Technical note: Recording rules for behavioral studies in growing heifers fed high-concentrate diets

Area of Science:

• Animal Behavior
• Animal Husbandry
• Ethology

Background:

• Continuous recording (CR) provides accurate behavioral data in ruminants but is labor-intensive.
• Time sampling (TS) methods offer potential time savings but their accuracy needs validation.
• Growing heifers fed high-concentrate diets present specific behavioral patterns influenced by housing and feeding.

Purpose of the Study:

• To compare the accuracy of various time sampling (TS) methods against continuous recording (CR) for behavioral measurements in growing heifers.
• To identify the most reliable TS intervals and sampling strategies for different behaviors in individually housed heifers.

Main Methods:

• Continuous 24-hour recording served as the control for evaluating TS methods (S2, S5, S10, S15, S20, S30, FS10, 4PF, 8PF).
• Accuracy was assessed using linear regression analysis with predefined criteria for coefficient of determination, intercept, and slope.
• Eight growing heifers housed individually and fed a high-concentrate diet were observed over six non-consecutive days.

Main Results:

• The S5 TS method accurately estimated most behaviors, with S2 required for drinking, social behavior, and wood-shaving rummaging, and S10 for self-grooming.
• Ruminating and resting behaviors were accurately captured by S20 and S30 TS methods, respectively.
• Sampling methods like FS10, 4PF, and 8PF proved inadequate for accurately measuring the studied behaviors.

Conclusions:

• Not all time sampling methods are suitable for accurately measuring all behaviors in growing heifers.
• The S5 TS method, with specific adjustments for certain behaviors (S2, S10), offers a reliable and efficient alternative to continuous recording.
• Linear regression analysis with specific statistical criteria provides a robust framework for validating time sampling accuracy.