HIGH MORTALITY IN LAMBS

Press, Volume LXXIV, Issue 22371, 7 April 1938, Page 12

HIGH MORTALITY IN LAMBS

WORK OF SCIENTIFIC EXAMINATION ■VISITS TO CANTERBURY FARMS PROGRESS REPORT ISSUED BY DEPARTMENT Causes of the present heavy lamb mortality on Canterbury farms are at present being investigated by two veterinary surgeons of the Department of Agriculture, working in conjunction with the staff of the Canterbury i . Agricultural College. Many farms have already been visited, and examinations made of affected lambs. The officers making the investigation for the department are Mr T. K Ewer, B.V.Sc., who is stationed a; Ashburton, and Mr G. K. L. Knott, M.R.C.V.S., who is working from Christchurch. To assist the work, a parasitological laboratory has been equipped at the Christchurch office, and an officer from the Wallacevillelaboratory has been transferred south to assist in this part of the investigation. A progress report on the work so far accomplished has been issued by the department in which details are given of the findings so far reached in the investigations. Wide Area of Investigation “Numerous farms over a wide area have already been visited, and complete parasitological examinations made of lungs and contents of stomach and intestines,” states the report. “The results so far indicate beyond doubt that the worms responsible for causing the death of lambs are species confined to the fourth stomach and small intestines. Sheep with an already existing infestation with these worms are certainly liable to attack b” the lung-worm, but it cannot be toe strongly emphasised that from !the mass of evidence existing, it has been found that death from lungworm alone, seldom, if ever, occurs in Australia and New Zealand. The reason for the confusion which appears to exist in the minds of many concerning the importance of lungworm, is explained by the readiness with which this large worm can be

seen, while the smaller but more dangerous worms in the stomach * and intestines are overlooked by laymen, “In reference to lungworm, one correspondent’s statement that in a mortality said to -be due to lungworm, ‘drenching definitely showed a check in the rate,’ only goes to prove that whatever drench was used exerted its effects on the stomach and/or intestinal worms. Drenching, in so far as lungworm is concerned,- is definitely ineffective, no matter what drug is used. Inhalations. or intratracheal injections are the only recognised methods of actual treatment. * Seven Species of Small Worms “In the fourth stomach and small intestine there are seven species of small worms of numerous varieties which are of varying pathogenic importance. Again, it is recognised that some of these are more dangerous than others. It is fully recognised that, as yet, no drench has been found to be 100 per cent.' effectual, but the fact remains that after exhaustive trials with all known anthelmentics, the bluestone nicotine sulphate mixture is the most effective for general use. It is essential that the counting of the worms should be carried out accurately by an expert, to decide definitely Which species is causing the ill-effects, as this knowledge is quite as important as the actual numbers. The freezing companies in Canterbury are co-oper-ating, and are providing selected specimens taken from lambs at the works for laboratory examination, in addition to those sent in by the field officers. Thus a more comprehensive picture is obtained. “As pointed out in one letter to “The Press,’ worms were found after drenching. This indicates that the infestation must have been extremely heavy, and had drenching not been carried out losses would have inevitably occurred. Moreover, in this particular case it is significant that certain dangerous species, namely, Haemonchus contortus and Ostertagia spp had been entirely eliminated from the stomach.” Discussing possible damage to the bowel, resulting from drenching, the report says:—“ Providing the drench is used in the approved strength and dose, no ill-effects will result. The report that bluestone drench burns the bowel is entirely without foundation.”