How to Tell the Gender of a Mare's Unborn Foal
Decide what you will do with the information on the foal’s gender., Schedule an appointment with your veterinarian., Learn the limitations of the procedure., Obtain the proper supplies., Use the transducer to scan the unborn foal., Determine the...
Step-by-Step Guide
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Step 1: Decide what you will do with the information on the foal’s gender.
From a business perspective, the gender of the unborn foal can have many implications.
Commonly, the gender can influence whether to keep or sell your mare.For example, you may decide to keep the mare if she is having a filly (female), or sell if her she is having a colt (male).Some horse owners may also consider selling a mare’s weanling based on the gender of her unborn foal.The gender of the unborn foal can also influence decisions concerning appraisal and insurance coverage.Horse owners may want a filly or colt by a particular sire.
For example, if a mare is pregnant with a filly by a particular sire, but the owner wants a colt, the owner may want to breed his or her mare to the same sire again to try for a colt.Discuss the potential options with your veterinarian.
You should decide what is best for you, whether it is from a business or personal perspective. -
Step 2: Schedule an appointment with your veterinarian.
During your mare’s pregnancy, there will be only one window of time (day 60 to 75) during which the unborn foal’s gender can be determined with nearly 100% accuracy.
Because of this, it will be important for you to schedule an ultrasound appointment with your equine veterinarian during this timeframe.Before scheduling the appointment, refer to your breeding records to determine the first day of your mare’s pregnancy.
Your veterinarian may want to perform the ultrasound at his or her clinic.
Confirm the location of the ultrasound when scheduling the appointment. , It is very important to understand that ultrasonography will only determine the unborn foal’s gender.
It should not be used to control the gender.
In other words, if the unborn foal’s gender is not what you desire, you should not terminate the pregnancy and quickly re-breed your mare to try to obtain the desired gender.Keep in mind that, by the time the unborn foal’s gender can be accurately determined by ultrasound, your mare will be too far into her gestation to re-breed her in time to have a normal foaling date the following year., Your equine veterinarian will perform the ultrasound, and will thus supply the necessary instrumentation to perform the ultrasound.
Supplies include an ultrasound machine, a five-megahertz transducer, and a portable viewing stand.Your veterinarian may also bring a printer to print out the images.The ultrasound machine will transmit high-frequency sound waves through the transducer.
When the sound waves hit a barrier between body tissues (e.g., soft tissue and bone), they will get reflected back to the transducer and then relayed back the machine to produce a two-dimensional image (called a sonogram).Because your mare will need to stand still during the procedure, your veterinarian may want to use fly repellent to keep away any distracting flies., Your veterinarian will insert the transducer into your mare’s rectum to view the unborn foal.
Before trying to determine the gender, he or she will first scan the unborn foal in its entirety.Be aware that an ultrasound may reveal that the unborn foal is not alive.If your veterinarian determines that the unborn foal is dead or dying, he or she will discuss how to handle the miscarriage. , After scanning the entire unborn foal, your veterinarian will then look for a particular body part—the genital tubercle—to determine the gender.
Although the genital tubercle is visible by ultrasound as early as day 40 to 45 of your mare’s pregnancy,it will be most easily visible between days 60 and
75.
At around day 55, the genital tubercle moves from its original position towards other body parts.
It will move towards the umbilicus in colts and towards the anus in fillies—this will be most clear via ultrasound after day
60.The tubercle will eventually develop into mature sexual organs: the penis in colts and the clitoris in fillies., External genitalia can be observed via ultrasound around day 110 of your mare’s pregnancy.Be aware, however, that external genitalia can be difficult to differentiate from surrounding soft tissue.Because of this, determining gender using external genitalia is not as accurate (about 80% accuracy) as identifying the genital tubercle’s location., The 'nail test' is a myth on how to determine the sex of the unborn foal.
To perform the test, you would take a section of hair from the mare's tail and tie a nail to it.
You would then hold the section of hair near your mare's hips.The myth is that the foal is a male if the nail swings back and forth in a straight line, and female if the nail swings in a circular motion.This is not a scientifically accurate method, and should not be used to determine the sex. -
Step 3: Learn the limitations of the procedure.
