Fading puppy syndrome: weakness in newborn puppies

Overview

The neonatal period covers a puppy's first 21 days of life. In fading puppy syndrome, deterioration and associated deaths occur within the first 2 weeks. It does not refer to a single pathogen.

Reported estimates of newborn puppy and kitten mortality range from 9–26%. Mortality is highest during the first week. Including stillbirths and deaths before weaning, losses may reach 30%. About half of these losses occur in the first week.

A newborn's fluid and energy balance are still poorly regulated. The immune system is also immature. Puppies are therefore vulnerable to disease and environmental stress.

Causes

Inadequate maternal milk production may leave a puppy undernourished. Failure to suckle can cause the same problem even when milk is available. Puppies have only small fat reserves. Their ability to make glucose from other nutrients is limited.

Glycogen reserves are used quickly after birth. Even a short period without feeding can therefore cause dangerously low blood sugar. Low blood sugar may also be associated with sepsis, a severe systemic infection. Other causes include a liver blood vessel shunt or a glycogen storage disorder.

Even common bacteria can cause a rapidly progressing systemic infection in a newborn. Possible causes of sepsis include Escherichia coli, streptococci, staphylococci and Klebsiella. Infections may affect the navel, respiratory tract or intestine, for example.

Canine herpesvirus can cause a severe, fatal systemic infection in newborns. Parvovirus, adenovirus and distemper virus may also be associated with fading. A congenital structural defect may not be apparent immediately at birth. A developmental heart or intestinal defect may underlie symptoms, for example.

A puppy can be injured if the mother lies on it or behaves aggressively towards it.

A puppy's kidneys do not yet concentrate urine as effectively as an adult dog's.

Risk factors

Low birth weight increases a newborn's vulnerability. A birth weight below 350 g in a medium-sized breed increases sepsis risk. Prolonged labour and difficult birth also predispose newborns to sepsis. Maternal uterine infection or mastitis can increase a puppy's infection risk.

A dirty environment is a predisposing factor for neonatal sepsis. Chilling and stress also increase vulnerability. Inadequate colostrum intake reduces protection against infection. Poor maternal care can contribute to illness.

Intestinal parasites, fleas and ticks may weaken a puppy by taking blood and nutrients. An immature immune system increases systemic infection risk, particularly during the first 10 days.

Typical symptoms

Growth and behaviour changes may be the first signs noticed at home:

• The puppy does not gain weight at the same rate as its littermates.

• The puppy moves little and struggles to latch on and suckle.

• The puppy stays apart from its mother and littermates.

• Vocalisation is weak and higher-pitched than usual.

• The puppy has diarrhoea or a swollen, tender abdomen.

• The puppy regurgitates or vomits and may struggle to breathe.

Advanced deterioration may cause extreme tiredness and loss of muscle tone. A healthy, well-fed puppy instead sleeps quietly when not suckling.

A healthy puppy tries to right itself.

Complications and consequences

Bacterial sepsis can cause rapid collapse and death. There may be few obvious symptoms beforehand. Chilling weakens immune defences, suckling and digestion.

Cold can stop normal intestinal movement. Feeding may then cause regurgitation and entry of milk into the airways. Excessive fluid treatment can also be dangerous for newborns. Delayed treatment can be fatal for a young puppy.

Severe sepsis can cause tissue death and sloughing at the ends of the limbs.

Diagnosis at the vet

Examining the puppy and mother

Newborn examination includes checking the mouth, navel, limbs, genitalia and urinary structures. The vet checks for a cleft palate. The urethral and anal openings are checked to ensure they are open and functioning. A normal navel is dry without surrounding redness.

Mucous membranes should be pink and moist. The puppy should have a suckling reflex. The abdomen should be soft and painless. The chest is listened to for assessment of breathing and the heart.

The mother's mammary glands and their secretions are also examined. The vet looks for mastitis and uterine infection. Maternal appetite, body temperature and care behaviour are monitored alongside the puppies.

Measurements and samples

Weight records help identify slow growth. During the first week, the normal rectal temperature reference range is 35–37.2°C. At 2–3 weeks, it is 36.1–37.8°C. Age must therefore be considered when assessing temperature.

Blood, urine and faecal samples may be collected alongside clinical examination. X-rays or ultrasound can help investigate the diagnosis when needed. Bacterial culture and susceptibility testing help select infection treatment.

If a puppy dies, a post-mortem examination may identify the cause and help protect the others from it.

Assessing vitality after birth

A modified Apgar score can also assess newborn vitality. It considers heart rate, breathing, reflex responses, movement and mucous membrane colour. A low score within the first 5 minutes is associated with greater early mortality risk. Repeat scoring may be performed at 5, 30 and 60 minutes after birth, for example.

A single Apgar threshold is not recommended as the basis for deciding to start resuscitation.

