Occurrence of diseases and their association with performance and passive immunity transfer in Holstein calves during the pre-weaning phase

Abstract

Pre-weaning diseases in calves can lead to both short- and long-term impacts. This study aimed to evaluate the occurrence of the main diseases affecting heifer calves from birth to weaning. Retrospective data were collected from a dairy farm located in Palmeira, Paraná, including Holstein heifer calves born between January 1, 2022, and January 31, 2023. Information was retrieved from the Del Pro software and organized using Microsoft Excel. Statistical analyses were performed using Graph Pad Prism (version 5, 2007). During the study period, 1,144 calves were born. Of these, 69.5% developed diarrhea, 12.3% were diagnosed with bovine respiratory disease (BRD), and 1.3% presented other conditions such as umbilical disorders and keratoconjunctivitis. Diarrhea was most prevalent in the second week of life (58.66%), while BRD peaked after four weeks of age (54.04%). Failure of passive immunity transfer (PIT) was identified in 10.77% of the calves (n = 120), and it was associated with a higher occurrence of BRD and the occurrence of multiple disease episodes. Calves with BRD or two or more disease cases showed lower aver-age daily weight gain compared to healthy animals or those with diarrhea alone. The mortality during the pre-weaning period was 2.31% (n = 24), with 50% of  the deaths occurring between the second and third weeks of life. In conclusion, among the disease groups evaluated, diarrhea and BRD were the most prevalent during the pre-weaning phase. Their occurrence was influenced by age and by the efficiency of PIT, which was directly associated with an increased incidence of illness and adverse effects on calf growth performance.