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Equine Reproduction - From the Stallion to the Foal

November 2017 - AAEP is on Stall Rest

AAEP is taking the month of November off from "Ask the Vet", but will be back in December to answer your equine health questions concerning winter weather care for your horse with expert, Dr. Christine Tuma.



Click here to read this month's questions and answers.
  1. I was told not to let week old foals have water. One foal is small and developed scours but was also eating the feed (hay cubes and beet pulp) that the mare would spilled out of her feed bucket. Is it the water the foal is drinking or maybe the mare's food that is causing the upset?

    (View Answer)

    Diarrhea (or scours) in foals should be considered an emergency and your equine veterinarian should be contacted immediately. Although many cases of diarrhea are simply due to diet (of the mare or the foal) it is a symptom of neonatal septicemia, which is a potentially fatal condition in foals. There is no reason to restrict water to any animal regardless of age. Madison Seamans, DVM, MS, Kuna, ID

  2. My 8-year-old mare has drooping udders. Is this normal? She is in with two older geldings.

    (View Answer)

    During late pregnancy, the mammary glands undergo rapid expansion as the mare prepares to function as a dairy animal--making up to 4 gallons of milk per day to provide for the nutritional needs of the growing foal. After the foal is weaned, the teats in some mares do not shrink back to their original size. Since they are no longer producing milk, they may lack tone and appear to "droop". This is relatively common and not considered abnormal. Madison Seamans, DVM, MS, Kuna, ID

  3. I bought an exceptional stallion 6 weeks ago, but he is cryptorchid with only his right testicle down. I heard that a surgical procedure could bring the crypt testicle down. Is it true that this can be done?

    (View Answer)

    Cryptorchidism is the absence of one or both testicles in the scrotum. During embryonic development, the testicles are formed near the tissues that eventually become kidney, high in the abdominal cavit at about the level of the last ribs. In the mare, the ovary stays in that general area. In the boys, however, it travels down a long path known as the gubernaculum and arrives in the scrotum before birth. In the cryptorchid stallion, for some unknown reason, the journey was interrupted, and the retained testis is somewhere in the abdomen. The retained testicle is capable of making the hormone testosterone, so cryptorchid males will act like a stallion, even without testicles in their normal location. However, the heat in the abdominal cavity prevents the full development of the testicle so sperm cells cannot be produced. Due to their diminished size, these underdeveloped testicles can be very difficult to find. 

    If a retained testicle could be located surgically, it may be possible to pull it in to the desired location. There are also hormonal treatments available that have been effective in achieving this. However, some breed associations are very restrictive when in comes to cryptorchid stallions in their registry, so they should be contacted regarding their policy on this condition before any correction is attempted. Madison Seamans, DVM, MS, Kuna, ID

  4. I am a small animal veterinarian and am trying to breed my own (geriatric) Thoroughbred mare. She is 20-years-old, was open last year because of repeated failures to get live semen shipped! She just checked 14 days in foal. I am getting a lot of pressure to check her progesterone because she is older. She has never been supplemented before. It isn't a problem as I have already purchased the Regumate. But, like a crazy horse person, because I am already daydreaming about this foal, my questions are more about what, if anything, is actually technically correct? What day do you pull blood to check for progesterone? I have been reading on VIN that it fluctuates so widely and is hard to get a result that really means she is persistently low. The "average" is recommended to pull 3-4 samples over 3-4 days. That said, can I pool those serum samples and submit them as one? Would that work as an average? I have been reading about how early abortions are so frequently caused by low level uterine inflammation/infection, and it probably has a lot less to do with low progesterone than we initially thought. Is that true? Like I said, I am a small animal vet, I have an old pregnant mare, and I already have the Regumate. It isn't a question of when or how or how many progesterones to send off, or whether to supplement her or not. I can do any or all of that, whether she needs it or not. My question is more along the lines of: what is the correct procedure for evaluating this? Or is there? Or is it something that we just do as cheap insurance?

    (View Answer)

    Progesterone supplementation to treat luteal insufficiency is a common scenario in equine practice. The fact that your twenty-year-old mare conceived at all puts you way ahead of the curve, and probably rules out the presence of inflammation due to a uterine infection--infected mares don't get pregnant. Her blood progesterone levels should be tested on day 5 (day 0 being the day of ovulation). One test should be sufficient, though each lab has their own range of "normal". Treatment with Altrenogest, or other progesterone product, should be initiated if the mare's levels are low and continued through the first 100 days of gestation. 

