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Hosted by members of the University of Minnesota Extension Beef and Dairy Teams, The Moos Room discusses relevant topics to help beef and dairy producers be more successful. The information is evidence-based and presented as an informal conversation between the hosts and guests.
Welcome to the Moo's Room. Today, I'm actually in Milwaukee, Wisconsin, attending the American Dairy Science Association. So it's a research meeting where a lot of us researchers in dairy from nutrition and genetics and repro and dairy foods all get together one time a year and kind of share our research and talk about research and so it's a three-day conference.
I hope to learn a lot here this week, and I'll probably talk about some of the things that I learn next week and what are some of the new hot things that are happening in the dairy research world that might be interesting to people or producers. And so today I wanted to share at least a couple of things that I'm gonna talk about there.
And one is on genetics of somatic cell count and its relationship to mastitis in dairy herds, 'cause mastitis is always on my mind. It's always a challenge, especially for our pasture-based herd. If I look at the somatic cell count of our organic herd right now, we're running-- It's kind of a, been all over the board from two fifty to three sixty in the last month.
Early May, we had a couple jumps to four hundred, four fifty, a couple pickups. So it's been kind of all over the board, and a lot of this has to do with some of the rain that's been happening here in western Minnesota. We've had a lot of rain. You know, early on, I think I had talked about it being almost a drought here.
We hadn't had any rain. Pastures were slowing down. They weren't growing really well. But now, all of a sudden, we have all of this rain. We just got done with first cutting alfalfa this past week, so June seventeenth we were just done with first cutting, so it was delayed because we had all of this rain.
There were a couple days we had four inches of rain, standing water in field. So it's been kinda wild, and that's certainly been a detriment to our somatic cell count. If I look at the last pickup here, we're running three sixty. So it's been quite the challenge, uh, in dealing with that. Our conventional herd, which is a little bit more confined, they're outside.
I guess I should say that the organic herd has been on pasture, and they've been in the barn as well, eating some TMR. And it's a compost barn, and a compost barn has always been challenging, especially for us with lowering somatic cell count. We've always had some cows that just don't do well. I think we had an E.
coli mastitis in a cow the other day, so it's probably related somewhat to the barn conditions that they're in, and I just don't like it, but it is what it is. We're trying to get repro back in the organic herd because we've gone 100% grass in the past, and I think our repro has suffered. And so we're trying to keep the nutrition up and, and manage those cows so we can keep maybe growing the herd.
But our conventional herd, we're averaging about 200 somatic cell count. Sometimes it jumps to 240, but for the most part, the last couple months we've been around 220. So it's been pretty good actually. So I was interested in somatic cell count and PTAs for mastitis, so I decided to look at cows in the US.
So comparing their genetic merit for mastitis and their relationship to somatic cell score. So that was the goal. So I got a lot of DHI records from DRMS, so that's the dairy processor in the eastern US, but they process herds all over the United States. So this data was from 30 states, and I looked at years of 2018 to 2024.
So I had 150,000 plus lactation records. So I had-- I kind of kept it separate. So I had about 70,000 Holstein cows, 15,000 Jersey cows, and about 12,000 cross-bred cows. So I wanted to look at the relationship of somatic cell count and what we saw So what did I find? Well, if I look at the average cell count by breed Holstein 155, Jersey 147.
So actually, the Jerseys, at least in this data set, had lowest. And the crossbreds were about 184,000. So actually all pretty good, less than 200,000. So, you know, minute differences. I don't know if there's anything to write home about that the Jerseys are lower, 147 compared to 155, but they're all quite low.
So then I had PTAs for all these animals, so genetic values for PTA for mastitis from CDCB, and then I had PTAs for somatic cell score from these cows, and then I had the lactation average somatic cell count. So the average that they had for their DHI tests compared to their genetic values. Well, if I look at PTAs for mastitis by breed, so the average PTA for Holsteins was minus 0.46, crossbreds minus 0.16.
