Pet Breeding Responsibly



Pet breeding takes a tremendous amount of work.  A lot of people come in to medical offices with new puppies and I have heard countless amounts of time that when the dog matures, they are “going to strike it rich”.  And I have some prime real estate in Florida for a penny an acre!  Wishful thinking.  Yes, breeders that sell purebred dogs and cats will sell them for XYZ price but look at the 70 plus days that they spend plus the cost of food and veterinary care.  You get the picture.  Breeders do this because they enjoy the whole environment of a pregnant dog and her puppies.  They enjoy selecting for certain characteristics in the dog they are breeding.




Small dogs and cats will sexually mature at about 6-7 months.  The larger the dog, the longer it will take for her first estrous cycle to arrive.  The Newfoundland will come into heat for the first time at way over one year of age.  Pet breeding rationale is that the best time to breed the female is at her second heat; which is about 6 months after the first cycle.  Most dogs usually come into estrous in late winter and late summer.  Cats can easily have 3-4 litters a year.  They are like birds!  They need about 12 hours of sunlight to come into heat.  They can mate, deliver, nurse and go back into heat immediately; not so like the dog which cycles every 6 months like clockwork.


She may be able to mate at 6 months but physically she is not mature.  The pelvic diameter needs to grow so as to allow mature fetuses to pass through the birth canal.  This happens at one year of age so wait till her second heat to start pet breeding.  Breed until about 5 years of age than get her spayed.  Pet breeding is possible with an older dog but with it increases the chances of a Cesarean section.


A lot of work is done before the actual mating begins.  Make sure the female is brought up to date on vaccinations so as to increase the chances of passive immunityPassive immunity is that type of immunity that protects new born animals from diseases such as distemper, parvovirus and others. It is passed in mothers first milk; which is also known as colostrum. The immunity only lasts a few weeks but protects the animal in the early stages of life.. She should also be tested negative for BrucellosisBrucellosis is a reproductive disease in mammals. The livestock version can even be transmitted to people. That species (Brucella abortus) is not in the U.S. The canine species, Brucella canis, can cause reproductive issues such as abortion in dogs.. A fecal exam should also be done, along with a physical exam, to rule out parasites that could be transmitted to the offspring.  Cats should be vaccinated for Chlamydia, Feline Distemper and Leukemia.  Rabies is always indicated for both species as a public health measure.




Oh, I forgot something!  You also need a male!  Make sure the male is up to date on vaccinations, fecal exam and negative for brucellosis.  The important thing here is to make sure that the male is about the same size as the female.  Large male, small female usually spells trouble.  Cesarean sections often need to be performed in this situation.  The male should be mated with the female every other day for about a week to increase the chance of an egg being fertilized.


When is the female dog or cat in heat?  Cats do not bleed.  Dogs do not menstruate!  Only humans and primates menstruate.  That blood is from the sloughing of the endometrium.  In dogs that is not so.  Dogs do not have a “period”.  Bleeding is vaginal in origin.  About five days after bleeding take the dog to the veterinarian to have a vaginal smear done.  When the doctor sees certain cells, she is ready pet breeding is ready to roll.  Behavioral changes in cats plus season of the year usually indicate heat.  If it is February onward and she is meowing and fluttering her tail like crazy; she is in heat!

Pet breeding is the way purebred genes are kept together. It requires a lot of knowledge and takes a lot of time and committment.



On average the gestation period for dogs and cats is about 60 days.  As in humans, this will vary from individual to individual but 60 days is an average.  Once the female has mated with the male, mark the date on the calendar and add about 60 days and that will be the approximate due date.  Pregnancy is usually detected by weight gain, mammary development and most easily by an abdominal ultrasound. Standard X-Rays can be done but they are not useful until the third trimester when the fetal skeleton is developing.  This skeleton is what the X-Ray will show.  Done too late, it is a waste of time as the amniotic fluid obscures all details of the fetal skeleton.




Nutrition is of prime importance in pet breeding.  The pregnant dog or cat should be put on a high caloric diet.  Hills® puppy or Royal Canin’s® puppy diet are perfect.  Remember, the mother needs not just calories for her needs but for fetal development and milk production (lactation).  Toy breeds should all be put on an appropriate Calcium supplement to prevent eclampsiaEclampsia is a medical term that leads to a low blood calcium level (hypocalcemia). This is seen in toy breeds that are carrying relatively large numbers of puppies. The demand for calcium is so huge due to the skeleton formation and milk production plus the mother"s needs that the blood calcium level drops precipitously. This leads to seizures in the mother. Rapid infusion with calcium gluconate is the treatment of choice in these animals and most do well. which is extremely common in toy breeds.




Many times clients called me and said that there was no way their female dog mated with a male yet they are producing milk and the breasts are enlarged.  This is called a false pregnancy and is usually seen about two months after the dog was in heat.  Sometimes they actually “act” like they are going to go into labor but normally milk production and making a nest are the most common signs.  These dogs should be spayed as false pregnancy increase the chances of breast cancer as the dog gets older.


What comes next is a waiting period.  That is what Stages of Labor in Pets is all about!

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