FEWER DEATHS

Ashburton Guardian, Volume 60, Issue 35, 21 November 1939, Page 6

FEWER DEATHS

PULPY KIDNEY DISEASE. PREVENTIVE VACCINATION. YOUNG LAMBS IN COUNTY. “Inquiries in the Ashburton County lead me to believe that the deathrate in young lambs, particularly those between what has hitherto been regarded as the danger ages—lo days to two months—has, this season,, proved to bo noticeably less than last year and very considerably less than what is reputed to have occurred in the past.” Mb T. K. Ewer, Veterinary Research Officer of the Animal Research Division of the Department of Agriculture, stationed at Ashburton, made this statement this morning- when an inquiry was made by a “Guardian” reporter as to the prevalence of the pulpy kidney disease in the district this season.

“I know several men who lost up to S per cent, of their most thriving young lambs from this disease last year,-who this time have lost barely 1 per cent.,” continued Mr Ewer. “Of course, there are properties on which losses of 4 to 5 per cent, .almost invariably occur through pulpy kidney disease and which this year have again experienced the same sort of thing. However, it has been most interesting to observe the effect preventive vaccination of the ewe during the winter has upon this ‘habitual’ mortality.” Actually, said Mr Ewer, more farmers tried vaccinating their ewes this year than has ever been the case previously, hut the only places where it would he fair to come to any conclusion about how effective this had proved were those where some control sheep were left unvaccinated, or where there had been this “habitual” death-rate.

“From what I can learn, it would certainly seem that the new alum-pre-cipitated vaccine issued by the Commonwealth Serum Laboratories which is recommended by the Department of Agriculture has resulted in a very definite degree of immunity being conferred upon young lambs suckling such vaccinated ewes.

Interesting Results. “Particularly interesting in this connection are the results obtained in one part of Ashburton County. Here there are four farms close together, each running between 700 and 900 sheep. Each year losses from pulpy kidney disease amounted to between 25 and 40 of thei best lambs. Last year three of these farms vaccinated their ewes, two of them leaving bout 50 unvaccinated as controls. There was a significant difference between the deathrates in the two groups, and each of these farmers was convinced that it had been a payable proposition. So this year they did ali their sheep, and another neighbour came in too. Now it has been most interesting to see that with the three men who re-vaccinated their ewes losses amongst the lambs have been practically negligible, the man who vaccinated this year for the first time losing the most. This is simply due to the fact that the immunity the other ewes carried over from last year was boosted up still 'higher by the re-vaccination.” Vaccinating the ewes was no use at. all. against protecting lambs against the disease occurring at 4 to 5 months and over, added Mr Ewer. The only way to do anything about that was to vaccinate the lamb itself, . preferably twice. Many farmers were trying this for the first time this year, hut it was too early to say how successful it. might prove. A Word of Warning. 1 ‘lt is probably true to say that the .scarcity of feed this spring has a lot to do with the lessened incidence of pulpy kidney disease, hut abundance of feed is certanly not the only factor in causing the death-rate to he higher. It was noticeable last summer and autumn when deaths were still occurring sporadically that often it was a lamb in store condition that'died. The same sort of thing has been reported in other countries. Earlier this spring I encountered a property- where mostly the lambs affected were twins —which at that stage were not “doing” too well either. “Finally a word of warning. I noticed that it was often just, after shearing last year that four or five lambs would suddenly he found dead from this trouble. I believe that is due to keeping the lambs away from the ewes for an unnecessarily long time, so that the lamb tends to overfeed when they are mothered-up. Certainly sudden over-feeding has been shown in, -recent experimental work to be a major cause, of precipitating the disease. It would be worth while trying to avoid this if possible.”