1937 Onderstepoort Journal of Veterinary Science and Animal Industry, Volume 8, 1937
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Item Studies in mineral metabolism XXXVII. The influence of variations in the dietary phosphorus and in the Ca:P ratio on the production of rickets in cattle(Pretoria : The Government Printer, 1937) Theiler, A.; Du Toit, P.J.; Malan, A.I.; Du Toit, P.J.1. Young heifers and steers were fed basal rations supplemented with CaCO₃ and Na₂HPO₄ in such a manner that the intakes of Ca and P were different in the respective groups. Vitamin D was present in abundance. 2. The basis of the experiments was respectively deficiency and sufficiency of P with varying amounts of Ca in the rations. 3. The experiments continued for approximately 24 months. during which period observations were recorded on weight increase, food consumption, blood analysis for P, Ca and phosphatase, clinical symptoms of disease and bone analyses – both chemical and histological. 4. The outstanding result of the experiments is that under the conditions mentioned P deficiency in bovines invariably leads to rickets or osteomalacia and that osteodystrophia fibrosa is not produced by P deficiency per se. With regard to the latter condition the suggestion is made that Ca deficiency may be the responsible factor. 5. Erdalkali-alkalizitat, like Ca:P ratio of which it really is a modification, is not the factor which determines whether rickets will or will not develop under conditions of P deficiency but both are associated with the severity of the complex result produced; for instance if they are not always associated with the severity of the microscopical bone lesions then with the earlier effects upon food consumption, growth and the development of clinical symptoms. 6. From the data available it would appear that a ratio of CaO:P₂O₅ of 2.5:1, when P was present in adequate amounts did not affect the animals significantly in regard to the observations registered. 7. A daily intake of 19 gm. P₂O₅ of which 53 per cent. was retained by the steers and of 24.0 gm. P₂O₅ with a retention of approximately 63 per cent. by the heifers provided sufficient P for normal growth and development while 13 gm. and 10 gm. were insufficient for the steers and heifers respectively. 8. Decreased food consumption which has invariably been observed in cattle receiving insufficient amounts of P in their diets is not wholly due to the inadequacy of the P but is also associated with the calcium content of such a diet or apparently therefore an effect of a disturbance in the Ca:P metabolism of the animal. 9. With regard to blood analysis the phosphatase and the inorganic P content of the blood afford valuable assistance in following the development of rickets but Ca determinations have been found to be of little help in presence of vitamin D. The periodic removal of portions of ribs causes the animal very little inconvenience and has advantages even over X-ray photography for studying the development of osteodystrophic diseases in the experimental animals.Item Subject index(Pretoria : The Government Printer, 1937) Anonymous; Du Toit, P.J.Item Author index(Pretoria : The Government Printer, 1937) Anonymous; Du Toit, P.J.Item Anatomical studies no. 62. On the effect of debudding on skull conformation(Pretoria : The Government Printer, 1937) Curson, H.H.; Du Toit, P.J.It is possible by the operation of debudding to alter the conformation of the skull in such a marked fashion as not to be able to recognise the original type.Item Chemical blood studies. VII. A serial study over a 12 months period of some organic and inorganic constituents in "laked" and "unlaked" blood filtrates of healthy bovines between 15 and 27 months old(Pretoria : The Government Printer, 1937) Hamersma, P.J.; Du Toit, P.J.In this paper, the seventh of a series of bloodstudies of domestic animals, data in respect of normal bovines have been presented. Determinations of Hb, T.N., S., N.P.N., U.N., "T"C.N., U.A.N., and A.A.N., as well as Cl, Na, K, Mg, Ca, P (inorg.), and Fe in the case of seven bovines are submitted and the salient differences briefly touched upon. Comparative data of other workers, from different countries have been appended.Item Bone biopsy as an aid to the study and diagnosis of deficiency diseases(Pretoria : The Government Printer, 1937) Thomas, A.D.; Van der Wath, J.G.; Du Toit, P.J.1. The objects and advantages of bone biopsy in the histological, haemocytological and biochemical study and diagnosis of nutritional deficiency diseases are enumerated. 2. The technique for such biopsies is described for the various domesticated animals, stress being laid on the likely sources of accidents and methods employed to prevent these. 