1 There is no proof that tertiary hypothyroidism occurs in the dog...primarily because there is no reliable assay for measuring circulating TRH (nor TSH). 2  Thus, the possibility is there...and clinical signs and histological appearance of the thyroid would parallel those described for secondary hypothyroidism.
Rats are very easy to breed. In fact, many people end up with unplanned baby rats! Rats can reach sexual maturity at 5 weeks of age, so the sexes should be separated at this age.Rats donât recognize incest, so brothers and sisters and even mothers and sons must be separated.ats are very easy to breed. In fact, many people end up with unplanned baby rats! Rats can reach sexual maturity at 5 weeks of age, so the sexes should be separated at this age. Rats donât recognize incest, so brothers and sisters and even mothers and sons must be separated.
Sexing rats is fairly easy with a few guidelines. First, check the rat yourselfâpet shop employees can make mistakes. By the time the baby rats are weaned (4 weeks of age) the malesâ testicles will have dropped, but they arenât always obvious because they can be voluntarily pulled inside the body.f you get just one rat you must spend a lot of time playing with him. Be sure roommates are the same sex, or have one or both neutered. A breeding pair can produce a litter of 12 babies every 4 weeks! And hereâs a warning: females over 5 weeks of age can already be pregnant if theyâve been with any males!