Episode 51: Dairy Insights: Navigating Milk Quality During Milking with Dr. Gary Anderson

On this episode of the Maine Farmcast, Drs. Glenda Pereira and Colt Knight sit down with Dr. Gary Anderson, Animal and Bioscience Specialist Emeritus, University of Maine. The conversation reviews milk quality guidelines and cleanliness during milking. Dr. Anderson was a professor at the University of Maine, and served in the role of dairy specialist working on programs such as milk quality and sanitation, estate planning, Green Pastures program and more. Dr. Anderson continues to be a resource for the dairy and livestock industries in Maine. In his free time, Anderson stays active with his grandkids. 

Important: Please work with your veterinarian to develop health management plans, and discuss protocols for maintaining milk quality.

Episode Resources

Automated Transcript

Colt Knight: 00:22

Welcome to the Maine Farmcast. I am one of your hosts, Dr. Colt Knight, associate extension professor and state livestock specialist for the University of Maine Cooperative Extension. I am joined by fellow co host…

Glenda Pereira: 00:35

Glenda Pereira, and I am the statewide deer specialist, and an assistant professor of animal science. And, today we have a treat because I’m getting to interview, the person who was in the former role of dairy specialist here at the And

Colt Knight: 00:52

my academic mentor when I came to the University of Maine. Yeah.

Glenda Pereira: 00:56

Gary Anderson. So Dr. Gary Anderson is in the studio today. And for those who might have interacted with Gary over the years, you know that we’re going to have an awesome episode filled with knowledge.

Gary Anderson: 01:07

Well, as Glenda mentioned, I was the extension dairy specialist in this office for several years. And one of the things I worked on was improving profitability on dairy farms. One of the other areas that we worked on quite a bit was improving sanitation and milk quality. So that’s what we’re going to talk about today.

Glenda Pereira: 01:29

And what keeps you busy? So for the a lot of people know you. A lot of people always ask me about you. What’s keeping you busy these days?

Gary Anderson: 01:40

I have several grandchildren that can keep me busy as well. That’s probably what takes up the bulk of the time.

Glenda Pereira: 01:46

Yeah. Awesome. Alright. So let’s dig into the topic today. We’re focusing on only milk quality.

Glenda Pereira: 01:52

So this is for the dairy folks. I kind of want to start at the beginning. You know, what’s a PMO, pasteurized milk ordinance, and kind of guide us through what the federal milk standards are to kind of set the stage.

Gary Anderson: 02:08

Well, the the PMO or the pasteurized milk ordinance, grade a pasteurized milk ordinance is an excellent resource for any dairy producer, whether they’re making cheese or producing milk because it gives you lots of guidelines from a federal level, from a countrywide level, how to construct your facility, cleaning procedures, materials that containers should be. So it’s it’s a huge book that’s over 450 pages, but it’s available for free on the Internet. So you can do searches and and look at that information on a regular basis. So if you think of it as the federal regulations and the national standard, it covers material on construction, inspection of farms, construction of facilities, cleaning, sanitation, and storage of utensils, facility regulations, and water quality. You can view it on the Internet for free or you can buy a printed copy.

Gary Anderson: 03:16

So either one is readily available and and great. It’s updated every two years. So the current version that we’re working off of now was done in 2023, so they’re working on the 2025 current version right now. And states will take the PMO and look at it, and they’ll either adopt it in whole or in part. So in Maine, they adopted in part because in Maine, the the PMO doesn’t support raw milk sales, but in Maine, can buy raw milk.

Gary Anderson: 03:51

So that part they don’t adopt. So it’s it’s an excellent resource for anybody to go to for making their farm operate better.

Glenda Pereira: 04:02

So if there’s like a Cliff Notes version, it’s really guiding us to make sure that we’re meeting the standards for food safety for consumption.

Gary Anderson: 04:13

Exactly. And if you follow that, your bacteria counts and your quality measures of your milk are going to fall within the regular guidelines. So it works out well. And one of those is somatic cells. And we see somatic cells milk, and that’s an indicator of inflammation or an infection in the udder.

