In this episode, we dig into “The Britt Hypothesis” to understand how the dry period impacts dairy cow fertility and the significant role of epigenetics. Dr. Jack Britt joins us to discuss dry cow management and its influence on future generations.
Dr. Britt challenges traditional dairy management practices, questioning the standard voluntary wait period and the conventional 365-day lactation cycle. With advancements in technology, he offers insights to help us rethink how to manage the herd to enhance fertility and productivity.
Born and raised on a dairy farm, Dr. Britt has dedicated his entire life to working in agriculture as a farmer, teacher, scientist, executive and entrepreneur. He has worked extensively in the USA and 23 other countries and has been an advisor to major government agencies that regulate foods and drugs. Today he provides expert worldwide consultation in emerging applied technologies; agricultural systems, biotechnology, and bioenergy.
If you would like to discuss this topic further, contact us. Contact us.
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Scott Zehr
All right. Hey, welcome everybody to Ruminate This with Agrarian Solutions. I’m your host, Scott Zehr. And, on tap today, we have a great discussion with Dr. Jack Britt. And Dr. Britt, you shared with us on a previous episode some things to think about maybe from a macro level, global level things we can do, or need to be thinking about doing as an industry to fill the demand for increased dairy product.
Today’s conversation though, Dr. Britt, I’d like to bring it down to maybe the farm level and say, nutritionally speaking, how do we actually fill that role? Right? So it starts with that cow. It starts with creating a better cow genetically. It starts with feeding her better and better management and so on.
So Dr. Britt, really quickly for the audience. So you, again, we talked about in the last episode, grew up near Bowling Green, Kentucky. Got your PhD in, physiology and biochem, at North Carolina. And, yeah, extensive collegiate academia career. Also Associate Dean, for research at the College of Ag and Life Sciences.
And in the college of veterinary medicine at North Carolina state. So Dr. Britt, I mentioned some of that because, I can’t think of anybody to have on here better to talk about this than somebody that’s had the impact on cattle nutrition. And, how we understand cattle than you have.
And I say that with respect, obviously, because we still talk about the Britt hypothesis today. a lot. In a lot of different ways. And Dr. Larry Roth is our vice president of nutrition. When he came on board, we were talking about inflammation. We’re talking about transition success and how mycotoxins play into that.
And Dr. Britt’s comment to me was, “Well, Scott, let’s go back to the BRIT hypothesis.” And, so yeah, I want to dive into that. And then we have some other questions that I’m going to throw at you today too, but essentially the BRITT hypothesis.
Dr. Jack Britt
Good. The BRITT hypothesis was formulated when I was speaking at a conference in Florida many years ago. And we were talking about heat stress as one of the issues. And then I got to thinking about the egg that is ovulated from a cow today. She comes in heat, she ovulates an egg today.
That egg started developing in her ovaries a hundred days ago. So when we look at a cow and we wonder why her fertility is low, we need to think about not what happened today or yesterday. But what has she been exposed to over the last 100 years or 100 days, excuse me days, when that egg was developed.
So, for example, a good example of this is you breed cows in October and you don’t have good fertility. Maybe even in November, the fertility is not so good and then it begins to increase. Well, that egg that was ovulated in October had been exposed to heat stress. In August and September when it was growing before it ever reached the October stage and ovulated.
So it brings some impairment to its state when it’s ovulated. And so we, we need to understand that fertility is not just affected around the time the cow’s in heat, but it’s been affected for the hundred days before she ever comes in heating this bread. And then we need to think back, what, was she sick sometime? Did she have dystocia? Well, did she have a foot problem?
Scott Zehr
Yeah.
Dr. Jack Britt
Was she in a sick cavalry? Was she healthy and going great through the old lactation? So there’s a history, if you will, associated with that embryo that’s been growing during that 100 days. So we shouldn’t say that the eggs just ovulated. The egg has been growing for 100 days before it was able to be fertilized. And so that 100 day history is important.
Scott Zehr
It is. And, you know, before… I’ll say it like this. So I, I started working in the AI space in 2013 as a technician. Five years into that career with, with Premier, I moved into more of a consulting role analyzing records. Trying to help farmers figure out how to get more cows pregnant faster, more efficiently, less semen, that kind of stuff.
