Analysis of Behavioral, Growth and Metabolic Indicators in Suckling Calves Under Outdoor Winter Rearing Conditions...

Area of Science:

• Animal Science
• Environmental Physiology
• Agricultural Engineering

Background:

• Cold stress significantly impacts dairy calf health and productivity.
• Optimizing winter rearing protocols is crucial for calf welfare and farm economics.
• Existing cold stress assessment methods lack comprehensive quantification.

Purpose of the Study:

• To scientifically assess cold stress in Holstein dairy calves under varying winter environments.
• To develop and validate a quantitative system for evaluating cold stress.
• To optimize winter calf rearing protocols based on scientific evidence.

Main Methods:

• A 60-day feeding trial with 20 calves in outdoor (-5~-28 °C) and indoor (5 °C) environments.
• Expert surveys and analytic hierarchy process (AHP) to establish a cold stress evaluation system.
• Fuzzy comprehensive evaluation, generalized linear mixed models (GLMM), and metabolomic analysis.

Main Results:

• Outdoor calves experienced mild cold stress (maximum membership degree = 0.64).
• Temperature-humidity index (THI) significantly correlated with physiological and biochemical parameters.
• Outdoor calves showed improved growth performance by day 60, with no compromise in health indicators.

Conclusions:

• A quantitative methodology for cold stress evaluation was established.
• Environment-physiology-behavior interactions were clarified, supporting outdoor rearing strategies.
• Outdoor cold exposure can be managed to optimize dairy calf growth and health in winter.