$omatic Cell Count$

Today we are talking with Dr. Andrea Mongini of M&M Veterinary Service and Ewetopia Dairy in Denair, California about the significance of somatic cell counts (SCC) and how this metric can be utilized to evaluate milk quality and udder health. 

Topics discussed include: significance of somatic cells in milk production, United States SCC limits and benchmarks, causes of elevated SCC, methods for evaluating SCC, basic troubleshooting for tracking down a high somatic cell outbreak.

Helpful links:
- AASRP: Find a small ruminant veterinarian: http://www.aasrp.org/about/find_a_vet.asp
-  Canadian Mastitis Network: California Mastitis Test procedure: https://youtu.be/YRbH_E7JtTU
- University of Minnesota: Easy Culture System: https://vdl.umn.edu/laboratories/laboratory-udder-health-luh/minnesota-easyr-culture
- National Mastitis Council: Order the Laboratory Handbook on Bovine Mastitis: https://www.nmconline.org/publications/


This podcast is sponsored by the American Association of Small Ruminant Practitioners as well as USDA National Institute of Food and Agriculture, Agricultural and Food Research Initiative Competitive Program, Antimicrobial Resistance grant # 2020-04197.

Questions or comments about today's episode can be directed to DairyGoatExtension@iastate.edu

Transcript

Michelle: 0:04

Hello, I'm Dr. Michelle Buckley from Iowa State University's College of Veterinary Medicine. Thanks so much for joining us on Baas and Bleats, sponsored by the American Association of Small Ruminant Practitioners. Just a quick note before we get started, this work is also supported by the USDA National Institute of Food and Agriculture, Agricultural and Food Research Initiative Competitive Program, Antimicrobial Resistance Grant Number 2020-04197, which funds my research on improving antibiotic stewardship in dairy goats to assure food safety and milk quality. As always, if you have any questions about any of our episodes, please email them to dairygoatextension at iastate.edu. I hope you enjoyed today's show. Thanks for joining us today on season one of Boz and Bleats, the American Association of Small Ruminant Practitioners podcast. This season we're focusing on improving milk quality and food safety in dairy goats. Today we're talking to Dr. Andrea Mongini of MM Veterinary Practice and Utopia Dairy in Daener, California, and we'll be discussing somatic cell counts in dairy goat production. Thanks for joining us today, Dr. Mongini. Can you tell us a bit about your veterinary career and your involvement in dairy goat production?

Andrea: 1:44

Sure. Thanks, Michelle. It's great to be here, and I'm looking forward to our talk today. I have been in dairy practice since 2000. I graduated from UC Davis. My husband and I are dairy veterinarians and I have worked in dairy goat veterinary practice and consulting for about 20 years now. I also have a master's in nutrition, and that has really helped me with getting involved in the management of large goat operations. I work with the creamery and I help manage their large dairy also. And I think having that hands-on approach to really growing a dairy, you know, starting it from scratch and then growing it and dealing with all the growing pains and management concerns, has really taught me a lot about how to manage herd health and goat milk quality and the things that matter from the standpoint of working with the creamery and working with the dairy together. I feel like that's really taught me a lot about what needs to happen on a dairy to produce the best quality milk for the shippers, for the creameries. We also own and operate a sheep dairy, and that has been really a fun challenge for us in terms of really learning about, you know, as a producer ourselves, then the hangups and the management concerns, and really how to do things so that they're cost effective but also effective from a herd health standpoint and an animal care standpoint.

Michelle: 3:15

Fantastic. So it sounds like you have a lot of different perspectives on uh goat milk production. So I'm really glad we were able to get you on for this episode. If we could just start at the basics and talk about what are somatic cells and why do we find them in milk and why do we care about them.

Andrea: 3:34

So somatic cells are uh shed in milk of all mammals, and what we call what we're in today talking about for somatic cells and what how they're what they're being measured as is the white blood cells. So, you know, you're familiar with blood as red blood cells, and then the white blood cells are things like neutrophils and macrophages, and really their job is to clean. So they circulate in bodily fluids and they look for bacteria and viruses and anything that shouldn't be there, and they kill it and remove it from the system. So when we measure somatic cells in milk, what we're looking at is saying, well, if there's a lot of somatic cells in the milk, then there's probably a bacterial infection in the milk, or it could be a yeast infection, technically, but that's very rare. So generally, we're looking at bacteria. So if the goal is to produce clean milk, then we want milk that has a low bacteria count, and so then we know that if it has a low somatic cell count, there aren't a lot of bacteria in the milk. So that's why we care about somatic cells in any animal, goats, sheep, cows, any dairy animal, we're always, you know, made there's federal standards for what somatic cells need to be, and the reason is that we're trying to produce the cleanest milk possible.