And I didn’t know some of this back then, but first service conception rate. You know, we would always get hung up and it’s, I think it’s because you can see it, right. But we’d get hung up on, well, are we giving all the shots correctly in the, in the protocol?
Are we, is the timing of the insemination matching up with the timing of the ovulation properly? And you go through this list of things. I always used to say, and I still say, if you don’t have first service success on conception rates, what’s going on at the transition period?
What’s going on with the dry cow pen? And it’s not just the pre fresh pen, it’s the far off dry cows too, right?
Dr. Jack Britt
Right.
Scott Zehr
So yeah, now I understand better why. So something that you figured out a long time ago.
Dr. Jack Britt
And if you think about what happens when a cow freshens, some of them will have a substantial loss in weight around that time of freshening. And that’s, that occurs regularly.
Scott Zehr
Yes.
Dr. Jack Britt
Cows, they come in a little too heavy. They’re not eating enough around the time they came and they lose weight. And then we wonder, well, why are they not very fertile? At 60 days postpartum when we breed them. It’s because that egg was already had been developing but for 40 days and it was exposed to that loss in energy around the time of calving.
And we now know that any loss of energy, body condition score around the time of calving is going to have an adverse effect on that cow that’s bred at 60 or 70 days postpartum. Because that egg was developing during that period, and it was exposed to that body condition loss.
Scott Zehr
Well, and it’s, it’s backed up even more and more now too, with with things like rumination monitoring.
Dr. Jack Britt
Sure.
Scott Zehr
So I don’t mention them to pick favorites cause I don’t really have one, but I know some research that cow manager has, has worked on where if you have a cow in the far off dry cow period, I’m going to say 50 days prior to calving, in that windo,w and she goes off feed for a day.
Even if she comes right back 24 to 48 hours later, she is way more likely, after calving, to experience things like DAs, ketosis, milk fever, mastitis poor repro. And it was an alarming number, I want to say like 85 percent more likely just from having one bad day in the dry cow program. You know, to me that, that’s, that’s just ties in everything you just talked about.
So how do we, you know from a, I guess, from a management standpoint, there’s a lot of things that, that we can do to, you know, proper hoof care and timing of hoof care, sand beds, you know, good floors, that kind of stuff. But you know, like you said, some of the processes it’s, she needs to mobilize that energy reserve if she’s not eating enough, right?
She’s not getting enough in her diet. She needs to do it, but there’s just a lot of unintended consequences behind it. So, you know, you talked about that cow being overweight. What if she’s not overweight, Dr. Britt? What if she’s actually in good condition, but she’s got that sore foot and makes her not eat. Does that, is that a compounding effect to where she doesn’t have that internal reserve to, to grab?
Dr. Jack Britt
I think that that is, any sort of situation, disease situations, a good sore foot is a great example, because she’s not only got a sore foot, she’s going to be off feed for a few days. She may be not laying as much with the sore foot, but she’s got to get up and down.
So there’s several different things going on with the sore foot. And so that is all associated with her ovaries and her reproductive system and what’s happening. And so, yeah, those… Another good example is a cow in Florida that’s heat stressed in August is going to have bad eggs until November.
Scott Zehr
Yeah. Yeah, yeah.
Dr. Jack Britt
December. And so…
Scott Zehr
You know, unfortunately, if you’re dairy farming in Florida, it’s not just the heat stress in August, you have to worry about this, the heat stress in April, May, June. Yeah. I asked myself whenever I’m in Florida on dairies why, why do people try to milk cows down here or get cows pregnant down here?
I’m not sure, but that’s a topic for another day. I won’t pick on our Florida dairyman, today. So, you know, you mentioned the heat stress. And again, you know, we’ve, we’ve come a long way. I mean, cross ventilation, sprinklers. We do, there’s a lot of herds that do a great, great job with heat abatement and rightly so.
The last time I looked up this, the statistic it’s about a, somewhere between 900 million and a billion dollars a year in economic impact to the dairy industry, just from heat stress. I mean, it’s, it’s a big, big number. But it’s, it’s not just the immediate economic impact, right? It’s not just the loss in milk or poor reproductive success.
