Humane Handling has Strong Connections to Meat Quality

Nelson Gaydos
By Nelson Gaydos, AAMP Outreach Specialist

Animal welfare and humane handling have strong connections to meat quality that many in the meat industry might not be aware of. By explaining this cause and effect relationship, meat processors can better their behavior in the transportation, handling and stunning of animals and in turn produce higher quality meat products. Generally, it is easier to notice humane handling issues on cattle immediately following hide removal; in contrast, issues in pigs are not observed until the deboning or packaging stages of the process.

Common or reoccurring injuries can often be traced back to issues in the trucks or slaughter floor. For example in cattle, bruises in the hip area can be an indication of narrow chutes and alleyways. These injuries can also occur when making tight turns out of trailers and pens. These issues are more prevalent in older processing plants designed for smaller, lower volume of cattle. Newer plant designs feature wider alleyways with fishbone pen designs (45º angle corners and exits) from pens and trailers. Widening these areas will also help to prevent balking and scraping.

Hip injuries can also occur when animals are unloaded too quickly and not in a calm, organized manner. It is important to have wider door openings and rounded frames and edges to prevent crowding if and when the animals rush to exit the trailer. Alley way backup gates, if not adjusted for the height of the animals or correctly counter-balanced, can lead to bruising of the back, spine and the loin. Rollers can also be added to the bottom of the gates to help alleviate these problems and stress on the animal. If a guillotine door is used in the stun box entrance, it is important that the bottom of the door is cushioned and slippery to prevent friction and bruising on the top of the loin, rump and tail area. Additionally, lowering of the guillotine door should not be used as a means to push the animal deeper into the stun box.

Evaluation of the heads of the animals after removal should be conducted on a regular basis. Irregular placement of the captive bolt or stun tool can be an indication of high stress and anxiety in the animal due to poor handling prior to entering the stun box. If multiple shots are required, such as a second “security shot” on a high percentage of animals, it is important to investigate and implement corrective actions.

Moving on to pigs, issues of animal welfare and humane handling are more visible during processing and packing. If a processor is experiencing a high amount of pale, soft, exudative (PSE) product, it is financially favorable to investigate their process and determine possible causes.

“Handling of pigs prior to the conversion process from live animal to carcass (pre-harvest) can affect muscle quality. Minimizing stress can reduce the conversion of energy stored in the muscle as glycogen to lactic acid, which lowers pH and promotes PSE (pale, soft, exudative meat) muscle production (Aberle et al., 2001). Pre-harvest stress may be decreased by less crowding of pigs during transit to market and in the holding area in the meat plant. Gentle handling without trauma as well as sufficient lighting in the holding area or from the holding area to restraining further reduces stress. Less stress is encountered if pigs can move in a clockwise direction on level ground or on a slight incline as opposed to a decline. Maintenance of a cool environmental temperature further reduces stress and use of a cool water shower prior to harvest is commonly recommended”. (Pork Facts, 2001)

Issues during electrical stunning such as broken backs and pelvises can be indicators of poor sunning procedures or constriction in the restrainer during stunning. Be sure to use a stunner that provides constant amperage (taking into account the varying size and weight of animals) and a wand that is clean and correct placement will help to decrease severe muscle contraction and, consequently, broken bones. Head-only stunning can result in violent kicking which can cause bruising and blood spots in the shank, ham and other areas. Blood splash occurs when blood vessels burst as a result of excessive muscles contractions during the electrical stunning process. Increased occurrences or amount of blood splash can indicate poor electrical stunning technique and placement of the wand, slower stun to bleed time, surface abrasion (before or after stunning) and body constriction during stunning. Unclean wands can have a buildup of soil and carbon on the surface which will result in poor conductivity and stunning of the animal.

CO2 stunning has been shown to be an alternative to electrical stunning. Several pigs can be placed in CO2 chambers together maintaining the animal’s natural herd behavior alleviating some of the stress of the animals.

Routine monitoring of the slaughtering process and identifying the location and frequency of bruising and other issues can aid in locating the source of these problems and how to correct them. Conducting trim loss studies can help processors assess their animal handling and slaughtering processes resulting in improved animal welfare and increased quality of meat.