3. The necessity for simplifying and accelerating methods of diagnoses of bone conditions when dealing with large numbers of animals is stressed and the methods evolved towards this end are described.Item Studies in sex physiology no. 18. On the growth of the gravid uterus in the Merino(Pretoria : The Government Printer, 1937) Malan, A.P.; Curson, H.H.; Du Toit, P.J.Item Studies in mineral metabolism. XXXVI. Fluorine metabolism in rats and bovines(Pretoria : The Government Printer, 1937) Du Toit, P.J.; Smuts, D.B.; Malan, A.I.; Du Toit, P.J.1. Appreciable amounts of fluorine is retained by bovines and rats on rations to which fluorine has been added. Bovines retain approximately 0.2 grm. and rats 1 mgm. of F per day under the conditions of the experiment. 2. The percentage F occurring normally in ash of rats varies from 0.039 to 0.05. 3. The ash per 100 grams empty weight in rats is increased by fluorine feeding. 4. Fluorine causes a decreased retention of both calcium and phosphorus in rats, a slight increase in calcium retention and a pronounced decrease in the phosphorus retention of bovines.Item Observations on bluetongue in cattle and sheep(Pretoria : The Government Printer, 1937) De Kock, G.; Du Toit, R.; Neitz, W.O.; Du Toit, P.J.1. Experiments are described in which it was possible to recover blue tongue virus from laboratory cattle exposed on the veld at Tzaneen. In these cattle no clinical evidence of blue tongue was manifested. 2. This Tzaneen strain of virus is capable of "breaking the immunity" of sheep immunized with the Onderstepoort vaccine, however, without any mortality and without the occurrence of typical blue tongue symptoms. 3. There is no doubt that some basal immunity persisted in these vaccinated sheep, even for considerable periods after immunization and utilizing exceptionally virulent viruses for the various tests. 4. The significant thermal reactions provoked in vaccinated sheep by this Tzaneen strain were referred to, and contrasted with the marked reactions and mortality in the blue tongue susceptible sheep. 5. These marked reactions could not be attributed to the size of the dose and the method of inoculation. 6. In one instance the virus prepared according to the existing method of preserving the virus, remained virulent for susceptible blue tongue sheep for a period of 8,5 months. 7. A passage of 15 generations through blue tongue vaccinated sheep and 9 generations through blue tongue susceptible sheep failed to attenuate the virus in respect of its virulency. 8. It was shown that cattle could remain carriers of the virus without manifesting symptoms for a period of 22 days after injection and in sheep up to 60 days. 9. The significance of first and second reactions in the same blue tongue susceptible sheep with the same strain of Tzaneen virus is referred to. 10. The nature of the most important lesions was considered as well as their pathogenesis and close relationship to the various forms of horsesickness in horses.Item Salmonella bovis-morbificans (Basenau) from an outbreak of food-poisoning in the Cape Province(Pretoria : The Government Printer, 1937) Henning, M.W.; Greenfield, E.C.; Du Toit, P.J.The antigenic structure of the Salmonella isolated by Greenfield and Judd (1936) from an outbreak of food-poisoning at the Cape Peninsula is described. As its antigenic components were found to resemble those of bovis-morbificans the following antigenic factors should be assigned to it: Somatic "0'' antigen, VI, VIII; "H" (Specific) antigen, r; "H" (non-specific) antigen, 1, 3, 4, 5. The reason why Kunzendorf failed to absorb all the group agglutinins from this strain of bovis-morbificans and vice versa is still obscure.Item Variation in Bacillus anthracis(Pretoria : The Government Printer, 1937) Sterne, Max; Du Toit, P.J.l. Smooth mucoid colonies developed in anthrax cultures held for long periods at 37°C. in a number of different media. Similar colonies developed in strains attenuated at 42°C. 2. All these smooth mucoid colonies yielded rough variants which were usually less virulent than the smooth parent and which in some cases showed a complete and abrupt loss of virulence. 3. The loss of virulence and smoothness was associated with a loss of the ability to produce capsules both in vitro and in vivo. 4. A number of these rough avirulent daughter strains produced immunity to anthrax in guinea pigs. 5. Fully virulent and freshly isolated anthrax strains always grew smooth mucoid on serum agar in carbon dioxide. 6. These virulent strains rapidly developed rough daughter colonies in the carbon dioxide, in the same way that attenuated smooth mucoid strains developed rough daughters under ordinary conditions (summary 1 and 2). 7. These rough variants obtained on serum agar in carbon dioxide were completely avirulent and uncapsuled in vitro and in vivo. 8. These rough a virulent dissociants were able to produce a high degree of immunity in guinea pigs and preliminary immunity tests on sheep were very promising. 9. Evidence is brought forward concerning the significance of the capsule in virulence and immunity. 