Strange thing with ETs

Something I've maybe mentioned on here before is my surprise at the variation that results from female ET calves retained as cows. I've only done it twice and in each case got 4 full sister heifers to rear so it's not a big sample to base a theory on. It appears to me though that using ET and flushing those extra number of eggs is not something that nature approves of as she appears to reward you with more outliers than would occur through natural breeding the same cow/bull. Could this mean that of all the hundreds of eggs a cow produces through her life it is not down to luck which one gets fertilized?
Out of these two groups of 4 I've raised I've had the full spectrum from fat slobs with hardly enough milk to raise a calf to average types, to excellent types, to infertile types. Could this be affected also by the rearing of the calves by recipients? In both cases heifer calves reared by big, milky sim x cows turned into the poorest performers while in both cases the outstanding heifer from each flush was poorly raised by a heifer recipient. Has anyone else experienced similar results or am I barking up the wrong tree?


A cow we flushed - 12 year old in this picture and off an "old type" bloodline, a throw back to a particular bull line in Scotland with lots of highland hair. I was interested to use her because her maternal predecessors have looked exactly like this for several generations despite being bred to a variety of different bull types.


4 daughters, all rising 2nd calvers ranked in descending order from very good, through 2 decent to 1 very poor based on their performance as heifers.

Grassfarmer wrote:

Something I've maybe mentioned on here before is my surprise at the variation that results from female ET calves retained as cows. I've only done it twice and in each case got 4 full sister heifers to rear so it's not a big sample to base a theory on. It appears to me though that using ET and flushing those extra number of eggs is not something that nature approves of as she appears to reward you with more outliers than would occur through natural breeding the same cow/bull. Could this mean that of all the hundreds of eggs a cow produces through her life it is not down to luck which one gets fertilized?
Out of these two groups of 4 I've raised I've had the full spectrum from fat slobs with hardly enough milk to raise a calf to average types, to excellent types, to infertile types. Could this be affected also by the rearing of the calves by recipients? In both cases heifer calves reared by big, milky sim x cows turned into the poorest performers while in both cases the outstanding heifer from each flush was poorly raised by a heifer recipient. Has anyone else experienced similar results or am I barking up the wrong tree?

Many have observed that heifers that got too much nutrition in some part of life got too much fat in the udder to be productive, or what ever the reason was. I have not seen this phenomenon myself even if most of my cows are heavy milkers, but some farmers are dead sure that this is important, and can speak endlessly about one generation in a cow family milked heavy, the second lightly, the third heavy, the fourth lightly e.t.c.

Regarding the differences between cow daughters from ET compared to the daughters the cow gave birth to herself, of course they are more diffrent from each other because they have not shared the same uterus environment, nor the same treatment from the cow. Genetically, full siblings will differ phenotypically from each other as long as their genome differs. The more inbred the less difference between siblings.

Tulip, in the vicinity of heterozygous daugter groups.

Tulip, I believe about the heifer calf that is over fat subsequently being a poorer milker as a result. I suspect that is at play here. But I think there has got to be more at play than that - one of the infertiles I had was the classic fat, infertile shape from nose to tail and surely that has got to be genetic and not a result of being reared by an overly milky recip? If the type of recip you use can influence the calves to this degree it would surely manifest itself in natural pregnancies as well? - i.e. it's not the case that every skinny heifer that is short of milk rears a wonderful daughter and every big milky cow rears a fat infertile daughter.
Going back to the ET process and the cows production of eggs - if a cow produces hundreds or thousands over the years are they all of similar potential or are there better eggs and poorer eggs? maybe sometimes when a cow doesn't settle first service the egg may be of poorer quality? What happens when you inject them with drugs to trick them into dropping a lot of eggs at once with the super ovulation process - do you get a bigger variation of egg quality. Saying that i don't even know if egg quality correlates to wider/narrower genetic variation possibilities.
One thing I did learn from my ET practitioner was that embryos out of very old cows are maybe not as good as they appear. We flushed my matriarch cow on the other thread at age 20 and got 18 "grade one" embryos but had very poor retention rates with them in recips. What my ET guy said was that they had recently discovered that in humans in their 40s and 50s the embryos could be considered grade 1 by cow standards at time of extraction but after a week or month of storage they appeared to downgrade and would be categorized as lower quality if re-examined which is not the case with embryos from younger women. He speculated that a similar effect may be at play with cattle. Has anyone else experienced particularly poor ET retention rates with these much older cows?

Quote :

Many have observed that heifers that got too much nutrition in some part of life got too much fat in the udder to be productive

Does the fat ever get used up out or the udder or once the fat cells are there they just repeat the growth cycle every time that the calf is weaned? Bad question but I'm asking if the condition ever changes in later calves so that milk function gets back closer to what it should have been? From experience, I'd say that I've seen little improvement. Just curious on other observations.

We happen to be involved in raising a heritage pony breed. Among the older and wiser breeders it has been discussed that the progeny from a mares younger years almost always outperforms her progeny from her older years. These often give birth 15 or 20 times, so there is much recorded data. The general idea is that the DNA is healthier in younger animals, thereby producing fewer small mutations.

Tulip, in the vicinity of wanting the early progeny from older proven cows...

What about the production of the young daughters of the old mares?

tulip wrote:

We happen to be involved in raising a heritage pony breed. Among the older and wiser breeders it has been discussed that the progeny from a mares younger years almost always outperforms her progeny from her older years. These often give birth 15 or 20 times, so there is much recorded data. The general idea is that the DNA is healthier in younger animals, thereby producing fewer small mutations.

Tulip, in the vicinity of wanting the early progeny from older proven cows...

Kent Powell wrote:

Grassfarmer wrote:

Tulip, I believe about the heifer calf that is over fat subsequently being a poorer milker as a result. I suspect that is at play here. But I think there has got to be more at play than that - one of the infertiles I had was the classic fat, infertile shape from nose to tail and surely that has got to be genetic and not a result of being reared by an overly milky recip? If the type of recip you use can influence the calves to this degree it would surely manifest itself in natural pregnancies as well? - i.e. it's not the case that every skinny heifer that is short of milk rears a wonderful daughter and every big milky cow rears a fat infertile daughter.
Going back to the ET process and the cows production of eggs - if a cow produces hundreds or thousands over the years are they all of similar potential or are there better eggs and poorer eggs? maybe sometimes when a cow doesn't settle first service the egg may be of poorer quality? What happens when you inject them with drugs to trick them into dropping a lot of eggs at once with the super ovulation process - do you get a bigger variation of egg quality. Saying that i don't even know if egg quality correlates to wider/narrower genetic variation possibilities.
One thing I did learn from my ET practitioner was that embryos out of very old cows are maybe not as good as they appear. We flushed my matriarch cow on the other thread at age 20 and got 18 "grade one" embryos but had very poor retention rates with them in recips. What my ET guy said was that they had recently discovered that in humans in their 40s and 50s the embryos could be considered grade 1 by cow standards at time of extraction but after a week or month of storage they appeared to downgrade and would be categorized as lower quality if re-examined which is not the case with embryos from younger women. He speculated that a similar effect may be at play with cattle. Has anyone else experienced particularly poor ET retention rates with these much older cows?

http://www.wlj.net/article-7348-subfertile-females-may-have-misplaced-male-dna.html

Could you do a copy and paste Kent? I can't get through to the article without signing up. Thanks.

I'm not registered either. I just thought it might be applicable to this subject.