For the Love of Goats

Squamous Cell Carcinoma in Nigerian Dwarf Goats

July 28, 2021 Deborah Niemann Episode 53
For the Love of Goats
Squamous Cell Carcinoma in Nigerian Dwarf Goats
Show Notes Transcript

After writing about our experience when one of our does had squamous cell carcinoma, I've been contacted by quite a few other goat owners who have had a goat that also had that form of skin cancer.

But Mary Brennan really got my attention when she emailed and told me she has had six goats with confirmed squamous cell carcinoma! She noticed that some of the goats were related, which caused her to dive deep into the history of the Nigerian dwarf breed, as well as skin cancer in other species. Ultimately that led her to a researcher at the University of California at Davis, who is now collecting data to study the potential role that genetics might play in this deadly disease.

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Introduction  0:03 
For the love of goats! We are talking about everything goat. Whether you're a goat owner, a breeder, or just a fan of these wonderful creatures, we've got you covered. And now, here is Deborah Niemann.

Deborah Niemann  0:18 
Hello, everyone, and welcome to another episode. Today, I am talking to Mary Brennan of Herron Hill Dairy in Western Washington. And, we are not going to be talking about her Grade A dairy that she used to have. Instead, we are actually going to be talking about squamous cell carcinoma, which is a type of skin cancer that I've experienced in one of my goats in my herd. And that story is on my website; we'll have a link to that in the show notes. Mary, however, has been raising Nigerian Dwarfs since 2003 and LaManchas since 2000. And, in her Nigerian herd, she has had six cases of squamous cell carcinoma. And so she's going to talk about her experience today, and we're also going to talk about some research that is being conducted right now at University of California, Davis to see if there's a genetic link within the Nigerian breed for this particular type of skin cancer. So, welcome to the show today, Mary!

Mary Brennan  1:20 
Yeah, hi! Thanks, Deborah, great to talk to you.

Deborah Niemann  1:23 
Yeah, it's really great to talk to you, too. I know when my goat had it, we thought she had some kind of a skin infection around her rectum. My vet didn't even know what it was. And ultimately, I figured out what it was after she died when I was at a conference, and a vet showed a picture of squamous cell carcinoma, and I just about fainted when I saw it because it looked exactly like what my goat had experienced. Can you tell us a little bit about what happened with your goats? And, like, the first time or two that you had one with squamous cell carcinoma?

Mary Brennan  2:00 
Yeah, well, in a lot of ways, it's very similar to what you're describing. I had three of the first Nigerian does that I bought ended up developing SCC—squamous cell carcinoma. And the first one, of course, I had no idea what was going on. And the vet didn't, either. I took her to a local vet, and first he thought she had some kind of infection, some kind of post-kidding infection, which was treated with antibiotics. And, it didn't go away, and he couldn't really figure out what was going on. So, I started to get a little frustrated. And I went a little further afield to more of a livestock vet, and he looked at it right away and said, "Oh, well, that's cancer." Right? So, even before the biopsy came back, he said that, you know, "That's cancer." Because he had seen it. It's something, you know, that does happen in a variety of livestock, in horses and cattle and goats. But he sent in the biopsy, it came back squamous, and at that time, there really wasn't anything to be done about it. There weren't a lot of treatments. And, within about a year, it had reached a stage where this little doe really needed to be put down. So she was put down. And then, within a couple of months, her half-sister also developed symptoms. And it progressed the same way. And then, about a year later, the third doe—who was related to one of the half-sisters, but not the other. So it was a different, you know, intersection of these lines. She also started to show symptoms. She was a little bit older when she started to show symptoms, and it was a little slower growing, so she lived with it pretty comfortably for a couple of years. But those were the first three.

Mary Brennan  3:52 
Yeah, and so of course, from there, I thought there must be a genetic component. But the vet didn't really seem to think so, because they were all light-colored goats with light pigment in their tails. You know, that's typically a typical presentation, is a light-colored animal—as in people. You know, white people are something like 22 times more likely to have skin cancer than Black people, because they don't have the pigment that protects them. Light-colored goats are also much more susceptible to it. But it didn't really make sense to me that, you know, these three goats, so closely related, would get it, while I had other light-colored goats who didn't get it. Goats who were unrelated to them, Nigerians as well as the LaManchas, so that was kind of where it started for me.

Deborah Niemann  4:46 
Okay, and then you've had three other goats get it since then. Were they also related?

