Evaluation of test duration for feed efficiency in growing beef cattle

Area of Science:

• Animal Science
• Agricultural Science
• Genetics

Background:

• Feed efficiency is a key trait in beef cattle production, influencing profitability and sustainability.
• Accurate measurement of feed efficiency traits requires optimized testing protocols.
• Nellore cattle are a significant beef breed in tropical regions, necessitating breed-specific efficiency evaluations.

Purpose of the Study:

• To identify the minimum test duration for accurately evaluating feed efficiency traits in Nellore bulls.
• To compare different test durations against an 84-day benchmark.
• To provide evidence-based recommendations for feed efficiency testing protocols.

Main Methods:

• Utilized data from 313 Nellore bulls, aged approximately 283 days.
• Implemented automated feed intake measurement systems (GrowSafe® and Intergado®).
• Assessed six test durations (15, 29, 43, 57, 71, 84 days) with body weight recordings and calculated correlation coefficients.

Main Results:

• A 15-day test is sufficient for mid-test metabolic body weight.
• A minimum of 43 days is required for accurate dry matter intake (DMI) measurement.
• A 71-day test duration is necessary for determining average daily gain (ADG), residual feed intake (RFI), and feed conversion metrics.

Conclusions:

• A 71-day test period, preceded by a 21-day adaptation phase, is recommended for comprehensive feed efficiency evaluation in growing Nellore cattle.
• Regular weight recordings (every 15 days) without fasting enhance accuracy.
• Optimized test durations can improve the efficiency and reliability of genetic selection for feed efficiency.