So that means that on average, th-they were lower. The Holsteins were the lowest for PTA for mastitis, so that's a good thing because the lower the PTA, the lower the chances of having clinical mastitis. On the other hand, the Jersey cows had higher PTA mastitis, 0.88, so they were positive, so which means on average those Jersey cows have a higher risk of having mastitis because they have a higher PTA for mastitis.
So the highest of all of the breeds. The other two breeds lower, Jerseys was positive. Well, what about- PTAs for somatic cell count
Well, what about the correlation between PTAs for somatic cell score and lactation average somatic cell count? All kind of moderate to high, so Holstein Jersey crossbreds right around .3 to .4, which means that there's an association between PTA for somatic cell score, so genetic value for somatic cell score compared to their actual lactation average
And then I also wanted to see what-- if there was any correlation between this PTA for mastitis and lactation average somatic cell count. Well, they were kind of low to weak. So, you know, Jersey .01, crossbred minus .02, Holstein minus .12. So they were kind of weak, so not really a strong association between PTAs for mastitis and lactation average somatic cell count So here are kind of the, the high points, the, the take-home points, I guess.
So these genomic predictions for somatic cell score were really generally effective at ranking cows for somatic cell count in herds, and the associations between PTA for somatic cell score and lactation average SCC from DHI were moderate and positive across the breeds. The correlations between PTA for mastitis and somatic cell count were weak, which really indicated a limited association with subclinical somatic cell count.
And of course, the Jerseys had higher
And the Jerseys had lower SCC and higher PTA for mastitis than Holstein cows, whereas the crossbreds kind of had a little bit higher somatic cell count, but not much higher than all So what's the key take home message of this little study that I did to try to see what was going on with somatic cell count or PTA for mastitis?
Well, in these dairy herds, the genomic predictions for somatic cell score align more closely with the observed somatic cell score from DHIA, from milk recording, than PTA for mastitis. So that means that the PTA for somatic cell score is probably a more useful tool to rank cows on somatic cell count than genomic predictions for clinical mastitis resistance.
And we know this, the, the heritability is a little bit higher for somatic cell score than PTA for mastitis, and PTA for mastitis comes in from producer-recorded clinical cases. So if producers aren't recording it, it's not really going into the data, so the predictions probably aren't quite as good from PTA for mastitis just because of incomplete data and, and poor data recording So it was kind of interesting to see what was happening there in, in those herds Well then I also was curious, so I've been kind of working on some heifer feed intake and Isaac Hagen here at Minnesota, and I have a graduate student that's been working on heifer feed intake in Holsteins And maybe we'll talk about that at a, a, a different day.
He's getting close to finishing his master's project, and we'll talk about some of those relationships that we've seen in a future episode. But I've been doing some of that here in Morris as well, looking at feed intake and comparing it to methane emissions and behavioral, um, m- emissions and behavior from sensors.
So this little study I, I had small number of cows, so is there a lot to write home about? No, but it's kind of an interesting little first study. We're gonna try to do more of this with the heifers and so we really had, we had eight Holsteins, 10 of our Normandy Jersey Viking Red crossbreds, and 16 of our Montbeliard Viking Red Holstein crossbreds.
And so we had methane, carbon dioxide, and other emissions from these cows. We had them on precision feeders, so smart feeds from Sealock, so that measures intake every time they go to the feed bunk. And then we also had CowManager sensor data on these animals. So I had about 800 green feed, so methane emissions, and about 800 feed intake records from these animals And quite a few bunk observations, so about 1,200 observations from the bunk.
So it's just kind of looking at precision feeding and see what, what we could find. Well, if I look at it, so daily feed intake on these animals From a dry matter basis, so Holstein about 8.6. This is kilos per day, so a little over 18 pounds of dry matter
7 for the Gray's Cross and 9.1 for the Pro Cross. So The graze cross, the smaller ones, so Jersey, Normandy, Viking Red consumed the least amount of feed, and the Holstein and the other procross about the same
And I should say these were about yearling heifers, so most yearling heifers are gonna consume somewhere in that six to eight kilos per day. So these were pretty close to average what, what we would see maybe a little bit more for some of the crossbreds. Now these animals, they weren't on a restricted diet, so they could eat as much as what they want, so maybe they ate more than what they should have because after I, I did this study for a few months and then I looked at them and go, "Ooh, there's, uh, some crossbreds and even a few Holsteins that are carrying a little bit more weight than what they should have."