    Our older mares have many challenges in carrying a normal foal to term, so if they need a little hormonal boost to help accomplish this, it would be considered poor management not to provide this. However, it would be equally poor management to treat her without knowing what she is capable of producing. Progesterone testing is good husbandry for all older mares or any with a history of fertility problems. It is cost effective and should be considered an essential part of the best possible prenatal care. Madison Seamans, DVM, MS, Kuna, ID

  5. My dad has a foal that the mother will not accept after the foal was stuck in the mud. He has been bottle feeding it, but the foal has now developed scours. What can he do to help her?

    (View Answer)

    Scours (diarrhea) in foals should be cause for concern and treated as an emergency. Although this can be a temporary response to stress, and being rejected by the mare certainly qualifies as a stressful event, it is also a sign of a life-threatening illness called neonatal septicemia. This foal should be seen by a veterinarian immediately. In addition, an equine veterinarian may be able to administer treatments to the mare to stimulate normal maternal behavior, so you won't need to bottle feed the foal. Madison Seamans, DVM, MS, Kuna, ID

  6. My 13-year-old maiden made has had her third uterine infection in less than one year. I was told by my veterinarian that her cervix is to tight and doesn't release all fluid. At this point, she is not rideable due to pain under saddle. How can I fix the reoccuring infection?

    (View Answer)

    Uterine infections in teen-aged mares is not uncommon. These infections are usually sub-clinical, meaning there are no outward signs like vaginal discharge, illness or elevated temperature, but they will impair fertility. The source of this type of infection is commonly from fecal contamination, not "venereal" transmission, so no stallion is required. Normally, the vaginal opening is perpendicular to the ground, so fecal material is not likely to enter the reproductive tract. In middle-aged and older mares, the vulva gets pulled up over the pelvic rim so it is at an angle that allows fecal contamination. In addition, older mares tend to loose the ability to clear themselves of infections in this area, and this is the source of fertility problems.

    Treatment of endometrial infections includes flushing with sterile fluids and infusions of antibiotics. Due to the nature of this infection, it is extremely unlikely to be the source of pain, so diagnostic efforts to determine why she cannot be ridden is advised. Madison Seamans, DVM, MS, Kuna, ID

  7. My gelding has a swollen sheath. His previous owner said this normally happens in the spring but he had no problems last spring. It gradually began swelling but now has become very swollen. He still continues to move around but seems somewhat more sore when moving last night, but still continues to run in the field. The area is not tender to touch.

    (View Answer)

    A swollen sheath is a very common presentation in equine practice. In most cases, a thorough cleaning will fix the problem, but the products available at the feed store will not always be sufficient. This usually requires sedation with products not available to unlicensed persons, so the horse will prolapse his penis and allow complete examination and cleaning. However, the cause of swelling in this area may be more complicated. Some deep-seated infections and even skin cancer can be found in these tissues. For this reason, a call to your local AAEP member is always a good idea. Your equine veterinarian will be able to examine, diagnose and provide the necessary treatments for this and other concerns you have about your horse. Madison Seamans, DVM, MS, Kuna, ID

  8. A good friend of mine breeds miniature horses. She bred 5 of her mares this past year. Unfortunately, in the last month she’s lost 3 foals, the most recent one being this past Saturday. They were all full term but all died at birth or just before giving birth. The vet took the 3rd foal, along with its placenta, and sent it to Cornell University to have it autopsied to determine the cause of the deaths. Unfortunately, we will not have the results for at least 2 weeks, which doesn’t help the current mare that is overdue.

    Her vet came out yesterday to do a sonogram and to check the 4th mare that is currently 3 days overdue, as of today 4/12/16. He gave her bad news and said that same thing will probably happen to this foal that the mare will "red bag". We are not sure why this is happening? The vet got in touch with Cornell and they suggested the following…and hopes the mare holds off and doesn’t give birth for 3 or 4 days to gets the meds in her system.

    Twice a day
    6 SMZs 500ml ea
    Banamine 125lbs
    Pentoxyfylline is 3ml

    It is our understanding that when the mare is about to give birth, we only have about 5 minutes to get the foal out to see if it can be saved. The mare is currently being watched around the clock with someone taking a shift. If you can give any insight as to why this could be happing to her mares as she has never had this happen to her in the past, it would be very much appreciated. Thanking you in advance for your time.

