Breeding St Bernards requires rigorous health screening for hip, elbow, and heart defects, paired with precise management of the physical challenges inherent to giant breeds. Due to their extreme weight, matings frequently rely on artificial insemination to protect against joint injury, while round-the-clock supervision during whelping is required to prevent accidental puppy crushing.
The decision to breed giant dogs should never be taken lightly. A full-grown St Bernard bitch weighs between 60 and 80 kilograms, while stud dogs often exceed 80 kilograms. Managing animals of this scale demands specialized equipment, substantial financial resources, and a deep understanding of canine genetics. Before entering a pair into a breeding program, you must ensure both animals pass comprehensive health clearances and possess the stable temperament that defines the breed standard.
Essential health clearances for breeding St Bernards
Because giant breeds are susceptible to severe hereditary orthopedic and cardiac conditions, health testing is non-negotiable. Breeding untested animals risks propagating debilitating diseases into future generations. All health testing must be completed after the dog reaches two years of age, as skeletal growth plates are not fully closed before this point.
- Hip and elbow dysplasia evaluation: Radiographs must be submitted to the British Veterinary Association (BVA) or the Orthopedic Foundation for Animals (OFA) for scoring. St Bernards suffer high rates of hip and elbow dysplasia, which cause painful arthritis and lameness. I advise breeding only dogs with hip scores well below the breed median and clear elbow scores (grade 0).
- Cardiac examination: Subaortic stenosis (SAS) is a congenital heart defect prevalent in St Bernards where a band of fibrous tissue obstructs blood flow from the left ventricle. Breeding stock must be evaluated by a board-certified veterinary cardiologist via an echocardiogram and auscultation.
- Ophthalmic screening: Annual eye examinations by an expert veterinary ophthalmologist are required to screen for ectropion (inward rolling of the eyelids), ectropion (drooping lower eyelids), and juvenile cataracts.
- DNA testing for Degenerative Myelopathy: DM is a progressive disease of the spinal cord. Genetic screening identifies clear, carrier, or affected status to ensure carriers are never mated with another carrier.
Evaluating temperament and physical conformation
Health testing alone does not make a St Bernard a suitable breeding candidate. Temperament is equally vital. The official breed standard describes the St Bernard as steady, friendly, and watchful, never aggressive or excessively shy. An ill-tempered or unstable giant dog presents a significant safety liability. If a dog displays unprovoked reactivity, resource guarding, or acute anxiety, it must be removed from any breeding consideration regardless of its physical beauty or pedigree.
Physical conformation directly influences the health and longevity of the offspring. Breeders should aim to correct structural flaws in their line by selecting complementary partners. Look for a strong top line, deep chest, correct angulation in the hindquarters, and a wide, sound gait. Overly exaggerated features—such as excessive skin folds, overly loose eyes, or extreme body mass that hampers mobility—should be actively bred away from to promote functional health.
Mating techniques: natural ties versus artificial insemination
Mating giant breeds involves unique physical risks due to the immense mass of the dogs. A natural tie occurs when the male’s bulbus glandis swells inside the female’s vagina, locking the dogs together for anywhere from 10 to 30 minutes. During this period, the stud dog typically turns around so the pair stand back-to-back.
In giant dogs like the St Bernard, natural ties carry a substantial risk of physical injury. The stud dog can strain his hind legs or back while attempting to mount, while an unstable female may collapse or attempt to sit down during the tie, causing severe trauma to the reproductive tract or spinal column of both animals. If you choose natural mating, at least two experienced handlers must be present to physically support both dogs throughout the entire process.
In my view, artificial insemination (AI) is the safer and preferable choice when breeding St Bernards. Utilizing transcervical insemination (TCI) or progesterone-timed side-by-side AI eliminates the physical strain on both animals, reduces stress, and completely removes the risk of joint or spinal injury during mating.
Managing gestation and maternal nutrition
The average gestation period for dogs is 63 days from ovulation. Accurately determining ovulation through serial progesterone blood testing is essential in St Bernards, as it provides an exact target date for whelping and allows you to prepare for emergency intervention if labor fails to progress on time.
Nutritional management during pregnancy requires careful control. During the first five to six weeks of gestation, the bitch’s dietary requirements do not increase significantly. Overfeeding during early pregnancy leads to excessive weight gain and fat deposition in the pelvic canal, which significantly increases the risk of dystocia (difficult birth).
During the final three weeks of pregnancy, fetuses experience rapid growth. Gradually transition the bitch to a high-density, high-protein puppy or performance formula. Increase feed volume across several smaller meals throughout the day to accommodate her compressed stomach capacity.
Do not supplement dietary calcium during pregnancy. Administering calcium supplements before whelping suppresses the bitch’s parathyroid hormone production. When labor begins and milk production starts, her body will be unable to quickly mobilize calcium from her bones, severely increasing the risk of eclampsia (hypokalemia), a life-threatening emergency.