Michelle: 4:54

Do somatic cells affect the quality of a finished product, like milk or cheese, as well?

Andrea: 5:02

There's thought that there that that is a concern. So the um one of the things that happens with um white blood cells is uh when they are killing bacteria or if they're present in milk, they use acids, um, naturally occurring acids as part of the process of you know chemical warfare basically against these bacteria. And the thought is that if there's a higher somatic cell count, that can lead to a lower pH and some acidification of the milk, and that that can affect things like cheese quality, cheese yield, um the way the curd sets. So if you talk to creameries, especially these boutique creameries, where they're really trying to make some unique cheeses and the consistency and the flavor and just the maturation of that product is really important, they really struggle with high somatic cell count milk. And that that's definitely an issue with milk. The thought with fluid milk we're talking now, so milk that's bottled or canned and put on a shelf, the thought is that it can affect flavor or shelf life stability. Now, if you start digging into research, there is some research that shows that that is not necessarily a direct correlation. And I did some reading up actually for this podcast over the weekend, and it was interesting because in all the studies where they were able to prove that somatic cell count didn't matter, the milk components were extremely low. So the butter fat and the protein were under 3% for this was goat uh cheese that was being made. And at that point, you have so many other factors affecting cheese eel that I just have to wonder if the reason that those studies showed a lesser effect with somatic cell count is because they were already making really poor quality cheeses out of that milk.

Michelle: 6:52

Wow, that's really interesting. I think that's a rabbit hole that we will need to go down on another episode, um, since that was just supposed to be an introductory question. But let's talk about how somatic cell production is different in goats versus cattle and sheep.

Andrea: 7:07

So goats are unique, and if you are a goat producer and have goat background, you already know that the and the reason we're talking about this today is because it's sort of a black box. The somatic cell counts in goats are different than sheep and cows in terms of how we measure them, can be there's some differences that are important. So one of the things that's really important to keep in mind, and the reason that the somatic cell count limits are higher in goats is because goats are what's called an apocrine shedder. So when they produce milk, they release the droplet of milk inside of a cell. Whereas when sheep and cows produce milk, the udder is making the milk, and then that cell essentially bursts open and the milk is released into the udder and leaves the teeth. So goats are actually releasing tiny cells full of milk, and eventually that breaks down and then there's just milk. But those cells of milk can interfere with a somatic cell count reading, and so that the fact that they produce milk a little bit differently can lead to a higher somatic cell count reading on the standard machine readings that are done by most labs.

Michelle: 8:19

I know we mentioned in the beginning that bacteria are the most common cause of elevated somatic cell count. Um, can you speak a little bit more in depth about what different categories of bacteria we tend to see that can cause elevated somatic cell counts? Um, and do certain groups of bacteria cause higher elevations than other groups?

Andrea: 8:44

We'll keep it simple with generalities here. So there's two main families we're talking about in goats with mastitis. So there's gram positive and gram negative, and it doesn't really matter as a producer except to know that the gram positives are things like staph aureus and coag negative staph, and the gram negatives are things like E. coli. In goats, we really tend to see a lot of coag negative staph, and there's a lot of staph aureus in goat dairy herds around the country, and especially in herds that aren't doing surveillance and checking and culturing to see what types of bacteria are present in their herd or in their bulk tank milk. The thing that is most significantly different about goats from cattle, although sheep do this also, is goats are really good at having subclinical mastitis. So I visit a lot of farms around the country and I'll say, Well, what you know, how's your mastitis? Do you have, you know, what sort of mastitis incidence do you have? And they'll say, Oh, we don't ever have mastitis. We have no mastitis, which is unlikely. And if you start looking at these herds, they have a lot of half udders. So the subclinical mastitis means that the milk isn't abnormal, but the somatic cells really high in that half or in the whole udder, and chronic inflammation in that half will actually dry that half off. So the reason that this is significant and really important for goat dairies to keep track of and manage is because these goats with half udders, and in the process of having these subclinical infections where there's an infection in the udder, but the milk looks normal, and these udder halves are shrinking, which is sort of the warning sign, is that the somatic cell count is extremely high. So these goats that are having these subclinical infections with coagulase-negative staph will often have a somatic cell of three or four million. I I've seen seven million. I mean, very, very high. So one goat can contribute to the bulk tank somatic cell quite a bit. And so it's not uncommon for me to deal with a dairy that's on the verge of being degraded and their somatic cells running, you know, two million in the bulk tank. And we'll go through and uh sample goats and we'll pull out 20 or 30 doughs out of, say, a thousand, and we can get them legal again.