10. The above findings are discussed.Item Investigations into the transmission of horsesickness at Onderstepoort during the season 1932-1933(Pretoria : The Government Printer, 1937) Nieschulz, O.; Du Toit, R.M.; Du Toit, P.J.During the summer of 1932-1933 our work on the natural transmission of horsesickness was continued at Onderstepoort. The summer was extraordinarily dry, the total rainfall from November, 1932, to April, 1933, being only 11.43 inches. Notwithstanding the dry character of the season horsesickness was extremely severe throughout the country during the second half of March and in April. At Onderstepoort, animals which were always stabled at night also contracted the disease. In contra distinction to the general opinion, therefore, there appears to exist no very close relationship between rainfall and the occurrence of horsesickness and stabling at night does not afford a sufficient degree of protection against infection. Two extremely important epidemiological facts so far as the planning of experimental work was concerned thus proved to be unreliable. An insect survey carried out in the field at Onderstepoort confirmed the results obtained during the previous season as to the important field species of Aedes, viz. A. caballus, A. lineatopennis, A. hirsutus, A. dentatus and Mucidus mucidus. An extensive search revealed the unexpected result that larvae of Anophelines, especially of Anopheles gambiae, A. pretoriensis, A. rufipes and A. mauritianus were present in fair numbers during the driest part of the season in a river bed and in a marshy area formed by accidental leakage of water. Rain of even medium intensity destroyed the breeding places. Anophelines appear to find suitable breeding conditions in very wet or very dry seasons and had thus to be regarded as potential transmitters. The occurrence of Anopheles gambiae, an important malaria carrier, at Onderstepoort during a very dry season is of special interest. The experimental technique was the same as that worked out during the previous season and already described in a separate paper. The strains of virus used for infecting the mosquito were derived from a number of spontaneous cases. Only fresh material or early generations were used. In some experiments the virus horses were infected with different strains at the same time. In all, 31 experiments were carried out with mosquitoes in which experimentally infected insects were either injected subcutaneously into or refed after varying intervals on susceptible horses. 591 Specimens were injected after 5 to 54 clays, and 615 mosquitoes refed after periods of from 5 to 36 days. One experiment only was positive in which 8 Anopheles gambiae, 8 A. mauritianus and 7 A. pretoriensis were injected in the form of an emulsion 7 days after having fed on a virus horse. The other experiments were all negative. The negative results comprised the injection of: 21 Aedes caballus after 7 days, 27 A. lineatopennis after 16-39 days, 398 A. caballus and A. lineatopennis (mixed) after 31-39 days, 8 A. nigeriensis after 7-9 days, 50 A. argenteus after 7-30 days, 3 Culex annulioris after 30 days, 16 Mucidus mucidus after 5-24 days, 4 Anopheles gambiae after 27-54 days, 5 A. mauritianus after 39-54 days and 19 A. pretoriensis after 5-54 days. The negative results obtained by feeding mosquitoes consisted of the feeding of 137 Aedes caballus after 5-20 days, 28 A. lineatopennis after 11-18 days, 5 A. caballus and A. lineatopennis (mixed) after 7 days, 88 A. hirsutus after 11-16 days, 16 A. dentatus after 7-19 days, 55 A. argenteus after 10-23 days, 3 Culex annulioris after 19 days, 26 Mucidus mucidus after 7-22 days, 36 Anopheles gambiae after 7-36 days, 60 A. mauritianus after 7-35 days, 70 A. pretoriensis after 7-36 days, 76 A. rufipes after 7-36 days and 15 A. squamosus after 7-35 days. During the previous season, in a total of 35 experiments, 1,434 specimens of Aedes, Culex and Anopheles had been injected after intervals of from ½ to 65 days and 704 Aedes and Culex had been refed after 1 minute to 65 days. During the two seasons, together 2,025 mosquitoes had been injected and 1,319 specimens refed after intervals of up to 65 days. Positive results had been obtained occasionally by the injection of relatively large numbers of mosquitoes at intervals of up to 7 days but never after this period or by feeding. The important species of all the promising groups of mosquitoes, viz., Aedes, Mucidus and Anopheles have been controlled with sufficient material for transmission purposes to justify the conclusion that, mosquitoes are not vectors of horsesickness. It is of interest to note that even in the case of Aedes argenteus, the vector of yellow fever and dengue, the horsesickness virus displayed no tendency to persist for any length of time. Finally, in two experiments, the eggs of 10 Rhipicephalus appendiculatus and 1 Hyalomma aegyptium, which had engorged on a spontaneous case of horsesickness, were injected without producing a reaction. With the present state of our knowledge we are unable to indicate any probable vectors of horsesickness the transmitting capacity of which might be investigated, once mosquitoes have been excluded. Further information will have to be obtained by means of insect surveys in the field and the new epidemiological facts established during this season will have to be taken into consideration.Item Observations on the morphology and life-history of Gaigeria pachyscelis Raill. and Henry, 1910: a hookworm parasite of sheep and goats(Pretoria : The Government Printer, 1937) Ortlepp, R.J.; Du Toit, P.J.1. The hookworm, Gaigeria pachyscelis, is a very common parasite of sheep in South Africa; it is also found in the Congo, India and Java. In South Africa it is practically confined to the more arid regions, namely South West Africa, N.