Mary Brennan  4:53 
Yeah. Well, this is where I started to do a little more investigating, and as I was reading about it, you know, there are versions of squamous that are related to papillomavirus. And so I thought, "Well, maybe that's why these three related goats got it." So, I kind of... That's how I explained it in my mind. But then, about five years later, a daughter of one of those original does also came down with squamous. So at that point, I started, you know, doing more research. And, I put together my own little database trying to trace back a little further than the ADGA database goes—because it sort of ends at 2005. And I was thinking, you know, "Maybe I'll find some common ancestor who shows up in all these pedigrees." And by that time, other people had also contacted me, and I was sort of becoming aware that it was a problem in the Nigerian breed. A lot of people seemed to have had these cases of squamous. So I thought, if I traced back, I might find a common ancestor among all these different goats. I didn't really find that. But what I found was that, you know, when you get back to the foundation animals, all Nigerians are pretty closely related. So, if there was a genetic tendency or predisposition, you know, it could have spread really widely. So I think that, when you get back into the pedigrees of all of the, you know, Nigerians, they're all purebred. So there's no outside blood coming in. And when you trace back to the foundation animals, there are really probably only a couple of hundred, you know, animals there. So, the gene pool starting out was pretty shallow, which would mean that, if there had been some kind of genetic predisposition or some kind of mutation going back to those animals, it would be pretty widespread by now. So, that's kind of what I took away from the pedigree research that I did.

Deborah Niemann  7:02 
Okay. And now you have been talking to some people at University of California, Davis about actually researching this to see if they can find a genetic link. How did that get started?

Mary Brennan  7:17 
Yeah. Well, you know, over the years trying to find an answer for this, I did a lot of research that kind of went nowhere. But I had contacted a few places. And I had contacted a professor in Australia, in Sydney, who had done a lot of work with goats. And he said to me, immediately, you know, "This could be a mutation in the DDB2." It's, you know, kind of complicated, but it's a protein in the body that repairs UV damage. So, when you have UV damage to your skin, this protein goes out and sends a message like, "Hey, some DNA is damaged here. Send the team in to fix it," right? And, when that protein mutates and is no longer sending the signal, UV damage doesn't get repaired, because that signal never goes out. Well, I spoke to him for a couple of times, and he actually then retired. So that really didn't go very far.

Mary Brennan  8:15 
But then, a little bit later, I was reading about this study at UC Davis on squamous cell carcinoma in Haflinger horses, and it was exactly as this professor had said. They had discovered a mutation in this DDB2, which meant that Haflingers were not able to repair UV damage. They get an eye cancer, a different form of squamous, in the light pigment around their eye. But what's interesting about Haflingers is that they are a color breed, right? So, they're all the same color. They're kind of a gold-chestnut color with this flaxen mane and tail. So, they're all the same color; they should all get cancer at the same rate if color is, you know, the only cause behind it. But what they found was the Haflingers with this mutation were more than five times as likely to get cancer. So, when I heard about that, I contacted UC Davis, and they were very responsive. And they said, "Well, yeah, let's do some research, and let's get some samples, and some cases that have been confirmed by biopsy—so we know that it really is squamous—and, you know, we can start studying what's going on." So that's where we are right now.

Deborah Niemann  9:36 
Wow, that is really exciting!

Mary Brennan  9:38 

Deborah Niemann  9:38 
And so, what can people do if they want to participate in the research?

Mary Brennan  9:43 
Well, I would just love anyone who can, sort of, meet the criteria. Your case does have to be confirmed by biopsy. So, they would want the biopsy results. They would want you to take pictures of your animal from the back—and there's details about that on my website and on the Facebook group. And they would want a DNA sample. So—and you can do that yourself. Pulling hair. There's a tutorial, you know, on the UC Davis site on how to pull hair for DNA. And then, they would need a signed consent form. And that's really about it.

Deborah Niemann  10:20 
Okay. That sounds pretty simple.

Mary Brennan  10:23 
Yeah! Anyone could do that. It would be a tremendous thing. So, they're in the very early stages of it now. But hopefully, they can write some grants and get some funding if they, you know, get data that's worth pursuing and sort of figure out what's going on. So, even if we reach the cut-off of animals that they need, it still would be great to have more people, because if they expand it later, they'll need more participants. I did just email Dr. Bellone the other day, and she said, you know, if your animal has passed away, obviously, you can't submit DNA. But, if you did have an animal that was biopsied, passed away, they still would welcome your input with the pedigree information, because if they end up doing pedigree analysis, you know, just knowing that this is a confirmed case and here's the pedigree could be very helpful down the line. So that's another way to participate.

