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

  • ️Sun Jan 01 2017

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

Frank M Mitloehner et al. Animals (Basel). 2017.

Abstract

Fine particulate matter with less than 2.5 microns diameter (PM2.5) 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 PM2.5 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 PM2.5 (e.g., fighting, mounting of peers, and increased locomotion). PM2.5 samplers measured respirable particles with a mass median diameter ≤2.5 μm (PM2.5) 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 PM2.5 concentrations were measured at dusk, when cattle that were fed according to the ALT vs. the CON feeding schedule, demonstrated less PM2.5-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 PM2.5 concentrations were similar between the treatments. Downwind PM2.5 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 PM2.5-generating behaviors and reduced generation of PM2.5 when feed delivery times matched the natural desires of cattle to eat in a crepuscular pattern.

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

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1

Schematic of experimental setup for particulate matter (PM2.5) and behavior sampling. A total of 4 PM2.5 samplers were used to measure PM2.5 concentrations upwind (south side) and downwind (north side) in the south and southwest pens of the feedlot, in 1 pen per treatment per day. The 4 PM2.5 samplers were moved daily from 1 of the 7 pens (per treatment) to the next. For example, on d 1, upwind and downwind locations were sampled in pens A1 and B1 as shown above. On day 2, upwind and downwind locations were sampled for PM2.5 in pens A2 and B2 etc. Behavioral measures were recorded in 15 min scan sampling mode by live observation using a camera that was mounted to a 10-m high rotating tripod on top of a mobile behavior lab from 1600 and 2100 on the same days when PM2.5 was measured. The mobile behavior lab remained at the depicted location throughout the duration of the study. Prevailing wind direction was from the South.

Figure 2
Figure 2

Average PM2.5 (particulate matter, <2.5 μm) concentrations over 24 h in mg/m3 in a West-Texas feedlot under 2 different feeding time regimens (ALT = fed at 0700, 1000 and 1200 h vs. CON = fed at 0700, 1000 h and 1830 h). PM2.5 was measured over a period of 7 days in April 2000. Panel (a) shows upwind PM2.5 concentration, which was 0.035 mg/m3 in ALT versus 0.036 mg/m3 in CON (Pooled SE; SEM = 0.006, Treatment p = 0.87, Treatment by time p = 0.08). Panel (b) shows average downwind PM2.5 concentrations, which was 0.072 mg/m3 in ALT vs. 0.115 mg/m3 in CON (SEM = 0.007, Treatment p < 0.01, Treatment by time p < 0.01).

Figure 2
Figure 2

Average PM2.5 (particulate matter, <2.5 μm) concentrations over 24 h in mg/m3 in a West-Texas feedlot under 2 different feeding time regimens (ALT = fed at 0700, 1000 and 1200 h vs. CON = fed at 0700, 1000 h and 1830 h). PM2.5 was measured over a period of 7 days in April 2000. Panel (a) shows upwind PM2.5 concentration, which was 0.035 mg/m3 in ALT versus 0.036 mg/m3 in CON (Pooled SE; SEM = 0.006, Treatment p = 0.87, Treatment by time p = 0.08). Panel (b) shows average downwind PM2.5 concentrations, which was 0.072 mg/m3 in ALT vs. 0.115 mg/m3 in CON (SEM = 0.007, Treatment p < 0.01, Treatment by time p < 0.01).

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