Canine Neonatal Period Overview

Defining the Canine Neonatal Period

• The definition of the canine neonatal period can vary from a minimum of 3-4 days to a maximum of 84 days.
• Some sources may refer to it as the time from birth to weaning.
• The lack of consensus regarding the duration of the neonatal period can affect the accuracy of mortality rate calculations.
• The American Animal Hospital Association (AAHA) defines the neonatal stage as birth to weaning, which occurs around 3 to 4 weeks of age, while the pediatric stage extends from weaning to sexual maturity.
• This article utilizes the AAHA definition of the neonatal period, which is from birth to weaning.

Factors Impacting Canine Neonatal Health

• Hypoxia and sepsis are the leading causes of canine neonatal death.
• Hypoxemia, a state of oxygen deficiency, can arise from various factors, including decreased oxygen intake, hypoventilation, ventilation-perfusion mismatch, or a diffusion barrier.
• Canine genetic disease screening has increased in availability due to the expansion of the PCR market and mapping of the canine genome.
• Pre-breeding genetic testing helps reduce the incidence or eliminate specific conditions within purebred populations.
• The Canine Health Information Center (CHIC) provides comprehensive screening recommendations for purebred dogs based on breed.

Pre-Breeding Screening

• All canines intended for reproductive use should undergo a thorough evaluation before breeding to identify potential risks impacting neonatal health.
• The evaluation should include patient history, preventative care measures, physical examination, and temperament assessment.
• The CHIC website (https://ofa.org) offers detailed breed-specific screening recommendations.

Pregnancy

• Medical management of a litter may begin as early as 3 to 4 weeks gestation.
• Around parturition, several factors can increase the risk of circulatory failure in neonates.
• These factors include: 
  • High-volume, low-pressure cardiovascular system dependent on heart rate.
  • Bradycardia in neonates isn't vagally mediated, and sympathetic innervation of the heart is incomplete.
  • Anoxia leads to significant bradycardia (less than 45 beats per minute) and hypotension (less than 25 mm Hg).
• Despite these risks, neonates can maintain circulation and be resuscitated after a hypoxemic or anoxic event if systolic blood pressure remains above 8 mm Hg.
• The neonatal respiratory system has several features that make them more susceptible to airway collapse, respiration fatigue, hypoxemia, and rapid oxygen desaturation.

Parturition

• Lung surfactant production is inadequate to support life before 62 days from the LH surge.
• Dystocia is a major contributor to neonatal mortality, with asphyxia and hypoxemia linked to 60% of neonatal deaths.
• Tocodynamic and fetal heart rate monitoring, as well as observation for “red flags” during parturition, can improve neonatal health outcomes.
• Sustained fetal heart rates below 180 beats per minute indicate fetal distress.
• At birth, newborn canines have a lower spO2 than adult dogs, but these values rise after birth and stabilize at 1 hour and 12 hours following spontaneous vaginal birth and cesarean birth, respectively.
• Resuscitation efforts should focus on keeping airways open, delivering oxygen, and maintaining warmth.
• Umbilical cords should be trimmed, ligated, and treated with 2% tincture of iodine to prevent sepsis.

The Neonate

• Neonates are distinct from adult dogs and require careful monitoring for age-appropriate normal values.
• The early neonate (0–2 days) is particularly vulnerable to hypoxemia, hypoglycemia, hypothermia, and dehydration.
• Owner education is crucial for early detection and intervention.
• Sick neonates should be separated from the dam if possible.
• While virtual visits have increased since the COVID-19 pandemic, they may not be feasible for establishing a valid client-patient relationship in all areas.

Herpesvirus

• Canine Herpesvirus (CHV-1) can affect various organ systems.
• Neonatal losses occur when a naïve bitch is infected during pregnancy or when neonates are infected during the first weeks of life.
• Strategies to minimize risk include:
  • Pre-breeding screening to identify seronegative females and isolate them during pregnancy and for at least 6 weeks postpartum.
  • Vaccination of the bitch before breeding and again six weeks later if a canine CHV-1 vaccine is available.

Fluid Therapy

• The choice of fluid bolus rates depends on the neonate's body weight and physiological status.
• Peripheral venous access is possible for some patients, but jugular or intra-osseous routes might be necessary for others.

Biosecurity

• Implementing appropriate biosecurity measures is crucial for safeguarding canine health.

Explore the defining features of the canine neonatal period, including its duration, impacts on health, and definitions from different authoritative sources. Understand the factors influencing neonatal health and mortality in puppies, emphasizing critical conditions like hypoxia and sepsis.