Talk about epigenetics, right? So the, the research there, I mean, that’s becoming more and more widely adopted to where it’s, I want to say widely adopted, like we know this, but the, the conversations that I have farm level, people are no longer, when I have this conversation with them, they’re no longer sitting there going, “I don’t know, Scott, you sound like you’re full of crap.” So just kind of walk us through that. How, how that impact happens long term.
Dr. Jack Britt
Well, epigenetics is, has been known for 50 years or 60 years. Normally when we talk about genetics, we think that the gene has to change for genetics to change. The gene sequence has to change for genetics to change.
We now know that just a methyl group, a carbon group, basically can jump onto that gene at a certain space, certain site and change how that gene functions. And we call that epigenetics because the genes haven’t changed, but the function of the gene has changed.
Scott Zehr
Function has changed.
Dr. Jack Britt
The functional activity of the gene has changed. And so things like heat stress can cause that. And so the genes are not behaving the way that we would expect them to. And so epigenetics, we now know that many things: feeding, heat stress, environmental influence, where they are in the country, if you will, or in the, in the, all of those things are going on and then…
We, you know, ee can actually find markers on the genes that shows that it’s not a simple test, but the technology exists and we’re learning more about how do we control epigenetics.
When we, we have to do it through good management, really. Doing things that benefit the cow, if you will. And if you want a few, if you want fewer epigenetic responses that are adverse, you just have to provide awfully good care to the cow not only feed, but resting and walking, comfort, milking, everything. And so that’s, that’s a hot issue right now in the, in the management of cows.
Scott Zehr
Yeah. I don’t know if you’ve listened to any of my previous episodes, Dr. Britt, but as you can see over my left shoulder there’s a portrait there. It’s probably hard to make out, but that’s that is the great Vince Lombardi.
Dr. Jack Britt
Yes.
Scott Zehr
And, and I’m not a Green Bay Packer fan. I’m actually a Dallas Cowboy fan. But the reason I keep the Marty up there is, is it doesn’t say it in this particular portrait, but he used to like to tell the players, if, if you don’t master the fundamentals, you don’t have anything. We’ll just keep it a PG here.
But yeah, there’s a lot of those fundamentals like you just talked about with the management side of things. Unfortunately, it gets overlooked far too often on some dairies. And, and the long term impact of that, I don’t think is realized. What’s your thoughts there?
Dr. Jack Britt
It’s interesting now. You know, there, the technology exists from a company in California to monitor what’s going on in the milk and parlor, every step, every person, every step. And while things may look like they’re going fine, if you see a towel used on one cow and then used on the next cow, it’s not going fine.
And some of that’s become automated now, so you can get a score. And I don’t think it’s, I don’t think people make mistakes intentionally. They sometimes say, well, I can do it quicker if I just use this. It’s not too dirty. I’ll use this rag again on the next. Yeah. So, so actually training people to understand why you can’t do that.
Why it’s important to have a clean towel. Why it’s important to clean the T and, not just kind of…
Scott Zehr
Not just the sides.
Dr. Jack Britt
… not just the side. You know, I think that if people working in the facility at the farm in the, in the milk and parlor on the farm, they understand why they should do this, they’re going to do a much better job.
And that may be become challenging in some cases if you’ve got three people in the parlor and they all speak a different language. It’s not necessarily easy to talk to them. And so we, we have to improve our methods, whether it may be pictures or drawings or illustrations that we present. I’m going to show you how. Watch my hand.
Scott Zehr
Yeah.
Dr. Jack Britt
Those are things that are important for us because we really have a diverse population of people working in, in the milk and borrowers today.
Scott Zehr
Well, the why. so have you ever read a book called “Start with Why” by Simon Sinek?
Dr. Jack Britt
Right.
Scott Zehr
Yeah. So Simon, author, speaker, he’s got a book called “Start with Why,” and he’s got a theory called the golden circle and it’s, it’s ‘Why’ it’s in the center.
And then how, how you do it and what you do. And when you talk about if people understand why it’s important to do something, it, it drives home way more effectively than the result, right? It’s, we don’t want you to clean those cows teats because it’ll make us more money. It’s, we need you to clean these cows teats because the cow’s health is of utmost importance, right?
