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An 18-month-old alpaca developed nervous signs, including swaying of the head and neck, a wide-based stance and hind-limb ataxia. No certain diagnosis was made but the animal recovered after successive treatment with amoxycillin, vitamin B1, ivermectin and copper oxide, followed by vitamin E and selenium. The differential diagnosis rationale of treatment is described.

An outbreak of acute myopathy occurred in a group of 23 Hereford cross and Aberdeen Angus cross 18-month-old heifers, running outside with a bull in February. One morning two were found recumbent, five were ataxic and one had fallen into a river and drowned. Subsequently two of the ataxic ones became recumbent. Serum creatine phosphokinase values were found to be directly proportional to the severity of the clinical manifestations. Myoglobinuria was not observed. Serum calcium, magnesium and inorganic phosphate levels were all within the normal ranges. Treatment of affected animals with selenium and/or alpha-tocopherol had no clear effect; from biochemical estimations carried out, the selenium and alpha-tocopherol status of both affected and unaffected animals was considered adequate. Five recovered, two spontaneously without treatment, but the two most severely affected did not improve with therapy and had to be slaughtered 13 and 25 days respectively after the onset of symptoms.

The benefits of the inclusion of cobalt and selenium supplements in anthelmintic preparations were demonstrated in a 10 week trial with cobalt- and selenium-deficient blackface wethers. The anthelmintics were based on oxfendazole and on levamisole plus oxyclozanide; three doses provided, in total, 38 mg cobalt and 7.2 or 11.3 mg selenium. Administration of the supplements prevented the weight loss and reduction in food intake observed in unsupplemented animals. Blood glutathione peroxidase activities were restored to normal and increases in serum vitamin B12 levels were observed which were consistent with the prevention of both cobalt and selenium deficiencies.

The efficacy of the selenium and cobalt contents of a trace element supplemented anthelmintic was evaluated in a series of trials with lambs in Scotland and Northern Ireland. The product was compared with other methods of supplementation and was found to be an adequate source of selenium when administered at monthly intervals. Its cobalt content was shown to be of some nutritional benefit on four of five sites but not as effective as the monthly 250 mg oral cobalt dose, vitamin B12 injection or intraruminal soluble glass bolus treatments also used. No growth responses were obtained and unsupplemented animals generally had an adequate cobalt and selenium status. No toxicity problems were encountered from either element.

Three methods of selenium supplementation, by subcutaneous injection, intraruminal pellet and addition to water, were tested in experiments with cattle and a fourth method, oral supplementation of a sodium selenite solution, was evaluated with lambs. All four methods worked effectively for periods ranging from four months to one year after treatment. It is suggested that choice of treatment will depend on the circumstances of each case, including cost, husbandry system and ease of administration.

A syndrome characterised by the birth of lambs with varying degrees of rigidity of the limbs and spine has been encountered on several occasions in Rhodesia. Outbreaks have occurred in autumn-born lambs from Dorper ewes grazing heavily fertilised Star grass cv No 2 (Cynodon aethiopicus) pastures. The condition appears to be exacerbated by the application of sulphur to the pasture and is partly prevented by the administration of selenium and vitamin E to the ewes before lambing. The aetiology is unknown.

The occurrence and incidence of pneumonia in housed calves were not related to the selenium status of the herd as measured by blood glutathione peroxidase activity nor were they affected by selenium treatment of calves during the neonatal period. Pneumonia was related more closely to herd size and building design.

Barium selenate was developed as a long-acting subcutaneous injection for selenium treatment. The results from trials using this product show that it is a safe preparation for treating and preventing selenium deficiency in sheep. It produces a satisfactory selenium status which will be maintained for at least six months and, when injected into pregnant ewes, results in the transfer of selenium from the ewe to its progeny.

A double blind controlled trial was carried out on four commercial dairy herds, to investigate the effect of one 50 mg injection of selenium, 10 days before parturition, on the incidence of weak calves. Although the treatment marginally increased the selenium status of treated calves it did not decrease the incidence of the weak calf syndrome.