Cow size

[grassfarmer]

Another thing I would dispute is the assumption that big cows breed big calves and small ones small calves. I bought a bunch of registered red Angus cows at a reduction and am just running them as commercial cows. These will be my heaviest cows, i'm sure some will top 1600lbs but they will certainly average 1450lbs. Absolutely consistent breeders of calves weighing under 80lbs. One smaller cow (1350lbs) had a 50lb calf last year - as a mature cow! These calves don't grow big either they are just small cattle out of huge mothers. Maybe the breeder was moving in the right (in my opinion) direction with downsizing his cattle - they make for damn inefficient cows though and I'm glad I only have a few left. Most cows were culled out in the first two years because they couldn't live in my system. Funny that because the breeder advertises his bulls as being from a forage raised herd!

[farmers_son]

Most would agree that there is not one best size of cow, although I believe the gist of the slide presentation in the link was that a Leachman bull would breed a “right sized” cow (whatever that is).

Grassfarmer is correct to point out the cost of barley and corn burner genetics. However it needs to be also pointed out that the high cost of feed has changed the way weaned calves are priced. In the fall of 2000 when barley was cheap there was a 30 cent per pound slide between 450-500 and 600 pound calves. A 475 pound calf could bring within $40 a head of the larger 600 pound plus calf. Last fall there was not much price per pound difference between any of the calves and the 100 pound heavier calf would have brought $100 more dollars, depending on the sale day. As the price of feed continues to rise I think you will more of that in the fall of 2008 and the dollar per head advantage of the heavier calf will be even greater. Feedlots are going to severely discount any type of calf that is not an easy feeder.

[smcgrath76]

LOL. I think the Leachman story is part of the beauty of bankrolling the presentation. I think that big calves are good, more calves are better, and more big calves are better yet. The smaller the cow that can do that job the better it is. The balance is the tricky part. It is proven that curve bender genetics (low BW, High Growth) result in smaller mature size cows (in general).
For example if I can run 110 smaller cows, versus 100 larger cows that both raise the same weight of calf from my resource base I am better off. At some point I may sacrifice growth for cow numbers and that is the tipping point.

[grassfarmer]

What an opportunity though farmers_son - 4 weight heifers bringing the same price per pound as 8 weights. Buy or retain the lightweights, rough them over the winter on straight hay then grass them to gain 2lbs a day for a daily grazing charge of around 70 cents. Cost of gain - 35 cents/lb. Surely the light must be coming on somewhere that this is a smarter way to rear cattle?

[rkaiser]

Roughing them through the winter hey. Is this not a way to build efficiency into your program? Not only do you bring down your feed costs, but you keep the heifer size down and thus her need to eat less for at least the first couple of years. Her mature size and weight may end up close to that of her mother unless you are making an attempt through genetic selection to bring down size. (ie. Size of Bull and his parents.)

Interesting in our little heifer pen. As I said this is the first group of girls that have seen no grain whatsoever. Have a cow with twin heifers in the pen with them. She is one of my top cows and I am spoiling her a bit to bring these twins on and bring up her condition. I take a bit of grain in the pen for her each morning and the cow eats on her own. The heifers don't know what grain is and are not even interested.

Breeding grass based cattle is not only genetic, but environmental as well. I predict that our bulls will look for grass and bloody well eat it to supply their needs for the rest of their lives. They moved out into the sloughs all winter long to graze while their hay feeder was full.

Randy

[cswilson]

It works on cows and horses too-there's alot to be said for just letting them grow up at their own pace. In as far as breeding stock goes-our little hay fed bulls are still working past ten years old in alot of circumstances. TRandy is right about cutting costs by running heifers a bit tougher-we have a couple 4H heifers every year for the last 12 years or so-they are treated better but don't last as long as the heifers that run out and lick snow. As far as horse I've seen more crippled up unsound horses from outfits that overfeed their young stock. We bucked a couple three year old studs this weekend that wintered on straight hay-they were hard,fit and were 3-0 at the rodeo.

[smcgrath76]

From the most recent beef cow/calf weekly...

These Are Not Your Grandfather's Cows


Mature weight and milk production of many commercial beef cows are both greater than they were 30-40 years ago, says Glen Selk, Oklahoma State University Extension beef cow specialist. "Many ranchers haven’t recently weighed the adult cows in their herd to know what average mature weight to expect. Therefore, most commercial ranchers would underestimate the mature size of their cows. To expect large, heavy-milking cows to be in moderate body condition at calving and maintain condition through breeding, they must receive more feed than smaller, lighter-milking cows."

A larger, heavier-milking cow requires about 34% more energy on the average for an entire year, he says. Consequently, an operation that was carrying 100 of the smaller cows must carry only 66 of the larger cows in order to utilize the same quantity of forage from that farm or ranch. She also will need 34% more winter hay and supplement to maintain body condition.

