00;00;11;03 - 00;00;40;23 Brad And welcome to The Moos Room. Brad here again? It's almost spring here. Well, it's March, but the weather is trying to decide whether it wants to be winter yet, or it wants to be spring. We keep having these weather fluctuations up and down. Some days it's very cold. The next day it's 40, 50 degrees out here in Minnesota. So we're kind of into that winter spring time, which is getting exciting. 00;00;40;23 - 00;01;04;09 Brad I can't wait for cows to go out on pasture, albeit it's probably a couple months yet, but that's going to go by pretty fast anyways. I wanted to talk about some of the research that we've been working on with a group of scientists here in the US looking at mastitis and somatic cell counts. And for the most part, this data is really focused on some organic dairy herds in the US. 00;01;04;09 - 00;01;27;20 Brad And we've gotten a lot of DHEA data. So this is a lot of information from lots of different farms. And we'll kind of go through it here and look at what cow levels or farm level factors are affecting somatic cell count. So the study was done by Constanza Hernandez Cattell. And she's a PhD student with Pablo Pena Nieto at Colorado State. 00;01;27;20 - 00;01;52;06 Brad So this group was the lead on this. But we've all kind of worked together on this project, and there's probably going to be a lot more coming out from this project on mastitis. And I have a few papers and a few studies that I've looked at here myself, looking at sires and mastitis and but I kind of wanted to go through this one today because I think it provides some kind of interesting information. 00;01;52;06 - 00;02;26;09 Brad So the study looks at cow and farm level factors that affect somatic cell count in organic dairy herds. And why is this important? Well, it's certainly driven by consumer demand for sustainability and animal welfare. You know, the US organic dairy industry has seen an increase about 50% in farms and about 65 and 65% increase in cow numbers from 2008 to 2019. 00;02;26;09 - 00;02;54;12 Brad So that is increasing. And for those of you out here, if you think about milk price kind of as a side tangent, I looked at our conventional milk price 1680, our organic milk price right now, $40.80. So more than double the milk price of the conventional dairy world. Anyways, alas, back to the study. But there's a lot of health management challenges. 00;02;54;14 - 00;03;23;00 Brad You know, in organics. The standards prohibit antimicrobials. Farmers must find alternative ways to manage mastitis. And this is obviously the most frequent and expensive disease in the dairy industry. It doesn't matter if you're a conventional herd or if you're an organic herd. By far the most costly disease, there's some herd dynamics in the US. Organic herds typically differ from conventional ones. 00;03;23;00 - 00;03;56;17 Brad They often feature more crossbred cows. So there are Holstein herds, but there's certainly a lot more crossbred cows. They have a lot older animals, cows with greater lactation, and they have a higher age at first calving. And the role of somatic cell count kind of remains the primary metric for milk quality and subclinical mastitis in these herds. And how high somatic cell count is directly linked to milk yield loss and economic stability. 00;03;56;24 - 00;04;27;25 Brad So really, this research was to kind of fill a knowledge gap, really, regarding how somatic cell count fluctuates within organic dairy herds specifically. And that was kind of the goal of this research study. In these organic herds, it can be a challenge to manage without antibiotics. Obviously, it's a tool that conventional dairy herds use for treating clinical mastitis and preventing new infections at drift. 00;04;27;27 - 00;04;57;26 Brad But we can't really use those in the organic world because of a strict ban on antimicrobials or antibiotics. There is a huge economic threat that we see, and really the only way to kind of manage that in organic herds is looking at somatic cell count, whether in the bulk tank or whether from individual cows. We got dairy records from all over the United States. 00;04;57;26 - 00;05;33;27 Brad So we went to dairy records management Service in North Carolina. So that's the dry processing center in North Carolina, includes a lot of dairy herds within, mostly in the East Coast, but a lot of herds in the West. In the Midwest, there were over 2 million DHB test day record. So we looked at individual cow milk records. There were 160,000 cows that we looked at, over 300,000 unique lactation. 00;05;33;27 - 00;06;02;12 Brad So that's a lot of data that we looked at for these cows. And this was really on 430 organic farms in 31 states. So kind of a national level study and really the data spanned from 2018 to 2025. So we had seven years of data on all of these cows from a lot of farms in the US. We kind of broke things out. 00;06;02;12 - 00;06;23;25 Brad You know, we had Midwest, the South, the West and the East Coast. So what are some things that we looked at to try and determine some of these somatic cell dynamics in these herds? Well, we had cow level factors. So we looked at age of cows and lactation number. We looked at the lactation stage. So that's days and milk. 00;06;23;25 - 00;06;44;13 Brad So we looked at across the whole lactation of these cows. We looked at genetics for the most part in this study will be hosting Jersey and crossbred. So we looked at milk yield. And then we had some of these extrinsic factors. So farm factors environmental factors that we looked at with climate. So seasonality and heat we had geographies. 