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Discussion Starter · #1 ·
Can anyone explain to me what we are supposed to do with information from a veterinary ophthalmologist where he says one dog is not recommended for breeding unless getting a DNA test for RD/OSD (AND) another one is not marked as normal even though he thinks the abnormality is the result of injury and not really a fold (AND) two dogs that have totally clear eyes and ARE MARKED NORMAL will still need to be tested by a veterinary ophthalmologist again every year since just because they are clear now, they might not be clear next year?

I am SOOOOO corn--fused!!!!!

If I buy a pup out of parents who passed the CERF or the CAER that means NOTHING? Because the parents might still be carriers?

If mom & dad were "clear" or "normal" but they can still produce pups that have OD, then why do the test in the first place???? And if the dog has NOT normal or clear eyes they might pass a DNA test because the folds that the vet saw were not an indication of OD?

If they do not clear the CERF/CAER but they clear the DNA test, we can submit this info to the OFA and get the dog re-categorized?

Why doesn't the OFA just require the DNA test, same as EIC & CNM and skip the ophthalmologist in the first place?

And finally: If mom and dad were both "normal" or "clear" and the pup was "normal" or "clear at 8 weeks, the how on God's green earth can the pup NOT pass the test at two years old?

Am I the only one that can't figure this whole thing out?
 

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CERF looks at many eye problems, no just RD. You check them yearly to ensure problems do not occur as they age. Only problem there is that often dogs have been bred by the time these later in life diseases appear. Other things they look for are cataracts and PRA.

RD/OSD carriers may have folds, they might not. They may disappear for a whole when young and reappear later. Best course of action is the DNA test for rd/OSD in addition to yearly CERF.
A carrier can be bred, but it is likely carrier pups will be produced, have RD, and be unable to pass a CERF.
There are some forms of retinal folds not related to rd/OSD. If a dog has folds on CERF, do DNA test. If clear DNA, send results to OFA and the dog can have a CERF number with breeder option noting the problem.

Now for PRA. Carriers have no symptoms. Affecteds often show no symptoms and pass CERF for several years. Only way to know status for breeding purposes is DNA test.
 

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If the breeding stock is DNA tested for PRA and RD/OSD, and they do not carry the alleles for these eye diseases, they will not produce pups affected by these specific mutations. On the other hand, if both parent Labs are carriers of the mutation for PRA then the parents may be asymptomatic and can pass the eye exam but they will produce affected pups.

There may be other forms of PRA etc. in Labradors caused by different mutations, and so the DNA tests will not screen for all forms of PRA.

PRA and RD are just 2 hereditary eye diseases. The eye exams screen for more than just these two hereditary eye diseases.

Since some of the eye diseases are late onset, a dog can have perfect eyes at age 1 year and pass the eye exam but have impaired vision at later ages. A dog with two copies of the PRA gene, for example, may pass an eye exam when very young year but be blind at age 5 years.
 

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Discussion Starter · #4 ·
Thank you Mary Clark & Renee P. But.....I am still confused. Are the DNA tests separate for PRA & RD/OSD? And if someone thinking of breeding a dog whose parents both passed CERF, the pup passed CERF at 7/8 weeks...DNA test or multiple DNA tests came back clear, a litter could still have severe issues?

I just wish there were a clear standard. It seems to me that we should do the DNA test (or tests) first and then take the dog to the Ophthalmologist so that when he/she sees folds while the dog is bucking and twisting as they shine their lights in pup's eyes, everyone can say, ok those folds are ruled out for causing x or y. It also seems like, if the dog is "clear" the DNA test/s will say "Wait a minute! This dog is NOT clear--even though it looks clear."

I am horrified that after being careful that my dog's parents were screened, AND the pup was screened at 7/8 weeks by breeder, she is now exhibiting problems (only visible to the ophthalmologist) at 2 yo. Now I need to spend $100s more on DNA testing and am not sure if that will help get answers. If DNA comes back positive for RD or PRA, obviously there is an answer. (AND NOT THE ANSWER I WANT!) But if DNA comes back with "clear" status (or whatever) then I still don't know if her pups will have problems?