That’s the why. Yeah, good stuff. Okay. So heat stress effect on epigenetics, but you mentioned there’s, there’s other things that, that can cause, you know, have an epigenetic effect. What are some of those other factors? Like, is it like lameness? Would that have an epigenetic effect? Mycotoxins? What, what are we dealing with here?
Dr. Jack Britt
I think almost any interruption of normality, if you will. What’s normal for the cow? What’s expected? If you interrupt her feed intake today, if she gets a sore foot because the alleys weren’t cleaned accurately or carefully, or if the bedding in the freestyle is wet or, or dirty, we got this whole list.
Another good example is, is being in the holding pen with 300 other cows and not enough fans are cooling there. And so she gets, she may only be heat stressed for 10 minutes, three times a day, but that’s 30 minutes of heat stress.
Scott Zehr
That’s 30 minutes of heat stress.
Dr. Jack Britt
And so we have to think broader than just what’s happening this moment. Think about what happens to that cow in the last 24 hours.
Scott Zehr
Yep.
Dr. Jack Britt
Another good example is, is the feed bunk that doesn’t have any feed in it. She gets back from the parlor and walks up to the, to the stall, the head gate, and there’s no feed there. Whoever’s feeding today is running late, right? So all sorts of examples.
Scott Zehr
Anything that doesn’t allow those genes to express themselves.
Dr. Jack Britt
Exactly. Exactly.
Scott Zehr
Yep. Yep. I almost want to repeat that again: “anything that does not allow those genes to express themselves.” And, you know, I think people, again, I believe everything’s on the bell curve and there’s still some, some laggards on that bell curve that say, “Hey, any bull I get from the, the auction barn to breed my cows, as long as they’re pregnant, it doesn’t matter.”
But I think those guys still exist. But we, for the most part, we all believe in the genetic progress we’ve made. I mean, it’s, it’s undeniable. The investment we’ve made as an industry in genetic progress is amazing.
And to, to put it that simply the epigenetic effect, anything that does not allow those genes to express themselves is really another way of, you know, it’s kind of that next level of saying like anything, anything that’s not going to let those genetics express themselves, right? It’s, it’s tying it together.
Dr. Jack Britt
The genes, the genes are in the semen. And that’s going to be in the egg. But if you don’t manage that cow, so that the egg is taken care of.
Scott Zehr
Exactly.
Dr. Jack Britt
And you’ve defeated your… your good genetics.
Scott Zehr
And it all has to work at the same time to make it worth it. So going back to how you just mentioned it, you mentioned the egg. So what, what would you think is one of the biggest challenges facing dairy reproduction today?
Dr. Jack Britt
I think the biggest challenge facing dairy reproduction today is trying to breed cows too early.
We still hang around, we need to breed her about 60 days after calving. Well, if she’s milking 120 pounds, do we need to milk her 60 days after calving? I, I think that we really need to be looking at what is the ideal time? What, when does the ideal fertility occur? And most of our cows today, the best fertility is going to be at 90 to 100 days on the spot.
It’s not going to be in 60 or 70 days. So we’ve got a little longer lactation per drop period may end up being about the same as it should be. But we still are hung up on this 365 day cycle when maybe we needed a 13 or 14 month cycle to think about. I mean, all of our data is still 365 days. Should we be changing the way we talk about what a, what a lactation is?
Scott Zehr
That’s an interesting question because you have, some of that’s predicated on economics. Some of it’s predicated on what tech, what is that cow producing? Right. If, if you told my dad who milks 80 cows in the tie stall and make 65 pounds of milk that he needs a 14 month calving interval, he’d say, “well, that’s why I’m only making 65 pounds of milk.”
But, we have conversations on farms of, you know, I’m struggling to dry cows off because she’s still making 85 pounds of milk. Well, it stands to reason. If we’d brought her a little later, right? And we’ve, we’ve seen, we’ve seen some push back to 75, 80 days, maybe 90 on two year olds.
But, I think I was talking with Lyle Cruz a couple of years ago about this topic. From Select Sires. And, talking about the ideal time to breed cows more on a, more on an individualized basis, you know, when, when’s that individual cows, optimal time to get bred.