"Because we have very high feed and fertilizer prices, this is a time to reconsider herd size to better fit the stocking rates required. Reduced stocking rates will be necessary on improved pastures if lower amounts of fertilizer are applied. The larger mature cow size also impacts the principle of percent body weight needed for heifers to reach puberty. Many ranchers underestimate the target weight for replacement heifers. If the cow eventually will be 1,000 lbs., the target for heifers is 650 lbs.; if she’s going to be the 1,250-lb. cow, then she needs to weigh 812 lbs. going into her first breeding season to expect a high cycling and pregnancy rate," Selk says.
-- Ron Hays, Radio Oklahoma Network

[farmers_son]

The fellow’s math in your quote is very misleading, even wrong. Yes the bigger heavier milking cow will need more energy and therefore more pasture but it is not a one to one ratio. The links you provided earlier show that the larger cows are more efficient and consume less dry matter per pound of cow weight than the smaller cow.

Please see:
AN EVALUATION OF THE RATIO OF CALF WEIGHT TO COW
WEIGHT AS AN INDICATOR OF COW EFFICIENCY http://jas.fass.org/cgi/reprint/46/3/614.pdf

Some producers may have small cows as a goal for their herd for reasons other than feed efficiency. While this goal might now be questioned not only because of the low relationship to efficiency but also because of the usual undesirable relationship to variable costs, it would appear that a selection index approach involving weaning weight and cow weight would be more effective than the ratio in achieving both goals of high efficiency and small cow size.
Undue attention to cow size could result in substantial loss of efficiency in the cow herd.

[farmers_son]

I did some more work on cow size. I went to Cowbytes and compared a 1400 pound cow to a 1000 pound cow. What made the most striking difference was not cow size but milking ability. A heavy milking cow could eat 25-30% more than a poor milking cow. It would seem that more milk equals more pounds of weaned calf but there might be questions about whether it is cheaper to put pounds on the calf some other way than through milk, for example early weaning. It does seem though that milk is the key more than cow size. You can have a herd of 1000 pound cows but if they are milking heavy they are going to have to eat. The 1000 pound cow producing a lot of milk could easily eat as much as a 1400 pound cow producing a moderate amount of milk.

[grassfarmer]

It depends what you read F_S, I've read plenty of research findings that show an 1100lb cow is the most efficient for the US northern plains so I would assume that to be similar to southern Alberta. There really is no right answer to this one as there are so many different circumstances. If you run cows on a headage basis on rented pasture where the landowner doesn't adjust for 1400lb cows versus 1100lb AUDs the big cow certainly has an advantage. Again it depends if you are a commercial breeder or a purebred one, if you are a commercial breeder that buys replacements you are in a different position to someone who breeds their own. On the commercial ranch buying in replacements the size of cow may be determined by weight/price of differing size replacement heifers relative to potential cull cow value. Another research finding I have encountered several times was that as cow mature weight increases fertility decreases.
Fertility is many times more important than feed efficiency on a ranch.

As a purebred/commercial breeder who runs all my cattle on a system where they really have to forage for their living my experiences have been thus:
1. Heavier and milkier cows are a disaster on my system - they cannot retain condition and rebreed although they may wean the best calves.

2. Some larger cows can prosper here - but in every instance it is because they are lower milkers and thus their calves are not much (if any) larger than the small cows calves.

3. Some small cows milk far too much and have the same problems as #1 cows

4. The cows that do best here are small or medium size cows that do not milk too heavy. There is no particular advantage to the medium size cow over the small in this category as they DO NOT consistently wean bigger calves.

5. Much of the data we read on cow efficiency is based on the assumption that a cow will eat x% of her body weight in forage per day. This is an assumption that bears no merit in the real world as it overlooks foraging ability - the cows desire/ability to go out and harvest their feed daily. I am convinced there are real differences between same weight/same breed cows in this trait. Of course if you haul harvested feed to them for 200 days this maybe has less relevance.

6. Longevity should be considered as to have it requires fertility. As an example we bought a group of simm/red angus heifers that have been great performers. From heifers to third calvers they all weaned a calf (a heavy calf) every year but with age they have fallen by the wayside, turning up open and I doubt if 25% will reach 8 year old.
By contrast I have one grading up line of purebreds that consistently wean calves in the bottom 25% on weight yet the cows are always fat. To test them out I ran the heifers off this line with mature cows instead of feeding them with my other heifers. They can handle this treatment and I'm convinced could winter on a straw only diet as mature cows. Now I think they are an efficient forage line - for my system, and my guess is they will last to 15 year olds. Of course to realise their full potential as feed savers I would need to feed them seperately or have a whole herd of them. Fed amongst less feed efficient cattle they carry more condition and don't wean a big enough calf.

But at the end of the day I realise the cows herd I have is the result of the selection pressure I put on them. If my ambition was to have a 1400lb cow herd, and managed/selected them accordingly some of my current "best" cows would look poor in comparison. It truly is a matter of horses for courses.