It is so frustrating that even with everyone being so "responsible" I still have a dog with "folds" in her eyes.

Top it off with the conversation I overheard (after the group testing event was over) between the vet testing all the dogs for heart defects and the ophthalmologist about how inexact their tests are...

Is there currently a standard that any dog bred (whether clear on CERF or not) must be DNA tested as well?
 

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I think the reason for the CERF is that it is a less expensive test and your first warm and fuzzy about the state of the dog's eyes...if something crops up, then you can proceed down the more expensive route of DNA testing.

Sorry about your puppy, I hope things turn out for the best....
 

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The mutation that causes PRA in Labrador Retrievers is different than the one that causes RD/OSD. A sire and dam cannot pass on genes to progeny unless they carry the genes, so no, parents who do not have the PRA or RD/OSD genes will not pass them on to progeny. This is junior high biology.

The DNA test for PRA in Labrador Retrievers is for the common recessive form of the disease. It is believed that carriers of this PRA gene have normal eyes, and therefore a CERF exam will not identify carriers. Therefore two CERF normal dogs can produce PRA affected dogs. There may be other forms of PRA in Labradors that have not been identified, and therefore that would be missed by the existing DNA test.

The RD/OSD mutation is thought to be a dominant trait with incomplete penetrance with respect to its effects on vision. Dogs carrying only one copy of the gene may or may not have normal CERF exams, they may or may not have visual defects. Therefore a parent with a normal CERF exam could be a carrier of the RD/OSD gene and therefore produce affected dogs. I have no idea how likely this is.

There are other things that cause abnormal eye exams, some are hereditary some are not. Some are equivocal, like the retinal folds.

The Optigen site has pretty good info about the PRA (http://www.optigen.com/opt9_test_prcd_pra.html) and RD/OSD (http://www.optigen.com/opt9_rdosd.html) mutations.

I have to bring my dogs in to the eye vet soon, I will ask about how PRA carrier dogs do on the CERF exams. I suspect they pass when young, but fail as they age. I will also ask about the likelihood of a carrier of the RD/OSD gene passing the CERF test. Also a list of other hereditary eye diseases that the CERF exams screen for, in addition to the two we have DNA test for, would be nice to have.
 

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Discussion Starter · #7 ·
"A sire and dam cannot pass on genes to progeny unless they carry the genes, so no, parents who do not have the PRA or RD/OSD genes will not pass them on to progeny. This is junior high biology."

Renee: This is part of my confusion. If the genetics may or may not show up in a CERF test and dogs who test clear can still have the genes for PRA and RD/OSD (AND) dogs who do not pass the CERF might NOT have the PRA/OSD genes....I am just wondering why we are all supposed to have the dogs get a CERF test. The CERF test seems pretty useless to me.

Is it like FOM says? That if the dog passes the CERF test we get to feel all "warm and fuzzy" about having a clear dog? And get a free pass to breed a dog that might very well be a carrier--even though it passed the CERF?

When buying a pup in the future, I was just wanting to know how to get a clear pup? It seems like there is no method to find a clear pup? I am hoping I am wrong and someone will set me straight about what the proper method is for making sure pups are clear.
 

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The annual eye exams are like for humans--you don't just have your eyes checked once and never check again. All sorts of things can pop up--injuries, as well as genetic things or cancerous growths.

There are multiple forms of PRA, multiple forms of RD. The genetic tests help us eliminate THOSE versions, but there may be others that do not show up until later in life. Unfortunately for Labradors, many of the genetic eye diseases may not show up until later in life.

It is really not very different from hips and elbows. We can have good or excellent parents and still produce a pup affected with hip dysplasia. Everything we do as breeders is to reduce the incidence as much as possible for the things we CAN test for.

Meredith
 

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PRA and RD/OSD are just two hereditary eye diseases occurring in Labrador Retrievers. The CERF screenings are supposed to help identify dogs with signs of ALL hereditary eye disease, not just the those two. The CERF screenings in breeding stock will increase the chances but not guarantee that puppies will have healthy eyes. The best you can do is stack the odds in your favor.

