FARM-KILLED MUTTON AND PORK.

New Zealand Journal of Agriculture, Volume XXXVII, Issue 6, 20 December 1928, Page 392

FARM-KILLED MUTTON AND PORK.

GUIDANCE FOR HYGIENIC EXAMINATION OF CARCASSES

J. E. McIlwaine,

M.R.C.V.S., Live-stock Division, Wellington.

It occasionally happens when a sheep or pig is killed on the farm for human consumption that some abnormal feature is met with on dressing the carcass. The following notes are intended as a guide for the farmer on such occasions.

Before an animal is killed it is well to note whether it appears to be in normal health in every way. An animal .should not be killed for food if affected with severe diarrhoea or showing any symptoms of fever. It is advisable to have the selected animal fasted for twelve hours before being killed. The superior quality of much farm-killed mutton is in great • measure due to the fact that the animals are not subjected beforehand to fatigue through travelling.

An apparently healthy animal having been selected and fasted, the slaughter is carried out, particular attention being paid to the fact that thorough bleeding is essential for the appearance and keepingqualities of the meat. The internal organs should be removed as soon as possible after skinning is completed. This will prevent staining or discoloration of the carcass, which sometimes occurs when the entrails are left in position too long. There is also less danger of contamination with bacteria from the contents of the stomach and intestines.

Speaking generally, sheep in New Zealand are remarkably free from disease (and especially any disease likely to be transmitted to the human subject through, consumption of their flesh). At the same time there are certain conditions which render the flesh objectionable and unfit for food. During dressing it is well to note the presence of any adhesions in the body-cavities. If such are associated with abscess formation it is advisable to reject the carcass. The seat of castration is sometimes subject to abscess formation, and this requires complete removal. ' ,

While thus examining the abdomen the presence of hydatid cysts in the liver or on the walls of the abdomen may be noted, and it sometimes happens that these cysts are seen in large numbers. The characteristic cyst, is a thin sac or envelope containing a watery fluid. If ruptured and its lining examined with a magnifying-glass a whitish area will disclose the head or heads of future tapeworms. Any organs containing such cysts must be destroyed ; in fact, if the cysts are very numerous it is advisable to destroy the entire carcass. Here it must be strongly stressed that such rejected organs must not be . given to the dogs on the farm without thorough cooking, as such a procedure directly infests the dogs with tapeworms. The infested dogs as a result will again contaminate the pastures, and cattle, sheep, or pigs grazing on such pastures will be later found the subjects of hydatids. These cysts often become degenerated through age. Then they show a cheesy appearance, are yellowish-white in colour, and of firm consistency. Organs containing such cysts should be condemned.

In the chest-cavity of the carcass the presence of hydatid cysts in the lungs may again be noted, and if any are present the lungs must

be effectively destroyed. The lungs normally are free and easily removed, and if any adhesion is seen between the lungs and chest-wall pleurisy has been the cause. As in the case of adhesions in the abdominal cavity, if only localized and no abscesses present the carcass is fit for use.

A disease of sheep known as caseous lymphadenitis, characterized by the presence of abscess formation in the lymphatic glands, requires to be looked for. These glands are more commonly spoken of as “ kernels,” and those most commonly affected in this disease are situated in front of the shoulder-blade in the fore limb, and in the hind limb those situated below and in front of the stifle-joint, when the carcass is hanging up. Occasionally such abscesses are deep-seated and only seen when the carcass is cut up, and sometimes abscesses due to this disease are seen in the lungs and liver. If one or two glands are affected, only the quarter concerned should be destroyed : if several are affected throughout the carcass it should be rejected entirely. The pus in such abscesses has a characteristic greenish colour.

In connection with pigs slaughtered on the farm for home use the remarks made regarding hydatids and adhesions in the chest and abdominal cavities apply as stated in the case of sheep. Abscess formation in pigs at the seat of castration is more commonly seen than in sheep, as are abscesses in the abdomen. A condition sometimes seen in pigs which have been fed extensively on whey is that of gasformation in the membrane supporting the intestines ; this condition does not affect the carcass, but is mentioned as it might be mistaken for something more serious.

In the case of the pig, however, there is one disease which requires particular attention when examining a carcass, and that is tuberculosis. As the lymphatic glands or kernels are the most common seats of this disease, particular attention must be paid to them, and as many as possible examined by cutting into them with a knife. As there is a greater tendency in the pig for the disease to spread, this point is most important. The viscera of the pig can be examined as they are removed from the body. A chain of these. small glands is situated in the membrane immediately above the intestine itself, and, although only the size of a pea or a bean, their position when diseased will be easily recognized. Another small group of these glands is situated on the liver where - the large vessels enter this organ. A third group is situated on each side of the backbone after evisceration. When the animal is affected with tuberculosis these glands are enlarged, and contain a whitish gritty material. At times they may also contain pus when the disease is active.

When the lungs and heart have been removed the glands of the lungs should then be examined. These are situated on each side of the windpipe where it enters the lungs. The lungs themselves may be affected, and can be examined by the hands for any hard centres, after which they may be cut into with a knife. In advanced stages the disease may be present on the lining-walls of either the chest or abdomen or both. The disease is here recognized by the presence of small whitish nodules the size of millet-seed or a pea. The head now remains to be examined, and in this connection it must be mentioned that the glands here are more commonly affected

with tuberculosis than any of the others in the body. Although a number of glands are situated in the head region, only two will be mentioned here, and these are situated one on each side of the lower jaw to the inside of the bone in front of the angle of the jaw. If the glands of the head only are affected and the rest of the carcass is healthy, the head should be destroyed, and the carcass can be used.

In the inspection of carcasses for tuberculosis it may be laid down that when the internal organs are only slightly affected the carcass can be safely used for food after destroying the affected organs. If, however, the disease is extensive throughout-the internal organs, or if any part of the dressed carcass itself or the glands contained in it are affected, the entire carcass should be rejected.