B (1:49)

It's like, I should not. It's like the buffet. I should not have done that. And I just looked at that. Cats like that. That's kind of funny.

A (1:58)

Yeah, but.

B (1:59)

But yeah, he's so proud of himself. And it did not feel good.

A (2:02)

Didn't feel good.

B (2:02)

No.

C (2:03)

Philip, you know, I'm trying to think. I mean, we've had. I'm not a cat person. No, we had barn cats on the farm, you know, but never. No, no pet cats. The. We've had dogs that have done stuff, but trying to think of, I mean, one that sticks out. When I was a kid that I can remember that it was. I don't remember whose birthday it was, but we had leftover birthday cake. And mom had left it on the dining room table. And I don't know, we were gone for whatever reason. And we came back and half the birthday cake was gone and the plastic Saran Wrap that was over had been moved off, you know, and as we kind of figured out that one of the dogs had somehow come in the house because they're not allowed in the house. They'd never been in the house. Somehow came in the house and found the birthday cake on the dining room table.

B (2:56)

Have a hidden camera. The party guys, parents are gone.

A (3:01)

Oh, see, even our, our kids came home from college and they had forgot. You can't leave food out like that because they're like, hey, at my house I can, but not at ours. So let's, let's jump in. We've got a really good listener question today, and I'm going to read you guys parts of it because it's, it has a little bit of depth to it. So the question is two bulls, bull A and bull B. And they are full.

B (3:30)

They're twins.

A (3:31)

They're twins.

B (3:32)

Same genetics.

A (3:32)

Same genetics, right. So Bull A, nine months old, goes to a commercial herd. He's with 15 cows, doesn't really have chance to mature as much in a growth environment, goes out, and by the time he's a yearling, he starts breeding cows. He's with the cows 100% of the time. So his growth and full maturity size a little bit different. Stunted bull B goes, gets weaned, gets put on feed, goes to a similar scenario as a bull test and actually doesn't start breeding bulls until he's 24 months of age. So he goes to a bull test, he gets more growth. He starts at 24 months of age. The question is, will the calves from bull A and bull B be different because bull B went through a longer development period and was a little bit bigger size. Will those calves come to a different size? And how will the bulls turn out, longevity wise? So I'll let you guys jump in.

B (4:35)

Yeah. So, and the final question that the listener asks is, does that change the DNA in the semen that the bulls produce? And, you know, I'm, I'm the oldest one in the room. And the way I was taught genetics, the answer would be easily, no. No, that does not matter. That, you know, DNA is set. You get, you know, just random selection between parents and those kinds of things, but it's not affected by environment. And I, I think the reason we've always thought that is that's probably kind of mostly I mean, mostly true. And that it's. It is DNA is what you got from your parents and that can't be changed. But I'm not quite as adamant as I used to be. And I'm going to turn to the female side. So we know some things about, you know, fetal programming and things like that, that the environment, as the environment does affect the genes that are turned on and things like that. I'm still not convinced in this case that the sperm cells are different, but I'll turn it.

A (5:32)

So the DNA is the same, but what's expressed could be different.

B (5:35)

We're starting to wonder that.

C (5:37)

Yeah, so, yeah, so I'm not so sure because, yes, the primary DNA sequence, the nucleotide sequence is set, as far as we know. And I understand that doesn't change. But what does change over time is the. And with different environmental cues and things like that, and nutrition can be. One of those is that there's secondary molecules that are added to the primary DNA sequence. Particularly one of the things that we talk a lot about are methyl groups. But basically these secondary molecules influence the expression of genes. And we had some evidence that I've seen, and I'm not a geneticist, I don't spend a lot of time in this area. But those secondary molecules are passed on when the DNA chromosomes and splicing and stuff happens when sperm meets egg, some of those are passed on. So the primary sequence would on average be the same between these bulls that they pass on, but the secondary markers that affect the expression of those genes could be different. Yeah, I don't know that we have evidence that I'm aware of to know that late, I'll say later life nutrition changes those molecules, but we know that early life nutrition changes those molecules when an animal is in utero.

