The Influence of Age and Winter Environment on Protein Block Intake Behavior of Beef Cattle Winter Grazing Mixed-Grass Rangelands

Samuel A Wyffels,Darrin L Boss,Julia M Dafoe,Timothy Delcurto,Cory T Parsons,Boone H Carter

doi:10.3390/ruminants1020014

Samuel A Wyffels, Darrin L Boss + Show 4 more

Open Access

https://doi.org/10.3390/ruminants1020014

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Abstract

This study evaluated the influence of cow age and temperature adjusted for windchill (Twindchill) on supplement intake behavior of cattle winter grazing rangelands. A mixed-age herd of Angus-based cows (291 and 316 in year 1 and 2, respectively) were classified by age (1-, 2-, 3-, 4-, 5–7-, and ≥8-year-old) and grazed rangeland pasture (329-ha) for two consecutive winters. Cows were provided free-choice access to supplement protein blocks in a SmartFeedPro self-feeder system. An Onset HOBO Weather Station collected data throughout the grazing period. Supplement intake (expressed as kg∙d−1 and g∙kg body weight−1), the coefficient of variation in supplement intake and intake rate (g∙min−1) displayed Twindchill × cow age × year interactions (p ≤ 0.02). In general, cow age displayed a quadratic effect on all supplement intake variables (p ≤ 0.04), where 3- to 4-year-old cattle had the greatest supplement intake with the least variation, while yearling cattle had the least amount of supplement intake and the greatest variation. In conclusion, winter environmental conditions interacted with cow age to affect cattle supplement intake behavior and, consequently, the efficacy of nutrient delivery systems for beef cattle winter grazing on rangelands.

Highlights

During winter months, beef cattle grazing at northern latitudes are frequently exposed to chronic cold and often windy environments resulting in prolonged periods below their Lower Critical Temperature (LCT)
The findings of this study indicate that winter weather conditions, cow age, and year interact, influencing supplement intake behavior of grazing beef cattle
Beef cattle production and management on winter rangelands are enhanced by evaluating nutrient delivery of self-fed supplements and the interaction of cow age and environmental stress

Summary

Introduction

Beef cattle grazing at northern latitudes are frequently exposed to chronic cold and often windy environments resulting in prolonged periods below their Lower Critical Temperature (LCT). To maintain homeothermy during conditions below the LCT, cattle raise their resting metabolic rate resulting in an increase in energy expenditure [1,2,3]. Forages under winter grazing conditions at northern latitudes are often dormant, resulting in a low-quality, high fiber forage resource. Voluntary intake is limited by forage fiber content NDF [7,8,9], suggesting cattle may not be able to increase intake to the level required to meet the increased metabolic demands to maintain homeothermy

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