Michelle: 11:12

Wow, I think some dairy vets that were tuning in may have just clutched their chest when they heard those uh somatic cell numbers. That's quite high compared to what we see on the bovine side. But that's good to know that it it could be uh a limited problem potentially if it's only a few bad actors that are spiking that um somatic cell count up so high. So it's a good thing for folks to keep in mind if they do need to start tracking down um a high somatic cell count issue. Um so what does somatic cell count mean with respect to other health, milk quality, and standards that are set by USDA milk processors?

Andrea: 11:57

So we touched on this a little bit already, um, but what and again going back to the goal of you know in America, you know, we have standards set, um, and they're set under what's called the pasteurized milk ordinance or the PMO. So creameries then have to follow the PMO. And the PMO is what dictates the legal limits for somatic cell count and standard plate count and lab pasteurized count and all these numbers that you're familiar with if you're a milk shipper. Uh, the somatic cell count that is legal federally is 1.5 million, which is a very doable number, but it does require management of utter quality, milk quality, herd health. Um there's just a lot of different areas that need to be managed, but there's no reason that herds can't produce at 1.5 million. Grade A standards are a million. Um so there's grade A, which is fluid milk, and grade B is for cheese. And so there's a lot of creameries. The most of the milk in the United States is going to cheese production. So most goat dairies are operating at 1.5 million as they're cut off.

Michelle: 13:16

So you kind of mentioned that you've had some incidents with uh clients potentially being degraded before. Um can you talk a little bit more about what the penalties are for having excessively high somatic cell counts?

Andrea: 13:31

So when a dairy has, so we have inspectors that come out that are either you know county or state or federal, depending on your jurisdiction and what you're producing for and your area. But somebody's coming out and inspecting your premises and taking a sample, and that's happening monthly. Those samples are the ones that affect your ability to ship milk. So if an inspector comes out and takes a sample and it is over 1.5 million, you will get flagged and your inspector will notify you. At that point, you have they will reach sample you two more times. So in a month's time, if you have three samples over the limit, then you get what's called degraded. So if you're grade A and you're at a you know you need to be under a million, um, and you're saying 1.2 million, you could be degraded and then become a grade B shipper, at least to find a home for your milk until you've solved your problem. If you're grade B and you're at 1.6 million, then there's no home for your milk. So at that point, the creameries legally cannot take that milk. Sometimes there's um people can find outlets for the milk in the meantime, but it becomes a really frantic scramble. So avoiding getting to that position is really, really important. And I think we all know that as producers, that that's sort of all we care about is getting that milk off the premises and getting a check, you know, back from the creamery. On the other side of that, this chronic high somatic cell definitely affects milk production, milk volume, longevity of the goat. So a goat with a high somatic cell has a lower chance of staying in the herd for a long time. She's more likely to be cold. She's cold as in sold. Um we really want to aim for goats with great quality udders, great udder health, um, just general herd health, right? All disease affects production negatively. So a healthy animal is going to last longer, live longer, produce milk for longer. Those things are really important. So, although we're sort of focusing on high somatic cell count at this point, I think at some point Michelle and I are going to loop back around and talk a little bit about why having a healthy udder and a low somatic cell count is just is more important, really.

Michelle: 15:58

Yep, that was exactly my next question. So, can you talk about not only the financial benefits of having a low somatic cell count, if there are bonuses for goat milk uh processors like there are for bovine processors, but also obviously the animal health component and uh what kinds of improved longevity we see when we're not dealing with chronic low-grade inflammation in the udder, like you've talked about with subclinical mastitis.

Andrea: 16:28

Yes, most creameries do offer uh premiums uh for low somatic cell, and they're different, they're creamery specific, they're region specific, but of course, again, the creameries want uh producers that are producing good quality milk, they can make a better product, the product is more sellable. And I think as producers we have to keep in mind that we're making a product that's gonna go on a shelf somewhere, so it's not just trying to make milk, but we're really trying to make we're helping build this economy of goat milk products in the United States, and that that ultimately is what feeds us as producers. Um so with low somatic cell count animals, uh what I've found from working closely with these goat dairies and really being involved with the management and following you know this one dairy that I've worked with for over 10 years now is that we have a lot of goats that are milking over a thousand days in milk, and all those goats are low somatic cell count. And if we start looking at goats that are, you know, we're rebreeding them at 300 days or rebreeding them at 400 days, a lot of it is correlated to goats that start having utter inflammation. So the re the rebreed points are set for milk production, right? We have daily milk weights, so we can set parameters and run lists of goats under five pounds, say, and then that goat is flagged as a rebreed or a cell, depending on where she what she looks like and what we want to do with her. But I definitely believe that the goats that are milking over a thousand days have superior utter health, and they that is very profitable as a producer, then and it becomes worth it to manage somatic cell count only because if you have a goat that can milk for a thousand twelve hundred days, the risk of her kitting back and having an issue and being sold is highest in that close-up and fresh period. So these goats that can just keep milking are very profitable. We're not paying for downtime, we're not paying for lost milk when they're dry. Um, there are less interventions in that animal in terms of veterinary care and just general handling. So if we really want to have goats and maximize their ability to do their job, keeping them healthy and really maintaining utter health becomes a much higher priority.

