1944 Onderstepoort Journal of Veterinary Science and Animal Industry, Volume 19, 1944

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Contentes Pages: Onderstepoort Journal of Veterinary Research, Vol ??, 19??

CONTENTS

Volume 19: Numbers 1 & 2

Section I: Virus Diseases

The transmission of blue-tongue and horse-sickness by Culicoides	Du Toit, RM	7

Section II: Bacteriology

Some remarks on black quarter vaccines	Scheuber, JR	17

A note on strains of tuberculosis from the Cape Kudu	Robinson, EM	23

The tuberculin test in guinea-pigs and cattle. The allergic response of animals to tuberculin and extracts of non-pathogenic acid-fast bacteria	Canham, AS	29

Section III: Parasitology

Sheep Blowfly Research. VII. Investigations in the Cape Winter-rainfall Areas	Monnig, HO & Cilliers, PA	71

Section IV: Toxicology

Some aspects of the toxicology of hydrocyanic acid in ruminants	Van der Walt, SJ	79

Section V: Nutrition

The nutritive value of the protein of a few South African soybean meals	Myburgh, SJ	161

Section VI: Anatomy

An improved method of staining lipides: acetic-carbol-sudan	Jackson, C	169

Author index		179

Subject index		179

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Subject index
(Pretoria : The Government Printer, 1944) Anonymous; Du Toit, P.J.
Author index
(Pretoria : The Government Printer, 1944) Anonymous; Du Toit, P.J.
An improved method of staining lipides : acetic-carbol-sudan
(Pretoria : The Government Printer, 1944) Jackson, Cecil; Du Toit, P.J.
1. A method is described of using Sudan III, which gives a more complete demonstration of lipide substances, especially those that are refractory to ordinary Sudan III, Scharlach R, or Sudan IV techniques. 2. This improvement does not appear to depend on superior preservation of lipides, but on enhanced staining powers due to the colloidal nature of the solution. 3. Used in this way, the colouration obtained with Sudan III equals that usually obtained with Scharlach R. 4. The method possesses the advantages of constancy, rapidity, and absence of precipitates as compared with the methods of Romeis, and it succeeds with a variety of samples of the dye. 5. The best variation of the technique is as follows: (a) Fix in formol or formol-saline. (b) Frozen sections in distilled water. (c) 50 per cent. alcohol 1 minute. (d) Acetic-carbol-Sudan (60 per cent. carbol-Sudan plus 2·5 drops of glacial acetic acid per c.c., prepared as described) 1½ hours (sometimes longer) in a small well-corked container. (e) Differentiate in 5 per cent. acetic acid in 50 per cent. alcohol (10 to 60 seconds). (f) Wash in distilled water (1 minute). (g) Counterstain in filtered Delafield's haematoxylin diluted with two parts of distilled water. (h) Differentiate in acid water (10 to 20 seconds). (i) Blue in ammonia water (5 minutes). (j) Wash in distilled water. (k) Mount in glycerine-jelly. 6. Positive results have been obtained with two lipides which are not stained by ordinary techniques (so-called "Sudanophobe" lipides) and the method is especially to be recommended wherever the existence of such substances is suspected. 7. No conclusions regarding the absence of lipide substances should be drawn from negative results of ordinary Sudan or Scharlach techniques, until acetic-carbol-Sudan has been used. 8. It is anticipated that acetic-carbol-Sudan technique will supersede all previous Sudan methods, wherever critical demonstration of lipides is required.
The nutritive value of the protein of a few South African soybean meals
(Pretoria : The Government Printer, 1944) Myburgh, S.J.; Du Toit, P.J.
From the metabolism data in the tables, the following are the main points of interest:- 1. Raw Product and its Heated Product or "Soma meal" (ex Delmas). The mean biological value of the Raw meal was: 49·6 ± 3·092 which is considerably lower than the meal biological value of 63·3±1·354 of the Heated Soybean Meal. The heat application had also improved the digestibility from 67 per cent. to 71 per cent. In calculating the Nett Percentage Nitrogen Utilization, the heated product was 54·5 as compared to only 39·7 of the raw product. 2. "Processed" (not baked) Soybean Meal. This meal had a mean biological value of 5·1 ± 1·945, which is higher than that of the Delmas Mills. The digestibility, however, is lower, namely, 62 per cent. Comparing the Nett Percentage Nitrogen Utilization the difference is slight, namely, 41·9 per cent. in the case of the processed meal and 39.7 per cent. in the case of the Delmas Raw Meal. The superiority of the proteins of the "Soma meal" (one heated South African variety of Soybean) confirms the findings of previous workers, namely, Hayward e.t al. (1936) and Johnson et al. (1939), indicating that in practice it would be the best policy to use the heated meals, not only because of a better palatability but also because of its higher protein efficiency.
