Bulls

[Anonymous]

Do any of you think the older a bull gets the better calves he throws. Have a bull that this years calves are much better than last years. Just curious, Bobby

 

[Frankie]

Do any of you think the older a bull gets the better calves he throws. Have a bull that this years calves are much better than last years. Just curious, Bobby

No. His genetic make up is the same whether he's a yearling or a five year old. Some people use young bulls on heifers, then on mature cows as he gets too big for heifers. Then they'll think his calves are getting better, but it's actually that mature cows will generally wean heavier calves than heifers. I can't think of any reason that a bull's contribution to a calf should change as he gets older.

 

[MikeC]

Do any of you think the older a bull gets the better calves he throws. Have a bull that this years calves are much better than last years. Just curious, Bobby

I wouldn't think the age of the bull has anything to do with the quality of calves if they are the same cows.

All the bull is doing is fertilizing an egg with the same genes that he had last year.

 

[Anonymous]

I did'nt think so just might be the way it worked out this year with my cattle. It is the same cows as last year.

 

[Victoria]

It depends on the age of the bull and on the rate of puberty. If you are using a yearling bull it is very possible that his semen is not as high quality as it will be when he gets older because he has not fully matured. He also will not have as much semen as when he ages. So the answer is yes, if your bull was being bred as a yearling those calves probably weren't as good as they are now that he is two years old. The Western College of Veterinary Medicine has done studies to show that only 33% of beef bulls have satisfactory sperm at 12 months of age and only 60% at 14 months of age. Most bulls will have satisfactory sperm at 16 months. Some take longer though.

 

[ALACOWMAN]

Kind of on the same line as the old tale that you can breed a sire to his daughter the first time with no problems. has anybody else heard this one? i would think that during his peak production years would be his better calves :hat:

 

[Workinonit Farm]

The Western College of Veterinary Medicine has done studies to show that only 33% of beef bulls have satisfactory sperm at 12 months of age and only 60% at 14 months of age. Most bulls will have satisfactory sperm at 16 months. Some take longer though.

I would think that sperm quality would have nothing to do with the genetic "markers" within the sperm itself. The quality of the sperm/semen probably has more to do with the quantity of sperm in the smen, the quality meaning motility etc. The sperm cells themselves contain the genes of that bull whether there are 10,00 sperm per ml or 100,000, whether they are "fast movers" or slow.
Just my 2 cents.

Katherine

 

[CattleAnnie]

Could be several different factors.

For example, young cows might be coming into their milk production as they are maturing; a better year forage wise; maybe a change in your management as pasture management in units per acre, minerals, etc.

Just a thought.

Take care.

 

[Victoria]

The Western College of Veterinary Medicine has done studies to show that only 33% of beef bulls have satisfactory sperm at 12 months of age and only 60% at 14 months of age. Most bulls will have satisfactory sperm at 16 months. Some take longer though.

I would think that sperm quality would have nothing to do with the genetic "markers" within the sperm itself. The quality of the sperm/semen probably has more to do with the quantity of sperm in the smen, the quality meaning motility etc. The sperm cells themselves contain the genes of that bull whether there are 10,00 sperm per ml or 100,000, whether they are "fast movers" or slow.
Just my 2 cents.

Katherine

I've read a few things stating otherwise. It's the same in people - a young teenage boy who has just reached puberty has a greater chance of having a small and/or unhealthy baby than a man in the prime of his life. Same as these 60-70 year old men that often have unhealthy children.

 

[Victoria]

Thankfully it doesn't happen often! ;-)

 

[S.R.R.]

It depends on the age of the bull and on the rate of puberty. If you are using a yearling bull it is very possible that his semen is not as high quality as it will be when he gets older because he has not fully matured. He also will not have as much semen as when he ages. So the answer is yes, if your bull was being bred as a yearling those calves probably weren't as good as they are now that he is two years old. The Western College of Veterinary Medicine has done studies to show that only 33% of beef bulls have satisfactory sperm at 12 months of age and only 60% at 14 months of age. Most bulls will have satisfactory sperm at 16 months. Some take longer though.

Are you sure you are not thinking Quanity instead quality. The study has more to do with the amount of sperm produced at 12 months-16 months old. DNA is the same from the time of conception til death.

 

[Frankie]

It depends on the age of the bull and on the rate of puberty. If you are using a yearling bull it is very possible that his semen is not as high quality as it will be when he gets older because he has not fully matured. He also will not have as much semen as when he ages. So the answer is yes, if your bull was being bred as a yearling those calves probably weren't as good as they are now that he is two years old. The Western College of Veterinary Medicine has done studies to show that only 33% of beef bulls have satisfactory sperm at 12 months of age and only 60% at 14 months of age. Most bulls will have satisfactory sperm at 16 months. Some take longer though.

Are you sure you are not thinking Quanity instead quality. The study has more to do with the amount of sperm produced at 12 months-16 months old. DNA is the same from the time of conception til death.

SRR, you're right. This study addresses the quality and volumn of sperm a bull produces; it doesn't address genetic quality at all. A bull's genetic make up won't change as he gets older.

 

[Victoria]

Taken from the Miss. University:

The age and weight at which puberty occurs also vary greatly among breeds and level of nutrition during development; however, research with various breeds suggests that a practical indication of imminent puberty is when scrotal circumference is between 27 and 29 cm. However, simply because a bull can produce semen does not translate directly to fertility. Sperm quality and quantity continue to increase for several months after the initiation of semen production. About 35 percent, 60 percent, and 95 percent of 12-, 14-, and 16-month-old bulls, respectively, are reproductively mature and produce good quality semen.

