University Place

The Science of Dairy Milk Harvesting

[Tom Zinnen, UW-Extension]

Welcome everyone, to Wednesday Nite @ the Lab.

I’m Tom Zinnen. I work here at the UW- Madison Biotechnology Center. I also work for UW-Extension Cooperative Extension, and on behalf of those folks and our other co-organizers, Wisconsin Public Television, the Wisconsin Alumni Association, and the UW Madison Science Alliance, thanks again for coming to Wednesday Nite @ the Lab.

We do this every Wednesday night, 50 times a year.

Tonight, it’s my pleasure to introduce to you John Penry, who’s here with the Department of Dairy Science.

He was born in Melbourne, Victoria, in Australia. He went to Xavier School in Melbourne and then got his doctor of veterinary medicine at Melbourne University, then spent 21 years at Camperdown in Victoria in practice as a DVM. He also went back during that time to get a master’s degree in dairy production at Melbourne University. For the last three years he’s been here at the University of Wisconsin Madison getting his PhD.

Today he’s gonna talk with us about dairy in Oz and dairy here in Wisconsin. He’ll be talking about the science of dairy milk harvesting, an Australian perspective alongside UW research.

If you’ve never been to Australia, I highly recommend it. It should be on everybody’s dairy bucket list. Please join me in welcoming John Penry to Wednesday Nite @ the Lab.

[audience applauding]

[John Penry]

Thank you very much, Tom. So, folks, in the Wisconsin dialect, good evening.

[audience laughing]

Thank you very much for coming. Sorry, Wisconsin.

[audience laughing]

In the slightly ruggish Australian slang though, I feel it’s on my duty to say just simply to you, “G’day, how you goin’?”

And you would reply, “Very well. Thank you very much.”

So, folks, tonight we’re going to take a three-part wander. A three-part wander. It’ll be a pretty simple story. Lots and lots of photographs, a couple of wayward tales. Partly in Australia, partly in Wisconsin, and right at the end we’ll see where these two things clash.

But I wanna start off by just showing you what I think are the two best examples of taking a mechanical process and combining it with an animal production system. So, this is the opening gambit for this evening. On the left-hand side, we have a milking machine from 1922. On the right-hand side we have a sheering handpiece, ironically invented in Australia. This is a handpiece, it’s a modern handpiece, but the actual basic technology was invented prior to 1900.

So, both these bits of technology basically date from the late 1890s, early 1900s, and essentially they have remained the same. But here we have probably the best marriage yet of a mechanical process with an animal production system.

Now, quite frankly, I don’t care much for sheep. So that’s the last time you’re gonna see anything to do with sheep. We’re just going to concentrate on the cows for now, okay? Because, as we all know, dairy cows are far smarter than sheep.

[audience laughing]

Okay, now, I just want to also start off by saying I have two jobs tonight. The first job is to quench your curiosity because I’m presuming that you’re all here because you’re curious. So, my job is to make sure that I do a good job of fanning those curiosity flames.

The second thing is to give you a little bit of enthusiasm about the dairy industry and in particular the dairy industry in Australia and how it intersects with the dairy industry here.

My aim is for each of you to be able to, next time you go to a dinner party or the pub and the conversation dies off, you can say, you know what? I know a bit about the dairy industry, and I would like to tell you that right now.

[audience laughing]

That may not happen, but I always live in hope.

Now, this image here, folks, is one of the most famous photographs ever taken in our country. It was taken by a fellow called Max Dupain. It’s called the Sunbaker. I put it up because I’m sick of putting up images of kangaroos and koalas.

[audience laughing]

And given that most people think that people who come from Australia do nothing but go to the beach or avoid kangaroos and koalas, I thought I would just put this up. Because this is, in part, an Australian story. But we do do things other than go to the beach.

Okay. So, I assumed that there were some people in this room who know a little bit about the dairy industry. Some people who dont know much at all. So, what I thought that I would do is start off with dairy the basics. And the dairy industry, its a bit like describing a box factory. Because all youve gotta do is describe the box and everything else is just how you arrange them. Okay.

So, heres the heres the dairy industry in very simple terms.

Lets say that we have a timeline here, here on the screen. Januarys up this end and Decembers down that end. And lets say you have got one dairy heifer- so this is a female dairy animal and lets say shes thirteen or fourteen months of age. You have got her pregnant. Shes marching through pregnancy. And she gets to the point where she calves.

So, here she is calving right here this one needs a bit of assistance.

Lets say this is February. So, this animal has calved for the first time in February. She calves. You remove the calf after about twelve hours, and you start milking the cow. And in most places in the world youre milking the cow twice a day mechanical milking this is twice a day, sometimes three times a day. But essentially the cow is being milked regularly much as it would be suckled by the calf. And this goes on for about three hundred days. And thats one lactation. And its that simple.

The only other complicating factor, of course, is you want to get her back in calf so that we can repeat this process the next year. So, at some point, probably in April or May, you either are using semen or you are using a bull to get her back in calf.

