Timing Your Bitches with Dr. Hutchison, DVM

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Transcript

Laura Reeves I love it! So now we are going to move into the second part of our conversation, which is the timing of our bitches. We’ve talked about the stud dog. Now we’re going to look at the timing in the bitches. I know you talked about this last time, and we had some follow-up questions from the audience. Last time you were here, we talked about questions about the ideal progesterone number for breeding to come back up again. Can you talk a bit about how to use progesterone, LH surge technology, vaginal cytology—all the considerations: “It’s 5 when I do this, it’s 10 when I do that, it’s 15 when I do the other thing.” That particular conversation is what people are interested in.

Dr. Hutchison Well, first of all (and I probably mentioned this before but I get this a lot) there is no magic number to breed at. A study we did with hundreds of samples—and just to refresh the memory of those that’ve heard this—we took serum samples. All bitches bred with frozen semen. This is when we used to do all surgicals, before we started doing so many transurgicals. These samples were all drawn, bitches being bred with frozen semen. We took the variable of semen length of life out. They’re all having a surgical, and they hadn’t even woken up yet. We drew the sample. And we had hundreds of samples. And we sent them all to the Case Western Reserve Medical School in Cleveland and had the statistics department—because I was young at one time. I was like all these new guys. I wanted to believe it was so easy, that I would send these samples in, and we had them looked at for conception rates, litter size, body weight of the bitch, and age of the bitch. I figured there had to be a number. That I would do is I’d look at you, and I’d say, “Okay, at 21.4—bingo! Your bitch has 9 puppies, 8 of them are females. Life is good. We’ve conquered this field.” What we found out was that there is no magic number. That’s why you have to do your progesterone and see when they swing by that. Usually 5-7 range. That usually corresponds with ovulation, about 90+% of the bitches. And then you do want it to go up. You want it to be just like a rocket taking off. But to say there’s a magic number… And what really amazed me was in the study we did, looking at conception, the lowest progesterone level in that was 11. A bitch had puppies, a Saint Bernard. The highest in that study was a Westie who had 4 puppies, frozen semen, whose progesterone was 50.4. These are nanograms we’re talking about. So what they came back from the statistics department was they said, “This is all interesting, but there is no statistical significance to the number of a progesterone if you want it to go shooting above the ovulation date.” When people come to me and say, “Geez, I just started with a new person, and they told me we’re going to breed at this progesterone number,” I kind of smile, because they will learn as I did that life is not that easy, that you wait and—some people say that you have to be above 18. If that’s the case, that Saint Bernard never would’ve been bred! She never would’ve had her puppies because if I waited till 18, she’d have died of old age before she got above 18. No one in their right mind—including me—would run a first progesterone on a bitch and it came back 50.4 would I say, “Wow, it’s perfect! Let’s breed her!” Well, no. You wouldn’t have done that at all. But that’s another thing, I think, to emphasize about progesterone numbers: just because you run a first progesterone number and it comes back 28, it may be perfect. Or you may have missed it. So that is where some of the other detection methods come in.

When you talk about the bitch’s cycle, let’s refresh our mind. Because there’s anestrus, there’s proestrus, and there’s diestrus in the bitch. So, geez, those are nice names but what’s their significance? What is the difference between a proestrus and a diestrus? She’s still bleeding on my carpet! Well, an anestrus—the definition of anestrus is—the progesterone is baseline. There’s no visible hormonal activity taking place in the bitch. She’s not swelling, she’s not bleeding. The male dogs are leaving her alone. The ovaries are still working. They’re still getting low levels of estrogen. Back to the pituitary. The pituitary, then, is keeping the luteinizing hormone low, and that’s because it was called this negative feedback. So even when the bitch isn’t in season, her ovaries are communicating with the pituitary. And this has become real critical stuff, now that we’re talking about: Should some bitches have ovary-sparing spays? Should some bitches not be spayed at all, the ones that carry the sarcoma genes? This luteinizing hormone looks to be the culprit. So when you spay a bitch (and this is not saying you shouldn’t spay a bitch), some of the concern right now (the Golden Retriever study, for example), in individuals carrying sarcomas, is if you don’t have ovaries, then it’s not constantly feeding back this low level of estrogen. In the old days, back when I was in vet school, we thought when a bitch wasn’t in season, she was the same as a spayed bitch. We thought nothing’s going on! So, therefore, she’s the same as a spayed bitch. We now know that it’s totally wrong. If keeping luteinizing hormone low (if you have a breed that carries a sarcoma gene, some of the giant breeds that leak urine post-spay), it is because we aren’t having this feedback to the pituitary.