A little further in the study:

 

[Victoria]

Oops hit submit accidently

A little further in the study:

Semen quality
Semen quality is determined by the volume of the ejaculate and by the motility and morphology of the sperm cells. It is important to remember that substandard nutrition, extreme environmental temperatures and disease can reduce semen quality, and that the quality of semen from a single bull may change over time.

Sperm motility is calculated by evaluating the percentage of spermatozoa with forward movement in a sample ejaculate. This is calculated by placing a drop of semen on a microscope slide and observing (at 100x magnification) the number of spermatozoa with forward movement in relation to those with other than forward movement.

Sperm morphology is calculated by evaluating the number of normal spermatozoa in a sample ejaculate in relation to sperm with primary and secondary abnormalities. Primary abnormalities originate in the testis during spermatogenesis. Secondary abnormalities originate in the epididymis, during sperm transport. The designation of primary and secondary abnormalities refers to the origin of the defect and not to the severity of the defect. Therefore, both types of abnormalities are equally important when evaluating sperm quality.

Sperm morphology influences pregnancy rates. In a recent study, bulls with less than 20 percent abnormal sperm elicited pregnancy rates at least 4 percent higher than randomly selected bulls (Table 2). Therefore, selection of bulls with greater than 80 percent normal sperm can increase overall pregnancy rates in a herd.

Granted it talks mostly about how many cows a bull can impregnate but my point of including the paragraph on semen quality was because it shows that when they talk about how semen quality being affected in young bulls they include motility. Other studies on both people and animals show that lower motility rates of sperm can cause health problems or stunted growth.

The DNA doesn't change but it can be affected by different factors.

 

[ollie']

Victoria you sure about that. Motility as the article states has to do with sperms ability to reach the egg. While it can have good morphology, it can't get to the egg to fertilize the egg. I am unaware of any study relating morphology or motility to quality of livestock produced. I am open to new insight though.

 

[Victoria]

Hi Ollie,
Sperm cells are made continuously and therefore mutate. Just as diet of the bull (or human) can affect sperm so can age. I have been trying to find the article that talks about animals age and sperm but so far I can not find it again. It's been a few years - a friend of mine was telling me about it because she has a down syndrome child and scientists were discussing the possibilty of Down's Syndrome being related to not just the age of the mother but also the age of the father. It was discussing the motility being an issue not just on actually making it to the egg but also what happens if a poor quality sperm does make it. All I can find now are articles that discuss the fact that it is the reason that the sperm has motility problems that causes the defects not the actual motility that causes the defects. So perhaps that is true and they have thrown the other study out the window. Which would then make my last point invalid, I owe everyone an apology and I am glad you made me look into it further.

However, on my quest of finding out this information I did find a couple of interesting articles about a father's age and whether it causes birth defects. These are about old age and so do not prove my point totally but they do show that genes are not the same regardless of age.

http://www.palmbeachpost.com/heat/conte ... 14764.html
http://www.newscientist.com/article.ns?id=dn1989

My husband's friend is a molecular biologist so I am going to e-mail him about this and see if he has any insight. I will let everyone know what I find out.

 

[S.R.R.]

Victoria you sure about that. Motility as the article states has to do with sperms ability to reach the egg. While it can have good morphology, it can't get to the egg to fertilize the egg. I am unaware of any study relating morphology or motility to quality of livestock produced. I am open to new insight though.

Have to agree with ollie. Sperm motility has nothing to do with what a calf will be like. It only tells you how likely a sperm will reach the egg ie. fertility. Even if the sperm has a very low motility if one reaches the egg the calf will have the same genes as if the sperm had a high motility.

 

[S.R.R.]

Read the studys but should point out that they are dealing with birth defects not the average quality of children/calves. If you were seeing a high number of birth defects in your calves that would be another story. To say that at different ages a bull will throw bigger or smaller calves with better or less growth qualitys ect. is not possible.I have a bit of inside knowledge on the subject as well so will be interested to see what your Husbands friend comes up with. I will add that when I was 18 I sure wish my sperm had a lot less motility :lol: :lol: oops did I just say that!

 

[Victoria]

Here's something that I hate doing - admitting that I was wrong.

I wrote our molecular biologist friend and I am not going to try to post his entire reply. He is a genius and as a genius he knows his stuff but sometimes you get more information than you ever asked for. I did learn more about Biology in two e-mails than I did in all my teaching in school though. ;-)

Just a couple of things that he wrote were really worth mentioning:

DNA is an idea that is
crystalized in a molecule. The idea is forever but the molecule is subject
to damage. All of your cells come with little machines that detect and fix
damages, but these machines themselves come from the DNA, and as the
damages accumulate, the machines become more faulty. It stands to reason
that an older male will have more chance of "bad" sperm than a younger
one. But not much. Most of the cellular machinery in the body is
concentrated on the singular task of protecting the chemical integrity of
the gametes.
The younger the male the better the chances of correct sperm. Period.

The sperm are in better shape the closer they are to their original
manufacture, at birth. They are desinged to be time released from puberty
on, but they are never as good as when they're first made.

I know I read the study I was talking about but as he points out to me:
I wouldn't take that too seriously, as the medical
profession is notorious for publishing a refutation of all previous
statistics ever 5 or 10 years. It's entertainment like everything else and
has to keep the audience interested. I am sure the situation with bulls is
very similar

So I apologize for giving incorrect information but I am glad that I did. Had I not said anything and been questioned about it I would never have gone digging any deeper and I would still be believing the wrong thing. This guy is the one guy I trust far over anything else I read. Thanks everyone for calling me on my information and making me learn more, that's why I love this board!

 

[MikeC]

Victrola you have hurt my feelings. You believed a "molecular biologist" over me and other old world wise cattlemen on here.

Just kidding! Thanks for the info. Glad to see that some can admit a mistake. That's an honorable trait.