B (7:13)

Yeah, we're probably both talking beyond our knowledge on this, but I'm going to say maybe there's a scenario where nobody knows as much as we would like. One of the. And so I started with kind of talking about some of that heifer fetal programming and things like that. Well, I'm going to point out a difference between the males and the females. On the females, every egg she will ever ovulate was made and done before she was born. So all of the, all of the, the gametes, the eggs in females, there is no new eggs produced after she's born. That's not true for sperm. Sperm that is egg ejaculated was made in the last couple of months. All right. And so some of the things we talk about with programming on the female side that it's really important while she's still a fetus, while she's, before she's born, you know, some of the signals she's getting in the, in the uterus and we think nutrition and, you know, low stress and those kinds of things are really important. That may be different on the male side. Now I'm, and I'm going to say maybe because there may be some things, again, as that gonad, the testicles are being produced in that fetus, there's probably some programming going on, but it's not going to be exactly the same as what we see in the females. So there's just. I'm going to say, you know, what I led with was, of course not. There's no difference in the bulls based on environment, their DNA is the same. That's kind of the old answer. The new answer is I'm not sure. I mean, that is still true. The DNA hasn't changed. But does it affect their offspring? I'm going to lean towards probably not. Or if it does not much not, you know, like as in difference in weaning weight or something like that. I would be kind of surprised if there was a big difference, but I also wouldn't be surprised if there's a small difference.

A (8:59)

But that makes, could, could make sense because you've mentioned fetal programming a couple times. And just to delve into that a little bit, the nutrition of the dam while the fetus is growing has been shown to have some effects on that fetus which can bear out over the lifetime of that animal that's born. So which is what you were saying, the very, the very young, in utero young. But it's not as clear that it.

B (9:25)

Impacts like the offspring of that fetus. So that'd be like the grandchildren of the cow at the beginning. It does affect that fetus lifetime. Does it affect the genetics that that fetus will pass on? It's like, wow, now we're getting into the second.

A (9:40)

We're really asking is, does it affect. On the bull, does it affect their sperm and spermatogenesis, could it impact that? But those are carriers of genetic information.

B (9:51)

So I'm picturing, you know, when we look at testicles and you look at testicles under a microscope, you don't actually.

A (9:57)

Have to look at testicles under a.

B (9:59)

Microscope, but you can see them.

A (10:01)

You can see them with your naked eye.

B (10:02)

But if you do look at them under the microscope, what you'll see are, you know, the cel that they're called, nurse Cells, they're the cells that take care of little baby sperm cells before they're mature. You want those to be healthy. And you can see under a microscope when the testicular tissue that supports sperm cell development is damaged, it's not working well. Well, the sperm cells don't develop well. And if that, if that tissue that, that handles and promotes the growth of those sperm cells is healthy, everything goes better. So one of your questions is basically, could that be determined even early in life that is permanent? Such as those cells that take care of the sperm cells, are they permanently affected either for the positive or for the negative?

C (10:52)

But does that change the DNA that goes into the sperm cell?

B (10:56)

Oh, no, it doesn't change the DNA. It does change. And so then this starts, it's, we're jumping back and forth. It might change the fertility of that bull. Yes, but does it change the DNA.

C (11:07)

He'S going to pass on when he does, when he does breed a cow?

B (11:11)

That that's all. That's a bigger jump for me.

A (11:13)

Yeah.

B (11:13)

I'm not saying that someday people won't make that leap. That's a bigger jump. Yes. So let's use the female example and the male example. Does the, the early, while she's still a fetus, affect that heifer and her future fertility? Yeah, I think so. But would it affect that male's fertility? That makes sense to me that that could happen. Does it affect the offspring?

C (11:38)

Yeah, well, yeah. Does it affect the DNA that they pass on?

B (11:41)

And that would be beyond my current.

C (11:44)

Understanding of and I guess my, my thought is the primary nucleotide sequence. No, I think that set, that's what they're going to pass on other than the random snips that happen and in, during replication. But I think, I mean, I think there's some evidence that these secondary molecules, this epigenetic component is heritable to some degree. And so there are some of that that's passed down. And so I don't know if like I said, later life nutrition affects that epigenetic pattern and then affects the expression of the genes that go on to the offspring or not.

B (12:21)

I've been talking about when the bull or heifer is very, very young. What about a three year old bull that's successfully bred in the past but then goes through a rough winter, he loses weight, he gets sick, he's on a poor plane of nutrition and the weather's horrible. I've given him disease, stress, weather stress and nutrition stress.

C (12:38)

Yeah. And so his epigenetic pattern may have changed for some degree and there's testicular stresses for like cold or heat or something. Does that influence those epigenetics?

