Treadmill exercise is not an effective methodology for producing the dark-cutting condition in young cattle1,2

Investigating the impact of pre-slaughter management factors on meat quality outcomes in cattle raised for beef: A scoping review

Introduction

The pre-slaughter management period is a critical juncture in the beef supply chain, having implications not only for animal welfare and product quality, but also for profitability. During this period, cattle are exposed to many stressors in a short time, many of which have been shown to impact meat quality. Understanding how cattle management during this terminal step in the production chain affects meat quality and economic outcomes is crucial.

Methods

The objective of this study was to investigate, synthesize, and report on research evaluating the impact of management factors during the pre-slaughter period on beef meat quality. A systematic approach was used to search for peer-reviewed and primary studies published in English in CAB Abstracts, PubMed, and Web of Science. A total of 3,217 non-duplicate records were screened for eligibility; articles were deemed eligible for inclusion if they included beef cattle in the pre-slaughter period and reported at least one meat quality outcome. After three screening rounds, 85 articles met all inclusion criteria. Data pertinent to the scoping review’s aims were extracted, including study location, population characteristics, pre-slaughter factors reported, and outcomes of interest.

Results

Europe (35, 41%) and South America (21, 25%) represented approximately two-thirds of the studies. Bulls (37, 43.5%) and steers (34, 40.0%) were the most reported sex classes, with the most frequent breed types reported as predominantly British or Continental and Bos indicus breeds (24, 28.2%; 24, 28.2%, respectively). Transportation (n=46), lairage (n=36), and handling (n=35) practices were the most reported pre-slaughter factors. Overall, 59 studies reported pH as an outcome of interest – almost double that of the next highest outcome, bruising (n=35). Muscle pH was most assessed with predictors at the abattoir (n=37); conversely, the effects of transportation were most evaluated on bruising (n=23).

Discussion

A trend across all the categories was that there were relatively few studies evaluating the impact of pre-transport factors on meat quality. Charting the relevant literature is a critical step towards understanding the relationship between pre-slaughter management and end-product quality; doing so will help industry stakeholders in the beef production chain optimize management practices that improve meat quality and enhance profitability.

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

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.