Treatment

Breathing and warmth are secured first

At birth, a puppy that is not breathing or is gasping needs prompt breathing support. Drying and gentle rubbing help stimulate the newborn. These must not delay necessary assisted breathing. A slow heart rate at birth can result from oxygen deficiency.

Do not swing a puppy to remove fluid from its airways. Swinging risks bleeding inside the skull, injury and aspiration of stomach contents. A normally breathing, alert and vocal newborn does not need resuscitation.

A wet newborn loses heat quickly. Dry, warm bedding reduces heat loss. Warming is supervised to prevent overheating and skin burns. Even an alert puppy may not move away from an overly hot surface quickly enough.

During the first week, the recommended temperature in the puppies' area is 28.9–31.7°C. At 2–3 weeks, the environmental reference temperature is 26.7°C. The whole room does not need to be heated to the nest temperature. In hospital, an incubator allows control of temperature, humidity and oxygen concentration.

Fluids, energy and infection treatment

Dehydration in an ill newborn is corrected with fluids suited to its condition. Confirmed low blood sugar may be treated with glucose solution. A very weak, unresponsive puppy may need glucose given into the circulation. Antimicrobial selection takes the newborn's physiological immaturity into account.

Drug elimination through the kidneys is also lower in newborns than adults.

Bacterial sepsis needs promptly started antimicrobial treatment. The vet adapts the medicine to culture and susceptibility results. Nutritional and temperature support are needed too. Good hygiene is part of caring for an infected litter.

Supporting suckling and nutrition

Feeding may be supported by assisted suckling, bottle feeding or tube feeding arranged by the vet when needed. Tube feeding starts only once a chilled puppy's temperature has returned to normal. The mother's milk is the first-choice food if available. Commercial milk replacer is preferable to a homemade mixture.

Overfeeding milk replacer can cause osmotic diarrhoea. Stools may then be yellowish and curdled.

After caesarean section, suckling is supervised as the mother recovers from anaesthesia. Puppies are left alone with her only once she has recovered and shows good maternal care.

A healthy newborn usually gains 5–10% of its body weight per day. Weight is recorded daily for the first 2 weeks. Alertness and passing urine and faeces are assessed alongside weight gain.

Prevention

Good maternal nutrition before birth helps support puppy survival. Planned parasite control also reduces risks to newborns. Timely management of difficult labour can improve survival. The bitch's routine vaccination protection is planned before mating.

Puppies need colostrum soon after birth to acquire passive antibody protection. Intestinal absorption of IgG antibodies usually ends within 24 hours of birth. Where available, the mother can be vaccinated against canine herpesvirus to protect her puppies. Protection still reaches the puppy through the vaccinated mother's colostrum.

A clean environment for mother and puppies helps prevent bacterial problems. Maternal care behaviour is also monitored to prevent puppy injuries.

Important for dog owners

Identify each puppy and keep an individual weight chart using the same scales. Record birth weight, later weights, suckling and whether the puppy seeks its mother. Note diarrhoea, unusual vocalisation, abdominal swelling and breathing changes too. Bring the records to appointments so changes can be timed as accurately as possible.

Tell the vet about the whole litter and the mother: labour, milk production, appetite and any illness. Ask how to keep the puppy warm during transport and whether the mother and other puppies also need examination. If a puppy dies, agree on investigation of the cause and storage before submission. Ask for clear home monitoring instructions on temperature, feeding and follow-up.

Frequently asked questions

Is fading puppy syndrome the same as herpesvirus infection?

Several different factors can contribute to fading at the same time. Herpesvirus is one possible cause of severe systemic infection in newborns. Other causes include inadequate milk intake, congenital defects and bacterial infections. Symptoms do not always establish the precise cause.

Why must a puppy's weight be monitored?

Slow growth can be a sign of neonatal sepsis. A fading puppy may not grow at the same rate as its littermates. A healthy puppy usually gains 5–10% per day. Weights are recorded daily for the first 2 weeks.

Can a cold puppy have milk straight away?

Tube feeding of a chilled puppy is delayed until body temperature returns to normal. Cold can suppress intestinal movement. Food may then be regurgitated and enter the airways. Warming is supervised at the same time to avoid overheating or burns.

Does the mother need examination if only one puppy weakens?

Maternal mastitis or uterine infection can predispose a puppy to sepsis. Low milk production may also contribute to undernutrition. The mother's mammary glands, secretions and general health are therefore assessed after birth. Monitoring her appetite and care behaviour complements observation of the puppies.

Can examining a dead puppy help the rest of the litter?

Post-mortem examination can investigate the cause of death. This may help prevent other puppies dying from the same cause. In bacterial disease, culture and susceptibility testing guide treatment. Treatment of deteriorating live puppies starts without delay. Blood, urine or faecal samples from live puppies may also be needed.