So, she calves. She starts lactating straight away, in fact, shes building up to lactation just before she calves. You remove the calf to rear it separately. You milk her twice a day or three times a day, that maintains the lactation. You get her back in calf. You get her back pregnant again and thats it. Thats one cow, one lactation thats the dairy industry. It is literally that simple.

Because the only other complexity to it and this is where things get muddled up with a lot of agriculture the only other complexity to it is essentially: how do you feed her? How do you group them for calving? And how do you milk her? Thats it.

So, youve got different permutations and combinations of that. But essentially, youve got one animal, one lactation, repeat. Repeat. Repeat. Okay.

So far, so good?

Excellent. I love a smart crowd.

[audience laughing]

Okay. So, here, in an American first, Im going to the difference between the way animals calve on a dairy farm using nothing more sinister than a Solo cup. Ive always wanted to try this. Could be dangerous, well never know.

Lets say for example, that here is January

[pointing at the near end of a table]

and here is December

[pointing at the far end of the table].

Okay. You have ten cows. One. Two. Three. Four.

[placing cups on the table]

I wonder where the nut is. It’s like going to the football. There we are.

So, it’s very high tech, this presentation.

So, January through to December.

[points to row of cups]

And on this farm, with 10 cows, we are calving a cow most months of the year.

January

[Lifts first cup]

March

[Lifts second cup]

April

[Lifts third cup]

August, and so on. So, this, my friends, is a year-round calving pattern. Classic for America. Classic for the UK. Relatively uncommon in Australia. Relatively uncommon in New Zealand.

[audience laughing]

But in lots of places. Thank you for laughing about New Zealand.

[audience laughing]

I do quite commonly, as it turns out.

So, this is a year-round calving pattern. Animals are calving all the way through the year.

Happy with that?

Okay, so let’s go to Australia, let’s go to New Zealand, and let’s go to the southern parts of Australia especially. And let’s pick a month. Let’s pick… Let’s pick August.

[removes cup from line of cups]

So, here we are at August and as it turns out,

[restacking cups into three rows of two cups per row other cups stacked evenly on top]

I have got most of my animals calving

[pointing to the three rows]

in August, September, and October.

And that’s it. There’s nothing calving at this end of the year.

[points to empty near end of table]

They’re calving during the spring in the southern hemisphere. So, this is called a seasonal calving pattern. Classic for Australia. Almost de rigueur for New Zealand.

So, the cows are calving in a bunch, in a seasonal group. It fits in with the production of pasture. And so that means you’re doing other things in batches too. You’re doing your joining in a big group, calving in a big group, calf rearing in a big group, okay? So, seasonal calving pattern.

There is one other permutation on the theme. And that is a batch calving or a split calving pattern. So, let’s say, for example, it suits you to try and milk all the way through the year. So you’re going to take these animals from, say October,

[takes one row of cups from far end of table to near end]

and you’re going to put them here in March.

So, March and maybe a little bit of April

[moves the row of cups on the near end next to each other]

I’m calving these animals. No calvings in the middle of the year. And then I get into the spring in the southern hemisphere, and I’ve got another bigger group calving. So, this is called a split or a batch calving system. And that, folks, is it. That’s it.

Lactation, getting calf, have the calf, start milking, milk for 300 days. Where do I calve in the year? is the calving pattern. And the only other thing to worry about is how am I gonna get fed and how am I going to get milked. That’s it. That’s dairying.

So, did the Solo cups work?

[audience laughing]

Excellent, well done. Well, well done to the Solo cups anyway.

Okay, and just in case that didn’t work, here’s exactly the same story except with more attractive Holsteins. Okay, so that’s the first part of the story finished. Dairy 101. Everyone’s got that swedged away.

How are you going with the accent, by the way?

[Audience member]

What accent?

[John Penry]

Okay. What accent? Ha!

[audience laughing]

There’s a comedian born every minute.

[audience laughing]

[John Penry]

Okay, so now we’re going to southern Australia. In fact, we’re going to the part of the world where I used to live. I know this because this is the clock tower in my hometown. This is Camperdown in Western Victoria.

So now let’s have a brief look at Victorian dairy, or Australian dairy.

This will be one of the few slides with any words or numbers on it. This is to give you a ballpark of what the Australian dairy industry looks like.

And in a nutshell, for the recent two years, about 1.7 million cows. That’s actually dropping at the moment. Average herd 294, but the herd size goes anywhere from about 150 up to about 1500, encroaching 2,000 in some cases.

The average cow produces not a lot by European or American standards. I’ve converted it into pounds for you. About 13,000 pounds of milk.

It’s our third largest rural industry, after wheat and sheep, or sorry, wheat and beef, I beg your pardon.

And 38% of what we produce we export overseas, mostly as products like skim milk powder and cheese.

Now, if we were in New Zealand, God help us

[audience laughing]

This number here would be 95%, okay? So that’s the guts of it.