B (12:49)

First of all, he's probably less fertile because of all the things I just said. But let's say he gets some cows pregnant. Does that affect the offspring of those calves that were bred by a bull that's under some challenges? Maybe.

A (13:02)

It'd be hard to know. And we don't know the genetic expression. But let's take, let's take the same question from a slightly different angle. Of the two bulls raised in those two different ways, one basically kind of.

B (13:15)

Had to go to work early.

A (13:16)

Yes. And the other prep school. Everything wound into it. Right. I mean, he went through the slow process. What do you think about the longevity of those two bulls in the herd and the fertility? So beyond the genetics, think about how they were prepared nutritionally and likely. Let's just assume the one that didn't go until 24 months of age to start breeding reached a higher mature weight. So his phenotypic type is a little bit different than his genetically identical twin. Reached a better mature weight, bigger bull. Which one of those is better long term in the herd?

B (13:52)

I don't know. I could make an argument to that either. I could make an argument either way. And I could make an argument that that bull that's a little bit. Not asked to go out and breed cows as young has more time to develop, grow, those kinds of things. But, but the reality is a lot of times the reason bulls leave herds are because of musculoskeletal issues. And so then my answer would be, well, which of those bullshit bulls has a more sound musculoskeletal system? And I could make an argument either way. I could say that bull that's kind of slowly developed heavy weight, maybe higher body fat, he may be worse. I could also see where if that bull, during some growth periods around puberty, that bull that's kind of asked to work earlier, if he doesn't lay down as good a cartilage and that kind of stuff, I could picture a story.

C (14:41)

Does it.

B (14:41)

It's not clear to me which of those bulls would have more.

C (14:43)

I don't either overall. But does, does it affect their spermatogenesis in the long term? Would it affect their ability to pass a BSE as a five or six year old bull?

B (14:54)

To me, and from what I. So I know now, I'm getting into some things where there have been some research studies. It's actually interesting that. And back to our earlier conversation, the nutrition of these bulls pretty Young, like even before they're weaned. So what's the forage quality? What's the milk production of their damage prior to puberty? That does seem to impact how well the testicles are made and how well they produce in the future. When we get into trouble sometimes is overnutrition after weaning can have a neutral to negative effect. And so when we talk about good nutrition on bulls, a lot of times, because we're the caretakers, we're thinking post weaning, it actually may be that the most important time for the nutrition on that bull is actually a little bit before we wean them, when the cow's still taking care of them. So. So yes, I think the nutritional management of these bulls can matter, but it may be at a timeframe that we're not thinking of.

A (15:45)

Well, and I think too, you have to look at it from the standpoint of lifetime productivity or longevity. The reason we care about longevity is productivity. Right. The more years in the herd. Well, bull A in this scenario did not take a red shirt year. He's got one whole year of production.

C (16:03)

Can we throw in some more like sports? And yeah, he's got more calves reduced.

A (16:08)

It's just like having more yards for scrimmage. I could do it all in sports analogies if you want, but it is. He's got his total productivity. Even if he stays in the herd a year less, he's still got those first year calves going. So I think you could go either way on that. And I appreciate you guys thoughts on this.

B (16:27)

Let me give one final thing. So there's so many things we've said we don't know, and this is an area where probably we're learning some more. What I do know is the Bullet himself is more fertile if he's in an appropriate plane of nutrition. An appropriate plane of nutrition is a window. So I want him to basically have the calories and protein he needs to develop and, you know, lay down bone, lay down muscle, lay down testicular tissue. And I don't want him to get over fat. I think that's. So whatever scenario, we get him to work early, we keep him around later. I think good nutritional management of bulls is positive. Now, what are all the positives and what are all the negatives from missing that window? I can't tell you for sure, but go back to the basics of monitor body condition, monitor the diet these bulls are given and kind of keep them in that window of pretty good body condition, but not over fat.

A (17:20)

Yeah, keep them right in the Middle of the lane. The Goldilocks.

B (17:23)

Yeah. Keep them in the middle of the lane. Right down the middle of the goalposts. Yeah. Don't take it off.

A (17:27)

I know. Wants us to be all in sports analogy, so we're doing it. I'll shift topics from sports analogies and go to another topic that has come up and there's some questions about.