If it turns out your pup has hereditary eye disease, you should be able to find other affecteds in the pedigree. So even if the parents don't have eye disease, if the pup has it and it is hereditary you should find it somewhere else in the pedigree.

I'm just repeating myself...

This looks like a good summary article: https://purinaproclub.com/resource-...g-help-breeders-reduce-blindness-in-labradors
 

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The confusion seems to be the OP calling CERF exam a genetic test. CERF is physical exam of the eyes, the vet is looking for signs of problems that may be, but not necessarily caused by genetics. The PRA and RD/OSD are 2 seperate DNA screening tests done with cheek swabs sent to lab. The CERF must be repeated annually, as physical condition of eyes changes over the years. DNA tests are a one time deal, as cannot change your DNA. The current available DNA eye tests do not cover all the eye problems our dogs can develop. Therefore the 2 different ways of testing are required, DNA and physical exam.

The confusion re DNA tests recommended after CERF....vet saw something that lead him to believe dog may develop problem in future. Only way to rule it out is DNA testing.

Is that little clearer?
 

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Kate, all of my litters born since 1999 have been CERF'd as puppies at ~7-8 wks. I have been lucky not to see anything outside of the occasional PPM (persistent pupillary membrane-- embryonic tissue that normally disintegrates w/ time). I have however been present w/ other breeders who learned of congenital blindness in one eye (this pup *was* pegged to go to go to a performance home initially!), retinal folds (which may or may not be genetic... hence why they take the next step and do the DNA test on those pups), etc. Other illnesses and infections can be caught by eye exams... the eyes are the window to a dog's health. I have had friends w/ severely allergic dogs or dogs fighting some other immune issue learn (thankfully early enough to treat in most cases) that their dogs' retinas were starting to detach due to illness.

So, there are a NUMBER of things that the annual EYE (as it's now called) exam can catch as others are saying here. A clear puppy CERF is a good start. At least you can say they had normal eyes when they left. If all breeders did an annual CERF/EYE exam, they'd know a lot more about their lines... because certainly other types of folds, cataracts etc can pop up over the years. One of the Seeing eye dog groups had some rude awakenings about folds back many years ago when they'd wait until 2yo to check for the first time. That's how the annual recommendations came to be as I recall. They started checking the pups at ~7 wks, then send the pups out to the puppy raisers, then bring them back at 18 mos or so only to find out there were folds that developed and they spent all that money for naught.

The CERF/EYE exam certificate is only good for 1 year as a result. Folds can pop up for the first couple years or disappear in some cases before age 2 and if you don't check, you'd not know! Juvenile cataracts can and do continue to pop up thru age 7 or 8 as I recall.... Before getting the PRA test in 2003, the CERF was the only way to determine if the lines had risks of PRA, and most of those dogs didn't start exhibiting signs of it until 6-8 yrs old, if not later. Life is much nicer now that we have a DNA test to rule that one out of a breeding program just as now they can at least rule out the one form of fold that is genetic by the test.

Not every fold or issue is genetic, but if the fold (or cataract etc) is located at a point on the eye that affects vision, it's good info to have. The info on whether it's genetic or not is important probably only if you plan to breed the dog.

Hope this helps clear your confusion.

Anne
 

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Discussion Starter · #12 ·
Kate, all of my litters born since 1999 have been CERF'd as puppies at ~7-8 wks. I have been lucky not to see anything outside of the occasional PPM (persistent pupillary membrane-- embryonic tissue that normally disintegrates w/ time). I have however been present w/ other breeders who learned of congenital blindness in one eye (this pup *was* pegged to go to go to a performance home initially!), retinal folds (which may or may not be genetic... hence why they take the next step and do the DNA test on those pups), etc. Other illnesses and infections can be caught by eye exams... the eyes are the window to a dog's health.


"I have had friends w/ severely allergic dogs or dogs fighting some other immune issue learn (thankfully early enough to treat in most cases) that their dogs' retinas were starting to detach due to illness. "

Anne
Anne: This is SOOOO interesting! Are you saying that allergies, infections and immune issues are able to be detected by an eye exam? And that a retina may start to detach because of some other issue in the body? Where can I access more information about this?

