Milk lactoferrin in heifers: Influence of health status and stage of lactation

The objective of the current study was to analyze the variations in lactoferrin (LF) concentrations in primiparous cows with intramammary infection and to study how the lactation stage affects these variations. In addition, we aimed to study the potential of the LF concentration in early lactation as a predictive factor for future infections. To accomplish this goal, a longitudinal analysis was performed for 96 primiparous cows. Milk samples were collected each month from individual quarters, and the LF concentration was determined for each sample. Criteria that included both somatic cell count (SCC) and a microbiological analysis were used to assess the health status of the quarters. Of the diseased quarters (SCC >200,000 or positive for pathogen isolation, or both), 62% corresponded to nonspecific mastitis (SCC >200,000 but microbiologically negative) and 25% corresponded to the category “presence of bacterial growth” (SCC <200,000 but microbiologically positive). Diseased quarters showed increased concentrations of LF compared with healthy quarters. However, this increase was greater during the first days of lactation compared with later periods. Kaplan-Meier analysis of time free of infection demonstrated that quarters with LF concentrations at early lactation (3-10 d in milk) greater than 0.1 mg/mL are more likely to become infected during the following lactation compared with quarters with lower LF concentrations in early lactation. The results support that LF plays a relevant role in combating intramammary infection, particularly during the first days of lactation. In addition, we present evidence of the potential use of LF as a predictive marker of future infections in the individual quarters of dairy heifers.