C (17:38)

You don't think you can throw any sports analogies in on udder quality?

A (17:41)

Yeah, I don't have any. Not going there. But on the. Well, you could. The Olympics of udder quality. If you're. If you're going to figure out how important is udder quality to the commercial cow producer and should I use utter quality or some metric or gauge or scoring system to cull cows?

B (18:05)

Yeah, it. As someone who remembers having to deal with cows that had, you know, kind of big balloon teats, difficult for the calf to get a hold of those types of. Yeah. No, no, producer. No calf wants to deal with a cow with poor udder quality. And so is it a problem? Yeah, it's. It can be a problem. The main thing is, I think as a producer, I'm not very patient with that. So a cow that has poor. And a lot of times, this is my experience anyway, you know, she might have really poor udder quality at the beginning of lactation. And then as by the time we're weaning that calf, that udder starts to look pretty good. And so I need to make sure that I remember that cow and not give her the chance to make another heifer. And I might not. I know. I don't. I wouldn't say might. I'm not going to keep her heifer. I. That is so frustrating to have to deal with a poor quality udder early in life for a calf that.

A (18:57)

So you think they're hereditary?

C (18:58)

I think that's. I do think it's.

A (19:00)

What's.

C (19:00)

What is. What is the heritability of utter quality or utter. Utter. Now, scoring is difficult because it's subjective.

B (19:07)

But and scoring at what time? So a lot of times we're making our. Our selection at the time the heifer is, you know, not that far from puberty. And I don't. I don't trust my ability to predict how that. So I'm gonna base it a lot on her dam in that if her dam has good udder quality.

A (19:25)

Yeah.

C (19:26)

I'm not gonna keep heifers out of cows that have bad udders.

B (19:28)

So. So your question is, how terrible is it?

C (19:31)

It's not a selection. It's a culling criteria.

B (19:34)

Yeah.

C (19:34)

So you're taking the bottom off and.

B (19:36)

I don't know how heritable it is, but it's enough that that's the way I behave.

A (19:40)

Maybe, maybe I. I don't know. I agree with you that. But it's the occasional cow that will have, depending on your herd, your genetics, what you're dealing with. It's the occasional to rare cow that will have a big teat. And I'm not sure if there was something else that was going on.

B (19:57)

So you're saying it could have been mastitis?

A (19:58)

Could have been mastitis. I think we underestimate how often mastitis could happen in beef cattle because we're not milking them every day. We don't have the ability to observe it.

B (20:08)

Try not to milk them. It's only.

A (20:10)

Yeah, try not to milk them ever. But it's. It's only the very rare case that's severe that might be noticed or identified. So mastitis could have led to that. And I would not base. Of all the things that I'm selecting heifers based on utter quality would be so low as to be inconsequential on my heifer selection.

B (20:34)

I agree. Unless. Unless I had problem with this.

A (20:38)

Unless you agree. Unless you disagree. That's kind of sounds like the most.

C (20:42)

Yeah, yeah, I think that's right. You know, there's something that happened to that cow and so you got to take that into account. But did a quick search and a couple of websites cite the heritability of udder attachment around 0.2 to 0.3.

B (20:58)

That's pretty.

C (20:58)

And heritability of teat size at 0.5.

B (21:03)

Wow. That's actually pretty high. Yeah.

C (21:05)

So there, there definitely could be something to it there. But I think you got to take into account that if there, if she had mastitis in that quarter or something else that happened that affected her. That's not heritability, that's just environment. Yeah, environment.

A (21:22)

But I don't know that. I would know. And I agree that it makes sense that both those things are heritable because a lot of our physically expressed traits, musculoskeletal issues are pretty highly heritable. So that makes sense. But how often are those teat size or utter attachment. I'll say out of bounds to stick with our sports team.

B (21:43)

Yeah. This is my opinion. I think it's. The reason that I think you said it's not that high on your criteria is you. You didn't run into very many. I mean you didn't have very many herds where your clients were really struggling with udders. No, and I would agree. And if a herd was struggling, I would then in that case put some selection pressure on the daughters out of cows that I had problems with. If I'm not having very many problems, it's not very high on my list of things to adjust. So I think it really is a herd by herd basis.

A (22:13)

Yeah, that makes sense. Thanks guys for your discussion on this and a couple good listener questions there. If you have further questions for us to discuss, you can send them to us@bcisu.edu.