    (View Answer)

    Late term abortion in mares can be due to many reasons. Infections of the placenta, twins, toxins, or severe illness in the mare can all have adverse effects on the foal. Several years ago, a large number of abortions in Kentucky were eventually diagnosed as being caused by Eastern Tent Caterpillars on black cherry trees! The loss of three foals on one farm in a single year certainly suggests a common cause. But, as was seen in the case cited above, this could be the beginning of a lengthy detective story. The answer may be very simple. For example, older mares may have damage to the lining of the uterus related to age and other factors. If all three mares are older, this could be an unfortunate coincidence of spontaneous abortion in a population of aged individuals. However, the process could be much more complicated, or never really determined at all. 

    The term "red bag" refers to the premature separation of the placenta. If this occurs, the oxygen level in the blood stream of the foal declines rapidly and causes other, major complications. In cases like this, it is very important that the foal be delivered quickly and start breathing independently--five minutes may be too long. 

    The course of action suggested by the farm veterinarian is certainly advised. However, further investigation, including the results from the diagnostic lab, a thorough clinical history and environmental considerations will be necessary to discover the source of the problem and facilitate treatment and/or prevention. Madison Seamans, DVM, MS, Kuna, ID

  9. I have a horse that should be giving birth any day but today I noticed it looks like she has a lump on the back of her belly. Could it have anything to do with her milk production? Is this normal?

    (View Answer)

    The presence of some swelling in front of the mammary glands is a common occurrence late in pregnancy. However, it is also common in mares with "a few extra pounds". Although the appearance of a lump in this area is probably not a cause for alarm, you should have her checked by a veterinarian. A small percentage of mares that were pregnant the previous spring lost the foal sometime during the winter with no obvious signs. In anticipation of the new birth, the mare was fed liberally. The extra feed in the non-pregnant may have caused the extra fat deposits noted here today. Therefore, it would be good to know if the mare is still pregnant and the lump you noted is part of the normal process of mammary development.  Madison Seamans, DVM, MS, Kuna, ID

  10. My Appendix quarter horse is 23-years-old and lives in an area of California where the temperatures can get up to 100°F. I have had him for seven years and we have always lived in the same area. His penis is peeling and I can't find anything online that would explain why this would be happening. Can you offer your expert advice?

    (View Answer)

    A common request for equine practitioners is to "clean the sheath". Although most horse people consider this effort as one of basic hygiene, a more important reason is to exam the skin in this area for early detection of skin cancer. Though not common, this is seen in Appaloosa and Paint horses more often than their solid-colored stablemates. As this occurs in a location that is not readily visible, a thorough exam of the penis and prepuce (skin around the "sheath") will require sedation. This will allow the horse to completely let loose, or "prolapse" his private parts.

    Once the area in question is exposed, the horse can be examined for the presence of a "bean", or waxy buildup in two pockets around the tip of the urethra common in many geldings. The smegma "beans" can be removed easily in sedated horses. The scaly, flakey material is almost always present on the rest of the penis, and even after a thorough cleaning, will return within a few days as a part of the normal process of skin/mucus membrane growth. If the tissue under the scales looks normal, there is probably no reason for concern, but you should consider having this done annually for early detection of any potential problems. Madison Seamans, DVM, MS, Kuna, ID

  11. I have a Thoroughbred mare that was bred and was ovulating from both ovaries. The veterinarian said that if she conceives twins, they will pinch one off. How safe is this procedure and how risky is it to the mare and remaining embryo? 

    (View Answer)

    The presence of multiple follicles is normal during every heat cycle in mares. Multiple ovulation occurs during about 25% of cycles, though twin conceptions are much less frequent. Although it may seem like getting two foals for the price of one, twin pregnancy is not good, as it is a common cause of late term abortion. Even if the twins survive to term, the foals almost always suffer major complications, requiring extensive veterinary care and a poor prognosis.

    An examination with ultrasound 14 days after breeding is the first step in helping the mare maintain a normal pregnancy to term. In the relatively uncommon event of twin pregnancies, ultrasound imaging allows us to reduce or "pinch" one of the embryos with minimal risk to the mare or the surviving embryo. Of course, all medical procedures involve some risk, and the location and age of the embryos will have some bearing on the treatment plan. However, this is a routine part of modern equine practice and the benefit far outweighs any potential harm to the mare. From a practical standpoint, a late term abortion of both fetuses is a distinct possibility and the mare will thus lose an entire year of productivity. With this in mind, early detection of equine pregnancy is an imperative part of good broodmare management. Madison Seamans, DVM, MS, Kuna, ID