The influence of loading, road transport, unloading and time in lairage on body temperature in finished feedlot steers

Abstract

<p><b>Context.</b> Transport of cattle can be stressful and may lead to increased body temperature. It is necessary to quantify the effect of transport on body temperature so that informed management decisions can be made. <b>Aims.</b> This study aimed to determine the effects of a 5.5 h, 430 km road transport journey on body temperature (<i>T_B</i>) of feedlot steers. <b>Methods. </b> Body temperature was obtained at 30 min intervals. All cattle were weighed and randomly allocated to a truck pen prior to transport. Cattle were transported on a single B-double truck, with three upper-deck and three lower-deck compartments. At 0630 hours, cattle were walked from their pens (25 m), weighed and loaded onto the truck. Loading was completed by 1030 hours. <b>Key results. </b>During the weighing and loading process prior to transport, mean <i>T_B</i> increased from 39.37 ± 0.11°C to 40.21 ± 0.11°C. Immediately following loading, mean <i>T_B</i> increased. The <i>T_B</i> of cattle on the upper deck was 40.96 ± 0.08°C and on the lower deck 40.89 ± 0.08°C (P = 0.6299). During the first 3 h of the journey, the <i>T_B</i> of lower-deck cattle decreased by 1.14°C (<i>P</i> < 0.01), compared with a 0.83°C reduction in cattle on the upper deck. Over the duration of the journey, which took 1 h longer than expected, the mean <i>T_B</i> of the cattle on the upper deck (40.47 ± 0.11°C) was greater (<i>P</i> < 0.0001) than that on the lower deck (40.04 ± 0.12°C). One hour after unloading at the abattoir, pooled <i>T_B</i> was 40.26 ± 0.12°C. Minimum <i>T_B</i> (38.87 ± 0.04°C) occurred at 10.5 h after unloading. <b>Conclusions.</b> The results from this study highlight that increases in <i>T_B</i> were more associated with cattle handling and loading events, rather than transport, under these environmental conditions. Understanding the magnitude of this increase will help managers decide on pre- and post- transport management of cattle. <b>Implications.</b> Cattle handling and loading for transport may lead to an increase in <i>T_B</i>, which can remain elevated for a number of hours. However, it is unclear what the impact of hotter climatic conditions would have on trailer microclimate and, as such, <i>T_B</i> regulation during road transport.</p>