Birth Weight/Calving Ease

[Ky hills]

Some of the current topics being discussed on here are informative and insightful.
We often hear a negative tone in regards to continuous use of low BW, high CED Bulls. It does make sense to me that over time it could definitely decrease weaning weights, and ability of females to calve efficiently, as well as extremes in small size in calves at birth.
On the other side of the equation, along the lines of the larger cows. My thoughts are would it be possible to go to far in the opposite direction? I have been at meetings where some of the U.K. Speakers, have suggested not keeping replacement heifers from Bulls with higher birth weights, as the female contributes to the calf size as well as the bull. I am wondering if by continual use of just an example Bulls with BW and CED like Gar Grid Maker, SAV Harvestor, Connealy Earnan would make for larger cows as well as larger calves at birth. Thus creating a calving issue when used in crossbreeding or herds of cows of smaller sizes? Somewhat like a Angus version of continental breed affect in calving and growth rates.

 

[Red Bull Breeder]

I like the middle of the road approach.

 

[sim.-ang.king]

I like to base what I want BW to be, according to what visible signs of CE a bull has.
Calf shape plays a big role. It's easier to push out a sausage than a cinder block.
If a bull has a small head, smooth shoulders, and lots of flex in his hip, I would be less worried about BW.
Big block heads, square broad shoulders, straight hip. All signs of low CE, and would need lower BW to compensate.
Of course some don't believe in looking at cattle for flaws. Then they end up with a mess, and can't figure out why?

 

[mwj]

The above post is spot on. Actual birth weight is easy for anyone to measure but calving ease is not.

 

[Ebenezer]

The sneakiest problem with calving ease is on the cow side and with the maternal grand dams. If there is extra BW there, it will come back to haunt you.

The curve benders are anomalies which most likely are high growth with short gestation periods, but in the average bovine, birth weight is related to mature weight. We used to have a state beef specialist with extension who had the repeated motto, "Challenge the cows on birth weight". A lot of lessons learned the hard way for believing listeners. It was a fad. Just like today the low BW is a fad. For fad followers, it requires abject failure to get their attention. Hang in the middle and note calf shape: all above and great advice.

 

[lithuanian farmer]

Yes, it would create a huge problem. Cattle with huge BW not always are big themselves when matured. It would create animals which won't be suitable for breeding and won't calve themselves. I'm pretty sure that there won't be anybody who would breed for a bigger BW. I don't mind bigger bw as long as it doesn't cause trouble calving and never use bulls which have big bw on females, which were born bigger and will produce a calf with a bigger bw.
As stated above the shape is important. Just have calves born from different sires and it's very clear. Those big framed calves with big bones are much harder calved even than the same weight but light boned, slimmer, longer calves.
The best suggestion would be to know your cows capabilities and keep in the middle. Too extreme to either side won't turn out well at the end.