Here are the numbers for Wisconsin.

So, this is your state. 1.3 million cows. So, slightly less cows than us. 130 is the average, but it’s a huge range in Wisconsin, as it is in Australia.

Twice as much milk per cow being produced per year. And only 14% of what the US produces in dairy goes overseas. And that number is much larger than what it used to be a number of years ago.

Okay, and this is just to give you a very brief snapshot of the fact that as we’ve progressed through the years, from the 90s through until the 2010 this one goes up to, essentially the yellow line is what we have produced that we’ve exported overseas. The blue line is what we’ve consumed domestically. So, very much a export-driven production system in our country.

Okay, so here is Australia. For those of you that are curious, the Australian landmass is almost the same size as the contiguous United States, which means it’s bloody big. All of the dairying areas that you can see are marked in red. So, I apologize for people who might have trouble with red or green. This isn’t my image.

As you can see, we have pockets of dairying, mostly in the southern part of the country but also up along the eastern seaboard. And the little patch over here near Perth, which is Tom’s favorite spot, over on the left-hand side.

So, to give you a sense of the scale, if I was to jump on a commercial airliner and fly from Melbourne, sorry, and fly from western Victoria, which is where I come from, this spot down on the lower left-hand side, if I was to fly to the northernmost part where dairying is practiced in our country, I would be sitting on the aircraft for four hours.

So, it’s a long way. It’s literally like flying from here to Los Angeles. I don’t know why you would want to do that, but if you did, that’s how long it would take.

So that gives you a sense of the scale. Very disparate pockets of dairying throughout our country. Most of the action, most of the cows live in Victoria, which is the place down on the lower right-hand side.

Okay, and here’s a pretty typical dairy cow. Every photograph I’m going to show you I took whilst I was in practice.

I was in practice for 21 years, and even though I did a reasonable amount of dairy project work, we have national based projects for animal health in Australia. Not regional or state based. So, I was fortunate, I got to sort of delve into both worlds. But here’s a smattering of the way the production system looks.

So, here are some animals that are heading up to calving for the first time. I know this because they are being fed very little pasture and mostly hay.

Our production system is based predominately on pasture. We grow most of our pasture from autumn or fall, so its flipped around. So, essentially, if it rains by April you throw a party. And then we dont grow a lot of grass through the winter months, through June, July and August. And then we have a reasonably large feed surplus in pasture in the spring. By the time we get to December, the whole country pretty much looks brown.

Its literally that simple. And Ill show you a photo in a tick. So very much built seasonal calving, built around the hump, if you like, of feed coming from pasture which is providing about sixty or seventy percent of those animals diets.

So, calving systems are relatively simple and straightforward. Here are two calving areas:
The one up on the left-hand side is a bit fancier. Its called a calving pad. This is the place where cows would congregate. Now theyre fenced into this area. They would stay in there until they calve. They would be on a special diet to help them overcome low blood calcium around the calving period. The farm on the lower right-hand side is a little bit more rudimentary but a similar principle applies. So, designated areas, cows calve, and then they join the milking herd.

When our calves are born, most of the time they are reared in sheds that are used for other purposes during the year. So, these are not purpose designed facilities. These are facilities that have multiple functions. Our calves are generally reared in batches. So, that may be quite different to what you might have seen in the US, and Ill show you a photo of that in a tick.

So, heres a pretty typical dairy herd. This is a herd thats in mid-lactation. You can see weve got a reasonable amount of pasture sitting there. This photo was taken during the winter. These cows are essentially eating the grass as its growing during this time of the year. The farmers are always looking for ways to try and keep a feed bank of pasture ahead of them.

And one of the things thats very important in our dairy industry is we have to conserve feed during the surplus. So, we have to make both hay and silage predominantly out of pasture. So, this is excess pasture thats being turned silage early on in the spring or mid-spring or hay going into the summer.

This stuff is literally coarse gold, if I can use that term. Farmers are very careful about how they store it, for the most part. They try and make a lot of it because it literally constitutes twenty percent of those cows diets. So, its a really important thing. And mostly its fed in what you would describe here in America as pretty low tech feeding systems. So, as you can see, heres a self-serve Bain Marie.

Do you use Bain Maries in America?

You have so many words that confuse me.

[Audience laughing]

[John Perry]

And apparently, I to you as well.

[Audience laughing]

So, imagine the place when you go to the cafeteria and youre scooping out your peas, and your scooping out your chicken, et cetera, et cetera. Well, thats the cow equivalent in Australia. Theyre still hunting for the peas, of course.

We do have feed systems as well in most of our dairy parlors, in most of our milking parlors. The vast, vast majority of Australian cows get fed some sort of grain when they come in to be milked. And to give you a sense of how much they might be fed, some cows were being fed up to ten pounds a day. Up to ten pounds per day split across two meals, morning milking and evening milking.