Gary Anderson: 04:41

And somatic cells are made up of two kinds of cells, white blood cells, which are there to fight off the infection. But then there’s the milk secretory cells that wear out, so they get sloughed off and some of those are in milk. So as a cow goes in late lactation and somatic cell will gradually rise a little bit because that milk secretory tissue is wearing out over time. So we measure that in thousands per milliliter. So somatic cells are at the state lab in Augusta.

Gary Anderson: 05:19

They’re measured electronically. And so if you’re above a hundred thousand somatic cell count per milliliter, then that’s going to start to indicate a an infection. The higher the somatic cell count goes, the more severe the infection and the more potential milk loss you have. So one of the real problems of of having a high somatic cell count is it’s not only the level of the count, but it’s the loss in potential milk production that you’re never seeing. Reducing that and having a healthy udder and healthy milk can increase milk production.

Gary Anderson: 06:09

So if you look at the legal limit, the legal limit is 750,000 cells per milliliter, which seems like a lot, and it is. But if you had that level, nobody would buy your milk in Maine because from a practical standpoint, because of some European regulations, 400,000 is the maximum that somatic cell count that will be sold in Maine. So you want to be well under the 400 you don’t want to be at the limit. You want to be well under that limit so that you’re producing a high quality milk product that has a long shelf life.

Glenda Pereira: 06:49

And most farms that I’ve been working with tend to be under that limit. You know, weather is a big factor into that summer versus winter. Bedding type, you you know, can be definitely an issue, for trying to remain under that limit. So there’s a lot of factors that go into to trying to be under that limit. But I’d say most farms sit around, 200 or less or they they try their best to do that.

Glenda Pereira: 07:15

And certainly, if you’re a processor, if you’re if you’re, you know, your milk’s going to processor, they have their milk quality standards as well and they try to troubleshoot some of that to keep you under.

Gary Anderson: 07:28

Exactly. So you want to move on to milking procedures?

Glenda Pereira: 07:34

Yeah. Let’s do it.

Colt Knight: 07:35

I’m excited.

Gary Anderson: 07:39

Well, one of the first things that we want to do is attach a milking machine to a stimulated teat so that we want to have that stimulation that we’ve done in the preparation of the of the teat for milking so that we get adequate milk let down and we get a good recovery of milk from the udder. So the first thing we want to do is to strip out some milk from the teat canal, the very the last, say, an inch of the of the teat. We wanna look at that material that comes out of the out of the teat and make sure that there’s no clots or flakes in the milk, which would indicate abnormal milk.

Glenda Pereira: 08:23

Yep. Yeah. So we’re gonna be force stripping ahead of time to do that visual eye test.

Gary Anderson: 08:30

Right. And and by doing that force stripping, we’re gonna flush out the high bacteria milk and some high somatic cell count milk, which has been at the bottom of the teat.

Glenda Pereira: 08:42

And I laughed because the eye test isn’t always the best guide. But it’s certainly, you know, the first step into … and then, you know, obviously implementing a California mastitis test if you have or something else. But the eye test can be a first good step.

Gary Anderson: 08:55

And this is one of the first places that we’re going to talk about some management practices that you want to make sure you follow. So I always tell people to take three to five squirts of milk out of the tea to make sure it gets flushed out. And that’s going to stimulate the release of oxytocin, a hormone that’s produced in the posterior pituitary of the brain for that stimulates milk letdown. And that’s going to remove the high bacteria and high somatic cell count milk. Yep.

Gary Anderson: 09:25

So the next step is to pre dip a clean teat with an approved product. So notice I said clean teat. So if you have dirty teats, which is another management issue you want to evaluate, If you’ve got a dirty udder and a dirty teats, then you really need to look back at what’s the condition of the bedding that the cows are in.

Glenda Pereira: 09:51

Where they if they’re

Gary Anderson: 09:52

walking to

Glenda Pereira: 09:52

the parlor.

