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This article was published in 1955
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
Hypocuprosis in Merino Sheep in Oberon District
R. C. & C. W. SPARKS, Carinya, Gingkin, via Oberon.
(Comment by D. G. CHRISTIE, B.V.Sc., District Veterinary Officer, Orange).
The property on which copper deficiency was diagnosed in 1954 is situated about 20 miles south of Oberon and was bought by the present owners in 1946. At that time it was classed as wether country on which introduced sheep under two years of age could not be expected to do well and wethers of various crosses were run by the previous owners. The soils are mixed, varying from basalt and good slate types to acid soils which of molybdenum oxide and limestone for the establishment of clovers.
In 1946 4-tooth Merino wethers were bought from Wellington, with satisfactory results. In 1950 2-tooth wethers with some Corriedale blood were bought from Cargo and these also did well. By this time some wire netting fences had been crected and areas of light and medium country sown to improved pastures and top-dressed, with the intention of breeding replacement sheep. A small lot of Merino ewes were bought in 1950 from a highly regarded property near Orange and were joined to average quality Merino rams.
The first drop of lambs in 1950 was disappointing. The fact that the lambs were inferior in constitution and wool to their mothers was attributed to the rams; so a change of rams was made next year, without improving results. In general, the breeding position from 1950 to 1952 was characterised by unthriftiness of the ewes and young sheep, accompanied by gradual wool deterioration in the former and slow growth and poor, harsh-handling wool in the latter. The problem, although worsening. was still regarded as due to breeding.
Accordingly, in 1953 fifty-guinea rams were bought from a prominent stud and further ewes for joining bought from a property about 5 miles away. The 270 joined ewes were helped through a hard winter with light hand-feeding of purchased oats. As lambing time approached they were in strong condition and the grass was growing nicely. A proportion of the ewes had been joined to lamb in August and this lambing was thoroughly normal. Hand-feeding was discontinued just prior to the main September October lambing and the ewes were transferred to green oats and improved pastures. This lambing began with the ewes on a high and improving plane of nutrition, but beginning to fall away visibly. Assisted births were common, apparently due to inadequate muscular tone to expel the lambs. Ewes had little milk and mothering was unsatisfactory. Pet lambs accumulated, simply because ewes were not interested in them.
Seasonal conditions kept improving and the condition of the sheep. including the August lambs and their mothers, continued to December. By this time they were in poor condition and badly worried by an extensive outbreak of mycotic dermatitis and a highly persistent form of pink-eye. The number of pet lambs reached 30, but not for long; deaths soon reduced their numbers, although they received milk daily and were grazing on clean, lush ryegrass and clover. Post-mortem examination of recently dead lambs always showed a moderate infestation of lung worms, no other internal parasites of any consequence and congestion of the lungs. The survivors were poor, anaemic and scouring-typical wormy sheep in appearance.
The position of Inspector of Stock at Bathurst being vacant at that time, a direct approach was made to Dr. G. L. McClymont at Glenfield Veterinary Research Station, who suggested copper and/or cobalt deficiency as a possible cause and who arranged for the analysis of two liver samples. Analysis demonstrated hypocuprosis: the copper content of the two livers being 23 and 34 p.p.m. respectively. Both liver samples were taken from ewes bought that year from the neighbouring property. Before the results of the analysis were received, all ewes and lambs were drenched with bluestone-nicotine sulphate and shortly afterwards with a copper-cobalt solution. Within a fortnight the sheep lost their anaemic appearance and typical lung-worm cough and started to improve. The pink-eye soon left them; and has not re-appeared since.
In view of the analytical figures and these encouraging results, all sheep on the property were drenched with bluestone solution at least twice during 1954 and the country used for breeding and for young sheep was top-dressed with 5lbs. bluestone (in superphosphate) per acre, as recommended. Monthly drenching of ewes and young sheep with copper-cobalt solution was continued until there were grounds for confidence that the bluestone top-dressing had been washed into the soil and had enriched the fresh pasture growth.
An experiment was begun in February, 1954, by the Bathurst Inspector of Stock, the District Veterinary Officer at Orange, and the Glenfield Research Station to prove and classify the copper deficiency and relate it to pasture analysis and to explore the cobalt position. For this purpose 60 lambs were selected and some small paddocks where lambs had previously proved unthrifty were omitted from the top-dressing programme. Unfortunately, the season was disastrously dry and the experiment finally was abandoned, but not before the correctness of the copper deficiency diagnosis had been supported strongly by the appearance of the sheep and the handle of their wool; though by a slight advantage only in weight gain. There the matter rests; the experimental paddocks having been top-dressed now with bluestone.