00;06;44;13 - 00;07;17;23 Brad So that's the region of the country. And then we looked at management scale. So herd size to determine what is happening in in these herds. So really what did we find. If you look at age or lactation number those somatic cell count consistently increased with successive lactation. So that means cows. As cows got older they had higher somatic cell count and older cows had a drastic decline in the lowest somatic cell count category. 00;07;18;00 - 00;07;48;09 Brad So a lot of older cows had much higher somatic cell counts. And we're talking 500,000 plus all of the older cows. Just high somatic cell count. So why does this happen in organic systems. Well you have cumulative exposure. So prolonged exposure to infectious agents over multiple years. You know these cows are just around a lot longer. So they're exposed to the environment much more in somatic cell count goes higher. 00;07;48;11 - 00;08;29;10 Brad What about chronic infections. So without antibiotic dry cow therapy to sort of clear some of these infections that may happen between lactation kind of in the dry off these chronic issues persist. So we see chronic cows quite possibly because of no dry cow therapy. I think that's debatable. But sometimes it does help clear some of those chronic infections between lactation and kind of what we call functional, where a dysregulated immune response linked to metabolic stress and where of the mammary gland over time. 00;08;29;12 - 00;09;01;23 Brad So it's just really age, you know, as these cows got older, the immune response goes down. They have increased metabolic stress at many different times throughout the lactation. And so it causes increased somatic cell count. So what about the lactation curve was kind of interesting. And we see some of these things in conventional dairy herds as well. So we see this huge spike an early spike in somatic cell count from 0 to 30 days. 00;09;01;23 - 00;09;28;00 Brad And milk that is the highest incidence of severe somatic cell count immediately after calving. And then it goes down so about from 31 to 100 days in milk. Somatic cell count kind of hits the lowest point during the lactation, kind of right when peak milk production is happening. But then it gradually increases as you get closer to dry off. 00;09;28;02 - 00;09;52;18 Brad So 200 plus days in milk, somatic cell count goes up again. So we sort of deemed some of this for from the no dry cow therapy effect. So without antibiotics the prior dry off cows are highly susceptible to new infections that kind of manifest early in that new lactation. Some of this is management. We see this in our herd here at Morris. 00;09;52;20 - 00;10;20;06 Brad A lot of mastitis in the early part of lactation. Could that be due to management, the conditions that these cows are in? You know, most organic cows tend to be outside. They're not housed in barns, so they're probably exposed more to those environmental conditions. And we we don't use antibiotics dry off. So the cows that maybe are chronic or have high somatic cell count at the end of lactation, well, kind of carries through to the beginning of lactation as well. 00;10;20;08 - 00;10;49;26 Brad You know, those cows just don't have a chance to clear those infections. And, you know, we're working on some of those things from an alternative perspective to see if we can help with dry cow mastitis. So what about milk production in breed. So really there's a stark inverse relationship between milk production and somatic cell count. Cows that had the lowest milk yield had the highest somatic cell count through the entire lactation. 00;10;49;26 - 00;11;15;10 Brad So if you had low milk production, you tended to have higher somatic cell counts in the cows with really high yield, low somatic cell count. It's kind of maybe the dilution effect. We call it the dilution effect. You know, higher milk production naturally dilute somatic cell count across a greater volume of fluid milk, which kind of results in lower somatic cell count in cows, medium yield cows. 00;11;15;10 - 00;11;42;04 Brad We're kind of in the middle. But again low production cows higher somatic cell count. And we looked at if you look at the log scores we're talking log scores of five and greater. If you have low low milk production. Well what about breed. Well the Holstein breeds genetic predisposition for higher milk yield kind of provides that structural buffer effect against elevated somatic cell count. 00;11;42;10 - 00;12;06;17 Brad So we see lower somatic cell count in Holstein cows. And we see that in many different instances 30 days in milk. Again the Holstein cows had the lowest somatic cell count if you look across the years. So January to December Holsteins were lower, the lowest breed across somatic cell count log somatic cell score about 4.4 average across the. 00;12;06;20 - 00;12;35;19 Brad The season jerseys were about 4.7. And if cross breads were in there, maybe ticked up a little bit to 4.8 somatic cells score across the time period. But again, Holsteins by far had the lowest somatic cell count compared to the other breeds. So what about seasonality? We think about seasonality. So January through December. And this is across you know all parts of the US. 00;12;35;20 - 00;13;04;02 Brad You know we have a wide range of climates from hot in the South, winter in the north, kind of get hot weather here in the summertime. But there are certain seasonal shifts that dramatically disrupt other health. So kind of during the hot season, May to September, the odds of elevated somatic cell count increase by almost one and a half compared to the cold season. 