This is Part II of our previous post on silent heats in the bitch ( in case you missed it, it’s here ). We left discussing the differential diagnosis of prolonged anoestrus in the bitch (=prolonged absence of visible heats, remember !) and why it was always important to rule out ovarian cysts. Now let’s move forward ! Read facts 11 to 20 below !
#11 If everything is ok, that’s great news ! It is still however important to figure out if this is silent heats we are dealing with. A way to check it out ? Assay the bitch’s blood progesterone concentration.
#12 Indeed, whether the bitch is pregnant or not, after ovulation she will produce progesterone for nearly two months. And remember: silents heats mean you do not see them, but ovulation does occur.
#13 If a bitch with prolonged anoestrus indeed did silent heats, the progesterone concentration in her blood should therefore be elevated in the two months following her ovulation. If your veterinarian find a high progesterone blood concentration therefore, it will definitely tell you that silent heats did occur.
#14 We don’t really know what causes silent heats in the bitch. In my experience it can happen anytime. In any given bitch.
#15 I often saw them in cases where bitches were going through a stressful period. For instance I remember a group of 4 bitches that all did silent heats while their owners moved with them to a new home.
#16 When bitches do silent heats, their next heats will generally occur at the regular inter-estrus interval. If your bitch cycles every 6 months, she might cycle again 6 months after the silent heats. Silent heats will not modify the inter-estrus interval.
#17 In certain bitches, silent heats tend to be the rule. Again it can happen in any given bitch but I have seen this a lot in small breeds, especially Yorkies and Chihuahuas.
#18 When this situation happens, it can be very difficult to manage. Our approach was to kind of estimate when the bitch would get in seasons and then do vaginal smears on a regular basis (every 2 weeks).