Recently an experiment was established to examine the cobalt position and while the result of this experiment is awaited the ewes, 2-tooths and weaners outside the experimental groups are being given a small cobalt supplement on the suspicion that it might be beneficial
The 1954 lambing was approached with confidence, although the late autumn and winter feed position had been bad and hand-feeding of the ewes with oats had been necessary. They began lambing in much lighter condition than in 1953. Lambing proceeded without a hitch; there were no assisted births and no pets. With a few exceptions, the ewes and lambs have done well, considering the season. In 1953 208 lambs were marked and about 150 survive. A few were destroyed as incurable sufferers from mycotic dermatitis, one was destroyed suffering from ataxia (the only definite case seen, although a few older sheep bred here sometimes show a suspicious weakness about the rump) and the balance died. Of the survivors, about 6 are badly stunted in growth but improving: the remainder being fairly well grown in the circumstances. Of 137 lambs marked in October, 1954, 135 are alive now (May, 1955).
In 1953 it was noticed that the greatest amount of trouble with lambing, milk supply and mothering, involved the ewes bought that year. A veterinary opinion obtained was that if a diagnosis of copper deficiency on this property is acceptable, there are good reasons for suspecting a similar state of affairs on the property from which these ewes were bought, as the ewes had insufficient stored copper to see them through the lambing. The owner of that property achieves excellent results with his cattle, which he sends away on agistment every winter. On the other hand, he has found the breeding of pure Merino sheep impracticable and lately he has changed his breeding sheep to cross-breds; buying grown Merino wethers for wool production. He uses phenothiazine for worm drenching. Similarly, in the 1953 troubles described above, the ewes had wintered on (apparently) good quality basalt country and lambed on paddocks of lighter soil where molybdenum oxide had been used to stimulate clover growth. Apparently, both types of country are suspected of being implicated in the deficiency.
It was of interest to hear recently that the original owner of the property regularly fed a commercial mineralised salt lick to his sheep; having found it was of benefit to them. Apparently the additional amount of copper required by the sheep is small, because later analysis of livers from sheep that died indicated that copper storage took place readily, and it might well be that the 1950-1953 difficulties in breeding and growing young sheep could have been avoided if bluestone-nicotine sulphate had been used as a worm drench instead of phenothiazine,
As a precaution, experimental plots were established in autumn, 1954, to test for response of subterranean and white clovers to added copper, but no indication of response was obtained.
A gratifying feature of these troubles was the generous and prompt advice and assistance given by all Departmental officers concerned and the kindness of Australian Fertilizers Limited in arranging quickly a special supply of bluestone-superphosphate mixture at a time of great scarcity.
(Mr. CHRISTIE: The diagnosis of Hypocuprosis in this case rested on levels of 23 and 34 parts per million; together with the dramatic response that followed drenching with copper sulphate and the improvement in the 1954-drop weaners over the 1953 unsupplemented weaners. It was intended to ascertain blood copper levels from the experimental group, but drenching with copper sulphate before the commencement of the experiment prompted the delaying of sampling until sufficient time had elapsed to reduce the control group to a hypocuprotic state. Unfortunately, hand-feeding became necessary and finally the trial was abandoned before confirmation of a hypocuprosis on blood copper levels was possible.
On the pasture side, analyses did not reveal a copper, molybdenum and sulphate inter-relationship which would induce a hypocuprosis. Pasture samples collected in February, 1954, showed the following: Poa spp. (1) Cu. 6.6 ppm., Mo. 0.65 ppm., SO4 0.08 per cent; White Clover (3) Cu. 7.8 ppm., Mo. 0.40 ppm., SO4 0.08 per cent; White Clover (4) Cu. 38 ppm., M SO4 0.88 per cent. Samples (1) and (3) showed low sulphate levels, while sample (4) was high in sulphate. Sample (4) also had an abnormally high copper level; while samples (1) and (3) showed normal coppers.
It should be pointed out, however, that pasture sampling on this holding was restricted to a few samples and these from only a small section of the property not top-dressed with copper sulphate. It is felt that pasture sampling should be carried out over a period to ascertain seasonal variations as well as variations between species. On other areas a marked difference between species has been noted; particularly in the case of sulphate levels, and to a lesser extent in the copper levels. The difference on comparable country was reflected in sheep which developed steely wool on lucerne (Cu. 2.5 ppm., Mo. 3.1 ppm., SO4 1.30 per cent.) and showed a return to normal wool when confined to a stand of Sudan Grass (Cu, 6.1 ppm, Mo 1.2 ppm, SO4 0.13 per cent.) in the next paddock (Warrumbungle). This inter-species variation prevents us from using analyses as a guide to possible effects in the sheep because of the selective grazing habits of that animal; particularly the Merino.)