Episode 31 - Resorbed Pregnancies, Small Litters and Antibiotics: The Latest Research

9/30/2025

Today’s question is about resorption of pregnancies and the advisability of using antibiotics to prevent future resorptions:

"We had a girl who was pregnant with at least one puppy at 28 day ultrasound and zero puppies on x-ray at 50 days...I'm curious what other people would check with the girl who absorbed before breeding again."

In this episode we discuss:

Things to check/do when your dam resorbs a pregnancy
How the vaginal microbiome affects fertility and prevents disease
The most recent studies on the prophylactic use of antibiotics in breeding bitches

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To read the transcript for this episode, click the link below.

Transcript - Episode 31

I'm Jane Messineo Lindquist. And this is a Puppy Culture potluck podcast. You bring the topics, we bring the conversation.

This episode is a discussion about the routine use of antibiotics in breeding bitches. And the question came in on our Facebook discussion group for our breeder course. That's the Newborn to New Home course. Here's the question.

We had a girl who was pregnant with at least one puppy at 28 day ultrasound, and zero puppies on xray at 50 days.

I'm curious what other people would check with a girl who absorbed before breeding her again. She's a maiden. We did side by side on days three and four post LH surge, but did not confirm ovulation because of travel, job, weather in the mountains. Semen was good at last check, boy was keen. AI was done by a friend who is a third generation breeder.

Okay me again. First of all, it's just a bummer when you lose a litter and I'm sorry about that. Then I just want to say I'm going to address the exact question that the querent submitted, which is, What should she check with her Dam. Because there are obvious questions here about the timing, the semen quality. There are other reasons why this could have been a miss and wound up with one puppy.

But let's just talk about the question on the table, which is what would you check on a bitch that showed a pregnancy at day 28 and then at day 50 there were no puppies.

I am going to go down a list of things, but I also want to say I would not be overly alarmed in this particular situation because you saw one puppy and then no puppies.

Okay, so it's very likely that there was something genetically wrong with that puppy and it it was resorbed. I mean, that that the puppy was just not meant to be. It didn't develop correctly. This happens. Okay, so one puppy to zero puppies not as concerning as if you had eight puppies and then zero puppies. That's a different profile.

So that having been said, here are the things that I would start with. First of all, did she have a brucellosis test? It's rare, but it's possible. And brucellosis is something that can cause resorption and infertility. So I would check that if you haven't had that done already. If you do get your bitch and whelp again, you might want to check her progesterone levels throughout the pregnancy because progesterone has to stay at about two in order for her to maintain her pregnancy.

And some bitches don't maintain that level. And if that is the case, you can supplement with progesterone to maintain pregnancy. Now, depending on the dam's age and family history, this is a case where I might consider doing a surgical insemination the next time, just so the vet can visually inspect the uterus. There could be cysts or a brewing pyometra that you don't know about, that would only be visible if you go in there and do a surgical insemination.

I don't have enough information in this case to say, if I were the breeder of this bitch, if I would do this, but it's on the table for me. Okay. If I really have checked off all the boxes as far as timing, semen quality, and I've had the semen evaluated by a thorough genealogist with good equipment, timing, I've really done my timing straight through. I'm sure that everything went well there and then I have a complete miss. I might want to have a look and see what's going on in there. I'm not saying that I'm recommending that to this particular person in this case, but it's on my list. Okay. If I have a especially if I have a complete mis or a really small litter and there's no other explanation for it in this case, I can't really say that she's checked off all the boxes, so I might not jump to going to a surgical, but it's on the table.

Okay. If I have an unexplained very small litter or no puppies, surgical is on the table just to visualize what's going on with the uterus. So those are just my first few quick thoughts. When I have a bitch that misses or has only like one puppy and everything else is good.

Now, if you went to a good repro vet, they probably would have other suggestions. I didn't mention thyroid and blood workups, which is always a good idea and I would hope that you would be doing routinely anyway. But if you haven't done that, that's important. And as I say, a thorough genealogist, it's a constantly evolving field, so they may have something else to suggest, but these are my tried and true punch list of things when I have unexplained infertility or low fertility in a bitch.

But now we come to the reason why I felt I needed to do a podcast about this. Because somebody wrote in and suggested giving a prophylactic course of antibiotics to flush out the bitch's reproductive tract. I mean, this is something that was really hot, like 20 years ago. You if you went to a repro vet, they were going to give you antibiotics to cleanse out.

So you would basically have a clean medium for reproduction. I'm going to talk a little bit about the most recent studies on this. But the overview is this. There really is no correlation between bacteria in the vaginal tract and conception. Bacteria naturally lives there. Okay. I mean, all the things that they would culture and say, you see they have E.coli, they have this, they have that.

No, that's there all naturally. Anyway, there's no study that shows any higher conception rate with the use of antibiotics. So there's no it's just not indicated. There's no support for this practice. And not only can it not help conception, it can really have an adverse effect on the dam and her puppies. First of all, the gut biome. If there is one thing that is correlated with fertility and also health in offspring, it is a robust and diverse gut biome in the dam and giving a course of antibiotics right before breeding just decimates that.