So sometimes these feeding experiments, it's hard to control. I don't have that precise feed intakes where it limits animals, so they can eat as much as what they want. So if I look at methane emissions, our ProCROSS heifers had the highest total, not statistically different, but they were at two twenty two compared to the Holsteins one ninety, so not much difference there.
So if you think about it from our cow perspective, these methane emissions in our heifers are about half as much as what a cow does. So cows four fifty, that's about what we're running here in Morris. So about half as much, maybe a little more than half the methane emissions And if I look at carbon dioxide, our graze cross, crossbred, so the Normandy Jerseys had less carbon dioxide emissions than Holsteins and, and the ProCross were about the same.
So if I look at it from a methane per kilogram of dry matter intake, they didn't really differ between the breeds You know, Holstein numerically was the lowest, 23 compared to the ProCross 25 and the Grace Cross 26. So all about the same from a methane per kilogram output. If I look at eating behavior from sensors, rumination, no difference, all about the same.
So they're ruminating about 400 minutes per day.
So that's about six and a half hours roughly for those animals' eating behavior The Holsteins were the highest, two hundred and forty-four minutes. The ProCross were the least, so they had the lowest sensor classified eating time, hundred and seventy-six minutes. So there was a definite difference in sensor behavior for eating.
Holsteins were more, so the ... which was indi-indicative maybe of the Holsteins eating a little bit more. And activity level was about the same. Maybe the ProCross were a little bit more active. So I looked at feeding behavior, bunk visits, and what we could find. Well, higher intake of animals was associated with longer bunk duration.
So obviously, if you're in the bunk longer, you're gonna eat more, so that was ... It's not rocket science. There was a small positive relationship in rumination with intake, so as rumination goes up, intake maybe went up. Activity, higher intake with more activity, so the animals that were more active had higher intakes, which would make sense
And visit frequency, if I look at duration, so more visits meant shorter visit duration. So these animals were coming up quite often, and I saw a lot of them. There was some bullies in the crowd, and they'd bully the other ones out of these feed bunks. And so there's just a lot of other things going on here.
If I average bunk visits per day, most of these heifers were averaging about forty-seven visits per day to these precision bunks, so that's a lot. So it records every time they come into this bunk, so they're in there a lot. So there's just a lot of activity going on. Bunk duration, minutes per day, about a hundred minutes per day, so they're spending maybe an hour and a half per day in the bunk eating
So it's kind of interesting, you know, we saw maybe a few differences in methane emissions. We see a little bit of differences in bunk visits and feed intake of these animals, and I think that's important as well. Even, you know, we don't really know what feed intake is of these animals and may give an indication.
Obviously, we would expect breeds to be different in feed intake, and maybe we don't need to feed them as much, especially if we had them separately. Whereas our grays cross crossbred, so our Jersey Normandy Viking Reds, they ate about two kilos less, so four to five pounds less than some of the other crossbreds.
So that four to five pounds, that can be a lot of feed across a, a long time period. So kind of an interesting little study that we did just to see what was happening there from a feed intake perspective
So there's lots of things happening here at our research center. There's kind of two of the studies. You know, I continue to do virtual fencing. That's kind of an interesting thing that's going on. I won't talk much about that. I'll save that for another day, but we see a lot of differences in, in animals.
There's a couple outliers that just love to get audio cues and not behave the fence, so that's kind of interesting. But anyways, I wanted to give a little perspective about what's happening here at our research station on some of the studies that we did, and hopefully you learned a little bit today about what's happening in somatic cell count and heifer feed efficiency.
So with that, I think I'll leave you today and I'll get back to my conference. And if you have any comments, questions, scathing rebuttals, feel free to contact me at The Moose Room. That's T-H-E-M-O-O-S-R-O-O-M @umn.edu, or find us on the web, University of Minnesota Livestock Extension, or UMN WCROC Dairy. And with that, I hope you have a great week.
Bye.