A dog usually comes into her first heat before she is fully mature, and if she gets pregnant, she will be losing the nutrients her body needs to grow properly to her pups. If you have an accidental pregnancy with the first heat, you must make sure to provide additional calcium and other vitamins to the mother. Depending on the size of the dog, it may not be advisable to breed her until 2 years old or more. German Sheperds, for instance, are not mature until 2, and most vets will recommend waiting to breed them.
Most responsible breeders do not breed the bitch in the first estrous cycle (heat), although it is possible for them to become pregnant during that first season. Until a dog is around two years old, many genetic problems will not have shown up yet, like hip dysplasia, for example. You would need to wait to see that the bitch is healthy (e.g., that her hips are good when she fully matures), or have the proper testing done on the dogs to be mated to assure that you are not going to end up with a litter of puppies with potentially serious genetic disorders or conditions.
Females are able to conceive ("go into heat") only approximately every six to eight months. They usually have their first estrous ("season") at around six months, but some don't for as long as 14 months. As a rule of thumb, if she has not had an estrous cycle by the time she is 14 months old, you should have her examined by a veterinarian.
The decision to breed should be made with great care and only after you have learned much more about breeding, whelping, and caring for pregnant bitches and newborn puppies. In addition, before breeding, determine that the puppies will be wanted and will have good homes. A commitment to find good homes for all the new lives you will be creating must be made before even considering breeding any dogs.
It's not harmful, but it's not suggested either.
Yes, a female no longer goes into heat if they are pregnant.
Yes but it has a better chance halfway through heat
No. Only a male can impregnate a female. No female mammal of any species can get another female pregnant. For mammals that have a "heat" cycle, being in "heat" is required for pregnancy by a male. If such a mammal (a dog for instance) is not in heat or doesn't have a male partner, pregnancy is not possible.
If by "Session" you mean estrus/heat; no. A female dog can not get pregnant if they are not in estrus. Many female dogs can not safely carry a litter to term if they where bred during their first or second heat, and reputable breeders usually wait till the dog is around three years old.
Female cats should not go in heat when they're pregnant because it may harm the fetus.
after they go into heat.
no they do not it dose not matter
They can be bred when they have their first heat cycle which can be as early as four months but is more typically around six months. It is generally not recommended to breed a dog on it's first heat.
No, a dog must be in heat to mate successfully. Otherwise she will not get pregnant.
it means if she is able to get pregnant
my female jack russel has not been on heat since november, why is this/
No they can not and they will typically not let a male mount them if they are not in heat.