The lower left-hand image is a pretty fancy-looking silage clamp or silage stack. This farm has spent a fair bit of money on this. I can tell because its neat; its being pulled off with forks on the front of a tractor. A lot of people dont do the silage this way. They do it in round bales and they cover it in plastic to help it ensile. So, theres some of the different feeding systems that weve got.

And remember where we started. The lactation is pretty simple. They calve. And you only have to work at how youre going to feed them, how are you going to milk them, and what groups theyre going to calve. And thats dairying.

Okay, and finally, during the summer, finding grain things for them to eat is really challenging. So, what we tend to do in our country and the Kiwis do this as well, is we feed what is called Brassica crops.

Turnips, ripe. Two of the more common plants. So, these are Brassicas. They grow in the summer as long as they get a little bit of water. They’re quite fibrous-y. Reasonable source of protein for those cows. And this is pretty, pretty classic.

You grow them in a paddock or a field. You put a hot wire or an electric fence. You give them a certain break of this food each day and you just keep progressing down the pasture.

So, this is to juxtapose. These two photos were taken in virtually the same spot. It’s only the camera was swung in a different direction. The photograph on the lower right-hand side was taken during the winter. I can tell that because you can see the marking of the paddocks where the cows have been eating and have broken it up.

The photo on the left-hand side was taken during the middle of the summer. So, that was taken in February. So, just spin it around. The month we’ve just gone through, essentially. It’s the equivalent of August.

And you’ll notice that these cows are looking for shade. The reason they’re looking for shade is because the day this photograph was taken, let me do the conversion, it was 97. It was 97. And most dairy cows don’t like it very much when you get much above 75 or 70 because they’re not designed for those sort of climates. So, being able to manage heat stress in Australia is a pretty big deal. It doesn’t matter where you live. Most of the time it’s low tech. It’s trees. Some shade shelters. But it just tries to give you a sense that the feed base of these animals really changes a lot during the course of the year.

This is not one of these things where the TV dinner is the same every night. These animals are seeing quite a vastly different diet as they go through the lactation. And one of the things that’s challenging for us is that cow’s rumen is not designed for that. It likes constant sorrow.

[audience laughing]

You know what I mean.

It likes a constant, a constant meal. And so, these cows have to do some rumen adaptation as they go through.

Okay, so let’s move on to milking cows in Australia. And, as it turns out, milking cows in Australia looks suspiciously like milking cows in America.

[audience laughing]

This is, however, an unusual parlor for our part of the world and it’s unusual because the milking machines are on both sides of the parlor. So, this is what we would call a double-up at home. This is very common in the United States. Not so common in Australia. For the most part in Australia, the milking machines hang down the middle of the walkway, and the machines are either swung to the left or they’re swung to the right. So that’s a classic double-up for America. Relatively uncommon for Australia.

Okay, now what’s very uncommon in the United States, or at least in my experience here anyway, is the rotary that you can see in the right-hand side. So, this is a rotary platform that cows walk on. It’s a turntable. It’s going around.

So, this rotary you can see in front of you does two things. It enables the cows to be milked. It also enables the cows to be fed because you can see some feeding stalls there in the front. And, again, they’re getting fed six or seven or eight pounds per day.

But one of the really nice things about rotary parlors, why they’re very common in Australia now, is because you can milk cows quickly. This parlor will milk 220 to 240 cows per hour. It’s very efficient with labor. You need two people to run this parlor. And the other thing is that they’re relatively cost-efficient to put in.

So, what you want to do, if you’re milking cows on pasture, of course, you don’t want them standing them off the pasture for too long. You want them to get in and be milked and then leave and go and have a feed. But the problem is that Australian cows have to walk from the pasture to the parlor. And that could be half a mile, a mile, two miles, twice a day. So, these animals are walking a fair way. If they’re walking, they consuming energy and they’re not eating. So, therefore, milking them quickly becomes important.

Okay, so just to juxtapose, we are now back in Wisconsin. So, there’s the photographs that I’ve taken in the course of my work here. And these are classic free-stall parlors in this part of the world. So, the cows are essentially living in these areas for most of the year. Certainly, for most of their lactation.

Here’s a much, here’s quite a large free-stall parlor. One of the really interesting things from my point of view is that the amount of money that American dairymen and dairywomen have to spend on infrastructure here to house animals is quite significant. Now, we don’t have that at home, but we also don’t have six inches of snow. Or seven inches, or seventeen inches per annum.

[audience laughing]

So, in one sense, we have to deal with the hot summers. But our winters are far more benign. Now, I wouldn’t have said that before I came here to live. But I’m absolutely saying it now.

[audience laughing]

I thought I was going to die the first month I was here in February.

So, here’s two American parlors. The one on the right is actually the parlor the university owns in Arlington. The one on the left was a parlor that we’re involved with some, with some research. So, these are classic parlors for the United States. Relatively well mechanized. Have the ability to remove the teat cups automatically. So, the humans are putting them on, the machines are coming off automatically.

So, Wisconsin and Australian dairies look quite similar, but there’s a lot more rotaries in Australia.

