Causes of puppy mortality.

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Every breeder sooner or later faced the problem of puppy mortality in the period from birth to 4-5 weeks. It happens that for no apparent reason, 1-2 puppies suddenly die, and sometimes the whole litter. I will try to classify the causes of puppy mortality based on veterinary studies and published articles.

Aerobic infection of the genital tract.

In 1987-88, a veterinarian from Australia, Donald R.Spira, attracted the attention of interested breeders with his publications. In them, he pointed out that, based on his medical practice, the cause of postpartum mortality, the birth of dead puppies, as well as embryo resorption is a widespread uterine infection caused by streptococci. The pathogen entered the scientific literature under the name “B-Hamolytische Streptokokken Typ Lancefield G und L”, and the infection itself is a BHS infection. Both a bitch and a male can be affected by streptococci, but it occurs most often in bitches.

Aerobic infection can cause the following diseases:

Irregular cycle: instead of six months, the cycle ranges from two to twelve months, especially in young bitches affected by this infection. The onset of a new estrus is greatly delayed, or estrus does not occur. Also, the duration of estrus varies, it can be either very short – from three to five days, or very long – from four to six weeks. With such violations, it is already necessary to think about the possible infection of the dog with BHS infection.

Inability to get pregnant (sterility).

  •  infections and (or) inflammation of the ovaries with the following consequences: immature eggs, the appearance of unfertilized eggs, non-onset of ovulation or (meaning by time) abnormal ovulation.
  •  inflammation of the oviduct. Due to inflammation of the oviduct, the channels narrow, the passage of eggs becomes difficult or impossible.
  •  inflammation of the walls of the uterus, leading to the destruction of seed cells, as well as the inability of the embryo to gain a foothold.

Resorbtion-Abortus-syndrome. Resorption of fetuses and miscarriages. Bitches affected by streptococcal infection can be fertilized, but outwardly a normal pregnancy stops at about the fourth to fifth week, the embryo resorption or miscarriage occurs. Resorption of fetuses is the consequence of poor blood circulation of embryos, which leads to their death. They detach from the walls of the uterus, shrink and eventually disappear. All this proceeds, as a rule, without symptoms, only with a miscarriage, if it occurred before 21 days, you can notice some symptoms, such as the dog’s poor health and the appearance of strong vaginal discharge.

Puppy death syndrome is the most severe consequence of BHS infection. Aerobic infection is detected by taking samples from the vagina of bitches and examining the milk of nursing bitches. In the conducted studies, Staphylococcus intermedius (similar to Staphylococcus aureus) was detected in most cases, including from the milk of bitches, in the rest – Escherichia coli and Beta-hemolytic streptococci. Sometimes the infection was mixed. The pathogen entered the scientific literature under the name “B-Hamolytische Streptokokken Typ Lancefield G und L”, and the infection itself is a BHS infection.

Males are, as a rule, only carriers of the disease, becoming infected from sick bitches. The causative agent of this infection in an unusual environment dies within 48 hours, so a male can infect a bitch during mating if he had previously knitted a sick bitch during this period of time. Infection of the bitch occurs with direct contact, for example, when urinating, the vulva comes into contact with dirt and debris, where pathogens can be found, as well as when licking the genitals of sick animals. Most often, infertile bitches do not show any signs of infection, it can be established only with the help of laboratory analysis. Simultaneously with the identification of the pathogen, the sensitivity of this species to antibiotics is determined so that the treatment is as effective as possible. The presence of microbes at the time of mating has a negative effect on fertilization, significantly reducing the activity of spermatozoa and leading most of them to death. If, after all, fertilization has occurred, then the formed zygotes undergo their further development in a free state, not attached to the wall of the uterus. Implantation takes place in the third week of pregnancy. During the entire period, including the implantation of embryos into the uterine wall and the formation of placentas, the bitch’s body is extremely sensitive to any infection that can cause termination of pregnancy and resorption or abortion of embryos at any time. The presence of Staphylococcus intermedius in the genital tract of a female bitch is often associated with its appearance in milk. These bacteria produce very strong toxins that cause the death of puppies in the first days or hours of life. Puppies born outwardly healthy weaken (this usually happens on the third day), their appetite disappears, later they are no longer able to suck, the skin of the abdomen acquires a bluish-reddish hue, they lose weight. If the necessary measures are not taken urgently, then the puppies die within a few hours. The bitch herself looks perfectly healthy. Dr. Spira’s research has shown that puppies of a bitch infected with this infection are born healthy, and become ill later by infecting themselves through mother’s milk. Sometimes puppies have very characteristic and severe seizures caused by toxins, when the puppy becomes petrified for a few seconds, and then relaxes again. In this case, it is urgently necessary to separate the puppies from the mother, and transfer them to artificial nutrition. The mother needs a course of antibiotic treatment, after which the puppies can suck her again.