Michelle: 18:56

There are a lot of components that go into maintaining utter health, um, especially management and and milking procedures. But do you notice that there's a genetic component to this as well?

Andrea: 19:09

I can't say that I can follow that in lines, at least in, you know, from my experience with the dairies I've worked closely with. But I will say that when we start saving uh breeding bucks, buck kids from the superior doughs, I think that that is how it happens, is that we keep selecting from doughs that are better quality animals that fit the environment that really perform well. So there's things like uh teat end quality and teat size and teat shapes. So there's certain breeds that years ago had like very like saunans years ago had very, very small teet orifices, and so then they were over milked, so the milk out times were very long, and then that could lead to higher somatic cell counts and mastitis. So in that region. Respect, there are breed differences, or these doughs that can have the really blown out, like they call it a carrot teat. Any of those abnormal utter teat conformations lead to a higher somatic cell count and a risk of an utter infection. Hopefully that makes sense. And so I think that when you start selecting for utter quality and utter type, you're also selecting for utter health, which I think is what you were getting at.

Michelle: 20:26

Yeah, that makes a lot of sense. And I think on the bovine side, we we have some more information on how all of that is related genetically and how it's transmitted. Um, so we can do a good job of selecting for that. And I think on the caprine side, we just aren't quite there yet with our genetic analysis. Um, so it's a lot more of observational than looking at DNA.

Andrea: 20:53

I agree. Yes, I I agree completely with that. Yeah, it's a lot more associations uh rather than direct correlations. Exactly.

Michelle: 21:03

Exactly. Um so we've talked about high and low somatic cell counts, but um could you give us an idea of what would be considered a low somatic cell count for a goat dairy in the United States, with the understanding that this is going to vary based on location, seasonality, where they're at and their lactation, since a lot of goat dairies are are seasonal milkers. Um so what would be considered a really low uh somatic cell count or maybe even like a rolling herd average?

Andrea: 21:36

Um I have worked with herds where we were intensively managing, and these are large herds, so I'm not talking about 20 goats, I'm talking about, you know, say 700 up to you know over a thousand. Um, where we had I have worked with herds where long term we were able to maintain a somatic cell at 300, 350. I have never gotten a herd probably lower than 300 on a somatic cell count with goats. So there is still some issues with um the way that we're measuring somatic cell count, but I don't I don't fully believe that the apricron shedding of milk, this different form of milk shedding, is the real reason why we have a high somatic cell in American herds. So I do think that we have a lot of subclinical infections that we're just not managing properly. Um I I also think that for a lot of herds, it's so much, it feels so daunting to, you know, maybe people don't feel like they have the tools to get their somatic cell under control. It just feels like too big of a problem or too expensive of a problem to address. And so a lot of herds run in that seven to nine hundred thousand range, and they just kind of float in there, and that's good enough, um, and it works. And so I would love to see all these herds under 500,000, and I think that's possible, but I think it it would take a lot of work and a lot of um really cleanup to get to that point.

Michelle: 23:11

So, what are options for evaluating somatic cell levels in our dairy goats other than having uh an auditor come out from your processor? Um and what do you recommend for the dairies that you are interacting with on a regular basis?

Andrea: 23:30

The herds that I work with regularly, where I'm involved with what's going on on these farms, uh, we we have a two-step process, and I think after the years and the time I've spent working through this and being a producer myself, I think in my mind this is probably the easiest way to um to stay on top of it and to manage it individually as a producer. So we I use two things. One is the California mastitis test or the CMT test. And if you're not familiar with that, there's a lot of great YouTube videos on how to do the test and how to interpret it. It's very simple, it's animal side, so the milker can do it in the milk barn. Um, but basic the basic premise of the test is that there's little wells on a paddle, so you strip each half into one of the wells so the milk is separate, and then you mix this diluent, it's just a squirt bottle, and you mix it 50-50 with the milk, and then if it it'll clump up and gel, like they say it's like snot, it gets kind of like a gross goo, and if it's that's a positive, and if it just stays liquid, then that's a negative. And so that's a very basic interpretation of it. But the more it gels, the feeling is the higher the somatic cell count. And that's a great way then to say this animal has an infection, this animal doesn't. And so I really like to use that as a basic animal side test. At that point, um, it's there's some really nice systems in place so that people can do their own culturing. So some herds are sending their, then you can selectively milk sample. So you could say anything that tests uh CMT positive, so there's a gelling in that sample, you could take a sample from that half of that goat. So at this point, then we're not sampling every goat on the farm because that's where we start adding cost. So we can do things like, for instance, if there's a lot of problems, like I've come into herds where you have the somatic cells running 1.5 to 1.7 and they just keep bouncing back to 1.5 to be legal, but they're barely legal, and so we really have to do some stop gaps. So we'll go through and train, have the milkers do the CMT testing, and then all of those positive goats get restring into their own string, and then all the negative goats live in their own strings, and that way we're not spreading infection anymore. Um, and then we can make a decision on what to do with all these positives. So we can culture them, we can treat them, we can sell them, we can dry a half. But having those tools and those options is is really nice. So I'm really a fan of on-farm culturing for larger farms and for smaller farms than just doing selective culturing.

