Understanding Meat Production and Animal Slaughter Process

Assist. Prof. Hussein AL-Jiashi 2021-2022

Definitions Meat is all parts of animal that are suitable for human consumption. This includes all domestic animals of the following species: bovine animals (including buffaloand bison), swine, sheep, goats. Carcass or carcase is the whole body of one of the above animals (except pigs) that has been slaughtered, after bleeding, evisceration and removal of the limbs at the carpus and tarsus, removal of the head, tail, udder and removal of the skin. The pig carcass still has the skin attached. Offal is fresh meat other than that of the carcass, whether or not naturallyconnected to thecarcass. Viscera is the term given to the offal from the thoracic, abdominal and pelviccavities, including the tracheaand oesophagus.

The Slaughter of Animals There is evidence of a link between the level of stress in the animal and the meat quality, and therefore animals should be kept and transported in comfortable conditions before they are slaughtered. Following the rigors of transport there should be an adequate period of rest before slaughterand an adequate supply of food and water. Animals should be handled without any unnecessary noise and they should not be stressed. For cattle and sheep this means a quiet and relaxing environment in the lairage. Legislation requires that animals should be stunned or rendered unconscious before they are bled. Exemptions are made for Jewish and Muslim slaughter (ritual slaughter).

Stunning: After stunning there are two distinct phases. The first phase is known as the tonic or rigid phase in which the animal falls to the floor and lies still and rigid with its front legs extended and the rear legs retracted towards the body. In the second phase, known as the clonic phase, the animal exhibits uncontrolled convulsions or kicking movements. During both of these phases no rhythmic breathing should be evident. There are three main methods of stunning an animal: (1) Mechanical stunning. (2) Electrical stunning. (3) Carbon dioxide (CO2) stunning. To ensure that the animal is stunned correctly it is very important that the correct site for shooting is used. In cattle this is a point on the forehead at the intersection of two imaginary lines drawn from the base of the horns to the eyes on the opposite side. In sheep and domesticated deer the point is at the highest point of the head at the midpoint between the ears and aimed towards the jaw line. In pigs it is about 2.5 cm above the level of the eyes on the mid-line and at right angles to the forehead. In boars and sows it is 5 cm above the level of the eyes and to one side of the mid-line to avoid the maximum thickness of skull bone.

Stunning Sites in farm animals

Bleeding of theanimal (exsanguination) (sticking) This is the only procedure that must be assumed to cause the death of the animal: none of the stunning methods can be assumed to have killed the animal. Legally, no other slaughter or dressing procedures should be carried out before the expiry of at least 30 seconds for cattle and 20 seconds for sheep, goats, pigs and deer. Sticking should occur within 15 seconds of stunning. About 40 60% of the total blood volume is lost during bleeding of the animal. The remainder is largely retained in the viscera. Only about 3 5% remains in the muscles.

Cattle: After the animal has been stunned and pithed, the skin is incised along the jugular furrow with one knife. A second knife is then used to sever the aorta in the thoracic cavity. The knives should be sterilized between each incision. Bleeding should continue for 5 6 minutes. The average amount of blood obtained from cattle is about 13.5 liters. Sheep: Sheep are generally stunned either by a captive bolt pistol or by electricity. If a captive bolt pistol is used, the sheep must be stunned separately and not in the sight of other sheep. Bleeding is done by making an incision in the jugular furrow close to the head and severing the carotid arteries. Bleeding should last for about 5 minutes and the amount of blood obtained is about 2 liters.

Ritual slaughter Legislation allows for the slaughter of animals without previous stunning in the (1) Islamic or Muslim and (2) Jewish methods. The same exemption also applies for the ritual slaughter of poultry. Apart from poultry, only cloven-footed animals that chew the cud are eaten by Muslims and Jews. In their slaughterhouses, therefore, only cattle, sheep and goats are ritually slaughtered. It has been stated frequently that animals bleed better by the Muslim or Jewish method than by other methods, but this is doubtful.

Jewish method of slaughter Shechita A swift cut is made across the neck with a very sharp knife. This severs the skin, underlying muscles, trachea, oesophagus, jugular veins and carotid arteries. The five principles of Shechita are that the neck should be cut without pause, pressure, stabbing, slanting or tearing. If the knife receives any nick during the operation the slaughtered animal is considered unfit for Jewish consumption. When the diaphragm is exposed during dressing of the carcass, the shochet or Jewish cutter pierces this and subjects the thoracic organs to a manual examination. This is known as searching . Any adhesions of the lungs found are examined visually, and if deemed detrimental to the animal when it was alive, the carcass is pronounced terefah or unfit for Jewish consumption. Carcasses found fit or Kosher must have the meat porged by removal of the blood vessels and sinews. It is for this reason that the forequarters, which are easily porged, are eaten by Jews. The hindquarters, which are difficult to porge, are seldom eaten by them but are sold to the non-Jewish population who, although they may be opposed to ritual slaughter, may eat such hindquarter meat without knowing that the animal was killed by this method

Muslim method of slaughter halal This method is similar to the Jewish method, but there is no searching or porging after slaughter and both fore- and hindquarters are eaten.

Rigor mortis After death, rigor mortis occurs. It develops 4 8 hours after slaughter in pigs, 8 12 hours after in sheep and 12 24 hours after in cattle. The pH of the muscle at the time of death is about 7, i.e. neutral. During the process of rigor mortis the glycogen in the muscle turns to lactic acid, causing the muscle to become more acid and the pH falls to 5.5 5.8. Owing to the chemical action taking place there is a rise in temperatureof about 3 C in the carcass. The characteristics of rigor mortis are: (1) Contraction and hardening of muscles. (2) Dullness of muscles through lack of transparency. (3) Stiffness and immobility of joints.

Rigor mortis It is associated with the breakdown of adenosine triphosphate (ATP) and its non replacement because of the lack of oxygen. Rigor mortis gradually disappears after 24 hours of its onset. Various factors can affect it. The higher the ambient temperature the quicker are itsonset and disappearance. Lower temperatures have the opposite effect. In fevered animals the resulting rigor mortis may bevery slight and transient. A low pH is a desirable factor for the keeping quality and tenderness of meat. The hardening of fat after death is due to the fall in temperature and not to rigor mortis.

Emergency slaughter Emergency slaughter of animals is carried out because of either accident or disease. Common causes of emergency slaughter are: (1) Fractures of limbs or pelvis. (2) Extensive bruising or injuries, e.g. accidents and trampling during transit. (3) Respiratory distress, e.g. in choke or tympanites. (4) Prolonged recumbency, e.g. milk fever. (5) Difficult parturition. (6) Partial asphyxiation occurring often in pigs during transit. (7) Heat stroke this also occurs in pigs during transit in hot weather. It is important to bear in mind the possibility of anthrax in emergency slaughter. The carcass and offal in any case of emergency slaughter should receive a very thorough inspection, and if there is any doubt, samples should be submitted for bacteriological examination.

Ante-mortem inspection Animals awaiting slaughter should be inspected before they are slaughtered and this is done in the lairages. These may be checked by a veterinary surgeon if the animal is displaying signs of being unwell. It is therefore important that the layout and construction of the lairages should be such that it is easy for the animals to be seen. While the ante-mortem inspection is being carried out, other points should be taken into account relating to regulations regarding feeding, watering, bedding, etc. Any signs of disease, distress, injury, etc. should be noted and the appropriate action taken. Important diseases that may be found at ante-mortem inspection are anthrax, foot and mouth disease, bovine spongiform encephalopathy, sheep scab, mange, orf, swine erysipelas, swine feverand swinevesiculardisease.