Gary Anderson: 09:53

And have access to. And and if there’s a lot of manure around as cows walk, they kick up that manure under the bottom of their udder. So another way you can evaluate that is to in a milking parlor is the people that are milking the cows look at their forearms and see how dirty they are. And you can actually buy some covers that would go over your forearm so that you could do a test to see how how good that is. And and so really what we’re trying to do is to disinfect the teeth skin, and we want to make sure that we we disinfect it all for the entire teat.

Gary Anderson: 10:38

So that is why we talk about pre dipping. Because when you dip that teat into a an approved pre dip product, you coat the entire teat, and you want to leave that in contact for about thirty seconds to make sure that you get a good kill of bacteria on the surface of the skin. Now, some people use a spray, and it’s very tough to get a good adequate spray on the entire surface of the teat. They always say that there’s four ways to get mastitis. Left front, right front, left rear and right rear.

Gary Anderson: 11:13

So you wanna make sure you coat the whole teat end with a preapproved, pre dip product.

Glenda Pereira: 11:21

Yeah. So one the spray doesn’t have as much surface area coverage as a dip will.

Gary Anderson: 11:28

Right. And the way you can test that is if you take a dipped teat and wrap a paper towel around the teat and then look at where the wetness is, you can see what coverage there was. If you have a bad spray job, then you’re going to get holes in the coverage of that model of the teat skin. Yeah. So some things to think about in the as you’re milking cows is you want to make sure that you start out with with clean hands, that you wash your hands.

Gary Anderson: 12:05

Always good to wear gloves. And most people wear a nitrile gloves in the barn to milk and and have some water wash available so that if those if your hands get dirty, you can easily clean them. So they always say you wanna apply a machine to a clean teat, not a cleaned teat. So if you have to clean the teats to put the milk to get them clean enough to pre dip and and put the milking machine on that cleaned ED teat, then that’s a real issue.

Glenda Pereira: 12:42

Yep. And we can attach to the notes, like prep lag times as well because that will help in your cow your cow being properly stimulated, as well as not waiting too long or not being, you know, not being too quick at doing all of that prep lag time. We’ll we’ll attach those show notes so folks have a good idea to see if they’re meeting those benchmarks.

Gary Anderson: 13:08

So then we want to look at the prep lag time, which is from the first the number of seconds from when we first touched that tea to squirt out that milk to evaluate it for abnormal milk. How long is it? Do we have to wait till we get good stimulation, good milk let down, and we can apply that milking machine and we want to be in that ninety to a hundred and twenty second interval. So usually we say halfway between that. That minute and a half or ninety seconds is when you want to be applying the machine.

Gary Anderson: 13:46

And you can evaluate that with a product with a machine called the lacto quarter. And really what that does is it graphs out the amount of milk over by second after you approach. You can look and see if you get two let downs, for example. So you get a small let down of milk and then all of a sudden the real let down comes in and you get a big rise in milk. You don’t want to have that.

Gary Anderson: 14:12

You want to have a good stimulated tea with good milk let down so you get the maximum harvest of milk. And so people that have corrected that on their farms actually have increased the total milk production significantly. Then after the cow’s milked, you wanna turn off the vacuum and remove the machine. And then we’re gonna use a post dip, which will again disinfect the teat, and it’s gonna be formulated a little bit different from the pre dip so that it has a little bit better adhesion to the teat and can provide some long term kill as that cow goes back to the barn. That is not wiped off.

Gary Anderson: 14:51

It’s left on. And the last thing to remember is that if we do have infected cows, cows that have mastotic infections and abnormal milk, we want to make sure we milk those cows last. And then where does that milk go? Is that saleable milk or is that milk that needs to be dumped? Yep.

Gary Anderson: 15:11

And collected?

Glenda Pereira: 15:12

That’s always a good practice and, you know, using a way to identify those cows. And oftentimes those cows just take so much longer to milk out too. So sometimes it’s just good to keep them back because you wanna like you were talking about, you know, the milk light down in the flow and one cow that has mastitis or that has a hard quarter will kind of mess up with the flow of everything. So those cows are good to identify those cows and then, you know, make sure that you’re kind of leaving it leaving that time to then appropriately milk them out. Because one of the ways to, you know, improve a cow in her recovery from mastitis is to make sure that she’s getting milked out completely.