Michelle: 26:27

And the CMT definitely seems like it could be a very viable option. Um producers that aren't experienced with it will probably need a lot of oversight from their veterinarian in the beginning to know obviously it does there's a a sliding scale, right? It's not just clear or looks like goo, there's a range, right, that it can look like um in between there. So, how do you know or what do you tell your producers as far as when there's a problem and when it's okay? Like what's your what's your breakpoint description on that?

Andrea: 27:05

So, to back up a step, the the solution you mix with the milk is purple so that it's easier to visualize and see. It's not just white milk on a white paddle. So we have this purple milk, which is a negative. Um, a one means it's starting to clump and that's a watch, and a two is solid. So what I tell milkers to keep it very simple and owners on farms is if it gels, it needs to be dealt with, and if it's not gelling, then we're just gonna let it ride. Because there's a lot of subclinical mastitis, a lot of coagulase-negative staph on goat dairies. That said, the first step in all of this is taking a bulk tank sample and looking for staph aureus, because staph aureus is a different family of staph, right? So we have coagulase negative staph and we have staph aureus. Staph aureus is contagious, it's not treatable, it's a it can be a real problem in herds if they have it because it's so contagious. And so the step one on any farm is finding out if you have staph aureus or not. And if you have staph aureus, those animals need to be milked glass, they need to be isolated immediately. Ideally, they could be sold, but in a lot of cases, there's too many animals, there's too many staph aureus positive goats. And so they go into their own string, and step one is just managing somatic cell count. So if they're at a 1.4 million somatic cell and they have 20 staph aureus goats out of a thousand, maybe we can milk them in their own string and milk them last. But when the somatic cell jumps up to 1.6 million, those are the goats we know we want to sell first. So they go into that pen, we find the three or four worst goats, and we sell them. Um or they're removed from the herd, whichever euphemism we want to use. Um, but at that point, um, we can slowly work our way out of a staph aureus problem because those are not goats we're going to be treating with intramammary mastitis tubes. We're not going to be, we don't even really want to dry those halves because those goats should become a do-not-breed. So they can stay if they're milked last, but we don't want them kidding back, we don't want them getting mixed back into the herd. You know, if you own goats, you know that they're masters of finding ways into the pens they don't belong in. And these goats are really a high-risk animal in for those situations.

Michelle: 29:26

And just kind of as an aside, um, staph aureus positive dose, how do you feel about using that milk for feeding kids?

Andrea: 29:35

I I don't think that we should be feeding staph aureus milk or milk with coagulase negative staph in it to kids. So when I see and I've experienced this in the dairies that I've worked with very closely, um, and that I still do work with, um, very intimate, like on a management level. If we have a pasture, so we have a pasteurizer, we heat treat colostrum, we have a pasteurizer. Um, if we have a breakdown in that system at any time we start seeing dolines freshening with high somatic cell counts. So we know that that those bacteria can enter the kid and they have a predisposition for the udder, and it will lead to dolines with uh mastitis issues. So I have gone away from feeding any staph aureus milk. I that needs to be dumped, but even the coagulase negative staph mastitis, the subclinical mastitis, even that milk is a risk for goats. So in herds where we feed heat-treated colostrum, uh, we are culturing that milk, and that's why having your own lab is nice because every batch needs to be cultured just to make sure that the pasteurization actually worked or the heat treatment worked if it's colostrum. I don't think I would ever recommend Staph aureus milk. And again, even with the acid treatment, it's too easy just to make a mistake, and those mistakes cost you so much more. You know, you think, oh, I'm saving money by feeding this milk, but that milk's actually not worth that much compared to the value of those replacement dolines. So ultimately, if you do the math and you really think it through, you only have to lose one doline to Staph aureus or to coag negative staff to pay for feeding a better quality product to those kids.

