Impact of Plasma Supplementation on Survival and Clinical Illness in Orphaned Neonatal Kittens in a Retrospective Shelter Cohort

Abstract

Introduction: The San Diego Humane Society annually supports thousands of kittens, many of whom are orphaned and high risk for illness and death. Failure of passive transfer (FPT) is presumed common in orphaned neonatal kittens lacking colostrum-derived antibodies. Although subcutaneous plasma supplementation can increase circulating antibodies, its impact on survival and illness in shelter populations remains uncertain.

Objective: To assess the effect of plasma supplementation at shelter intake on (1) hazard of death within 30 days and (2) time to onset of common clinical signs in orphaned neonatal kittens.

Methods: Retrospective cohort study of medical records from February to August 2015. Allocation of plasma supplementation was non-randomized, based on operational constraints. Kittens ≤ 4 weeks at intake were eligible; exclusions were death or euthanasia within 24 h of intake or missing weights within 14 days. Exposure was standardized as 3-mL of subcutaneous plasma administered within 24 h of intake. Outcomes were death within 30 days of shelter intake and time to first onset of diarrhea, upper respiratory signs, hypothermia, anorexia, weight loss, or neurological signs.

Results: Cohort included 544 kittens (Plasma-Supplemented [PS] group n = 193; Control group n = 351). Review of Kaplan–Meier curves suggested early differences in survival rates between groups (days 3–11); however, after accounting for demographics and onset of clinical signs, plasma supplementation was not statistically associated with decreased mortality risk at any time during the first 30 days after intake. Strongest mortality predictors were intake weight, average weight gain, and onset of weight loss. Plasma supplementation demonstrated a significant impact on delaying onset of diarrhea and weight loss, but no other signs.

Conclusion: Subcutaneous plasma supplementation at intake did not reduce mortality risk but delayed onset of key morbidities. Intake weight and weight gain were the most important survival predictors, highlighting importance of nutrition and suggesting that plasma supplementation may reduce common clinical manifestations in shelter populations.