Ewe problem may be less acute

Press, Volume CXII, Issue 33106, 22 December 1972, Page 8

Ewe problem may be less acute

It looks as though the problem of handling ewes at freezing works, mainly because of the new inspection requirements relating to socalled sarcocysts, may be less serious than had at first been anticipated.

Mr J. S. Chisholm, divisional manager (processing) of the Canterbury Frozen Meat Company, said last week that following experiments at their three works, in which they had had the co-operation of the veterinarians. they were reasonably confident that they could maintain last season’s killing rates. This would be achieved by bringing in extra trimmers on the detain rail. They had received assistance from the Ministry of Agriculture and Fisheries in training these men what to look for.

To help cope with the ewes. Mr Chisholm envisages sheep and lambs being intermingled in the daily kill, with perhaps 500 sheep being killed and then a few hundred lambs, but he says he believes that they might run into trouble if thev tried to handle a daily kill comprising two-thirds of ewes, and thev could also run into trouble where 100 per cent of the sheep in a line had cysts and had to be directed to the detain rail.

Mr G. H. Steel, livestock manager of the New Zealand Refrigerating Company. said that inspection procedures had been slightly eased and the situation now appeared to be slightlv better than had been anticipated. His company had carried out experiments in line with instructions from the ministry at all works and these had been reasonably satis-

factory with the percentage of rejects being slightly less than had been anticipated. Where a line of ewes was clean, he said, it would be possible to achieve last season’s rate of killing, but with lines of sheep with cysts there was a hold-up with carcases being detained for trimming. As yet, he said that sufficient experimentation had not been done to give a specific answer about what extra personnel might be required on chains. It will be into the new year, however, before works will be handling many ewes. Mr Chisholm said that they would be starting on ewes in late January or early February, but it would be mid-Feb"ruary to early March before they were deeply involved with them. Writing in a newsletter issued by the Meat Board, Mr I. M. Caimey, veterinary adviser to the board, says that the disease condition is known as sarcosporidiosis and consists of the presence .of varying numbers of sarcocysts in the muscle tissue of animals. Sarcocysts most commonly look like rice grains on the surface of the muscle tissue, but occasionally they can be very much larger. Only a few sarcocysts may be visible but sometimes they are present throughout the’muscle tissue of the carcase.

While it is believed that sarcocysts are caused by a type of parasite, this is not known for certain, neither are the detailed means by which animals become infected, although it is felt that this occurs through eating feed contaminated by droppings from infected animals. It will be evident from the foregoing that the knowledge about sarcocysts is very' scanty and consequently there is no basis for effective methods of control The disease occurs in

most countries and in 411 mammalian animals and in birds. It is particularly common in mature ewes. It occurs rarely in humans and there is no evidence of it being a cause of serious impairment of human or animal health.

Referring to meat inspection procedures in freezing works, Mr Caimey says that where large sarcocysts are found in any part of the viscera or carcase, they can be identified easily and the carcase can then be directed from the chain to the detain rail for re-inspection. The carcase is condemned if there is a widespread distribution of these large sarcocysts throughout the carcase. In the case of a light and not widespread distribution, the sarcocysts and surrounding tissues are trimmed out by works’ staff.

The percentage of carcases totally condemned for sarcocysts is relatively low. In some lines of ewes, however, a large percentage end up on the detain rail for re-inspection and trimming and frequently the detain rail becomes full and the killing has to be stopped until it is cleared. This often results in a large reduction in the daily rate of kill.