Impact of Feed Delivery Pattern on Aerial Particulate Matter and Behavior of Feedlot Cattle

Frank M Mitloehner; Jeff W Dailey; Julie L Morrow; John J McGlone

doi:10.3390/ani7030014

Impact of Feed Delivery Pattern on Aerial Particulate Matter and Behavior of Feedlot Cattle

Animals (Basel). 2017 Mar 1;7(3):14. doi: 10.3390/ani7030014.

Authors

Frank M Mitloehner¹, Jeff W Dailey², Julie L Morrow^{3

4}, John J McGlone⁵

Affiliations

¹ Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79409, USA. fmmitloehner@ucdavis.edu.
² Livestock Issues Research Unit, USDA-ARS, Lubbock, TX 79409, USA. jefftadailey@gmail.com.
³ Livestock Issues Research Unit, USDA-ARS, Lubbock, TX 79409, USA. fmmitloehner@ucdavis.edu.
⁴ Julie Morrow passed away; however, she has played a critical role in the completion of this work.. fmmitloehner@ucdavis.edu.
⁵ Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX 79409, USA. john.mcglone@ttu.edu.

Abstract

Fine particulate matter with less than 2.5 microns diameter (PM_2.5) generated by cattle in feedlots is an environmental pollutant and a potential human and animal health issue. The objective of this study was to determine if a feeding schedule affects cattle behaviors that promote PM_2.5 in a commercial feedlot. The study used 2813 crossbred steers housed in 14 adjacent pens at a large-scale commercial West Texas feedlot. Treatments were conventional feeding at 0700, 1000, and 1200 (CON) or feeding at 0700, 1000, and 1830 (ALT), the latter feeding time coincided with dusk. A mobile behavior lab was used to quantify behaviors of steers that were associated with generation of PM_2.5 (e.g., fighting, mounting of peers, and increased locomotion). PM_2.5 samplers measured respirable particles with a mass median diameter ≤2.5 μm (PM_2.5) every 15 min over a period of 7 d in April and May. Simultaneously, the ambient temperature, humidity, wind speed and direction, precipitation, air pressure, and solar radiation were measured with a weather station. Elevated downwind PM_2.5 concentrations were measured at dusk, when cattle that were fed according to the ALT vs. the CON feeding schedule, demonstrated less PM_2.5-generating behaviors (p < 0.05). At dusk, steers on ALT vs. CON feeding schedules ate or were waiting to eat (standing in second row behind feeding cattle) at much greater rates (p < 0.05). Upwind PM_2.5 concentrations were similar between the treatments. Downwind PM_2.5 concentrations averaged over 24 h were lower from ALT compared with CON pens (0.072 vs. 0.115 mg/m³, p < 0.01). However, dry matter intake (DMI) was less (p < 0.05), and average daily gain (ADG) tended to be less (p < 0.1) in cattle that were fed according to the ALT vs. the CON feeding schedules, whereas feed efficiency (aka gain to feed, G:F) was not affected. Although ALT feeding may pose a challenge in feed delivery and labor scheduling, cattle exhibited fewer PM_2.5-generating behaviors and reduced generation of PM_2.5 when feed delivery times matched the natural desires of cattle to eat in a crepuscular pattern.

Keywords: behavior; feeding management; feedlot cattle; particulate matter.