E. D. Andrews

Selenium-responsive diseases of animals in New Zealand

Abstract Extract Until recently, interest in the biology of selenium was focused on its properties as a naturally-occurring poison in plants grazed by stock in certain problem areas, notably in the western states of North America. The geological distribution of soils bearing seleniferous vegetation, the toxicities of various forms of selenium, including those of its inorganic salts, and the treatment and prevention of selenium poisoning have been dealt with in detail by Rosenfeld and Beath (1964), and those aspects will not be considered further in this review.

Prevention of goitre in new-born lambs from kale-fed ewes

Abstract Extract In a previous paper (Sinclair and Andrews, 1954), we showed that goitre in new-born lambs from ewes fed thousand-headed kale (Brassica oleracea var. acephala) was prevented by dosing each ewe during the latter part of pregnancy with potassium iodide at the rate of 140 mg a week for 6weeks. It was pointed out that, while weekly dosing with iodine compounds was impracticable underordinary farming conditions, larger doses, givenat longer intervals and towards the end of pregnancy, might afford an effective and practical method of preventing goitre. The use of iodized licks was also discussed. Under New Zealand conditions, all licks are subject to the disadvantage that many animals will not readily take them, but those containing the commonly-used potassium iodide suffer a special disadvantage because iodine tends to be lost from the mixtures. Because of its greater stability, potassium iodate appeared to be a better choice than potassium iodide as a lick ingredient. Since the iodine in potas...

Deaths due to goitre in new-born lambs prevented by iodized poppy-seed oil.

Abstract Extract In a previous publication (Sinclair and Andrews, 1958) the writers discussed methods of preventing goitre in lambs from ewes fed brassica crops. In particular, it was found that two oral doses of an inorganic iodine compound, one given. about two months and the other about one month before lambing, largely prevented signs of the disease. Death rates associated with severe outbreaks were markedly reduced. Later, Myers and Ross (1959) reported that injections of “Neo-Hydriol” (May and Baker) an iodized poppy-seed oil preparation of specific gravity 1·375 and containing 40 per cent, (weight/weight) of bound iodine, had a significant effect on the thyroid glands of ewes as measured by decreased cell height and increased iodine content. The main aims of the work reported here were to determine the effects of single injections of Neo-Hydriol given to ewes grazed during the last two months of pregnancy on thousand-headed kale (Brassica oleracea var. acephala), on gestation periods, lamb lamb bir...

Failure of mild goitre to influence growth rates in kale-fed weaned lambs

Abstract Extract In previous publications (Sinclair and Andrews, 1954 and 1958), we discussed the problem of goitre in new-born lambs from ewes fed thousand-headed kale (Brnssica oleracca var. accplzalu). It was found that, under the experimental conditions at Manutuke, there was invariably, to a greater or lesser degree, an incidence of goitre in new-born lambs. In particular, when ewes were fed on kale for as long as 8 weeks before lambing commenced, the disease was severe and neo-natal mortality rates were extremely high. The incidence of goitre was greatly reduced and high death rates were prevented by closing the pregnant ewes with iodine compounds. Although there was no obvious evidence of goitre in the ewes, radio-iodine studies showed that this feed exerted an antithyroid effect in these animals (Wright and Sinclair, 1958).

An outbreak of polio-encephalomalacia in cobalt-deficient sheep

Abstract Extract In New Zealand two forms of polio-encephalomalacia have been recognized in sheep. The mild form is characterized clinically by blindness (amaurosis), and pathologically by laminar necrosis of the cerebral cortex (Mullins et al., 1958). The severe form is characterized clinically by a wide variety of neurological signs and pathologically by extensive cerebro-cortical necrosis (Hartley and Kater, 1959). The mild form has a relatively high morbidity and low mortality, whereas the severe form has a low morbidity and a very high mortality.

The effect of cobalt topdressing in preventing cobalt deficiency disease of lambs in southland

Abstract Extract From trials carried out in the North Island of New Zealand and in the Nelson district it was concluded (New Zealand Department of Agriculture, 1954)that cobalt-deficient land should be top-dressed each year at the rate of 5 oz. cobalt sulphate per acre.

An attempt to reduce calcium phosphate deposits on cobaltic oxide pellets by citric acid treatment

Abstract Extract At least under New Zealand conditions, the use of cobaltic oxide pellets (“cobalt bullets”) to control cobalt deficiency in sheep is limited by a tendency of the bullet to accumulate deposits of calcium phosphate (Andrews, 1961). Although the use of steel “grinders” (for example, in the form of 1/2 in. × 1/2 in. engineers grub screws) has been recommended as a means of keeping the surface of the bullet in a satisfactory condition (Anon., 1960), very little published information on the efficiency of the method is so far available from Australian sources, and, in one New Zealand experiment with lambs (Andrews, unpublished), grinders were of little effect in reducing the amount of calcium phosphate deposited.

The effect of phenothiazine on cobalt-deficient and cobalt-dosed lambs.

Abstract Extract Recently, Hunter (1953) has pointed out that, while there is as yet no experimental evidence to show that mineral deficiency in sheep is a cause of parasitic infestation, there is a general impression that in many areas both conditions occur together. In this connection it is of interest that early investigations (Webster, 1935) associated “Morton Mains Disease” of lambs in Southland. New Zealand, with abnormally high parasite counts. Later, it was shown (Askew and Dixon, 1936) that the primary cause of the disease was due to a deficiency of cobalt. Thereafter, interest in parasites as a possible contributing cause waned, since experience showed that if cobalt deficiency was corrected, lambsthrived.