Okay, so just to finish up, this is the second part of the story, okay?

One of the things that’s really apparent to me coming here to work is how much your cows are like Ferraris crossed with Porches out of a Lamborghini.

[Audience laughing]

So, these cows are doing a lot of milk. You’ve got cows here that are doing 100 pounds of milk a day. So just think about that for a tick. 100 pounds of milk coming out of their four teats a day. And what will even scare you even more is for every pound of milk there is 400 pounds of blood that has gone through the udder to make the pound of milk.

So, these things are high performance racing machines. Massive amounts of milk coming out of those animals.

And it’s a lot less in Australia. It’s about half, and that’s fundamentally because these animals are on pasture. They’re foraging. We just can’t get the feed matter into them.

However, one thing is for sure.

The people who are involved in dairying, whether it’s in Australia or the United States, these people, as near as I can tell, are pretty much the same. So, here’s a crew from a farm that we did some research on in Australia. This is a 500-cow farm. This is how many people it takes to run a 500-cow farm in Australia. So, very, very typical Australian dairy farmers.

Has everyone got that?

Typical Australian dairy farmers. Now I just want to explode a myth right now. The average Australian dairy farmer does not look like this guy.

[Audience laughing]

So, I just want to make that perfectly clear. This, however, is what the average Australian cattle veterinarian looks like, so

[Audience laughing]

So, well done us.

One of the things that is also common in Australia is, and this has been nice coming her and working as well, is we have the same infrastructure of service providers in the dariy industry at home.

So, people who are involved in herd improvement, veterinarians, nutritionists. Its the same sort of set of players that sit outside those farmers. The same sort of networks. The only thing that I would say is that we just have a lot less people in the zoo. So, we have less farmers. We have less service providers. Most of the cattle vets in Australia I know by name. So, that gives you a sense of how big the, how big thes place is.

Okay, now, I just want to finish off this second part. I just want to inject a little bit of reality into the conversation. One of the things that is preoccupying me at the moment is I finish in three months. And currently I’m looking for a gig.

Anyone?

[audience laughing]

And one of the things that has become very clear to me is how, perilous is the wrong word, but how fragile dairying is in some parts of the world at the moment. And the reason is if you’re a dairying country that is exporting most of your milk, Australia, New Zealand, two classic examples, you are absolutely exposed to the world trade price, mostly in milk powders, okay? Because that’s how a lot of the stuff is shipped around the world. It’s dried into powder, and then it’s shipped.

And I wanted to show you this because the milk price in Australia has absolutely collapsed. Currently it is below the cost of production, let alone the cost of production and then covering your interest costs.

So, if you’re an average dairy farmer at home and you might owe the bank a million dollars the average Kiwi dairy farmer owes a bit more than that at the moment you can’t even pay your operating costs. You certainly can’t pay the bank the interest.

And the reason is this, here is the world price for skim milk powder from 2011 through to 2016. So, this is in Australian dollars. Yes, it’s in Australian dollars. Look at the volatility. So, the scale goes from 1,000 up to 5,500. So, if that’s not a roller coaster, I don’t know what is. And this is how farmers are getting paid. It’s based on, essentially, the world price for what is being traded overseas. So, at the moment, dairying is a difficult industry to be in.

And I don’t want to, sort of, bring a downer to this, but I just want to inject a little bit of reality about what the current situation looks like. Now, of course it will bounce back, but it’s a volatile, hard industry to be in and the people who are in it have to be smart operators. It’s just that simple.

Okay, now, let’s liven the mood up a fraction.

[audience laughing]

The tulips. I just want to pause for a minute and tell you that when you come from a country with no tulips in it, the tulips here are pretty bloody good. So, every year when the tulips pop up, I walk down the road from where I work and I take a photo of the tulips and I spend a quiet 10 minutes there just enjoying the flowers, basically.

Okay, so now we are segueing back into the UW. And I want to tell you a story about UW milk harvesting research and eventually we’re going to cross back to Australia.

Back in 1992, there’s a fellow and I’m about to show you his photo he established the milking lab here in the UW. Now, it’s based in the Biological Systems Engineering or the Ag Engineering lab, which sits opposite Animal Science.

It’s a lab that was originally funded under a cooperative program by virtually every dairying company in the US and in Europe. There are three, three milking labs left in the world. There used to be a lot more, but now there’s only three. There’s the UW, there’s one at the University of Bern in Switzerland, and there’s one that’s just restarting at Moorepark Research Institute in Ireland. So, this is a science that has waxed and waned, but at the moment we’re on a bit of an uphill climb. We’ve got a bit of momentum going at the moment.

So, the UW Milking Instruction Lab, Research and Instruction Lab, everyone who is involved with this university should be very proud of this little gem that sits in the middle of the campus, just next to the dairy farm that also sits in the middle of the campus.