Can a theory like that be carried out on a large scale? Do you think what, do we have the technology available? Are we still kind of hamstrung by aligning groups of cows? You know, I’m just hoping they fall in a range.
Dr. Jack Britt
I think we have the technology. I mean, we know, we know the body condition score. We know whether she’s gaining or losing weight. We know how much milk she’s, she’s producing.
We know what our success rate is for breeding cows on this farm. And so… I’m not sure there’s a rule that will work. You really have to look at the farm and what practices it has, how much milk they’re producing. What can they modify to get more cows pregnant? You know, if their first service conception rate is 17%, there’s something wrong.
Scott Zehr
And I’m the type…
Dr. Jack Britt
Look, look at the data.
Scott Zehr
Yeah, exactly.
Dr. Jack Britt
Exactly.
Scott Zehr
And, and I’m, I’m the type that says if, if you’re not, if you’re not hovering that 50 percent plus first service conception rate ,there’s, there’s probably still something wrong. Cause it there’s, there’s guys that are doing it, man.They’re doing it. They’re doing 60 percent there.
You were seeing sorted semen conception rates on first service you know, plus 50 so it just tells me there’s opportunity for more, right? The genetic level, the, the daughter pregnancy rate as much as we focused on that the last 10 years, I’m not sure. I think there’s just a lot more about these cows that we don’t know.
That’s, that’s my thought. maybe you’re going to tell me differently, but I think there’s a lot more we don’t know.
Dr. Jack Britt
I think the move to producing dairy beef and what we’re doing there may actually be beneficial to reproduction. Because, we’re, we’re breeding our heifers at the right time.
They’re going to be the first animals go in, in the herd, and we’re going to breed a few top cows to good semen. And then we’re going to breed everything else to beef bulls and sell Holstein Angus calves for, for a fortune. But in some ways that gives us an opportunity to enhance reproduction.
Scott Zehr
It does.
Dr. Jack Britt
The semen that we use and about when we inseminate those cows. And the way cows are milking today, you know, the old idea that you gotta breed a cow at 60 days is outdated. Even for Jersey it’s outdated.
Scott Zehr
No, well, there’s only two breeds of cattle anymore, right? There’s Jersey and Holstein.
Dr. Jack Britt
Right? Basically.
Scott Zehr
I just, I just made some people mad, but yeah, so there’s still Guernseys Brown Swiss. I’m not, I’m just kidding.
Dr. Jack Britt
We had one Ayrshire cow in our herd and two Brown Swiss, everything else was Holstein.
Scott Zehr
So what, I want to say so many things about some of those breeds, but I, no, I’m just. What does reproductive success look like on a dairy farm in your eyes, Dr. Britt?
Dr. Jack Britt
Reproductive success, I’m going to start with the heifers. And I want heifers to be bred with one straw or no more than two to deliver a calf by at 23 to 24 months of age.
Scott Zehr
Yep.
Dr. Jack Britt
And so paying good attention to heifer management and breeding heifers. The beef cattle guys sometimes do a better job on their heifers than we do with the, with the dairy because they…
Scott Zehr
I would agree with that.
Dr. Jack Britt
They pay attention to when those heifers are coming in heat. We’re not out checking whether our Holstein heifers are coming in heat. We’re just assuming that they’re coming in heat. And so I think we need to pay a little more attention to that. And they’re going to represent the herd, you know, in the next lactation.
I, I think the, the dairy beef, it gives us an opportunity to do some really good things reproductive wise. Maybe to reduce the, for fertility and some cows. I mean, pretty good evidence that if you put, put Angus semen and hosting cows, you’re going to get a little better fertility.
Scott Zehr
Yeah.
Dr. Jack Britt
Yeah. And that…
Scott Zehr
And then we’re also essentially calling that genetic line.
Dr. Jack Britt
Right. Sure.
Scott Zehr
And so, yeah, yeah.
Dr. Jack Britt
The numbers I’ve seen recently say that dairy beef is adding about $2 or a hundred weight value to our milk. $2 to a 100 weight is a big jump.
Scott Zehr
It is, yeah. That’s a big jump.
Dr. Jack Britt
I don’t think we’ve realized the impact, but that’s about what it’s, that’s what it turns out to be.
