it's possible that the estroven may not have had the protective effects that the vet intended. there isn't any real estrogen in it just plant estrogens and a lot different herbs to calm menopause symptoms. that could be part of a cause of the issues. here's a great article on exactly what's in estroven: <link>
what are the long term effects of estrogen overdose in a dog? . my dog was on synthetic estrogen for about 5 years. i used over the counter estroven for humans 1/2 pill daily. my 1st vet was ok with it. she's been off the estrogen for 2 yrs. we have seen 3 more vets since. issues are: she is bald (except for her head) and her rear joints are deteriorating fast. she is 9 yrs old. no success in help for baldness or joint issues. could long term od of estroven be the cause?