The following symptoms help to diagnose:
irregular cycle and periods of estrus,

  •  abnormal duration,
  •  unusual discharge,
  •  disinterest of the male if the bitch flows,
  •  the inability to get pregnant with absolutely normal mating,
  •  miscarriages and resorption of fetuses,
  •  increased body temperature,
  •  the death of puppies.

Not all antibiotics are safe for the body of a pup bitch. For example, Endrofloxacin, Ciprofloxacin (a group of quinols) disrupt the development of cartilage and bone tissue in developing animals. There have been cases of puppies being born with a “cleft palate” in almost the entire litter, as well as the absence of milk teeth in puppies if the bitches received a course of antibiotics of this group before mating or during pregnancy. It is also not recommended to use antibiotics of the tetracycline group (Doxocycline, Oxytetracycline), which have a negative effect on the bones and teeth of developing fetuses and are harmful to the mother. A group of aminoglycosides (Gentamicin, Kanamycin, Amikacin) can have a toxic effect on fetal kidneys, so it is worth avoiding its use during pregnancy. Among the safe antibiotics can be called a group of penicillins and cephalosporins. Penicillins (Penicilin G, Ampicilin, Amoxicillin) penetrate the placenta, but they are safe for fetuses. Very good results of treatment were given by combined amoxicillin drugs – Amoksiklav (Leck, Czech Republic) and Synulox (Pfeizer, Germany).
Bacteriological examination of females is part of the solution to the problem of infertility. Do not make erroneous conclusions and just “prophylactically” feed the bitch a course of medications. As a result, the opposite effect can be obtained when the bitch loses the natural barrier, and bacterial strains with increased resistance to antibiotics are formed. The problem must be solved when it arises.

Helminthic invasion

All puppies are born infected with ascaris larvae, which penetrate through the placenta from the mother’s body into the fetus on the 42nd day of birth. At the same time, the mother may not be a carrier of sexually mature forms of parasites. Another way of infection is also possible – through milk. Hookworm larvae can also penetrate through the skin. Spreading through the female’s body, they penetrate into the uterus, infecting puppies. During the “journey” through the puppy’s tissues, which lasts about 20 days, the worms reach the lungs when the clinical picture of the disease is detected. Puppies then turn two weeks old. The first litter is the most affected, the next ones will already be less affected, since the number of parasites in the mother’s muscles decreases, unless, of course, she gets infected with them again. This disease is as severe as sepsis, and it is incurable. It remains only to carry out regular deworming in puppies. In this regard, it is recommended, starting from the 14th day of life, to carry out preventive deworming of puppies every 14 days.

Herpesvirus infection.