Michelle: 31:29

Well, we'll dig into this more at a later episode, but um, just as a teaser, I had to throw that in there. So um let's get back to talking about somatic cell counts. Um how often do you recommend doing somatic cell evaluations? I know if a herd was going to be on DHI test, they might test once every 30 or 45 days, some even do every 60 days. Um so what's your preferred interval for DHI test? And then uh what about with um your California mastitis method?

Andrea: 32:04

I think if you're going to be on a DHI testing program, you should be testing every 30 days. I think that that's important for milk production. I think that's important for somatic cell count monitoring. So I would recommend a 30-day, but of course it just varies farm to farm, and there's so many reasons why we do things that aren't ideal, but just because they need to be done that way. So, best case is 30 days, but I think 60 days is a long time, more just from a management standpoint. The herds that I work with closely are all on daily milk weights, so we don't use DHI testing, so we don't have access to that somatic cell count information. So that's the reason that CMT plus the um the on-farm culturing works. So, in herds where we aren't doing a monthly DHI test, what I recommend and what I do for my own herd is um within the first week of kidding, ideally by day three, we have a CMT sample on that dough. And we know um she's positive, we can treat her immediately and get it dealt with so she starts her lactation, you know, off to a good start, or she's negative and she just keeps going. So then if we sample a goat and we treat her, um it's important to keep in mind that the so the somatic cells in the milk, right? Somatic cell count remember, these are white blood cells. If you have a bacterial infection in that udder and you treat it with antibiotics, so we use intramammary um infusions, tubes that we can inject into the udder, it's not painful, but it you know will kill these bacteria, hopefully. Um, but if you want to follow up and check and see if the medicine you used actually was effective, you can't tell right away. So those white blood cells don't just disappear as soon as that bacterial infection is treated. It though they have to migrate back out of the udder essentially, or be milked out and stop having a reason to go into the udder, if this makes sense. So you we usually we wait four to six weeks after amastitis treatment to determine if the somatic cell has gone down, or if we're doing a CMT test, if the CMT is returned to normal. So if you do this bacterial antibacterial treatment with an antibiotic and you check your you have a DHI test or a CMT test a week later, that goat will still have a really high somatic cell count, and that's normal that it that you would expect that. So we do a follow-up treatment ideally six weeks, but sometimes four weeks, if that's where we're at, to see if that animal is either declining or is normal, so a negative on these tests. And then at that point, the only time that we're resampling during the lactation cycle is if a goat starts having an unbalanced udder, or if the milk is abnormal, of course. So if there's abnormal milk, it's bloody, there's clot-like chunks of call it gargot, anything abnormal about the milk, the utter half feels hot, those things are indications of an infection. But again, with subclinical mastitis, everything looks totally normal. So the the visual cue then is that the utter half starts to shrink on one side. And those animals should have an immediate CMT test. And then if it's positive, we can go on and again do our treatment or a culture to confirm that it's something that we do want to treat, that it's not staph aureus. But if it's not staph aureus and it's say coag negative staph, then that animal would be treated. Ideally, um, and it this only works in herds where we have good records and good animal ID and good management. Uh, but ideally, I really like to do a CMT when we get close to drying an animal off. So maybe within the last two weeks. And if that goat has a higher or an elevated CMT test and she's positive, then she would receive a selective dry treatment. And Michelle is doing a lot of great work on that, which is really exciting because she's going to bring us a lot of new knowledge that this industry really will benefit from. But that selective dry treatment is really beneficial in these cases. Um, it's just the management is really important so that when that dough freshens again, everybody knows she's going to have a milk residue and her milk has to be diverted for a set amount of time, and that colostrum should not be fed to kids. So it with good management, those are that's a great system, but it it requires, you know, people having a lot of systems in place ahead of time for their safety and the safety of the milk they're producing.

Michelle: 36:56

Thank you so much for that plug, Andrea. And I'm really excited to be able to share a little bit more about that research um later in this season. Um, but that was a great teaser. Um just as a follow-up on what you were mentioning with milk cultures. That's not something that I would expect a lot of uh uh non-commercial dairies to be really familiar with or comfortable with, but it does seem like an attainable goal, especially for dairies that are milking maybe a few hundred, um, and maybe even less if they're really motivated. Um so is there a resource besides your local veterinarian? Um, because that's always going to be our number one recommendation. Um, but are there courses maybe at local colleges or is there a national program where producers can become proficient at running milk cultures on site? Um and for those that aren't comfortable running their own cultures, um, where is a good place to look for sending uh milk samples for evaluation?

