From Observation to Action: Using Birthweight to Identify High-Risk Puppies Early

In canine neonatology, the window for effective intervention is narrow. Many neonatal deaths occur within the first few days of life, often before clear clinical signs have fully developed. This makes early identification of at-risk puppies not just important, but essential for improving survival outcomes. Among the available tools, neonatal bodyweight offers one of the earliest and most objective indicators of risk^1,2. 

The Challenge of Subjective Assessment 

In clinical and breeding environments, the initial assessment of neonates is often based on visual observation. Puppies that appear smaller or weaker than their littermates are typically flagged for concern. However, such subjective evaluations can be misleading. A puppy may appear small due to litter dynamics yet still fall within a normal physiological range, while another may appear normal but actually be underweight relative to maternal size¹. 

This limitation underscores the need for an objective parameter that can reliably distinguish between normal variation and clinically significant underweight. 

The Role of Maternal Context in Interpretation 

Neonatal bodyweight gains have clinical relevance only when interpreted in context. Maternal bodyweight plays a central role, as it directly influences fetal growth and, consequently, birthweight. In addition, litter size and gender contribute to variations, with larger litters generally producing smaller puppies and certain breeds exhibiting early sexual dimorphism¹. 

Without accounting for these factors, NBW alone cannot provide a complete picture. This has led to the development of more integrated approaches that consider the relationship between neonatal and maternal weights. 

N-MBW% as a Practical Clinical Tool 

The neonatal-to-maternal bodyweight ratio (N-MBW%) offers a straightforward and universally applicable method for assessing neonatal adequacy. By relating the puppy’s weight to that of the dam, this metric eliminates many of the inconsistencies associated with breed-specific references¹. 

Clinically, this approach allows veterinarians to rapidly determine whether a puppy falls within an expected range or below a threshold that indicates increased risk. Puppies with lower N-MBW% values have been shown to have a higher likelihood of mortality within the first week, making this metric particularly valuable for early risk stratification. 

Translating Assessment into Clinical Action¹ 

The true value of any diagnostic parameter lies in its ability to guide intervention. In the case of NBW, early identification of underweight puppies enables timely implementation of supportive care. This may include ensuring adequate colostrum intake, providing thermal support, and increasing monitoring frequency during the critical early period. 

It is important to recognize that not all small puppies are at risk. Some may be physiologically smaller due to litter size or breed characteristics but still fall within acceptable ranges. Conversely, puppies that fall below expected thresholds require immediate attention, even if they do not initially appear compromised. 

Special Considerations in Clinical Practice 

Certain scenarios require additional caution. In large and giant breeds, variability in NBW can be more pronounced, and overlapping values may occasionally complicate classification. Similarly, in cases where the dam is underweight or overweight, adjustments to maternal bodyweight may be necessary to ensure accurate interpretation¹. 

Despite these challenges, the simplicity of the N-MBW% approach makes it highly adaptable for routine use across diverse clinical settings. 

The Importance of Owner Education 

Veterinary intervention is not always available during parturition, making breeder awareness a critical component of neonatal care. Educating owners to weigh puppies at birth and recognize deviations from expected values can significantly improve early detection of at-risk neonates¹. 

This collaborative approach between veterinarians and breeders helps ensure that intervention occurs at the earliest possible stage, improving overall outcomes. 

Conclusion 

The transition from subjective observation to objective assessment marks a significant advancement in neonatal care. By integrating neonatal bodyweight with maternal context, veterinarians can identify high-risk puppies with greater accuracy and intervene before complications arise. In a field where timing is critical, tools like N-MBW% provide a practical and effective means of improving neonatal survival. 

References 

1. Alonge S, Beccaglia M, Trovò C, Melandri M, Migliaretti G. Neonatal–Maternal Bodyweight Ratio at Birth: An Indicator for First-Week Survival Prognosis in Canine Newborns. Animals. 2023 Nov 1;13(21):3397. https://www.mdpi.com/2076-2615/13/21/3397 
2. Mugnier A, Mila H, Guiraud F, Brevaux J, Lecarpentier M, Martinez C, Mariani C, Adib-Lesaux A, Chastant-Maillard S, Saegerman C, Grellet A. Birth weight as a risk factor for neonatal mortality: Breed-specific approach to identify at-risk puppies. Preventive Veterinary Medicine. 2019 Nov 1;171:104746. https://www.sciencedirect.com/science/article/am/pii/S0167587719301060