DM intake by feedlot beef cattle: factors that impact intake patterns.

Area of Science:

• Animal Science
• Agricultural Engineering
• Ruminant Nutrition

Background:

• Dry matter intake (DMI) is a key performance indicator in commercial feedlots.
• Accurate DMI prediction is essential for optimizing cattle feeding strategies and resource management.
• Factors influencing DMI include initial body weight, sex, and intake during adaptation and previous weeks.

Purpose of the Study:

• To evaluate the relative impact of various factors on daily DMI in feedlot cattle.
• To develop and validate a prediction equation for weekly mean DMI using early-available data.
• To identify key predictors for DMI throughout the feeding period.

Main Methods:

• Utilized a dataset of 4,132 pens (485,458 cattle) from a commercial feedlot (2009-2014).
• Split data into 80% for regression model development and 20% for validation.
• Employed generalized least squares regression, incorporating correlations between DMI and factors like previous DMI, adaptation DMI, initial shrunk body weight (ISBW), and sex.

Main Results:

• Daily DMI from the previous week was the strongest predictor (explaining ~70% of variation) from week 6 to 31.
• Mean daily DMI during the adaptation period (weeks 1-4) and ISBW were significant predictors from weeks 5-12 and 5-20, respectively.
• Sex became a significant factor after week 8. The four factors accurately predicted weekly DMI (r² = 0.98, RMSE = 0.155 kg).

Conclusions:

• Mean daily DMI in feedlot cattle can be accurately predicted using readily available early-period data.
• Previous week's DMI is the most influential factor for predicting subsequent intake.
• Integrating previous DMI with adaptation DMI, ISBW, and sex provides a robust model for feedlot DMI prediction and management.