I want to point out the fellow, the good looking fellow who looks like he’s just dropped out of an Amish commune

[audience laughing]

on the upper left-hand side, that’s Graeme Mein. He comes from Melbourne, Australia. He’s one of the best milking machine scientists in the world. He started the lab here at the UW. He worked here for 10 years from 1990 to 2000.

The reason why I wanted to put this photo up, my boss is Doug Reinemann, who is third from the left in the front row, wearing the blue gloves. Thank God he’s wearing the blue gloves because no one else is.

[audience laughing]

So, Doug is my peer, my boss. And the reason why I wanted to show this photo is that all of the people in this photo represent essentially four, five countries. Five countries. These are all people who’ve been involved with research here. This was part of a research project we ran last year.

The milking machine or milk harvesting research fraternity is relatively small. We all tend to know each other, and there’s a lot of communal effort is what I’m trying to say to you.

[Audience member]

Which is the Irishman?

[John Penry]

The Irish guy, John Upton, is the guy on the right-hand side. Yeah. A good operator.

Okay, so milk harvesting research at the UW in 10 minutes. Here we go.

[audience laughing]

There are three things you want to do when you milk a cow. Ideally you want to milk her quickly, you want to milk her gently, and you want to milk her completely. Now, I’m gonna argue with you. I’m gonna argue that the two on the left-hand side with speed and gentleness, gentleness on the teat tissue, they are the big players. The completely is a bit of an evolving story. It’s bit of an older story. Not so important anymore, in my opinion. So, there are our three aims. The first two aims are the most important.

And here is, here is the fundamentals, the physics, of how milk comes out of a cow when you milk her with a machine. So, here’s the teat. The big P stands for higher pressure, the small P stands for lower pressure.

Here is a milking liner right here.

[Displays milking liner]

It’s attached to a vacuum or low pressure here.

[Points to bottom of milking liner]

The teat goes in the top, like so.

[Places his thumb in top of milking liner]

So, you’ve got lower pressure under the teat, higher pressure inside the teat where the milk is sitting. So, it’s the exactly the same as a weather system. It’s exactly the same as how a plane lifts off, thanks to Mr. Bernoulli. It’s exactly the same. Gases and fluids like to go from high pressure to low pressure.

So here we go. Here we are. So, the milk is flowing from high pressure to low pressure because you have put a vacuum underneath the teat.

And one of the other things that happens if we were sitting here 25 years ago you’d be saying oh, the teat canal that the milk comes through is a hole and the hole gets stretched. No, no, no. That’s not the way it works at all.

It’s a piece of folded skin, and it unfolds under vacuum. So, what happens is it’s folded, it’s interfolated, if you like. I can’t do it with my fingers, like that. And then under vacuum it opens up to a hole that’s about two millimeters across. I’m sorry I can’t do that in inches, but it’s two millimeters across. So, it unfolds during milking because of the forces of lower pressure and higher pressure inside the teat. And that’s how, essentially, cows get milked.

And one of the things which is really cool about the cows teat canal, which is a piece of skin, it’s one-inch worth of skin. So, four teats, she’s got four teat canals, this skin is the most specialized skin on a cow. It’s a bit like taking a piece of bread and putting some butter on it and then sprinkling it with some sort of sugary condiment.

Do people have hundreds and thousands in this country?

Yeah, okay. So, imagine hundreds and thousands on a piece of buttery bread.

So, the skin is leaving as the cow is being milked because it’s got carotene in it. And as it’s leaving during the process of milking, it’s taking some of the bacteria that happen to reside in the teat cup, it’s taking that bacteria away. So, highly specialized skin, constantly producing carotene and then shedding it during the milking process. It’s a beautiful, magnificent, protective mechanism for the cow’s teats.

But one of the other things that happens during the process of putting vacuum underneath the teat is not only do you bring milk down, but you’re also taking blood down to the end of the teat as well. And we don’t want that to occur because it’s like belting your thumb with a hammer. You don’t want the teat to become engorged with blood. So, there has to be a way of moving the blood around. And this is the way it works.

So, here is three X-rays of three liners. The important dimensions of the liner are the opening at the top, the size of the mouthpiece, which is this part just here, and the width of the bore of the liner. They’re the three important dimensions.

To give you a sense of how different these things are, there’s about a hundred different liners on the American market. There’s about 80 on the Australian market. Is there any difference between these two puppies, other than the color?

Do they look different?

Well, they look different because they are. Yeah, okay. So, silicon. Rubber. Narrower bore. Wider bore. Bigger hole at the top. Smaller hole at the top. A bit more tapered. Not so tapered. All of this comes about because of different sort of design philosophies, et cetera.
So, one of the things that we’re fundamentally interested in is how these things behave because, for the most part, it’s been trial and error not science.

One of the other things to considered is that the four teats have a milk curve which is different. So, these are four independent quarters milking through four teats. And these quarters are not all doing the same thing. So, some quarters milk out quickly, some quarters don’t. Sometimes they’re relatively the same. Other times they are vastly different. And we have to account for that in the way that we milk these cows.