The respiratory form of herpes in adult dogs is almost asymptomatic. But it is extremely important in the transmission of infection. Herpes is transmitted not only sexually. The dog can also get infected by airborne droplets, or, for example, through your clothes, and then abortion or resorption of the fetus will occur. A vaccine against herpesvirus infection in dogs has not been developed. Treatment of sick dogs should be aimed at increasing the overall stability of the body and suppressing secondary bacterial infection. Herpes is one of the few diseases that any veterinarian can quickly diagnose based on the results of an autopsy of a dead puppy.The autopsy clearly shows traces of kidney damage specific to herpes. Puppies die from herpes only because they are not able to react with an increase in temperature. At the age of 2 to 3 weeks, puppies learn to control their body temperature. Previously, their body temperature depends on the environment. This phenomenon is called poikilothermy. The treatment of the litter in the case when a herpes infection was established by the results of an autopsy of one of the puppies, consists in an increase in the ambient temperature. If your puppy has died, cool the body (without freezing) and take it to the veterinarian as soon as possible for an autopsy. Then ask the veterinarian to explain how to increase the temperature of the remaining littermates. You can lose puppies at any time of your life. Puppies can “dissolve” or be stillborn, they can become infected with the herpes virus, during childbirth, in utero before birth, or through contact with an infected secret (airborne droplets or through contact with vaginal secretions) after birth. In bitches infected with the herpes virus before or during mating, symptoms never appear during the period of bearing puppies. The most reliable way to prevent the loss of puppies during pregnancy or after birth is to put the bitch in quarantine three weeks before mating and keep it in quarantine for 3 weeks after the puppy. In order to determine during pregnancy whether the bitch has recently come into contact with the herpes virus, and therefore did not bring puppies, take two samples of blood serum with a break of two weeks and determine the titer of antibodies to the herpes virus. Antibody titer change (drop or rise) indicates that the herpes virus could have caused the loss of puppies during pregnancy. A herpes infection in a bitch, without causing premature termination of pregnancy, can cause low body weight in puppies at birth, their weakness or stillbirth. Puppies who survive a viral infection may have permanent damage to the nervous system, kidneys or lymphoid tissue, as well as a suffocating puppy can damage internal organs, which can cause problems later in life.
In adult dogs, the virus usually sleeps, as in humans, and wakes up in a stressful situation. Imagine the stress during the mating games:

  •  Temporary hormonal changes that prevent the body from successfully fighting infection.
  •  Transporting, mating and transporting the bitch again if she goes to the male.
  •  Possible concomitant bacterial infection of the genitourinary system.
  •  Exhibitions.
  •  In females older than five years, due to a decrease in the level of thyroid hormones.
  •  Any stress, for example, temperature.

The fact that stress is able to activate the herpes virus (which can then cause the death of embryos during the first 3 weeks of pregnancy) can serve as a good explanation for the fact that the bitch, who was undoubtedly pregnant for the first four weeks, but could not give birth in due time, or that the litter was much smaller than expected. Almost any dog was in contact with herpes. It cannot be said that this infection is transmitted only or mainly sexually. Infection with herpes occurs not only during mating – usually the virus is transmitted by airborne droplets. The immunity that occurs after contact soon ends, and the dog is again at risk of infection or relapse of the dormant virus. In fact, it would be very difficult to say that any repeated infection is associated with a relapse, and not a new contact with a highly contagious virus. Even a simple visit to a male dog can become a dangerous contact for a bitch; if bitches often come to the kennel, they can bring a new infection with them. If a breeding male or his kennel neighbors participate in exhibitions or visit a training ground, the level of virus release can be quite high. The dog simply cannot avoid contact with the virus in its habitat. But contact can be limited; if you have a trip to the dog, avoid flights, stay in motels with your bitch and do not leave her in the kennel of the dog. If you attend exhibitions, change your clothes completely and wash yourself before approaching any of the tied bitches at home. If there are dogs in the kennel who visit the training ground or exhibitions, isolate the bitch from them and pay attention to caring for and cleaning her earlier than others, always observing the rule “from clean to dirty”.
However, those bitches who live at home with their owners as a pet and do not often meet with other dogs or come into contact with viruses are more susceptible to infections than others. Such a bitch, when in contact with a virus carrier, will be exposed to a more serious danger than one who regularly comes into contact with the virus “in small doses”.
A male breeder after mating with an infected bitch can be a carrier of infection and be either the one who transmitted the infection to the bitch, or the one who received an acute infection from her during mating. It does not make sense to do an analysis for virus transmission during the mating period, since almost all individuals surrounded by a bitch may be at various stages of the disease or recovery. Once again, it is worth repeating that respiratory infection is easy, and its clinical symptoms are rare in adult dogs. Only paired blood serum samples taken at different times in order to determine an increase in the titer of antibodies (development of the disease) or a fall (recovery) can carry certain information. Obviously, the information obtained in this way will be too late to use at the time of binding. The benefit of this paired antibody analysis is seen more in determining the loss of puppies due to herpes infection after the fact. It is only possible to confirm or exclude a viral infection as one of the possible causes of “resorption of fetuses”, a case of stillbirth or weakness of newborns.

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