Whelping setup and box requirements for giant breeds
A standard whelping box is inadequate for a dog of this size. A St Bernard whelping box must measure at least 1.8 metres by 1.8 metres (6 feet by 6 feet) to allow the bitch to lie down fully extended without cramping her litter.
The most crucial feature of a giant breed whelping box is the installation of anti-crush rails (also called pig rails). These internal ledges should be mounted approximately 20 to 25 centimetres off the floor and project 20 centimetres inward from the walls. If the dam rolls over against the side of the box, the pig rail creates a safe cavity beneath it, preventing her from trapping and suffocating a puppy against the wall.
Place the whelping box in a quiet, temperature-controlled room free from drafts. Keep essential supplies prepared well before day 60, including:
- Digital weight scales measuring in grams
- Suction bulbs for clearing neonatal airways
- Clean, absorbent towels and vet bedding
- Surgical scissors and sterile umbilical clamps
- Canine milk replacer and puppy feeding tubes
- Surgical gloves and water-soluble lubricant
Managing whelping complications and uterine inertia
St Bernards are prone to whelping complications due to their large litter sizes—often ranging from 8 to 14 puppies—and their bodily build. Labor consists of three stages. Stage one involves uterine contractions and cervical dilation, lasting 6 to 12 hours. Stage two is the active expulsion of puppies, and stage three is the passage of placentas.
The most common complication during St Bernard whelping is uterine inertia, which occurs in two forms:
Primary uterine inertia occurs when the uterus fails to start active contractions despite a full-term pregnancy. This is often caused by an over-stretched uterine wall from an exceptionally large litter or hormonal failure.
Secondary uterine inertia occurs when the bitch begins labor normally but becomes exhausted after delivering several puppies, causing contractions to stall while unborn fetuses remain in the uterine horns.
Contact a veterinary surgeon immediately if any of the following signs occur:
- More than 30 minutes of strong, continuous abdominal straining without producing a puppy
- More than two hours between puppies without active straining
- Greenish-black vaginal discharge before the first puppy is delivered (indicating placental separation)
- Signs of systemic illness in the bitch, including high fever, severe lethargy, or muscle tremors
Because emergency surgical intervention is common, you must have a veterinary clinic lined up that is equipped to handle a giant breed C-section at any hour of the night.
Neonatal care: reducing crushing risks and managing large litters
The first two weeks of life are the most perilous for St Bernard puppies. Newborn puppies weigh between 500 and 700 grams, whereas their mother weighs up to 100 times as much. Because newborn puppies cannot regulate their body temperature or move quickly, maternal crushing is the leading cause of neonatal mortality in giant breeds.
To eliminate crushing risks, you must maintain round-the-clock supervision for the first 10 to 14 days. Breeders should establish a shift system to watch the whelping box 24 hours a day. When the bitch adjusts her position, physically guide her legs and ensure no puppy is trapped beneath her hips or shoulder blades.
Monitoring daily weight gains is the most accurate metric of puppy health. Weigh every puppy at the same time each day using a digital scale. Any puppy losing weight or failing to gain over a 24-hour period requires immediate evaluation and supplemental feeding.
In large litters, weaker puppies may be pushed off milk nipples by stronger littermates. Implement a rotating feeding schedule or supplement smaller puppies with specialized canine milk replacer via bottle or tube feeding. Ensure every puppy receives maternal colostrum within the first 12 to 24 hours to absorb essential passive immunity antibodies.
Who should avoid breeding St Bernards?
Breeding St Bernards requires an immense commitment that does not suit every prospective breeder. In my view, breeding this giant breed is unsuitable for:
- Individuals without substantial financial reserves to cover potential veterinary costs, including emergency C-sections and intensive puppy care.
- Breeders with limited physical space or lacking a dedicated, climate-controlled whelping area.
- People unable to take off several consecutive weeks from work to provide 24/7 neonatal supervision during the critical early rearing phase.
- Those unwilling to take lifetime responsibility for offspring, including taking back dogs if buyers can no longer care for them.
Related guides
Sources: St. Bernard (dog breed), Saint Bernard Dog Breed Information
Frequently asked questions
How many puppies are typically in a St Bernard litter?
A typical St Bernard litter consists of 8 to 10 puppies, though litters of 12 to 14 puppies are not uncommon. Managing such large litters often requires supplemental feeding and strict supervision to ensure equal milk access.
How much does it cost to breed a St Bernard?
Comprehensive health testing, stud fees, reproductive veterinary care, extra feed, and whelping supplies typically total several thousand pounds. If an emergency C-section or intensive neonatal veterinary care is needed, overall expenses increase significantly.
What is the minimum age to breed a female St Bernard?
A female St Bernard should not be bred until she is at least two years old and has completed her second or third heat cycle. This ensures her growth plates have fully closed and all preliminary health testing can be completed.
How long is a St Bernard pregnant?
St Bernards have a standard canine gestation period of 63 days from ovulation. Accurately tracking ovulation via progesterone testing helps pinpoint the precise expected whelping date.