Anestrus—this is when progesterone is down, estrogen is low level but still there. When you do a vaginal smear here, you see all the cells look like big fried eggs. They have big nuclei, they have clearer cytoplasm around them. You’ll see mucus. You’ll see white blood cells. But then that is anestrus. Low progesterone, minimum estrogen.

Proestrus—this is when the bitch starts bleeding. The bitch starts swelling. The bitch starts becoming attractive to the male dogs. This is an estrogen-dominated phase. So we’ve gone from low progesterone, minimal estrogen—now we’re going strong estrogen. This causes the tissue to take up fluid. So this is why the vulva swells and is hard. You get the leakage of the blood into the uterus. The spotting comes from the uterus, the vaginal tract. The blood, then, leaks out of the uterus. This is the estrogen phase. This is what proestrus is. When you’re doing your slides, this is where you’re seeing your cells changing from fried egg cells—big nuclei, then they start to shrivel up, because the vaginal wall thickens under estrogen. It goes from 1-2 cells thick to 20-30 cells thick. As the cells get farther from the blood supply, they starve to death. So your vaginal cytology is valuable in saying, “Yes, she is in season. This is not from pyometritis. This is not from cystitis or something.” This is under the effects of estrogen, because all the cells start to look like cornflakes. About the follicle developing—that is where the estrogen’s coming from. And then we start to get some beginning progesterone, produced by the follicle, before she ovulates. This is unique! This is unique in domestic species. Cats, for example, they ovulate. There’s a couple of days before you see the progesterone rising. In the bitch, the progesterone starts to rise before the ovulation occurs. In about 2-3 days before the follicle is totally ripe, the cells are 100% cornified on the vaginal sear (so we’ve monitored estrogen), as the follicle gets ripe and progesterone rises (usually around 2-3 nanograms), this then is what tells the pituitary we’re ready to move to the next phase.

This is when the luteinizing hormone is released. It goes about 1 nanogram. It goes about 12-24 hours. POP! The eggs are ovulated. And in the bitch, all the eggs are ovulated over a 12-hour period. It’s not over days. It’s all over from the one LH surge. So then what’s happening: we have the estrogen drop, the progesterone starting to rise. This crossover is what we call the estrus part. We go from anestrus, proestrus is estrogen, estrus is now the crossover. The estrogen is dropping, the fluid’s going out of the vulva. The color is lightening up to some degree. The male is able to penetrate. The bulb’s engorged. The tie takes place. That’s how we get a natural breeding.

Does our vaginal smear help us here? No. All our vaginal smear did was measure estrogen. Once it told us we were 100% cornified, vaginal smears are of no more value. They stay that way until 6 days after ovulation, 100% cornified. The luteinizing hormone test is on the market. It takes 3 drops of serum. It’s called a wicking test. You drop the serum, and it’s pulled up almost like filter paper, and if it crosses the line and is higher than 1 nanogram of luteinizing hormone, then this line turns bright red. At one time, we thought this was going to be the main thing we were going to focus on. The trouble with luteinizing hormone, as we said, it lasts 12-24 hours. Period, amen! That’s it. So in a full year, an intact bitch who comes in season twice, is under the effects of luteinizing hormone for a grand total of 2-3 days. So it doesn’t have a long-lasting effect. What does that mean? If you’re going to use luteinizing hormone as your indicator of when to breed your bitch, she has to have blood drawn every day. There is no other test, other than one that’s running on serum. So she has to be bled every day, and it doesn’t matter if it’s Sunday. It doesn’t matter if it’s your birthday. It doesn’t matter if it’s your national specialty. It’s always the day you miss that’s the day you wish you had back. So, if you know that the luteinizing hormone spikes (let’s say we’re running our samples and, sure enough, here’s that bright red line), well that doesn’t tell you everything you need to know. It just says, “Okay, now I’m looking 4-8 hours later to confirm my bitch ovulated, because of the progesterone going up.” Just because a bitch has an LH release, doesn’t mean she always responds to it. You can have some cystic situations on the ovary. You can have some stress situations. You’re sticking a bitch on a plane, send her to strangers. Even if you get the LH spike.

So, in our practice, do we use LH on every bitch? No, we don’t. It just is not feasible to have your bitch brought every day to have her blood drawn. What we’ll do—especially on some bitches that maybe had problems in the past, maybe bitches that missed that we didn’t think should’ve, sometimes when we have hospitalized bitches—we will take the blood, freeze it, and use it to refer back to, to confirm that our anticipation on the ovulation was correct. Then you move from the estrus phase (that’s when the bitch is gonna be bred, that’s when the eggs are being released). Remember also the bitch ovulates an immature egg that has to go through another meiotic division—it has to go through a whole other division after ovulation! This is crazy! It doesn’t happen this way in other species. But it has to do that before it can be fertilized, so that is why frozen semen appears to be used late, 3-4 days after ovulation. Fresh semen will last 6-7 days. You can breed them any time. It probably doesn’t matter.

