 lb calves from purchased first calf heifers that were built like a box, about as wide as they were long.

I also believe this is why BW EPD is still a valuable tool as it presents some context, when analyzing CE EPD, as to the type (size) of heifers the bull in question has been bred to. It gives context as to the size of heifers the CE EPD was generated around.  Just because a +2 BW bull has the same CE EPD as a -2BW bull doesn't mean their calving ease will be the same on ALL heifers.  They may calve the same when bred to 1200lb grown out heifers but when bred to common 800lb commercial heifers, this is where their ease of calving tends to vary.

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For an EPD to be a valuable tool it has to be based on the belief that the data used to obtain that EPD is accurate and not manipulated. Our Association does not require a BW to be turned in. If there is not an actual BW turned in the Association assigns them "breed average" BW EPD. I fail to see how this EPD can be a valuable tool when thousands of calves are assigned a breed average EPD. In all actuality the EPDs on a young animal are pretty much irrelevant until it produces enough progeny to accurately identify it's traits. For the bulk of breeding bulls, they will not have enough progeny to identify until they are 5 to 7 years old and in most cases they are long gone by then.

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