Andrea: 38:08

I have been so grateful and impressed with the University of Minnesota Diagnostic Lab. So they have done this, created this easy culture system. So they will they actually make the plates, the it's called auger, so this gel that's on the bottom of the uh plates that we're doing the milk samples with. They have impregnate, they they put the certain chemicals onto these plates so that all you have to do is swab, they sell the swabs, they sell the plates. Um, you just have to set swab the milk onto the plates, and then they have a nice booklet that shows you what you're looking for, so it's really user-friendly. You don't have to be a microbiologist. I will also I need to say that the National Mastitis Council has an excellent um you know user manual basically for interpreting um the microbiome the plates for reading these plates, and there's pictures, and so there's a there is a lot of really good support out there. Um, a lot of producers can go on eBay and find an incubator for really cheap. They are used incubators, they're small, they fit on a desktop or a countertop somewhere. So it does require, you know, some sanitation in terms of you don't want to do it in the barn. You need to have a clean place to store the plates in a refrigerator, you need to have the incubator in a clean room somewhere. But beyond that, it's not if you're big enough and you don't have access to a local place to run your milk samples to, then that's a really handy option. Again, as Michelle said, you know, your veterinarian, a large animal veterinarian should have access to. A milk culture lab. So if they're not doing it, somebody nearby is. And then your state diagnostic lab will always generally run milk samples. So you can reach out to your state diagnostic lab. You know, there'll be a website, you could just Google it for your state, and then if you call into submissions, they they'll be able to direct you to what to send and how to send it. So it there are a lot of resources actually out there once you know what to look for in terms of doing getting these cultures done. But culturing is really important, especially in the beginning when you're trying to figure out what your dairy what your dairy's footprint is. What do you have? What's your biggest problem? What are you struggling with? You know, do you have a lot of staph aureus? Do you just have a couple that you need to find? Do you have a lot of coagulase negative staph? All those things are going to help you develop the individual plan for your farm that works the best.

Michelle: 40:56

Certainly on-site cultures or cultures that are collected and sent in by clients are not meant to replace interactions with your veterinarian. Um, clients always need to have a good working relationship with their vet, a valid veterinary client-patient relationship needs to be in order. And and just as a reminder, that's going to get even more important next summer when um uh when it becomes a federal mandate that antimicrobials be used under the direct supervision of a veterinarian. So um it's helpful for clients to be independent in certain ways, and uh and certainly we don't want to waste anybody's time, the client or the vet, uh, by uh going out and making the vet collect uh cultures on every single goat that we think um could potentially have mastitis, especially in a herd of a couple hundred goats. Um, but it also can't be done completely independently. And so this is where there's a real synergy and an opportunity here for learning on both ends.

Andrea: 42:02

I really agree with that, Michelle. It's it it takes a really strong team to be successful on these operations, and so the more a dairyman can do to collect the information, the the more that they can save money there. But at the same time, like Michelle said, your your veterinarian is they're they're trained to they've had a lot of training in how to think about things and to come up with plans and understanding the bacteria process and the infection process. And so once you've collected all your information, you need to either talk to your veterinarian or find a veterinarian and say, This is what I have, where do we go from here? And and together then you can build something that works for you that they think will be effective in also solving your your issues.

Michelle: 42:51

And for producers that are having trouble finding a veterinarian, you can log on to the American Association of Small Ruminant Practitioners website, um AASRP.org, and there is a tab there for find a practitioner near me. And so you can utilize that resource to find someone near you who is interested in working on small ruminants and hopefully dairy goats specifically. So, Dr. Mongenie, um, to get back to kind of your process as a veterinarian, when you walk onto a dairy that let's say calls you out because they're having issues with their somatic cell count. Um it sounds like your first step is gonna be check the bulk tank, make sure that we don't have a staph aureus problem, and if you do, you need to chase that down numero uno. Um secondary is gonna be CMT testing um regularly and and identifying which goats are your higher uh somatic cell shedders and following that up with cultures to identify whether these are goats that we can uh potentially treat effectively with intramammary antibiotics or if they need to go on our do not breed um milk last and call list. Um kind of gotten things under control in those respects, how do you set goals for your individual producers?