00;13;04;02 - 00;13;32;15 Brad So what is the hottest month for somatic cell count? August? July 2nd September 3rd. So August kind of had that maximum frequency of somatic cell count in these herds. So if I look at somatic cell count in the hot summertime you see a little bit of a spike. You know, if you think about the Midwest where we're located, you see an increase June, July and August certainly goes up. 00;13;32;21 - 00;13;52;28 Brad You kind of see that in all of them. It probably increases a lot more in the South during the summer months than what you would here in maybe the Midwest or the northeast, the Midwest and the northeast. Low, somewhat lower somatic cell counts during the hot summer months, we think about the hot. It's kind of a dual threat. 00;13;52;28 - 00;14;39;10 Brad Lots of pathogens. These warm, humid conditions accelerate the growth of environmental mastitis. And we kind of have some immunosuppression going on. So heat stress physically impairs cow what we call leukocyte function. So it reduces the viability of immune cells in milk and weakens the memory defenses. So in the summertime the hottest months for somatic cell count August and so farms in the southern United States had three times higher elevated somatic cell count compared to the Midwest and of the Midwest, really maintain the lowest somatic cell count throughout the year. 00;14;39;13 - 00;15;07;25 Brad And if you if we look at somatic cell count across those, like I said before, log somatic cell count across the year a little over four for the Midwest. The northeast was about 4.3 in the West, 4.6 in the South, 4.8. So log somatic cell count from the Midwest 4.1 compared to 4.8 in the South. So the South definitely has higher somatic cell count. 00;15;07;28 - 00;15;41;08 Brad And you kind of have this grazing complication with all of this. So US organic regulations require grazing. And in the southern regions kind of fulfilling pasture days during the hot season really exposes cows to prolonged temperature, humidity index extremes. So it exacerbates immunosuppression in these cows contributing to the higher somatic cell count. So heat stress is really probably one of the biggest factors causing somatic cell count in cows, especially in the South. 00;15;41;10 - 00;16;08;14 Brad And we see that here in the Midwest as well. I can definitely tell when it gets hot in the Midwest. August somatic cell counts increase. We see it in most herds across the US. It just happens that way. Maybe not quite as extreme increase in the Midwest, in the northeast, but definitely we're seeing increased somatic cell count because of heat stress. 00;16;08;16 - 00;16;41;25 Brad So what about herd size? Well, farm size directly correlates with increased somatic cell count severity. So while large farms often possess more capital, they kind of have a maybe a distinct disadvantage at scale. So our baseline was 50 cows. So if you if you have 5150 to 100 cows, you have 1.2 times higher odds of having elevated somatic cell count. 00;16;41;28 - 00;17;10;26 Brad You have 100 cows to 500 cows two times higher odds of having elevated somatic cell count compared to less than 50 cows. And if you have more than 500 cows, we have 3.2 greater odds of having elevated somatic cell count compared to those herds that are less than 50 cows. So the highest somatic cell count categories are most heavily concentrated in herds greater than 500 cows. 00;17;10;28 - 00;17;37;03 Brad And we really attribute this risk to increased risk of pathogen transmission during milking routines in large scale parlor operations, where more quarters are exposed sequentially. So that really comes down to milking procedure and everything that we can sort of manage in the milking parlor to reduce somatic cell count. There's no we see this in in a lot of herds. 00;17;37;05 - 00;18;05;08 Brad So at least in this study, over 400 organic dairy herds, the larger herds had higher somatic cell count. And it was more than likely caused in the milking parlor. So kind of a trend over time if you look at this data over time. So we if you kind of look at the last three years of this data set, when it kind of stabilized, it kind of reveals challenges of heat and scale. 00;18;05;08 - 00;18;34;09 Brad They're kind of compounding. They're not stabilizing. So what about the size of highest somatic cell categories increased in large herds? We see this from 2022 to 2025. The frequency of high somatic cell count is only increasing in large herds. We also see this increasing in herds in the south and the West. In the last 3 to 4 years. 00;18;34;09 - 00;19;05;10 Brad So somatic cell count is going up in these dairy herds, larger herds and herds in the south. In the West, however, these medium sized herds tend to be decreasing. So those are herds from 100 cows to 500 cows. So they're successfully decreasing somatic cell count in those herds. So it's kind of an interesting find that we have. So the larger herds are increasing somatic cell count which is kind of counterintuitive what we see in the conventional dairy world. 