But then we move into the progesterone-dominated phase, which is called diestrus. Diestrus—so we’ve gone anestrus, proestrus, estrus, switch over, and now we’re under the effects of progesterone. This does not vary, whether a bitch is pregnant or non-pregnant. This progesterone-dominated phase (diestrus) lasts probably 2-2.5 months. And this we see 6 days after the bitch ovulates. We see all the cornified cells. The cornified cells—like all of a sudden somebody came in and BOOM! Erase the slate. Suddenly we see all these cornflake-looking cells being gone; they look like fried eggs again. There’s all these white blood cells pouring in. There’s all this bacteria, which is normal. And then we’re under the diestrus phase for another 2-2.5 months until the progesterone drops below 2, and then it goes back down to anestrus.

Where are smears valuable? Smears are valuable to tell you that your bitch is under the effects of estrogen. Period, amen. You cannot tell when a bitch ovulates. Those of you who use breeding guns, the breeding guns out there that are used—these are, again, measurements of estrogen. These are electronic vaginal smears. The basis of how they work has been shown in the bitch. As the estrogen rises, so does the electrical resistance of the vaginal mucus. So, these breeding guns are measuring the electrical resistance of the vaginal mucus, but don’t ask me what the numbers are, because I don’t know. Anyway, those are more like electronic vaginal smears. So they fall into the estrogen monitoring category. The wicking test that we use is called the Luteinizing Hormone Test. And luteinizing hormone is species-specific; it is different in the bitch than it is in the cow than it is in people, so you cannot say, “Well, I’m going to send my bitch’s blood to the human hospital and get a luteinizing hormone test.” It won’t mean anything.

Progesterone is not species-specific. Progesterone can be run at a cow lab, a human lab, a dog lab. Progesterone is progesterone is progesterone. Luteinizing hormone is species-specific. So, when we have this wicking test, there’s only one test available. There’s not multiple ones. That tells you: Is my follicle right? Is the pituitary responding to the initial feedback of progesterone? BOOM! There we see our red line. It’s of no other value. There’s no reason to run a luteinizing hormone a week from now, weeks from now, two days from now. And then a progesterone going on up tells us that we have had ovulation, the corpus luteum, the yellow bodies replace where the ovulation occurred from, that produces the progesterone, and that, indeed, is what maintains our pregnancy or what maintains our non-pregnancy as it goes on. Again, that’s why, because of the diestrus, there’s not a reason to skip a cycle in the bitch.

Laura Reeves Okay, excellent. You mentioned this a little bit earlier, and there was a question on it, and I wanted to get back to it and follow up on it. Split cycles, bitches that come in late (instead of coming in at 6 months, they come in at 18 months), or they start to come in season and then they go out of season—all of those sorts of abnormal cycles. Can we talk a little bit about that? And is there a way to make them cycle normally? Is there anything we can do to get them back on track?

Dr. Hutchison It depends on what we’re talking about. A couple of things. Most people, I’ll get a call, “My bitch is now 6 months and 1 day, and she’s not showing signs of being in season. Should I be worried?” Well, let me tell you this. It’s progesterone that damages the uterine lining, so that every heat cycle, the uterus is not as healthy after that heat cycle was before. Because the bitch does it to herself, to have normal progesterone. So then let’s say you have a bitch who you’re not going to breed. Let’s say you have a bitch that needs the hips X-rayed before you can breed ‘em. You’re going to wait until your OFA is done. Well, would you prefer to have a bitch who cycled at 6 months, 12 months, and 18 months—has therefore been under the effects of progesterone for 6 months of her life before you’re ever going to use the uterus? OR are you saying, “You know, I’m pretty happy. I’m not going to breed her. I don’t want her to come in till I’m ready to breed her.” When do I become concerned? When a bitch reaches 24 months of age without obvious heat cycle. I really don’t get too cranked up about them. There are some bitches that we will induce a heat cycle, just to prove they come into season. Very, very, very, very few bitches in my life—I can think of one—that didn’t have ovaries and a uterus. She had other chromosomal issues. Anyway, it doesn’t bother me if a bitch is 18 months and not having a cycle. I’m not worried at all. A lot of that can be genetic. Some of it can be physiologic. How mature are they? Very, very few have ever led to a worry. I have bitches that will come in for their first cycle, and sometimes they’ll stay in season and bleed for 4-5 weeks—

Laura Reeves Forever.