The dog I am concerned about with the partially detached retina was starting to show severe signs of allergies. I have been experimenting with her diet and she is now NOT showing allergy symptoms. Are the retinas able to re-attach if the systemic problem is corrected? Are the dogs blind with a detached retina?

Please, please tell me more about what you know about this subject.
 

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Sorry to just be seeing this Kate. Feel free to call me tomorrow but yes, a friend w/ a Lab w/ severe allergies was nearly at the point of retinal detachment a few years ago. Odd thing was, the only reason she was there was that she had a young pup from me as well who I insisted on having at last semi-regular eye checks at our clinic and I had convinced her enough to bring her other lab for a check.....

Another pup owner out of state w/ an older bitch was having what appeared to me to be thyroid issues years ago (girl had quit having heat cycles altogether and was obese) --ended up w/ SARDs (sudden acquired retinal detachment). Too bad it went to blindness in that case as I kept suggesting thyroid testing for years prior. :(

In both cases, my ACVO said yes, she'd have caught the issues earlier had they done regular eye checks. I'm at the point that I would just do them, breeding stock or not, at least every other year but really, if you have an ACVO near you, why not? I was just talking to our regional ACVO at the dog shows last weekend as I've got an old girl w/ what I think may be Horner's syndrome (not a big deal, but I wanted to run it by her). I'd run down to her in a heartbeat if I thought it was anything more than that.
 

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Re the previous question about retinas "reattaching". Retinas that completely detach must be diagnosed AND corrected surgically within 24hr, or dog is permanantly blind in that eye. I had a small tear in my retina and had laser surgery to "tack" down that area to prevent detachment. If I had been a dog, there would have been no way for me to communicate my symptoms, which were a sudden increase of a large number of "floaters" which are floating black spots across your field of vision. Mine was related to complications of severe myopia and aging. Here is simple explanation re dogs-
http://www.petplace.com/dogs/retinal-detachment-in-dogs/page1.aspx
 

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Sorry to just be seeing this Kate. Feel free to call me tomorrow but yes, a friend w/ a Lab w/ severe allergies was nearly at the point of retinal detachment a few years ago. Odd thing was, the only reason she was there was that she had a young pup from me as well who I insisted on having at last semi-regular eye checks at our clinic and I had convinced her enough to bring her other lab for a check.....

Another pup owner out of state w/ an older bitch was having what appeared to me to be thyroid issues years ago (girl had quit having heat cycles altogether and was obese) --ended up w/ SARDs (sudden acquired retinal detachment). Too bad it went to blindness in that case as I kept suggesting thyroid testing for years prior. :(

In both cases, my ACVO said yes, she'd have caught the issues earlier had they done regular eye checks. I'm at the point that I would just do them, breeding stock or not, at least every other year but really, if you have an ACVO near you, why not? I was just talking to our regional ACVO at the dog shows last weekend as I've got an old girl w/ what I think may be Horner's syndrome (not a big deal, but I wanted to run it by her). I'd run down to her in a heartbeat if I thought it was anything more than that.
I am quite flabbergasted by this response. For starters, SARDS usually refers to Sudden Acquired Retinal Degeneration Syndrome, it is not about disease that leads to retinal detachment.

You are blaming the owner for not getting biannual eye checks, as in an eye check every two years? What does "Sudden" then mean?

Sorry, but I'm flabbergasted!
 

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I am quite flabbergasted by this response. For starters, SARDS usually refers to Sudden Acquired Retinal Degeneration Syndrome, it is not about disease that leads to retinal detachment.

You are blaming the owner for not getting biannual eye checks, as in an eye check every two years? What does "Sudden" then mean?

Sorry, but I'm flabbergasted!
Mitty, I may have confused the "D" part of that acronym but that is what my ACVO and her ACVO both said-- the SARDs is related to other immune issues which if caught in a timely manner, can be prevented. For years that particular girl was obese, for apparently no reason other than thyroid. And oh, yes, she had allergies too. Then sudddenly went blind. SARDs was the dx made by an ACVO in her state and by that time, there was no possible way to reverse or even slow the issue.