Gary Anderson: 15:54

Exactly. And so if you think of milking in a parlor, say you have six or eight cows on on each side. And if you’ve got a slow milking cow, she’s holding up all those eight cows, which is increasing the time that you’re spending with that cow. So you want to really look at the number of turns of that parlor per hour that you’re doing and how long it takes to milk. So we talked about evaluating the udder cleanliness of milking.

Gary Anderson: 16:22

And so if the udders are dirty, why is that? Is it because the barn hasn’t been cleaned? Is it because of dirty bedding? Some or if you have different management systems, and how can you correct that reason for having a dirty udder? What’s the length of hair that’s on the udder?

Gary Anderson: 16:45

Because long hair manure sticks to it easier than it does.

Glenda Pereira: 16:49

Yep.

Gary Anderson: 16:50

Short hair. And and then we mentioned stall and bedding cleanliness. We talked about looking at the milker forearms and and then you can also evaluate milk filters to see how dirty they are. And and that all that that’s kind of a 30,000 foot view to figure out what do I need to concentrate on and look a little bit closer at in order to improve my milk quality. So we talked about tea dippers, and you only wanna use enough as much tea dip as you’re gonna use in a milking.

Gary Anderson: 17:26

You don’t wanna have extra teat dip in a teat dipper that’s going to get carried on to the next milking because even though even though those are strong disinfectants, you could get bacterial growth in in tea dip inside the teat dipper. So at the university farm, what they do is they have two or three different colors, and they wash them out at the end of milking, but then they go to the next color so that teat dip that’s used tomorrow is really kind of a rotation from two or three days. That teat dipper hasn’t been used for two or three days. So they’re cheap enough that you can get a couple of cover, couple different colors and hang them up on on the wall to make sure they’re thoroughly dry and get good kill so that they’re they’re clean and don’t have a lot of bacteria growing in them. But that could be a real issue.

Glenda Pereira: 18:23

Yep. Water is your friend and can sometimes be your foe. Right? We want a clean, dry surface.

Gary Anderson: 18:30

Oh, we’re gonna talk about water here in a minute. So water is is a potential big issue.

Glenda Pereira: 18:38

Friend and foe.

Gary Anderson: 18:39

Yeah. Mostly on the foe side. So if you’re shipping milk to a commercial person or commercial company, they’re going to evaluate that milk quality on a regular basis and give a report back to you. Now, if you’re gonna not ship to somebody and you’re gonna sell your own milk, or you’re going to make a product like cheese or yogurt, then that’s your responsibility to do those that testing to find out what the quality of your product is.

Gary Anderson: 19:15

And so some of those, if we’re going to evaluate an issue, and mostly that’s you find out about that issue when you get a report, you get a large increase in one of your bacteria numbers. And so the different measures that are put on that report are the standard plate count, which is an aerobic bacteria count, a coliform count, which looks at the coliform bacteria, a preliminary incubation count, which are gram negative organisms. That’s where we’re going to get back to water. The lab pasteurized count is bacteria that survive in milk that survive pasteurization and continue to grow. And then the somatic cell count that we talked about.

Glenda Pereira: 20:05

So folks should be maybe sending samples to dairy one.

Gary Anderson: 20:09

Right. And there is dairy ones in New York, but sometimes those samples get shipped off to Pennsylvania. So you have to really look at where did that sample go and how what was the time frame that it that it went? Not that it can’t be a good useful piece of information, but you want to make sure you know as much as possible about the testing procedure. So evaluating a problem, need to know is it a cow issue?

Gary Anderson: 20:40

So is it a mastitis issue or a cleanliness issue? Or is it an equipment issue? And is it because of cleaning issues or sanitation? Or is it both?