Dr. Hutchison Yes, they bleed forever. All that. So what’s wrong with this bitch? The answer is: Nothing. They don’t have cystic ovaries. They aren’t more prone to pyometra. All this is is hormonal incoordination. They’re developing this follicle in the body, saying, “What’re you doing that for? We’re not ready to be bred.” What happens in these bitches: they go back out of season without ovulating. They come back in, in 4-6 or 8 weeks, and as the ovulatory cycle, they’re normal from there on out.

What about bitches that go through two split cycles? Northern breeds are probably the most common. It’s called Wolffian Heat Cycle. These are bitches that come in, they bleed, they swell. Usually you can’t get a natural, so you do an AI. And they go out, and just about the time you’re ready to palpate to see if you’re pregnant, they’re back in season again. What’s going on? Well, these split cycles—what we see is they bleed, many times their progesterones will get up 2-3 nanograms. It’s one of these where they’re saying, “I’ve developed the follicle.” But there’s no response from the pituitary! So, the follicle goes back down. They come back in season usually 4-8 weeks, 6 weeks, they come back in. That’s the ovulatory heat cycle. You just have to be aware that that is there. So there’s nothing abnormal with any of the three bitches we’ve talked about so far, the ones that came in later than you or I thought they should, the ones that came in and bled all over your comforter and just about the time you though they were never going out of season they do and then they’re back in—that’s just physiologic. That’s hormonal coordination. And then the split cycles, oftentimes that’s a genetic issue. As I say, it’s common in certain breeds, in Northern breeds and that.

Some bitches that come in season and go out without ovulating—if there’s stress involved, this goes back to the olden days when we used to ship bitches before we could chill semen. You’d get this bitch. You’d be all ready. You’d put her on the plane, and then she’d get there, and she wouldn’t be in season anymore. You bring her home, she calms down, she relaxes. This time you’re going to breed her more local. She comes in at that 4-6 weeks, she ovulates, you breed her. Things are normal. Silent seasons occur. This is the one I hear from people who have a bitch 18 months of age that hasn’t been in season. I believe she has silent seasons. What is a silent season? They do occur. Silent seasons are bitches who don’t have estrogen receptor sites. Basically, they come in, the follicle develops, but they don’t swell. They don’t bleed. They don’t show the other outward signs of estrogen being present that we associate with that, as we said earlier (the bleeding, the swelling of the vulva, some of the pheromones given out). It’s going to be a little more difficult. It used to be that you always thought of Pomeranians. Those are the breed with silent seasons, but now I think the last ones I’ve seen have been Labradors. I had an Airedale. And how did you know? They say to me, “How did you know that these bitches went through a silent season?” It’s because the people who were watching them—next thing you know, the bitch is in a false pregnancy, things like this. What’s a false pregnancy? There’s nothing abnormal. It’s just the progesterone drops and the widening of the prolactin in the brain, in the progesterone dropping, the widening of that ratio—certain bitches think I think I had puppies. It’s not a false pregnancy. It’s a false labor! They think they had puppies, and they drive you crazy.

How do you tell a bitch that goes through a silent season, if you suspect it? Three things you can do. One: I just bring them into season. Because when we bring them into season, using the deslorelin implants, which are getting harder to get, unfortunately. But they’re in season in 5-7 days. You know. This is what the heat cycle looks like. Does she swell? Does she bleed? No? You’re on your progesterone. She’s still ovulating. Second of all would be like every 10 days, just do a vaginal smear. Because you’re going to see the cells change in the lining of the vaginal track, even though you’re not seeing the bleeding and the swelling. So what you would do is do a vaginal smear every 10 days, take it in, your veterinarian looks and maybe one day, says, “Wow! These all look like cornflakes.” Then you start running your progesterone. That’s usually the way that you do it. The third is you’re going to periodically run progesterone to see if she’s ovulating. But to me, if I’m running something to breed a bitch, I want her to be able to be bred. Finding out progesterone—hey, well, we’re a month late and two dollars short. We’re not accomplishing much! So if you think you have a split cycle, then what you do is you do the every ten day vagina cytology, try to bring the bitch into season.

Laura Reeves Alright, so our final question on this particular topic: Talk about reabsorptions and still-born puppies. Anything that we can talk about on that, in terms of optimizing fertility and getting our puppies through full-term?