Andrea: 44:22

Uh it is so individual, and it I mean, ultimately it comes down to economics, I think. So what are the benefits in terms of lost? How much how much do we have a lost milk issue just because we have a high somatic cell count issue? The next question would be what sort of a premium could we get from the creamery, and at what level? So some creameries just want you to be legal and they'll give you a bonus, and some creameries want you to be 750 million or 70,000, I'm sorry, and they'll give you a bonus. And so how much work is it going to be to get to a place, and what would the bonus be? Um I I do think that striving for a low somatic cell is important, but what I have found is in some cases it's we're we have so much to do to get there that um if you if if a dairy is really at a place of just barely being legal, which is not uncommon, especially if a dairy is not uh milking year-round and milking having a lot of milk throughs, which again could be partly it's partly nutritional and probably partly genetics, but also partly a milk quality issue, a somatic cell count issue. Uh, in those settings in the fall, we have a lot of goats going dry, and we can get we can go from 800 in April to 1.8 million in October, and that becomes a problem. And so those herds then that become very cyclical in their milk production also become very cyclical in their somatic cell count. And that's important as a producer and as a veterinarian when you're walking onto a farm is to think, well, what time of year is it? What season is it? Because in the fall we're going to always have higher somatic cell counts. Um, what is the stage of lactation of the herd? So did they just if you know there's a lot of herds, even you know, some of the ones that I work with, where we kid heavily in September because we get a bonus on winter milk. So we only kid once a year, but we only kid in the fall. So that means we have a lot of fresh goats. We don't have a lot of goats going dry. And if we have a high somatic cell count, then that means something different than if we have a lot of goats going dry in the fall and our herd's going to go completely dry. So it does make a difference in terms of what the stage of lactation of the herd is and the time of year. And I think then that that then helps me determine what we're trying to do. If we have a lot of goats going dry, we might want to CMT those goats and then do some selective dry treatments and then just dry them early and get us back down into a better place. And sometimes that's what we do, or we'll dry halves on goats that we know are a problem and just figure we'll dry treat them when they go dry and we'll deal with it later. Um, because in a lot of settings we just don't have the resources to really attack this. And you know, I've worked with plenty of herds where we've done the CMT and they're milking 1500 goats and they have 200 doughs that are high somatic cell count, and we can't pull those goats out of the milk string all at once and treat them. There's no hospital big enough, they can't afford the lost milk. So the strategies really are dependent on the individual herd.

Michelle: 47:50

So obviously, a lot of our troubleshooting is going to be very specific, but um are there some general common areas that um that tend to show up as problem areas and and things that maybe um veterinarians and producers who are dealing with a somatic cell problem should investigate first um when they're finding high cell counts on a goat dairy.

Andrea: 48:19

I really like to go look in the barn and try and watch the milkers um and look at T den quality. So when we it's not uncommon, um you know, in cow dairies we have, I would say 100%, but 99% of cow dairies we have automatic takeoffs. So machine gets put on by a milker, uh, there's a sensor in the line, and then when the milk gets low enough, that sensor pulls the machine off. And we know from cow dairies that if those auto-takeoffs are set wrong, then uh we can over milk the cow, and that T den damage sets the cow up for mastitis, which leads to a high somatic cell count. So with goats, we're working a word backwards, we're looking for a high somatic cell count to find the mastitis because most of these goats aren't showing signs of mastitis. But it's the same premise. So if we go into a barn, I want to look at T den quality, I want to see if there's signs of over milking. Oftentimes there are because we're not using auto-takeoffs very often. And so, in a lot of settings, the milkers are putting a lot of machines on and then just getting back to taking machines off whenever they get there, and that over milking can really damage the dose, and and that sets them up for definitely for mastitis problems. One thing to keep in mind with goats is that they let their milk down in waves, whereas cows really have a big milk letdown where the bulk of the milk is released from the udder and then it's milked out. And goats will have four to five letdowns, so she could let her milk down coming into the barn, and then if she's stressed in the barn, or say the vacuum levels are wrong, or the liners aren't fitting right, or there's fear, you know, there's a milker that's aggressive, or a dog, she could hold her milk halfway through the milking and actually be over milked in the middle of the milk process, if that makes sense. So, really watching goat flow and flow of animals through the barn and stress levels, looking at T dens when the machines come off. I also have found that a lot of goat dairies don't count the number of milkings on a liner, so they're changing the liners every six months, and if you do the math, it should be every three and a half months. And that damaged liner can do a lot of damage to a T den. So that the milk barn is the first place to start, I think, for producers and veterinarians.

Michelle: 50:50

Fantastic. Well, I think you've given us a lot to think about today with how do we know if there's a somatic cell issue that's affecting milk quality, and then how do we follow up on that? So I think it's about time to call it a day. Um I really appreciate all of your time and your insights today. And uh I'm gonna be including in the show notes some of the links that you've mentioned, um, like the uh National Mastitis Council plate interpretation page and also the University of Minnesota Diagnostic Lab Easy Culture System. So if folks want to know more about those and how to order them uh or learn more about those, they can find them in our show notes. And of course, if people have more specific questions, they're welcome to email us at dairycoat extension at iastate.edu. Um Dr. Mangini, thank you so much for the taking the time to chat with us today. And I hope we can get you back on here soon.

Andrea: 51:51

Yeah, thank you, Michelle. It was great seeing you today.