Deborah Niemann  11:22 
Okay. That's really exciting. And I don't think that we've really described what it looks like. So basically, in most cases, this presents around the rectum. So, like, under the goat's tail. There's not a lot of parts on a goat's body that are not covered by hair, and since goats walk around with their tail up, their rectum is obviously a place that's going to get a lot of sun exposure. And it just looks like there's something horribly wrong with the goat's skin. You know, like, for my doe, it looked like her rectum was just covered with scabs.

Mary Brennan  11:56 
Yeah, that's kind of a hallmark of it, Deborah, and there is some pictures in the Facebook group of people who have animals in various stages. So that might be really helpful. If you're wondering, like, "Wow, well, maybe that's what this is" or something, take a look at those pictures. Because you're right. The way you describe it is very accurate, that it'll be kind of a waxy-looking, and even sometimes it will get, like, a cauliflower look to it that is a lot of raised bumps. It can vary; it can be different presentations. But, when you see those waxy raised bumps, that's the keratin, which is one of the hallmarks of squamous.

Deborah Niemann  12:37 
And then what happens is that it basically spreads into the goat internally. And they basically, ultimately, wind up with cancer throughout their whole pelvic region, their intestines, their reproductive organs. And, in our case, we ultimately put down our goat because she was obviously in a lot of pain. Like, every time she would poop, she would be grinding her teeth. And nothing—obviously—nothing that we did helped, you know. Like, our vet didn't know what was wrong, and unfortunately, I did not take her to the university, which is what I usually do with most of my animals when something is questionable, but it just really seemed like, "Oh my gosh, she's got some kind of a terrible skin infection that is not responding to topical antibiotics. It's not responding to systemic antibiotics."

Mary Brennan  13:28 

Deborah Niemann  13:28 
And cancer never crossed my mind at all.

Mary Brennan  13:33 
Yeah, I know. The first diagnosis that I got, I have to say, I was really, really shocked because I walked in thinking like, "Well, we've tried these antibiotics; they're not working. I'm going to go to a different vet get some different antibiotics." And he just took one look at it and said, "That's cancer." So yeah, it is shocking for people. Now, I do want to just say one thing: One of the things about squamous is that it doesn't always metastasize. It doesn't invade other organs in the body. A lot of times what ends up making life unbearable for the goat is that it just gets to such a size that it's compressing all those vital organs for elimination in that area. And just as you described, you know, it becomes painful when the goat is trying to poop, and it's very uncomfortable. And it can also develop secondary infections just from, you know, sometimes they'll want to scratch it, and they'll break it open, kind of, and then it does get infected. So, it can be really problematic on a lot of levels. Now, it does, it can, metastasize and invade other organs. But it's something that happens a lot later on. 

Mary Brennan  14:45  
And one of the things that I've noticed is that, if you have a young doe—four or five years old—and she gets it, the tendency is for it to be very aggressive and sort of, maybe, only have a year or so to live. But if you have an older animal, who gets it maybe when she's eight or nine, it seems to be that there's a sort of slower growing version that you can manage a little better. And they do have some treatments now for it, including some, you know, freezing treatments and anti-tumor topicals. There's a cream called "imiquimod," which they use on tumors in horses—and also in people—and it stimulates an immune response to attack the cancer. So, the jury's kind of a little bit out on that. They've just—vets have just started prescribing it. But, you know, that could end up being something that makes it more manageable, keeps it from growing. Another odd thing that someone just posted on the Facebook group, it says, she posted... I've heard a couple of other people say the same thing, is that vets are recommending Preparation H, which, when you think about it, it kind of makes sense because, you know, tumors need a blood supply to grow. And what Preparation does is it constricts the blood vessels. So that would, in theory, you can, like, "Oh, well, that, you know, might be something." But some vets are suggesting that now, and that might be useful if you have one of these slower growing cases.

Deborah Niemann  16:16  
Wow, that's really interesting, because when I was at the conference in 2017, and they were talking about it, all of the vets in the room had said that they had had zero luck with all of the different treatments that they had tried. So it's nice to hear that they are trying some medications that have worked in other species, like you mentioned the tumor topical...

Mary Brennan  16:39  
Yeah. Imiquimod is one of them. They are actually two; the one I've heard the most about is a imiquimod. And yeah, it is something that you can just apply. It's not super expensive; you can apply it. If the vet gives you a supply of it that will last, like, a few weeks, you do it twice a week, and just apply it to that whole under the tail area. And when you're using it, usually things start to look worse before they look better, because it provokes this inflammation, which is its way of kind of attacking the cancer and stimulating an immune response. And you know, those things are... We'll see how well they work, right? The jury's still out. But at least there are some things that are available now, which there really wasn't anything 15 years ago. 