Dr. Hutchison There’s three different classifications of what you’re asking. There’s reabsorption of puppies. Up until day 38, these puppies can be reabsorbed totally. There was a study out in Europe that says probably 30% of all bitches reabsorb at least one puppy. This goes along with humans. You know with placental problems, genetic problems, whatever. The second is what are mummified puppies? When you’re going ahead, you’re doing a C-section or your bitch is in labor—all of a sudden, you have this little scrawny puppy that looks like a Eohippus horse. It’s just leather over bone. And then you have aborting. Aborting is when the puppies have reached the point where the body cannot reabsorb them totally. Three different things there.

Reabsorption—probably number one is uterine lining issues. As the bitch ages, you’re probably going to have less success, as far as the number of placentas attaching. Remember that placenta in the bitch is as deeply attached as any domestic species. So if you have cystic changes to the uterine lining, fibrotic changes to the uterine lining—many times, puppies just can’t be maintained, so you may have ultrasound and seen 7, and you end up with 2. Other things that cause reabsorption of puppies: if the bitch doesn’t maintain her progesterone level, the progesterone level drops below 2.5 nanograms, the body says it’s time to get rid of the puppies, regardless of if we’re at 30 days of 60 days. We’re starting to look at uterine lining issues. We’re starting to look at hormonal progesterone drop issues. The third thing that would cause reabsorption, again, is genetic issues. We’re starting to appreciate more and more some of the genetic influences on the placental development, different things like that. Those are the three main things of reabsorption. Yes, there are different chemicals we use. We use a product that causes the bitch to not maintain her progesterone if we have a mismating situation. But the main three causes of reabsorption are probably uterine lining, progesterone drop, genetic defects. Fourth would be some weird chemical they got into, or something like that. But that’s more common in horses and cows that graze.

Mummified puppies are where you have a puppy that died between puppies that are alive. Probably the number one cause of that would be genetic defects. We’re also starting to appreciate, too, that there are certain placental issues where the placenta grows so deep that some placentas don’t know when to stop. They can actually grow, not only through the lining; they grow into the muscle of the uterus, they grow into the serosa of the uterus. These are called placenta accreta, placenta percreta. We’re starting to appreciate those more and more. For something that stops the blood flow to the placenta, you get what’s called a placental infarct. Then the puppy will die because it starves to death. It can’t get nutrition from the uterus anymore. Remember there are only two things keeping a puppy alive in the uterus. One is the fetal heart rate, and the other is the blood flow to the uterus. So anything that affects either one of those two is going to make our puppies at least stressed, if not dead. The third thing, then, when we talk about aborting puppies—still number one I think is progesterone dropped prematurely. The bitch has these puppies, she’s at day 52, you’re all set, you’re getting the whelping box set up, and you go down and there’s all these naked puppies and things like that. Progesterone drop is number one. Here, though, you start to get infectious problems coming. This is where Brucellosis affects, causing any placentitis. Herpes can cause placentitis. Some of the respiratory infections cause placentitis. You can get E. Coli, you can get strep—anything that would cause an illness to go across the blood supply. When you think about it, if you and I were going to grow bacteria, where would there be a greater place than in a placenta? Heavy blood flow, no oxygen flow, dark environment—it’s the perfect place. It’s amazing we don’t have even more issues, to me, than that. So you’re looking at bitches dropping in progesterone prematurely, infectious processes. The third thing, again, some of the uterine linings, especially if you have fibrotic uteruses, where there’s scar tissue, because if the placenta can’t grow, the puppy basically starves to death but would be in an aborting situation.

Always when you have a bitch that aborts, the first thing that you want to do is check her progesterone level. Because if the bitch aborted the litter this time, due to progesterone dropping, then next time, you can supplement progesterone and carry the puppies to term. So it’s just one of the things we see. There probably is, in all honesty, a little bit of a genetic aspect to it: an immune-mediated effect against the ovary, not just the ovary failing. On the other hand, if all you have to do to get a beautiful litter of puppies is to give two injections of progesterone over the last ten days, that’s pretty good to me.

Anyway, those are the things that you look at. What I’ll mention about large animals: Fescues that large animals graze on that have hormonal activities, pesticides have an estrogen effect. We all know—how many years ago—when all the thoroughbred mares in Kentucky aborted because of the tent caterpillar problems they ingested. These are things that we probably worry about in the bitch.

What about dog foods? I get a lot of calls about the dog foods that carry peas and some of the other things like that, but they’re in such minimal amounts that you couldn’t use them. They wouldn’t cause a problem and are not worrisome. Everybody worries about the dog food, the dog feeding. Those of us who work in the business realize they’ll eat out of garbage cans and over-reproduce. Probably your food that you’re feeding is not the culprit if you’re having a problem, either with reproduction with a male or a female.