00;19;05;10 - 00;19;33;09 Brad And then we know that herds in the South and the West are mostly because of heat stress, having higher somatic cell count. So kind of the organic perfect storm here. So elevated somatic cell count in organic dairies is rarely one single thing. It's kind of a lot of many overlapping risk factors that kind of offset the natural defenses of a cow. 00;19;33;11 - 00;20;05;26 Brad So you have this lack of antibiotic dry cow therapy. So that leaves older cows and early lactation cows more susceptible to somatic cell count and clinical mastitis. You kind of have this genetic yield disadvantage. So lower yielding breeds lack the milk production. To dilute the elevated cell counts you have environmental stress. So prolonged summer heat stress during the mandatory grazing window suppresses immune function. 00;20;05;28 - 00;20;34;14 Brad You have this scale. So massive parlor operations greater than 500 cows act as rapid transmission vectors for resulting pathogens. So all of that you have maximum somatic cell count risk. So what are some things that organic dairy herds can do to minimize this. So what are some strategies that can happen. So we want to target early lactation intervention. 00;20;34;15 - 00;21;01;27 Brad So obviously we said that 0 to 30 days in milk is the highest risk period. And because antibiotics are banned. So we can't focus on that. Farms must develop rigorous non antibiotic preventative measures probably pre calving looking at the calving pens, paying special attention to management cleanliness looking at the older cows. You know we said older cows have higher somatic cell count. 00;21;02;04 - 00;21;25;00 Brad So maybe maybe it's time to cull some of those cows if they have chronic mastitis. So really looking at those cows, being able to monitor them right away from early lactation is probably the best defense. You know, there's some things that are out there. We can use a lot of different natural products in the organic world. There's maybe some natural mastitis treatments that are out there. 00;21;25;00 - 00;21;51;22 Brad Sometimes they work, sometimes they don't. But I think trying to develop some more of these strategies, and it's not going to be a one strategy fits all, but we have to target early lactation interventions in the early part of lactation to help with these problems. So what about heat abatement. So heat abatement is kind of non-negotiable. So seasonal heat stress is the single largest multiplier of somatic cell count. 00;21;51;24 - 00;22;18;08 Brad We know that southern herds and those with heavy summer grazing requirements they must invest in aggressive heat abatement. So shade cooling those are probably the two things. So if your cows are on pasture, somehow they have to have shade either shade structures that we buy trees, they can be in the barn. If you have a barn during the hot parts of the day, maybe you put them in the barn and you graze at night. 00;22;18;08 - 00;22;42;04 Brad So. But we need to have heat stress. And this is for organic curds. We need to have heat stress abatement for conventional dairy herds as well. We see this in conventional dairy herds too, but definitely trying to figure out how to have less heat stress in your cows shade and cooling. And then if we talk about scale. So it really requires hyper vigilance. 00;22;42;07 - 00;23;18;12 Brad So for herds that exceed 500 cows the scale is certainly a liability for other health. So so these large operations they must implement flawless milking hygiene to offset the increased pathogen transmission in really high throughput parlor. So paying attention to milking routine cleanliness, making sure employees are adequately covering teats with teat dip, getting those udders clean probably is the number one thing to help lower somatic cell count in larger herds. 00;23;18;15 - 00;23;43;21 Brad So kind of in the end, there's many drivers of somatic cell count. So we have the dynamics are multifactorial. So somatic cell count in organic systems is not really driven by a single issue. It's complex. It involves cow physiology herd management and regional climate conditions. What about cow level factors as well. Cows that are higher have higher lactation. 00;23;43;24 - 00;24;20;14 Brad So older cows cows that are within 30 days of milk and the lower yielding cows are probably the more biological drivers of high somatic cell count. Holsteins consistently maintain the lowest somatic cell count really because of dilution effect and environmental and scale multiplier. So obviously external environment heavily exacerbates somatic cell count. Hot summer season. Specifically in August, farms in the South and large dairy herds increase the odds of severe somatic cell count. 00;24;20;14 - 00;24;45;05 Brad Okay, with that, I hope you learned a little bit about managing somatic cell count and a little bit about what's happening in organic dairy herds across the US and related to cow level factors and heat stress and you name it. I think there's a lot of opportunity out there, a lot of opportunity for for everybody in the dairy industry to sort of lower somatic cell count in their herds. 00;24;45;07 - 00;25;08;12 Brad So with that, if you have any comments, questions, scaling rebuttals, feel free to contact me at the Moos room. That's tag o s r o m at n edu or find us on the web. University of Minnesota Livestock Extension, or find us on the web U of M or OC Organic Dairy. And with that, I hope you have a good week.