-W. Cape and Bechuanaland, where it is one of the most serious parasites affecting the sheep industry. 2. In South Africa the hosts are sheep and goats. It has been reported from cattle in other countries, but this is doubtful; the writer has not found it in cattle, neither was he able to infect calves artificially. Its presence as a natural infection in an Indian antelope is reported. 3. The larvae during their free life pass through three stages, each of which is separated by a moult. The cuticle of the first stage is shed, but that of the second stage is retained by the third stage larva as a protective sheath. 4. Under suitable conditions of aeration, humidity, food and temperature, mature larvae are developed in eight days. These larvae are climbers, skin penetrators, positively photo- and thermotropic, but their resistance to drying is very weak. 5. Infection of the host is shown to be through the skin, and all attempts at bringing about an infection through the mouth have been unsuccessful. 6. After entering the skin, the larvae proceed to the lungs, presumably via the blood stream and heart. In the lungs they remain about 14 days during which time the third stage larvae grow, moult and pass into the fourth stage; this larva possesses a globular provisional mouth capsule provided with a dorsal tooth and two subventral lancets. At first the sexes are not differentiated, but later the females may be recognised by their long pointed tails and the males by their short and stumpy tails. 7. The larvae leave the lungs from the 13th day onwards, and travelling up the bronchi and trachea reach the mouth where they are swallowed and so reach the small intestine. Here the larvae attach themselves to the villi and suck blood. The larvae grow and in about a week prepare to undergo another moult and pass into the final or 6th stage. During this transition the provisional buccal capsule is replaced by that of the adult worm and the details of the male caudal bursa also become differentiated. 8. After moulting, the adolescent parasites continue to grow, the sex organs become mature and the worms become fully grown and begin to pass eggs from about the l0th week after infection. 9. The development of the male and female genital organs is followed, as well as that of the male caudal bursa. 10. A comparison is made with related hookworms of the hatching of the egg, the biology of the infective larva, and the development of the mouth capsules. 11. The morphology of the Cephalic and Cervical glands and of the male and female Genitalia is described. 12. The status of the genus Gaigeria is maintained.Item Bovine theileriasis in South Africa with special reference to Theileria mutans(Pretoria : The Government Printer, 1937) De Kock, G.; Van Heerden, C.J.; Du Toit, R.; Neitz, W.O.; Du toit, P.J.1. It would appear that in East Coast fever areas in South Africa, the appearance of Koch's bodies in organ smears in a large percentage of single deaths must be attributed to T. mutans. 2. Under certain conditions T. mutans in non-East Coast fever areas may assume the pathological picture of T. parva from which it cannot be differentiated. It is, however, believed that under natural conditions in South Africa this seldom occurs. T. parva on the other hand causes mortality direct without the operation of other agencies without which T. mutans remains a harmless parasite. 3. Acute theileriasis in South Africa (T. parva and T. mutans) under certain conditions is associated with fairly characteristic changes in the lymphoid system particularly as revealed in the spleen and lymph glands. The pathogenesis of this is at the present moment not yet understood. 4. Although the Koch's bodies of T. mutans, after splenectomy, is of the nature of a "relapse", yet at the present moment it is not possible to state whether the greater majority of cases is of such a nature, or a re-infection, probably with a different strain. If it is of the nature of a relapse, then the pathogenesis of the various agencies that can bring this about is not yet understood. 5. The present East Coast fever policy, with the full co-operation of the farming community should be persisted in to eradicate the disease in South Africa, and every endeavour should be made to carry out the slaughter out policy where East Coast fever has been diagnosed.