So, essentially, what happens is here’s the invention that was invented literally in 1890 the twin chamber teat cup. The pulsation cup. The pulsation chamber, and the teat cup. And here’s the liner. One goes into the udder, into the other.

[audience laughing]

Freudian slip. Freudian slip. That won’t happen again.

And what happens, when you mount this, it creates a seal inside here. You’ve got a chamber between the outside of the liner and the inside of the shell that you can either put atmosphere into or vacuum. And what it does by creating a pressure difference in that pulsation chamber, it’s either open and milk is flowing or it’s closed like this, squeezing. And what you’re doing is milk is not flowing but blood is circulating back through the teat, okay? So, this is pulsation. Sixty times a minute. Open, closed. Open, closed. Open, closed. Open, closed, and so on. So that’s pulsation. And it’s that action of compressing underneath the teat that moves the blood.

[Audience member]

Do the threads have a resin?

[John Penry]

The question is, do the threads have a resin? Not much. Not much of a resin. Well, certainly not one that I want to go into now, I’ll give you that much.

Okay, so, one of the mysteries of liners is how much compression do they put on the teat when they collapse, like this? How much compression do they put?

And there’s a fundamental principle that I want to show you. The last time I did this people looked at me like I was strange, but there you go.

This milking liner is made of a piece of rubber that’s about two, two-and-a-half millimeters thick. Imagine if this was not made like that. Imagine if it was an infinitely thin piece of rubber. Infinitely thin. If you put a pressure difference across the bottom, it doesn’t apply much force to the teat. So, it’s a bit like doing this. A piece of paper. Imagine my head’s a teat. Just roll with me.

[audience laughing]

Okay? So, I’m doing this.

[Places sheet of paper on head, pulling it down]

And there’s not much force. Infinitely thin. So even though I’m pulling it down, not much force.

A bad hair day perhaps, but not much force.

Take something that’s thicker, like a milking machine liner

[Places thick magazine on his head, pulling it down]

and you do this, and, all of the sudden, you’ve got more force. So, the pressure difference is wrapping the bottom of the liner, and it’s actually helping to compress the tissue and shift the blood back up.

Does that make sense?

Excellent.

If you can get liner compression, then we’re home. We’re absolutely home. And this is one thing that which has been really difficult for us to work with because still, to this day, even though we’ve been milking cows with these devices, there is no way of directly measuring liner compression. So, we work with proxy measurements, and we’re trying to make those better. That’s some of our research here, but there’s no direct way of measuring it.

Why is it important?

It’s important because it directly influences things like milking speed and the gentleness of milking.

Okay, so, milking gently. We are trying to do things like circulate the blood, remove a bit of carotene with the milk out of the teat canal but not too much, and we’re also trying to make sure that we keep skin integrity intact. We don’t want to damage the outside of the teat skin with the action of milking.

And one of the things that we’re fundamentally interested in is: Can we use the opening of the teat canal to tell us how quickly the animal is being milked and how gently she’s being milked?

And one of the really nice things about the physics that we work with is the size of the opening of the teat canal is simply a matter of what’s the pressure difference underneath and how much milk is flowing through it. If you can measure those two things accurately, you can work out the size of the unfolded teat canal. And you can therefore work out how much congestion is there.

So, for example, on the left-hand side here, as we increase vacuum, the teat canal starts to unfold. It reaches its maximum elasticity or degree to unfold. And if it starts getting smaller as we apply more vacuum, it’s because the teat is becoming congested, and we don’t want that. We want to be able to predict that and go to that point but not go into congestion because therefore we will interfere with milking speed because we make the teat canal smaller.

So, one of the things that we’ve got here at the UW, there’s only two of these in the world, this device was invented here. It’s called the Mi4. It’s a quarter milking device that allows us to set the milking condition to all sorts of different conditions of milking for vacuum and pulsation. And we can change the milking condition every 10 seconds essentially. So, we can milk a cow 20 different ways in one milking. This is a fundamental leap for milk harvesting research anywhere in the world. It was invented here. It was invented by my boss. And it’s a really, really handy device. And it’s absolutely jet propelled some of the work that we’ve been doing here in the last three years.

Just to show you one brief outcome of an experiment. This is where we have taken a liner, and we’ve either put high vacuum in the mouthpiece to try and congest the teat barrel or low vacuum there, or we’ve put high or low vacuum underneath the teat end. And what we’re trying to see is if you congest the teat barrel but not try and congest the teat end, what does it do to the teat end?

And one of the revelations in the last 12 months for us has been that if you congest the teat barrel, this part here, you’re actually congesting the teat end a lot more than what we thought. And we just didn’t know this before because we weren’t able to accurately measure milk flow in the way we’ve been able to do it now. So, very, very interesting and important work from our perspective because now, when we start to assess the performance of liners, we are putting in the vacuum levels in the mouthpiece into our models, which help us to much better predict what the performance of the liner is going to do.