It just decimates her gut biome. And although she may be able to recover from that with time, you're decimating it right at the time that those puppies are being conceived and she's seeding the puppies gut biome. So now you have puppies being seeded with a decimated gut biome, so they're going to have less diversity. Their gut biome is going to be less robust when they're born.

Yes. I mean, through good weaning practices, we're going to increase that gut biome in diversity and health. But why would you do this? This is not it's not helping you get your bitch pregnant. And it potentially is really harming your puppies. You know, in humans, things like H pylori overgrowth, which they used to treat with antibiotics, they now say it's associated with lack of diversity in the gut biome and actually may be exacerbated by antibiotics.

So this is this sort of new realization in the medical community that when you hit something with antibiotic, it's an equal opportunity destroyer. So it just it hits everything, right? So let's say you do a swab on your bitch and you're like, oh, you know, she's got an imbalance of, pick something, E.coli. So you hit it with antibiotics.

But the problem is that when you level the playing field in this way and you take away all the good flora, it can create an opening for opportunistic infection because you don't have those competing organisms to crowd out the really bad pathogens. And sometimes even something that on a smear might look bad like streptococcus, can be protective against a worse pathogen.

So I'm looking at this paper from 2012, vaginal bacterial Flora and cytology in pro estrus bitches role in fertility. And very interestingly, they said vaginal presence of streptococcus in pro estrus was instead negatively associated with the development of uterine infections. Therefore, streptococcus could have a protective competitive role against more dangerous pathogens affecting fertility in the bitch.

So again, take out the strep. Sure, but you're just opening the door for something that potentially could be worse. This, again was studied in 2025. The canine vaginal microbiome during heat and fertility in healthy breeding dogs. Now they said a lot of things in this. I'm going to put up the study on the show page. It's worth a read if you're interested in this topic.

First of all, they said this has been often postulated, but scarcely investigated and not proven that antibiotics might be helpful, or that bacteria present in the vaginal tract is in any way harmful. However, they did say, It is undeniable that gynecological disease might be associated with bacteriological culture of specific bacteria, such as E.coli. The present data emphasize once more the opportunistic character of these organisms, as the genus E.coli was detected in all samples in the study, none of the genera could be identified as a marker for suspected sub fertility or infertility.

Moreover, underlying causes for the opportunistically pathogenic action of the vaginal microbiota should be investigated further. These might be the overgrowth in the absence of competing commensal bacteria. It's another way of saying that if you take everything out, yes, you may get something that you perceive as being a bad bacteria, like E.coli out of the vaginal tract, but it opens it up to other opportunistic infection, which could in fact be detrimental to your bitch's fertility.

I think the concept here that you have to wrap your arms around is that it's a very analog situation in the animals microbiota, meaning to say physically there are X number of spaces for things to live. I mean, that X happens to be billions and billions and billions, but literally there's finite space for things to live in your animal's microbiota.

And if you take something out or a lot out, it just leaves a hole. Like the way that an animal maintains health is literally by crowding out pathogens, like there's just no place for the pathogens to go, so they just pass through the animal. It's when you have cracks in that, when you have space, and then the pathogens can come in, that's when you get into trouble.

And that's the situation that you're in when you strip things out with routine antibiotics. The vaginal tract, I mean, it's down there. It's meant to have all this kind of, bacteria. It's a microbiota that's a natural microbiota for a vaginal tract. Trying to strip that out is just dangerous. Quite frankly, I'm sort of aghast, in fact, that it's even still a meme out there that just giving a routine dose of antibiotics is in any way beneficial or advisable. In these cases.

Now, there are some vets that will say, well, yes, but you know, you're way out of balance with something like there's an overgrowth of one kind of bacteria that they perceive as being bad. And I'm just going to say right now, if that were the case with my bitch, I would address it with diet. I would address trying to fix up her gut biome and her vaginal microbiota with diet, with adding some fermented foods.

She's probably in dysbiosis if this is the case. And again, I would not go the route of antibiotics. I just wouldn't do it. A, it hasn't been proven to help and B it has the potential for doing a lot of harm, especially when you consider that what has been shown to be connected to fertility and health in puppies is a diverse microbiota in the bitch and antibiotics are going to kill that.

Now, before I close out this topic, I'm going to hasten to add that if antibiotics are medically indicated, if if your bitch is sick or has some profound infection and she needs antibiotics, do not hesitate. Give her the antibiotics. It would be irresponsible not to give her the antibiotics in that case. Are you going to have some fallout with her gut biome and fertility and other things?

Yeah you are, but listen, we can deal with that. You can support her in other ways. My only point here is that routine, just prophylactic giving of antibiotics, number one, never. Never indicated. Never good idea. Number two, even if there is an overgrowth in the vaginal tract, if she's clinically normal and not ill from it, I would always treat that with diet and fermented food and not antibiotics based on the current science. As I read it.

If you liked this podcast, you'll love our breeder course from Newborn to New Home, available at madcapuniversity.com. Breeders, do you want to get your puppy owners started out on the right foot? Check out our bulk discounts of our puppy Course available at madcapuniversity.com.

Well, that's it for this time. Thanks for listening. Bye bye.