Risk Factors for and Prevalence of Failure of Passive Transfer of Immunity in Calves on Dairy Farms in Türkiye.

BACKGROUND

Failure of passive transfer of immunity (FPTI) is perhaps the most important factor in the health of neonatal calves. Given the variation between countries in FPTI, national data need to be documented to add to the international database for future meta-analyses.

OBJECTIVES

The aim of this study was to evaluate the prevalence of and risk factors for FPTI in dairy herds in Türkiye.

METHODS

Blood serum samples from 1026 calves in 76 dairy herds in 16 provinces of Türkiye were analysed using a digital Brix refractometer to assess FPTI, defined as a Brix value < 8.5%. Data on risk factors were collected during farm visits to sample calves. Herd size was categorised based on the number of lactating cows: Group I (≤ 20), Group II (21-100), Group III (101-200), Group IV (201-300), Group V (301-500), Group VI (501-1000) and Group VII (> 1000).

RESULTS

FPTI incidence was 22.4% overall. Significant factors associated with FPTI included small herd size (p = 0.002), lower dam parity (p = 0.005), breed of calves (p < 0.001), natural sucking of colostrum (p = 0.003) and birth in summer or winter (p = 0.005).

CONCLUSION

The prevalence of FPTI in Turkish dairy herds was within international norms but higher than recently recommended consensus prevalence. This research shows that there were both modifiable and non-modifiable significant risk factors for FPTI in Turkish dairy herds, specifically colostrum feeding method and season of birth and herd size, dam parity and calf breed.