I stand by my statement that I like to see folks have regular eye checks on their dogs, esp those who are competing or hunting. CERF/EYE exams can tip folks off to a lot of health issues well in advance of the problem becoming "that problem". 2yrs, 1 yr, whatever.... I realize not everyone has a clinic locally as we do, but it's a good thing to do.

Nuff said. It amazes me how many breeders THINK CERF/EYE exams are good for the life of the dog. That'd be like me saying my eyes and prescriptions haven't changed since I was a baby and that clearly (squinting) isn't true.
 

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Discussion Starter · #17 ·
Mitty, I may have confused the "D" part of that acronym but that is what my ACVO and her ACVO both said-- the SARDs is related to other immune issues which if caught in a timely manner, can be prevented. For years that particular girl was obese, for apparently no reason other than thyroid. And oh, yes, she had allergies too. Then sudddenly went blind. SARDs was the dx made by an ACVO in her state and by that time, there was no possible way to reverse or even slow the issue.

I stand by my statement that I like to see folks have regular eye checks on their dogs, esp those who are competing or hunting. CERF/EYE exams can tip folks off to a lot of health issues well in advance of the problem becoming "that problem". 2yrs, 1 yr, whatever.... I realize not everyone has a clinic locally as we do, but it's a good thing to do.

Nuff said. It amazes me how many breeders THINK CERF/EYE exams are good for the life of the dog. That'd be like me saying my eyes and prescriptions haven't changed since I was a baby and that clearly (squinting) isn't true.


Wow. Thanks to everyone who chipped in with information. And, Anne, I really was one of those folks that thought eye exams for dogs were good for the life of the dog. You guys have helped me understand better.

I had NO idea whatsoever that eye exams could tell so much about general issues of health! From what I have learned here from all of you it seems like an annual checkup with the eye doc would get the most information about what's going on since the dogs can't tell us.

So what I have learned about the subject is that for the purposes of buying a pup (or coming at it from the other direction for the purposes of breeding a dog) I would want DNA testing to rule out PRA or dwarfism.

Apparently there are other genetic issues for which no DNA test has yet been developed and for that reason the dog should be examined by the eye doc annually or at least before each breeding.

Further benefits from frequent eye exams are that they can expose other systemic autoimmune, hormonal or thyroid problems going on in the dog.

Please y'all let me know if I have it wrong!

I am still wondering why so many breeders advertise that the parents had "clear" CERFs way back in 2006 or 2007 as if that means something. I don't remember seeing ads for pups where both parents were cleared for PRA & dwarfism through DNA testing. It seems misleading, but then I think most people who are breeding field bred Labs are maybe not so aware of the need for DNA testing on these issues? How to make more people aware that they should be doing more than just a CERF before breeding a dog? Why are EIC & CNM issues more important than dwarfism? Is it a more rare occurrence?
 

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[/B]

Wow. Thanks to everyone who chipped in with information. And, Anne, I really was one of those folks that thought eye exams for dogs were good for the life of the dog. You guys have helped me understand better.

I had NO idea whatsoever that eye exams could tell so much about general issues of health! From what I have learned here from all of you it seems like an annual checkup with the eye doc would get the most information about what's going on since the dogs can't tell us.

So what I have learned about the subject is that for the purposes of buying a pup (or coming at it from the other direction for the purposes of breeding a dog) I would want DNA testing to rule out PRA or dwarfism.

Apparently there are other genetic issues for which no DNA test has yet been developed and for that reason the dog should be examined by the eye doc annually or at least before each breeding.

Further benefits from frequent eye exams are that they can expose other systemic autoimmune, hormonal or thyroid problems going on in the dog.

Please y'all let me know if I have it wrong!

I am still wondering why so many breeders advertise that the parents had "clear" CERFs way back in 2006 or 2007 as if that means something. I don't remember seeing ads for pups where both parents were cleared for PRA & dwarfism through DNA testing. It seems misleading, but then I think most people who are breeding field bred Labs are maybe not so aware of the need for DNA testing on these issues? How to make more people aware that they should be doing more than just a CERF before breeding a dog? Why are EIC & CNM issues more important than dwarfism? Is it a more rare occurrence?
fastpup,

I'm new to this thread, but have been following it and I'd say your take on the facts is accurate.