Scott Zehr
I think there’s so much opportunity in the virgin heifer population in the U.S., from breeding wise from management wise. So I, I have this question that I’ve thrown out there to a few people over the last six, eight months.
You know, we’ve, we’ve seen the virgin heifer population in the U S. We’re at really almost not, I don’t want to say a historic low, but we’re…
Dr. Jack Britt
We are.
Scott Zehr
…there’s a lot less. So my challenge to, to dairymen out there is if heifers are no longer a commodity as defined by their current population level, why are we still treating them, treating them like a commodity?
Dr. Jack Britt
That’s right. Good, good point.
Scott Zehr
Dr. Brett, I’m going to ask you this question. You know, you’ve been on a lot of farms. You’ve probably talked to a lot of people in the nutrition space throughout your career. Look at how much time is allocated as a nutritionist to focusing on the dairy diet versus the heifer diet.
Dr. Jack Britt
Yeah. Very little to the heifer diet.
Scott Zehr
And I, I understand it, right? Like the cows are making the money that pay the bills. And we’re, we’re seeing a shift. You know, I, I always joke that it was very apparent when you walked onto a multi generational facility you know, it was, uh, not to, not to pick on you, but it was, it was the grandfather that built a barn in the 1950s. Right?
So you had the 1950s bar in the 1980s barn, the 19 late nineties barn. And what happened? So the milking cows go to the newest facility, we shove the heifers, first the dry cows go into the 1950s barn, and the heifers go into the 1930s barn, and then they finally graduate up and we’re treating them like a commodity.
You know, it’s it seems backwards and it… I remember breeding cows on a, on a large dairy in New York a number of years ago, milked about 2,500 cows. And I walked into the dry cow barn and I was like, this is terrible. How do you expect me to get the cows in the new barn pregnant when this is where they’re housed?
Dr. Jack Britt
Yeah.
Scott Zehr
But that’s what we did and, and lenders like to give money to milk more cows, not to take better care of your heifers. So it’s, it’s kind of one of those catch 22 things that… but there’s still a lot of opportunity there, I think.
Dr. Jack Britt
I think heifer management is an opportunity that we need to take advantage of. We don’t take advantage of it as well as we should.
Scott Zehr
Yeah. Well, Dr. Britt, I appreciate you, joining in what’s maybe a final word you’d like to leave with us as far as, for dairymen to be thinking about when it comes to, heifer management or, or just having healthier animals.
Dr. Jack Britt
I’m going to say 100 days.
Scott Zehr
100 days.
Dr. Jack Britt
The heifer, that’s going to be bred today, that egg started developing through her system a hundred days ago. So you got to think about what have I done for the last hundred days to these heifers and cows.
Scott Zehr
So I’m going to ask actually a follow up question on that. So you’re saying we shouldn’t do a pen move at 13 months when we want to start breeding them at 13 months?
Dr. Jack Britt
That’s, that’s a very good example.
Scott Zehr
Yeah.
Dr. Jack Britt
We don’t, we don’t think much about a pin move, but a pin move for a heifer is a very adverse situation. She’s got all new inmates, you know?
Scott Zehr
Yeah.
Dr. Jack Britt
Find her place again. She’s gotta find a place to eat. She’s gotta take on a couple battles with other heifers. And so, yeah. I mean, she needs, she needs to be in a comfortable setting. If we’re going to assimilate her, not, not moved into the, we shouldn’t move into the breeding pen.
Scott Zehr
Yeah.
Dr. Jack Britt
It’s a mistake to say you’ve got a breeding pen…
Scott Zehr
That’s a, that’s a great point.
Dr. Jack Britt
…
Scott Zehr
Yeah, that’s a great point. Wow. Oh, you gave us some things to think about Dr. Britt. I appreciate you taking the time to jump on Ruminate This with us. And, yeah hopefully I didn’t beat you up too bad on any one topic. So maybe in the future we can, we can have another conversation, so…
Dr. Jack Britt
Thanks. Thanks Scott.
Scott Zehr
Appreciate it. Thank you. Have a great week.
Dr. Jack Britt
Okay.
Scott Zehr
And those of you listening, we will see you all in two weeks.
