Qualidade do colostro e transferência de imunidade passiva em bezerros leiteiros da raça holandesa: estudo de caso

Abstract

Passive immunity transfer (PIT) through colostrum intake is essential for the survival and proper development of calves in the early stages of life. This study aimed to evaluate colostrum quality using a Brix refractometer and to relate these values to passive immunity transfer and the zootechnical performance of Holstein calves during the first 60 days of life. Ten calves born on the Sítio Madureira farm, located in Honório Serpa PR, were evaluated between December 2024 and March 2025. The animals were divided into two groups based on the Brix value of the colostrum received (High Brix ≥ 23% and Low Brix < 23%). PIT was measured through serum Brix readings taken 24 to 48 hours after colostrum ingestion. Performance was monitored through weekly weight measurements and morphometric evaluations. The results showed that 80% of the calves achieved good or excellent PIT. Calves in the High Brix group showed greater average daily gain (ADG), higher body weight, and better morphometric development. A strong positive correlation was observed between colostrum Brix and serum Brix (r = 0.83), as well as between ADG and final weight (r = 0.76), indicating the influence of colostrum quality on early calf development. It is concluded that the use of the Brix refractometer is an efficient and practical tool for ensuring successful PIT and promoting optimal neonatal growth.