Effect of handling intensity at the time of transport for slaughter on physiological response and carcass characteristics in beef cattle fed ractopamine hydrochloride

Abstract

The effects of handling intensity on the physiological response and carcass characteristics of feedlot cattle fed ractopamine hydrochloride were evaluated at the time of transport to slaughter. Eighty steers (BW = 668 ± 36 kg) representing 10 lots of similar breed, frame size, and degree of finish were blocked by lot, stratified by weight, and randomly assigned to 1 of 2 handling intensities (HI) over a 1,600 m dirt alley course: 1) low-stress handling (LSH) or 2) high-stress handling (HSH). For the LSH treatment, 4 penmates were kept at a walk with the use of a lead rider. For the HSH treatment, 4 penmates were kept at a minimum of a trot and received 2 applications of an electric prod (approximately 1 s per impulse) at 2 separate instances: first in the alley before post-handling sampling, and again during loading for transportation to the abattoir. Behavioral observations and physical indicators of stress were recorded a minimum of 1 h before handling (baseline), immediately after handling (POSTHAND), and while in lairage after a 200 km transport to the abattoir. Vital parameters were recorded at baseline and POSTHAND. Venous blood samples were collected via jugular venipuncture at baseline and POSTHAND, and mixed arterial and venous blood samples were collected during exsanguination at slaughter. Muscle tremors tended to be more prevalent in HSH cattle at POSTHAND ( = 0.10). The HSH cattle tended to have greater POSTHAND heart rate ( = 0.08); however, there was no effect of HI on POSTHAND respiration rate or rectal temperature ( 0.34). The HSH cattle had greater lactate, epinephrine, norepinephrine, cortisol, and glucose concentrations at POSTHAND ( ≤ 0.02). Additionally, HSH cattle had lower POSTHAND blood pH, bicarbonate, base excess, and partial pressure carbon dioxide ( < 0.0001). Bicarbonate concentrations were greater in HSH cattle at slaughter ( = 0.05); however, there were no differences between HI treatments for the remaining blood variables ( 0.11). Concentrations of stress hormones and CK were significantly greater at slaughter relative to baseline and POSTHAND for both LSH and HSH cattle ( < 0.001). These findings suggest cattle trotted without a lead rider develop metabolic acidosis, and illustrate the importance of low-stress handling at the time of transport for slaughter. Further research is warranted to develop strategies to mitigate stress at the time of transport and ensure the welfare of beef cattle presented to abattoirs.

Characterization of Fed Cattle Mobility during the COVID-19 Pandemic

“…Other studies have explored the change in cattle mobility throughout the marketing process and have reported mobility scores more aligned with what was found in the current study [26][27][28]. Hagenmaier et al [27,28] reported that mobility scores increased (worsened) during the marketing process.…”

“…Other studies have explored the change in cattle mobility throughout the marketing process and have reported mobility scores more aligned with what was found in the current study [26][27][28]. Hagenmaier et al [27,28] reported that mobility scores increased (worsened) during the marketing process. For example, Hagenmaier et al [28] found that the prevalence of mobility scores > 1 increased from 7.1% after transport to 20.3% after lairage at the plant and similar changes were reported in Hagenmaier et al [27], with comparable values in the current study as well.…”

“…Mobility has been included as an outcome in studies exploring the physiological and behavioral responses of cattle to various management practices, such as shade provision, inclusion of beta-agonists in the diet, and animal handling techniques [26][27][28]. Additionally, mobility has been included as a parameter in the National Cattlemen's Beef Association's (NCBA) National Beef Quality Audit (NBQA) observational benchmarking studies [16,18].…”

“…Hagenmaier et al [27,28] reported that mobility scores increased (worsened) during the marketing process. For example, Hagenmaier et al [28] found that the prevalence of mobility scores > 1 increased from 7.1% after transport to 20.3% after lairage at the plant and similar changes were reported in Hagenmaier et al [27], with comparable values in the current study as well. Although the impact of weather parameters on mobility outcomes was not explored in the Hagenmaier et al studies [27,28], it should be noted that both studies were conducted in the summer and mean THIs reported exceeded the mean THI in the current study.…”

An epidemiological investigation to determine the prevalence and clinical manifestations of slow-moving finished cattle presented to slaughter facilities1

“…A substantial amount of research exists on the effects of distance traveled on stress and bruising in cattle, but such research does not include the assessment of cattle mobility or the presence of any abnormalities other than biomarkers of stress, including blood cortisol, lactate, catecholamines, CK, and others ( Mitchell, 1988 ; Jarvis et al, 1995 ; Hoffman et al, 1998 ; Nanni Costa et al, 2003 ). In two separate studies, Frese et al (2016) and Hagenmaier et al (2017) reported that aggressive handling can increase stress markers such as lactate and CK in cattle and can have detrimental effects on mobility. Such associations between blood biomarkers and abnormal mobility are explored further in Lee et al (unpublished data).…”