Reptile & Amphibian Forums

Jeff, Dave and whoever uses the doppler fetal heart tone monitors...

I've looked at a few models and it seems that the mhz on the probe could make the difference in hearing the heart beat tones or not. I thought it'd be interesting to try this technology out on some ferrets this year. I've got a couple who's pregnancy I confirmed via palpation so they'd make good test subjects. I had a look on ebay and found monitors from 2mhz - 4mhz. Sonotrax looks like the better hardware as compared to the no-name stuff. Any words of advice? Thanks in advance.
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Julie
www.[url ban]/gfx

Julie,
....I do love Ebay. My Doppler is a Contec Sonotrax Model B. It is 3Mhz. It works great but there are limitations. The greatest limitation is that you have to get a complete acoustic seal over the entire face of the probe and the face of the probe is too large for working with snakes. The scales on snakes cause small gaps around the edge of the probe face that have to be filled with plenty of sonogram transmision gel. As you move the probe along looking for heart tones it loses seal and the signal is lost. I did do some experimentation with the gravid snake submerged in water and had mixed results. At times it seemed to solve the acoutic sealing problem and at other times it seemed to not work so well. All of the reasonably priced Dopplers I saw on Ebay when I was looking had 2 and 3 Mhz probes and all have fairly large probes. Some of the much more expensive cardiac/vascular Dopplers are 8Mhz and have very small probes which would be ideal. Ideal, that is if 8Mhz is appropriate for our application. With my Doppler if I liberally apply ultrasound transmission gel and search I can find fetal heart tones in the last half of gravidity. Fetal heart tones of Rainbow Boas younger than that are probably too faint to find with these monitors. Perhaps the greater sensitivity of an 8Mhz model would work better. Using an 8Mhz vascular Doppler at work I am able to find very faint signals from greatly decreased blood flow in vessels in injured extremities. Reptile breeders who have much more sophisticated Doppler sonographs with imaging (like the sonographs used for imaging human fetuses) report problems related to probe size and incomplete acoustic sealing like I find with my much simpler fetal heart monitor. Some people have success with theirs and others do not. In summation, fetal heart monitors are an interesting tool for Boa breeders though perhaps we have not yet found the ideal frequency and probe size for our application.
....I do wonder if the hair on your Ferrets will also cause acoustic sealing problems?
Jeff

>>Jeff, Dave and whoever uses the doppler fetal heart tone monitors...
>>
>>I've looked at a few models and it seems that the mhz on the probe could make the difference in hearing the heart beat tones or not. I thought it'd be interesting to try this technology out on some ferrets this year. I've got a couple who's pregnancy I confirmed via palpation so they'd make good test subjects. I had a look on ebay and found monitors from 2mhz - 4mhz. Sonotrax looks like the better hardware as compared to the no-name stuff. Any words of advice? Thanks in advance.
>>-----
>>Julie
>>www.[url ban]/gfx

Thanks for the info Jeff. I've looked around ebay and it seems that there's 2 types of "vascular" dopplers from Sonotrax. One is the normal body "vascular" (looks like 4mhz or 8mhz) probe and they other is the normal body somehow tuned for vascular usage with what appears to be the same probe. The one that's marketed a the "true" vascular doppler is about $50 more than the usual model with the same probe.

It looks like the 4mhz and 8mhz probes are have a smaller face to seal than the 3mhz probe. Hopefully I'll be using this on BRB mommas in the future as well. The ferret momma is going to have less muscle between the doppler and the uterine horns than a snake momma so I'm betting 4mhz would be fine. Then again, the geek in me wants the 8mhz. Do you think there's a great difference between 4mhz and 8mhz? Do you think either would be a clearer sound or invite more noise unnecessary? If yours is one that can change probes, I'll be happy to send the smaller probe down to you when your girls are ready to have their bellies checked.

The ferret bellies are pretty lightly haired, I'm thinking it wont be as difficult to keep a seal on them. They start to lose all of that belly hair about 10 days before they're due. They're notorious for full-blown false pregnancies so having a tool that would be able to tell if they've carried to term or if they've absorbed and are just falsing would be great.
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Julie
www.[url ban]/gfx