Pre-slaughter Factors Research Articles

Ostrich leather quality: a review

This review summarises the research that has been published on factors that influence the various aspects of ostrich leather quality, a vital aspect to the economic viability of the commercial ostrich industry. The review is divided into three main sections: discussing intrinsic, pre-slaughter and post-slaughter factors that influence leather quality. Only one literature source that investigated the morphology of ostrich skin could be found. The high vascularity near the surface of the skin was indicated in making the skin susceptible to bruising, which influences skin quality, while the strength and flexibility of ostrich leather was attributed to the three-dimensional cross-weave arrangement of collagen fibres. Various studies reported a high degree of variation in quality within and between ostrich skins. The potential of genetic selection for improved skin quality was also considered, and it was demonstrated that most ostrich leather traits exhibited significant genetic variation. Findings on pre-slaughter factors, such as the effects of age, weight, nutrition and management practices, are also summarised. Few research reports on post-slaughter factors that influence leather quality were found. A few studies looked at the effect of storage on ostrich skin quality, but literature on the effect of processing techniques are lacking. Research priorities identified include the development of methods to assess skin quality on-farm and finding objective methods of evaluating ostrich leather quality.

A simulation model for studying the role of pre-slaughter factors on the exposure of beef carcasses to human microbial hazards

A Monte Carlo simulation model was constructed for assessing the quantity of microbial hazards deposited on cattle carcasses under different pre-slaughter management regimens. The model permits comparison of industry-wide and abattoir-based mitigation strategies and is suitable for studying pathogens such as Escherichia coli O157:H7 and Salmonella spp. Simulations are based on a hierarchical model structure that mimics important aspects of the cattle population prior to slaughter. Stochastic inputs were included so that uncertainty about important input assumptions (such as prevalence of a human pathogen in the live cattle-population) would be reflected in model output. Control options were built into the model to assess the benefit of having prior knowledge of animal or herd-of-origin pathogen status (obtained from the use of a diagnostic test). Similarly, a facility was included for assessing the benefit of re-ordering the slaughter sequence based on the extent of external faecal contamination. Model outputs were designed to evaluate the performance of an abattoir in a 1-day period and included outcomes such as the proportion of carcasses contaminated with a pathogen, the daily mean and selected percentiles of pathogen counts per carcass, and the position of the first infected animal in the slaughter run. A measure of the time rate of introduction of pathogen into the abattoir was provided by assessing the median, 5th percentile, and 95th percentile cumulative pathogen counts at 10 equidistant points within the slaughter run. Outputs can be graphically displayed as frequency distributions, probability densities, cumulative distributions or x– y plots. The model shows promise as an inexpensive method for evaluating pathogen control strategies such as those forming part of a Hazard Analysis and Critical Control Point (HACCP) system.

Small ruminant production systems and factors affecting lamb meat quality

The influence of sheep production systems on the environment of the Mediterranean area and the different productive systems of lamb in Spain are described. Moreover the actual knowledge (90s decade) about factors influencing the quality of lamb meat is reviewed, highlighting the importance of productive and pre-slaughter factors on carcass quality and post-slaughter factors on meat quality. Also the significance of culinary cultural back-ground on the acceptance of sheep meat is discussed.

Some preslaughter factors affecting the occurrence of bruising in sheep

The preslaughter handling and behaviour, and subsequent bruising was observed in 49 groups of sheep in a commercial slaughterhouse. A greater percentage of bruised carcases was found in lambs (71%) than in ewes (49%) ( P < 0.01). A greater percentage of severely bruised carcases was found in lambs from markets (20%) than in those direct from farms (12%) ( P < 0.05). Significant correlations were found between the occurrence of recent bruising and wool-pulls during unloading, riding by another sheep, and hits and squashes against structures at the slaughterhouse. However, even assuming that each potentially traumatic event observed in the slaughterhouse caused a bruise, only about one-quarter of the bruising could have been attributed to handling problems at the slaughterhouse. Eight-eight per cent of all bruises were estimated to have been caused within about 24 h of death, indicating that most bruising probably was caused by handling problems during loading on the farm, during transit and particularly at markets.

New technologies in the post-slaughter handling of meat

In recent decades there has been a growing realisation that the way carcasses are handled immediately post-slaughter and during subsequent storage has a much greater effect on meat quality than pre-slaughter factors such as animal breed, fatness, and nutrition. This, coupled with the financial benefits of centralising post-slaughter handling activities such as boning, butchery and distribution – is subtly extending the role of the slaughterhouse.

Effects of Sex, Age, Preslaughter Factors, and Holding Conditions on the Quality Characteristics and Chemical Composition of Turkey Breast Muscles

One-hundred-sixty 16- and 20-week-old hen and tom turkeys were randomized into five groups and treated to certain preslaughter factors and holding conditions. Variables studied included the effect of feed withdrawal, excitation prior to slaughter, anesthetization, sex, and age on certain quality characteristics and chemical composition of turkey breast muscle.Anesthesia completely eliminated struggle at slaughter and caused significant increases in initial pH (P<.01), tissue glycogen (P<.01), and waterholding capacity (WHC) (P<.01), whereas shear force (kg) (P<.01), yield (%) (P<.05), and color (aL) (P<.01) values for the breast muscle were significantly decreased as compared with the free struggle (control) group. However, anesthesia had no effect on the chemical composition and other quality measurements.Feed withdrawal had a significant effect on final pH (P<.01), WHC (P<.01), live weight (P<.05), and moisture content (P<.05) when compared with the fed group.Excitation prior to anesthetization resulted in muscles with a significantly higher WHC (P<.05), yield (P<.05), and aL values (P<.05) but significantly lower live weight, shear force, and L values than the nonexcited group.As age of the bird increased, tissue glycogen (P<.05), thaw loss (P<.01), and shear force (P<.01) of the breast muscle significantly decreased, whereas live weight (P<.01), yield (P<.01), L values (P<.01), and fat content (P<.01) increased significantly with advancing age. Male turkeys were observed to have a significantly higher live weight (P<.01) and higher ash content (P<.01) of the breast muscle as compared to the female.