Concerning the emboldened statements above, if a dog's eyes were found to be normal several years prior that does mean something; at least the dog's eyes were not affected by an abnormality at that time. However, it doesn't mean that he may not have developed an abnormality in the ensuing years. That's why, on more than one occasion, I've requested that a prospective stud dog have his eyes re-examined before I consider using him as a sire. Keep in mind that a dog who has passed his eye exam at the age of 8 years or more is very likely to remain free of inherited ocular abnormalities since nearly all would be observable on examination by that time. Again, a normal eye exam at that age may mean he's not affected, but not that he isn't a carrier. Only a genetic test will tell you that.

I raise field bred Labs and my current brood bitch is tested to be clear of prcd-PRA and RD/OSD. Not all people who raise a litter of Labs are aware of the tests or are willing to risk finding out that their "perfect" dog may have an issue. Ignorance is bliss. Money shouldn't be an issue as the testing is relatively inexpensive.

I'm not sure about the relative frequency of prcd-PRA, RD/OSD, EIC, or CNM in the field Lab gene pool. I'd be interested in knowing the answer to that question.

Swack
 

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It took awhile to get everyone on board for the EIC & CNM, which were definite issues that people could see in pups & adult dogs that were affected. The test was more of a definite (black and white), but it was also an elephant in the room, in field stock that (once there was a test) couldn't be ignored. The PRA test was only an at risk test for awhile, basically saying that your dog might have a risk of developing the condition or might not. Also there are many forms of PRA and many other conditions that might affect Eyes, so testing for one will not guarantee, that your pup will not get the condition, nor that the parents don't carry something relating to eyes that doesn't have a test. A lot of people were hesitant to come on board for a test that may or may not predict a chance of something developing. The only way to know your dog had a condition was to catch it in an eye exam; which pretty much catches anything that might affect the eye. The issue is still pretty grey although the test is now a (affected, carrier, clear) and (not at risk), but it's only for particular types of genetic PRA. Annual eyes test are still necessary to check for all conditions. Also for most field breeders PRA is not an Elephant in the room, that they feel needs to be addressed. Most breeders know their lines and have never seen the condition, nor produced a dog with the condition; thus the testing gets put aside for other tests that the breeder considers more important to their breeding-lines. If we tested a dog for everything we could test a dog for, it would be very expensive and most of the tests would be pointless for our particular breeding stock. Most breeders do what they can to produce the best pups they can, and then they also offer a blanket health guarantee over issues that can be determined to be inherit-genetic. So a buyer has a buffer against any genetic issue that pops up, whether the parents were tested or not; if a pup comes up affected with a genetic issue the breeder tests his stock, and the test becomes normal for his lines. If the issue never comes up that particular test is put aside for others that are more important to his line-stock.
 

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Yes Kate,

I think you're on the right track now. I know, it drives me crazy to see the one time CERF done at 2 yrs old and that's it-- the people think they are good for life. I'm w/ Swack and feel that once the dog hits 8 and is still clear, we're entitled to feel pretty good about things genetically (esp if you've had the PRA testing done). Our PSLRA club code of Ethics states that all breeding stock should be tested annually for CERF/EYE thru age 10 regardless, however, so I try to encourage stud dog owners to keep them current.

I recently had someone wanting to use my co-owned stud dog on referral by one of my vets. We went thru all the testing requirements and she got the hips, elbows and EIC testing (and even brucella screen which I told her to wait on!) done... bitch comes into season and she wants to get this ball rolling. I asked her where her CERF/EYE results were (I had even given her the name / phone of the ACVO to set up an appt 2 mos earlier). Didn't do it, and wasn't going to do it as she's never had any eye problems! I said, Fine, no deal. She was MAD! Oh well. Apparently she's been breeding 20 yrs and never has done CERF.. and if you don't test, you SURELY don't know what's back there! Unbelievable.

This same woman was going in for cataract surgery on her own eye about the time we were first chatting, so you'd think she'd understand the situation a little better than most but I guess a dog is a dog is a dog to some.
 
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