What question did this study set out to answer?

The objective is to explore how tongue-rolling behavior interacts with chronic stress to affect immune and milk protein indicators in dairy cows.

February 2, 2026Open Access

Interaction Effects Between Tongue-Rolling Behavior and Chronic Stress on Plasma Immune–Inflammatory Indicators, Milk Protein Composition, and Milk Proteome in Dairy Cows

Key Points

The objective is to explore how tongue-rolling behavior interacts with chronic stress to affect immune and milk protein indicators in dairy cows.
Classified cows into high- and low-stress categories using hair cortisol concentration
Selected cows exhibiting either tongue-rolling or normal behavior from each stress category
Established four groups for analysis: high-stress tongue-rolling, high-stress normal behavior, low-stress tongue-rolling, low-stress normal behavior
Analyzed plasma immune-inflammatory indicators and milk protein composition.
Significant interaction effects on plasma tumor necrosis factor-α and interleukin-6 levels
TR cows had lower levels of various milk proteins, including αs1-casein and β-casein
Milk from TR cows showed lower quality and immune dysfunction was heightened under high stress.

Abstract

Tongue-rolling behavior (TR) is commonly observed in dairy cows and is considered a stereotypic behavior indicative of compromised welfare. Chronic stress can impair lactation and immune function, yet the interaction between behavior (TR vs. normal behavior (NB)) and chronic stress (high vs. low) remains unclear. In this study, hair cortisol concentration (HCC) was used to assess stress levels in cows. The cows were first classified into high- and low-stress cows using K-means clustering. Subsequently, cows exhibiting high levels of TR and those exhibiting NB (i.e., no stereotypic behaviors) were selected from both stress categories to establish four groups (n = 8 per group): high-stress TR (HT), high-stress NB (HN), low-stress TR (LT), and low-stress NB (LN). We analyzed milk protein composition, milk proteome, and plasma immune-inflammatory indicators. Behavior (TR vs. NB) and chronic stress (high vs. low) showed significant interaction effects on plasma tumor necrosis factor-α (p = 0.046), interleukin-6 (p = 0.002), and proteomic profiles, involving multiple guanosine triphosphate-binding proteins (p < 0.05), transferrin (p = 0.001), and complement factors (p < 0.05). In addition, TR cows had significantly lower levels of αs1-casein (p = 0.019), β-casein (p < 0.001), κ-casein (p = 0.016), lactoferrin (p = 0.003), and plasma immunoglobulin A (p = 0.002). These results indicate that, under different chronic stress levels, TR cows differ markedly from NB cows in milk protein expression, immune function, and inflammatory responses. Moreover, milk from TR cows showed reduced quality, and immune dysfunction and inflammation were exacerbated under high stress. Overall, this study provides new insights into the physiological consequences of stereotypic behavior in dairy cows. These findings may help dairy farmers identify cows exhibiting TR as at risk of reduced milk quality and immune dysfunction, allowing for early management interventions to improve animal welfare and productivity.

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Cite This Study

Li et al. (Thu,) studied this question.

synapsesocial.com/papers/6980fc17c1c9540dea80ddbc https://doi.org/https://doi.org/10.3390/vetsci13020134

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