I want to show you a few ultrasound images from the milking research. So, this was the same experiment. We’re trying to congest the teats as part of this design.

So, here’s a normal teat. I hope you can see that image okay. This was taken by a friend in the Vet School. So that’s a normal-looking teat. If you congest the end of the teat, this is what it looks like. So, what you’re looking for is blackness in the image, essentially, which is fluid. Okay, so normal teat, congested at the end.

If you congest the barrel, it looks like this. See the congestion in the barrel?

So that’s congestion up around here because of high mouthpiece chamber vacuum. And if you congest all of the teat, the barrel and the teat end, you get a vastly different looking teat. So, this is a teat that has not been milked gently. This is a teat that’s not being milked quickly. Because there’s so much congestion, it’s decreasing the size of the teat canal. And this is pretty important work for us. This foundational work for us.

Okay, now, I just want to finish off with one final bit of the puzzle, and then we’re going to stop.

One of the things that we can do with that Mi4 machine that I showed you is on the vertical axis, on the vertical axis we’ve got vacuum going from lower vacuum to high vacuum, and on the horizontal axis we’ve got pulsation ratio where, on the left-hand side, the liner is spending an equal amount of time closed and open but, on the right-hand side, it’s spending a lot more time open than closed in the massage phase.

So, this allows us to put in all sorts of different milking permutations and combinations of vacuum and pulsation to see how the teats will respond. And if you can measure the milk flow really accurately, you can produce this, which is a liner map.

So, the way this map works is as you increase vacuum, which farmers can do, the teats will milk quicker to a point where they start to congest. And if you alter the pulsation so that the teats spend more time, the liner spends more time open, they will milk quicker, but you also have the risk of congesting the teats as well. So, this is like a topographical map. It’s trying to say as you change, on the farm, the conditions of vacuum and pulsation, yes you are going to milk quicker, but at some point congestion starts to encroach on the milking experience of the cow.

And one of the things which I didn’t put into tonight because it’s just a bit fiddly to explain is, along with the milking speed maps for those liners, there’s also congestion maps.

And we, I think, should be pretty proud of ourselves here at the UW because this approach of assessing liners and mapping liners and describing their performance was essentially invented here. And I think it’s very useful for the dairy industry going forward.

Okay, so, what does the future look like?

The future looks like this. This is a robotic milking unit. There is now about 30,000 of these boxes in the world. It’s the equivalent of every cow in Australia being milked by one of these. These are essentially quarter milking devices. And here’s what the future looks like for milk harvesting. The future looks like a tailored experience for your cow’s teats. So here I am. I’m Betsy. Let’s see if I can do this.

This could be dangerous for television.

Okay, so here’s Betsy’s four teats.

[Holds up four Solo cups, two in each hand]

And the future looks something like this. Through the process of milking her for the first couple of weeks, we decide that this teat here

[Holds up cups in his right hand]

likes a different milking condition to this teat here

[Holds up cups in his left hand]

and these two at the back like the same.

So, Betsy’s teats get a tailored milking experience, experience based on the first couple of weeks of milking her. And we keep reassessing that through the lactation. So, this is, essentially, what the future of milking is gonna look like. It means a quick milking but a gentle milking for this animal. And that’s probably where we’re going to end up.

Okay, and with that.

Ah, the final piece of the puzzle. What does research in milk harvesting in Wisconsin, is it transportable? And the answer is yes.

Unlike some parts of dairy research, the way we milk cows mechanically around the world is the same. So, it doesn’t matter whether we’re talking about milk harvesting in Ireland or New Zealand or Australia or in Wisconsin or, God help us, in California.

[audience laughing]

It’s all the same mechanics and physics and tissue, and that’s a really good thing. So, very, very transportable research.

And with that, I’d just like to acknowledge the sponsors of our lab, Avon, Dairy Australia, and Teagasc.

Does anyone know the name of the most famous cow in rock history?

No one?

So, this is Atom Heart Mother. She’s a cow from the 1970s. The most famous cow in rock. If nothing else, can you please remember her name for the end of this presentation.

[audience laughing]

And, finally, I just want to leave you with this. If you had to take a guess, being an Australian coming into Wisconsin, of what sort of things Americans like to say to you, what would your guess be?

[Audience member]

That’s not a knife.

[John Penry]

So, someone has said, “That’s not a knife.”

Anything else?

Any other takers?

How about something like, “Hey, John, throw another shrimp on the barbie.”

[audience laughing]

So, the two most common things that Americans say to Australians, like me, are this, “That’s not a knife. This is a knife.” Or, “Hey, throw another shrimp on the barbie.”

[audience laughing]

Ironically, both said by the same bloke. Paul Hogan, on the left in an ad for Australian tourism in the 1970s. On the right, as some bloke called Crocodile Dundee. So, there we go. Famous words uttered by one man who was pretending the whole time.

[audience laughing]

Folks, thanks very much for listening. I really appreciate it. Thank you very much. [audience applauding]