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weaning age question

SRBeef

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I was going through data on my calves tonight.

If I wean them at 205 days old and take their current weight + say about 78 days remaining to 205 X their current average daily weight gain (3.6 lb/day avg between last two weigh-ins) that will come out to weaning about the first week in November and most calves would project to weigh between 650 and 700 lb at 205 days. This would put a couple of the calves out of my smaller target 1200-1250 lb cows at about 54-55% of their dam's weight.

My question is: is there an advantage to the cow and not much harm to the calf if I wean them earlier, say 180 days?

Since there are no signs of any of the cows being in heat for quite awhile, I assume they are all pregnant. Is there an advantage to the growing calf, probably into its 2nd trimester by weaning time, to maybe wean the current calves a bit earlier than 205 days?

Watching them tonight, a 430 lb calf aggressively nursing on a 1200 lb cow just looks like a load on the cow which will only get worse as the calf passes 500 and 600 lb. Interestingly, The heavier cows' calves appear like they are growing and will wean at just about the same weight range that the lighter cows calves do. This would appear to put less stress on the heavier cows which will probably wean 42-45% of their weight compared to 50-54% for the smaller cows.

Will the rate of gain should stay about the same? It has increased as the calves have grown but I would think it would level off. The calves are grazing much more on their own than they did a couple weeks ago.

What do you think about weaning at 180 days rather than 205? Where did the 205 day target (used on EPD's) come from?

This is the first time I am doing this type projection. Is there something I'm missing or error in the assumptions? Last year I weaned at an average age of 205 days and some of the cows looked really pulled down in condition. They came back before the real cold weather hit but I don't want to do that anymore.

Thanks. Jim
 

KNERSIE

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You forgot that the calves weren't born at 0 lbs.

To get the adjusted WW...

Take the current weight and substract the BW.
Devide that by the calf's age in days.
That gives you the ADG.
Multiply the ADG by 205, add the BW.
Correct for age of dam. (you should be able to get the correction factors from the AHA, unless they see it as intellectual property)

In the first two trimesters the developing foetus grows very little and doesn't really have an influence on the cow. When your calves are 6 months old the developing foetus is at the end of the first trimester so the decision to wean now will have no positive effect on the foetus, the extra month on the cow will have a huge positive effect on the suckling calf, though.

It is actually beneficial for the cows to get suckled down somewhat, not saying to get them skinny before winter, but losing a bit of condition now for the benefit of the calf isn't going to hurt the cow. There is no cheaper gain for the calf than what he gets from mom's milk while she is grazing.
 

SRBeef

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KNERSIE":4uqnfyqp said:
You forgot that the calves weren't born at 0 lbs.

To get the adjusted WW...

Take the current weight and substract the BW.
Devide that by the calf's age in days.
That gives you the ADG.
Multiply the ADG by 205, add the BW.
Correct for age of dam. (you should be able to get the correction factors from the AHA, unless they see it as intellectual property)

In the first two trimesters the developing foetus grows very little and doesn't really have an influence on the cow. When your calves are 6 months old the developing foetus is at the end of the first trimester so the decision to wean now will have no positive effect on the foetus, the extra month on the cow will have a huge positive effect on the suckling calf, though.

It is actually beneficial for the cows to get suckled down somewhat, not saying to get them skinny before winter, but losing a bit of condition now for the benefit of the calf isn't going to hurt the cow. There is no cheaper gain for the calf than what he gets from mom's milk while she is grazing.

I'm not sure I follow you here. The average daily gain of 3.6 lb/day for the group is just the total weight on the 8/2 weighing less the total group weight on the previous weighing divided by the number of days between the weighings. It is the group rate of gain for about the past month or so only. It is very close to what comes out of Cattlemax also.

Knersie, Please see your pm. Thanks. Jim
 

KNERSIE

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The average daily gain of 3.6 lb/day for the group is just the total weight on the 8/2 weighing less the total group weight on the previous weighing divided by the number of days between the weighings. It is the group rate of gain for about the past month or so only.

Remember calves don't grow at the same rate for 7 months.
 

novatech

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If the cows are staying in good condition leave them on. This may change from year to year depending on your cattle and available forage. You don't want your cows getting to fat by the time the next calf is due as it may cause some calving difficulties. On the other hand you don't want your cows condition to get down to where it negatively effects the growth of the fetus.
 

dun

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We weaned a bull calf saturday and happened to have weights on him from a littel more then a month ago. I put the numbers into CattleMax as weaing wights and dates just to see what it worked out to.
7/6/09 age 169 days weight 582 adjusted 690
8/15/09 age 209 days weight 710 adjusted 698
 

SRBeef

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dun":jgo7mn5b said:
We weaned a bull calf saturday and happened to have weights on him from a littel more then a month ago. I put the numbers into CattleMax as weaing wights and dates just to see what it worked out to.
7/6/09 age 169 days weight 582 adjusted 690
8/15/09 age 209 days weight 710 adjusted 698

That's interesting and about the same ball park mine are in. Came out very close. This is one place where a scale and Cattlemax are very valuable.

In SW WI we have been very fortunate this year with the weather - almost the exact opposite from C TX. I hate to even post a picture after seeing how dry it is in TX.

I do want to show one of a 410 lb 120 day old heifer calf with her 1200 lb dam from the other day:



So far so good on cow condition but I feel 205 days was too long last year which was much drier in August.

What about weaning at about 150 days? They will not be going on feed, just the same grass you see but separate pasture. It is a pain in the neck to now have two groups but if it is worth it for the cows I can do it. If not it would be easier to leave them together to maybe 180-190 days.

Thanks for the responses. Jim
 

SRBeef

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KNERSIE":17dsl4wc said:
The average daily gain of 3.6 lb/day for the group is just the total weight on the 8/2 weighing less the total group weight on the previous weighing divided by the number of days between the weighings. It is the group rate of gain for about the past month or so only.

Remember calves don't grow at the same rate for 7 months.

I can understand they do not grow at the same rate and the past month (3.6 lb/day group average) is probably their peak. With monthly weighings I will have some data on how that changes at the end of this season. They will probably gain faster on the cows than on pasture only.

So from a calf production standpoint, leaving them on the cows to 180-190 days is preferable.

From a cow standpoint however I am concerned about a 600-700 lb calf pulling down a 1200 lb pregnant cow's condition too much. I am also concerned that if I wait until I can see a visible drop in cow condition that it may be too late.

Thanks as always for your reply, Knersie. Jim
 

kenny thomas

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The cow is only going to milk so much no matter if the calf weighs 500 or 700. Leave them on. If the cow can not stand to milk for 7 months look at the cow not the calf.
 

bigbull338

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i would leave the calves on the cows for 7 to 8 months.because at that age they shouldnt be pulling the cow down.because they are grazing.all of my cows breed back on time.an have their calves within 13 months of eachother or less.so far they havent missed a beat.
 

SRBeef

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Two things:

In the calculations above the 3.6 number is the WDA (wt per day of age) the actual Average Daily Gain (ADG) ranges from 2.39 to 3.18. The difference is the birthweight as Knersie points out. My mistake.

Shipped a couple steers to day to processor and weighed them all again as long as they were all in the corral. The heifer in the photo above was at 423 lb.

I also probably underestimate the slow down in calf gain if I take them off of the cows early.

Cow condition is not bad. Even the projected 50% of dam wt plus calves will be grazing more. I do not creep feed.

Probably best to leave the calves on the cows and just keep an eye on cow condition, especially with the good grass this year. It makes sense let let the cows earn their keep.

Thank you all for the extensive information, posted and pm. Jim
 
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