Glenda Pereira: 20:54

And most oftentimes, it’s people. Not always.

Gary Anderson: 20:59

And then you want to evaluate over time, does milk quality change as more milkings are added? So the first milking looks pretty good. But by the time that milk gets picked up, it’s not because maybe the refrigeration is off on that bulk tank. So it warms up. And so evaluate that quality over time.

Gary Anderson: 21:23

And you can do that with a computerized thermometer that you put in the bulk tank. So you can evaluate that over time and graph that out. So that’s very helpful. And does the milk quality change from the milk in the pipeline to the bulk tank? So is it an issue of so you measure the milk coming out of the drop pipe into the bulk tank versus what’s been in the bulk tank for a while.

Gary Anderson: 21:52

So that can help you pinpoint some issues and things to look at. And then we come to water. So most dairy farms have a well, and it’s and it’s not chlorinated on a regular basis. So but I have seen situations where a high PI count, which is a they’re non coliform gram negative bacteria grow. And you would think with the chemicals that we use to clean dairy equipment, it’s there’s there’s strong chemicals.

Glenda Pereira: 22:29

Not with hard water.

Gary Anderson: 22:31

That that would that that would kill those bacteria. But I have seen situations where we had to replace the whole water line from the well casing over to the milk room. And that’s what cleared up the problem. Right. Because you want to that case, for example, you know, if you use black plastic pipe and you if you cut that open, if you stick your finger in and it’s slimy, then that’s a good indication that needs to be replaced.

Gary Anderson: 23:04

And so you could or you can disinfect the well as well, but it never seems to clean out those bad water lines that come from the from the casing over to the milk robe. And then we can do mastitis culture, and you can ID the bacteria causing an issue. And I always like to recommend doing a bulk tank culture because that’s one of the tests that the diagnostic lab does run on a regular basis. It breaks it into environmental and contagious bacteria, and you get a good picture on an ongoing basis for a small investment of how your milk quality from a bacteriological standpoint is progressing. If you were gonna send in a bulk tank sample, you wanna make sure that you collect a sample over three to five days and then pool those together because some of those bacteria are not shed every day by cows that are infected.

Glenda Pereira: 24:02

Yeah. I think this is a good time to then kind of take us back through some of the the sort of takeaways. So if you don’t mind from the top, so we we can, utilize the PMO to guide us into what the best management practices. And then there’s, other guidelines that either you can send to you send milk to a lab to then get feedback on where you’re at in terms of these. And like you just mentioned, all of these metrics, you can send a culture to then see, is it an environmental issue?

Glenda Pereira: 24:38

Is it a contagious issue? And maybe, you know, start at the bulk tank and then try to identify the cows if you do have a problem with your numbers on a bulk tank measure. In in a future episode, we’ll cover kind of the tune you know, using these guidelines to then help us hone in hone in on the problem and and how do we go from there. So thank you, Gary, for giving us an overview of the current milk quality guidelines.

Colt Knight: 25:07

Yeah. We appreciate your help. Thank

Gary Anderson: 25:10

you very much, Glenda and Colt. Great to be here. Hopefully, get lots of information out to producers. Absolutely.

Colt Knight: 25:18

Yeah. And we would like to remind our listeners if you have questions, comments, concerns.

Glenda Pereira: 25:24

You can reach us at extension.farmcast@maine.edu.

In complying with the letter and spirit of applicable laws and pursuing its own goals of diversity, the University of Maine System does not discriminate on the grounds of race, color, religion, sex, sexual orientation, transgender status, gender, gender identity or expression, ethnicity, national origin, citizenship status, familial status, ancestry, age, disability physical or mental, genetic information, or veterans or military status in employment, education, and all other programs and activities. The University provides reasonable accommodations to qualified individuals with disabilities upon request. The following person has been designated to handle inquiries regarding non-discrimination policies: Director of Equal Opportunity and Title IX Services, 5713 Chadbourne Hall, Room 412, University of Maine, Orono, ME 04469-5713, 207.581.1226, TTY 711 (Maine Relay System).