Deborah Niemann  17:28  
Right, yeah. And even, like I said, 2017—all of the vets that were at that conference mentioned things that they had tried and said that none of them worked. So this is at least something that you can try that is potentially helpful.

Mary Brennan  17:44  
Yeah. And I did hear from one woman who—she was in Texas—she had a doe with a confirmed case. And I didn't see a picture of it, so I don't know what the presentation was, but she had it just removed, and it hasn't come back. You know, because of the way it kind of develops, it's not usually really self-contained that would make it removable. But I think if you're very aware of it, and if you say to yourself, "Hey, I have, like, these white Nigerians with pink tails, so I'm going to keep a really sharp eye on it," and you notice any little change, you might be in a position to do something really early about it that might be more effective. But it does—even in other species—it does have, in horses as well, it has a tendency to recur. So, it's not a great diagnosis; it's not something that you want your, you know, beautiful little goat to have. And hopefully, if, you know, this study does find some genetic link, then maybe there would be a way to test for it also—which is what happened with the Haflingers. They developed a test that will tell you, "This horse is a carrier. This horse is homozygous for the mutation, so is at a higher risk of cancer. And this horse is negative, so it doesn't have the same risk." And then people can breed accordingly, right? If they know, like, "Oh, okay, I have a carrier, so I want to make sure I don't breed it to another carrier," you know?

Deborah Niemann  19:12  
Right. And then, going back a second to what you were saying about removing it: That was one of the things that the vets were saying doesn't work—in their examples—that it had never worked. That they would try to remove them, and they would always keep coming back. And I, even, there's a picture on my other article on the website of somebody who—I would not have recognized it as a problem. And it looks just like a pink spot under the goats tail. And she had it removed, and she was really excited at first, but it was six or nine months later or something like that, she emailed me back and said, "It's come back." So, that didn't help.

Mary Brennan  19:52  
Yeah, I know. And that's, like, it's not a great diagnosis. But I think the things that are gonna be most effective are things that you do very early on. 

Deborah Niemann  20:03  

Mary Brennan  20:04  
And, you know, nine months later... Nine months is a long time in a goat's life. I mean, I would loved to have had my little goat for nine more months if she was comfortable, you know?

Deborah Niemann  20:13  
Yeah. I would love to know, because I have a lot of goats in my herd that descended from my goat that had this. And so, I would love to know which ones are carriers so that I, you know, could breed accordingly. Like, "Don't breed any goats to each other that are carriers" to try and reduce the risk.

Mary Brennan  20:34  
Yeah, yeah. And, you know, the whole, like, dairy goat world has been through this before with G6 and the Nubians. And that was something that was the same thing; it was a mutation that, you know, through a popular sire was just propagated really widely out into the Nubian world, and was a disaster. It was a huge disaster. And if not for this test that was developed, you know, it could be something people were still dealing with today.

Deborah Niemann  21:06  
This has been really interesting, and hopefully has helped to raise awareness of the potential for a goat to have this type of skin cancer, so that if people see it, they can not only respond accordingly, in terms of like, not misdiagnosing it as a skin infection, possibly trying one of these new treatments, and then also getting involved in the research that's being done at University of California, Davis.

Mary Brennan  21:35  
Yeah, absolutely. And that's what I'm so excited about. So, I mean, I really encourage people, if they go to my website, look at the information. If they have a confirmed biopsy—really important. I mean, you know, you can make a contribution. And we don't know what they're gonna find. Maybe these come out and say it's not genetic, I have a very strong feeling that there is at least some genetic component. So, the more people who are willing—and this is a confidential study. Anything that you submit is confidential. No one's ever going to say like, "Oh, you know, you have cancer in your herd," or this and that. If anyone is concerned about that, you know, that's important to mention. Please, if you can, send in your information.

Deborah Niemann  22:18  
That's great. Thank you so much for all of your research on this, and also for contacting the people at UC Davis to look into this more to see if we can figure out what causes it, and hopefully then just put an end to it through smarter breedings.

Mary Brennan  22:34  
Yeah, that would be the ideal outcome. So thank you, Deborah, for, you know, raising awareness of it. And I'll keep you posted on any developments.

Deborah Niemann  22:43  
That sounds great! Thank you so much. And thanks for joining us today to talk about this. 

Mary Brennan  22:47  
You bet. 

Deborah Niemann  22:49  
And, that's it for today's show. If you haven't already done so, be sure to hit the "Subscribe" button so that you don't miss any episodes. To see show notes, you can always visit, and you can follow us on Facebook at See you again next time. Bye for now!

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