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Step 4: Obtain the proper supplies.
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Step 5: Use the transducer to scan the unborn foal.
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Step 6: Determine the gender of the unborn foal.
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Step 7: Observe the external genitalia.
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Step 8: Do not use the 'nail test.'
Detailed Guide
From a business perspective, the gender of the unborn foal can have many implications.
Commonly, the gender can influence whether to keep or sell your mare.For example, you may decide to keep the mare if she is having a filly (female), or sell if her she is having a colt (male).Some horse owners may also consider selling a mare’s weanling based on the gender of her unborn foal.The gender of the unborn foal can also influence decisions concerning appraisal and insurance coverage.Horse owners may want a filly or colt by a particular sire.
For example, if a mare is pregnant with a filly by a particular sire, but the owner wants a colt, the owner may want to breed his or her mare to the same sire again to try for a colt.Discuss the potential options with your veterinarian.
You should decide what is best for you, whether it is from a business or personal perspective.
During your mare’s pregnancy, there will be only one window of time (day 60 to 75) during which the unborn foal’s gender can be determined with nearly 100% accuracy.
Because of this, it will be important for you to schedule an ultrasound appointment with your equine veterinarian during this timeframe.Before scheduling the appointment, refer to your breeding records to determine the first day of your mare’s pregnancy.
Your veterinarian may want to perform the ultrasound at his or her clinic.
Confirm the location of the ultrasound when scheduling the appointment. , It is very important to understand that ultrasonography will only determine the unborn foal’s gender.
It should not be used to control the gender.
In other words, if the unborn foal’s gender is not what you desire, you should not terminate the pregnancy and quickly re-breed your mare to try to obtain the desired gender.Keep in mind that, by the time the unborn foal’s gender can be accurately determined by ultrasound, your mare will be too far into her gestation to re-breed her in time to have a normal foaling date the following year., Your equine veterinarian will perform the ultrasound, and will thus supply the necessary instrumentation to perform the ultrasound.
Supplies include an ultrasound machine, a five-megahertz transducer, and a portable viewing stand.Your veterinarian may also bring a printer to print out the images.The ultrasound machine will transmit high-frequency sound waves through the transducer.
When the sound waves hit a barrier between body tissues (e.g., soft tissue and bone), they will get reflected back to the transducer and then relayed back the machine to produce a two-dimensional image (called a sonogram).Because your mare will need to stand still during the procedure, your veterinarian may want to use fly repellent to keep away any distracting flies., Your veterinarian will insert the transducer into your mare’s rectum to view the unborn foal.
Before trying to determine the gender, he or she will first scan the unborn foal in its entirety.Be aware that an ultrasound may reveal that the unborn foal is not alive.If your veterinarian determines that the unborn foal is dead or dying, he or she will discuss how to handle the miscarriage. , After scanning the entire unborn foal, your veterinarian will then look for a particular body part—the genital tubercle—to determine the gender.
Although the genital tubercle is visible by ultrasound as early as day 40 to 45 of your mare’s pregnancy,it will be most easily visible between days 60 and
75.
At around day 55, the genital tubercle moves from its original position towards other body parts.
It will move towards the umbilicus in colts and towards the anus in fillies—this will be most clear via ultrasound after day
60.The tubercle will eventually develop into mature sexual organs: the penis in colts and the clitoris in fillies., External genitalia can be observed via ultrasound around day 110 of your mare’s pregnancy.Be aware, however, that external genitalia can be difficult to differentiate from surrounding soft tissue.Because of this, determining gender using external genitalia is not as accurate (about 80% accuracy) as identifying the genital tubercle’s location., The 'nail test' is a myth on how to determine the sex of the unborn foal.
To perform the test, you would take a section of hair from the mare's tail and tie a nail to it.
You would then hold the section of hair near your mare's hips.The myth is that the foal is a male if the nail swings back and forth in a straight line, and female if the nail swings in a circular motion.This is not a scientifically accurate method, and should not be used to determine the sex.
About the Author
Richard Robinson
Enthusiastic about teaching practical skills techniques through clear, step-by-step guides.
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