Some aspects of the toxicology of hydrocyanic acid in ruminants
(Pretoria : The Government Printer, 1944) Van der Walt, S.J.; Du Toit, P.J.
Of the various methods the ferric thiocyanate method is selected for the determination of hydrocyanic acid both in plants and in animal organs. It is shown that erroneous results may be obtained in certain plants by the alkaline titration method. The ferric thiocyanate method is dealt with in detail and several modifications introduced. It is demonstrated that the method yields excellent results. For the liberation of hydrocyanic acid from the material to be analysed the aeration procedure is adopted as it yields the best results. The sources of hydrocyanic acid in cases of poisoning- in stock are discussed and the results of the examination of a large number of plants for hydrocyanic acid are given. The factors concerned in the causation of poisoning of animals by cyanogenetic plants are discussed in detail and these factors include the quantity of the plant ingested; the previous diet of the animal; the hydrogen-ion concentration of the stomach contents; the percentage of the total hydrocyanic acid in, the plant which it; present in the free state; the quantity of enzyme present in the plant; and the hydrocyanic acid content of the plant. In connection with the last-named factor, a detailed discussion is given on the manner in which it is influenced by the following: soil; climatic conditions; age of the plant; variety of the specimen; individual variation; part of the plant; and the state of the plant. The variability of the hydrocyanic acid content of cyanogenetic plants is illustrated by graphical representations of the hydrocyanic acid content, over a number of days, of Dimorphotheca Ecklonis and four strains of Cynodon plectostachyum. The effect of wilting on the hydrocyanic acid content is clearly shown. It is pointed out that the danger, which a cyanogenetic plant constitutes to stock, should be judged on the maximum quantity of hydrocyanic acid which can be developed by the plant. The physiological significance of cyanogenesis in plants is discussed. The ruminal contents and livers of sheep which had died at this Institute from causes other than poisoning by hydrocyanic acid were found to contain only traces of hydrocyanic acid. Hydrocyanic acid was, however, frequently demonstrable in relatively large quantities in the ruminal contents of animals, which had died from causes, other than hydrocyanic acid poisoning, under field conditions. Of the organs of sheep which were poisoned by hydrocyanic acid per os, the ruminal contents and liver contain the largest quantities of hydrocyanic acid of the organs analysed. The quantity of hydrocyanic acid ingested is shown to be reflected in the hydrocyanic acid content of the ruminal contents and liver. The hydrocyanic acid content of the liver and ruminal contents of approximately twenty sheep which had received varying quantities of hydrocyanic acid was determined. In the case of the liver the hydrocyanic acid content was 0·14 mg., or more, per 100 gm. in sheep which had received lethal quantities, or less than 0·14 mg. per 100 gm. in sheep which had received sublethal quantities of hydrocyanic acid per os. The corresponding value for the ruminal contents is approximately 1·0 mg. of hydrocyanic acid per 100 gm. The relative value of the hydrocyanic acid contents of the liver and ruminal contents in arriving at a diagnosis of hydrocyanic acid poisoning is discussed. It is shown: that the. hydrocyanic acid content of the ruminal contents serves as corroborative evidence for the hydrocyanic acid content of the liver and that it is essential to know the latter in order to arrive at a definite diagnosis. During decomposition of organs of animals, not poisoned oy hydrocyanic acid, significant quantities of hydrocyanic acid did not develop. It is demonstrated that hydrocyanic acid rapidly disappears from the liver but more gradually from the ruminal contents when they are allowed to decompose. Mercuric chloride was found to be an excellent preservative of ruminal contents and liver and completely prevented the disappearance of hydrocyanic acid from these materials during storage. This fact renders it possible to submit specimens of liver and ruminal contents to a laboratory for analysis. It was demonstrated that in the intact animal, considerable diffusion of hydrocyanic acid occurs from the stomach contents into the liver after death. The problem of chronic hydrocyanic acid poisoning is fully discussed. The experimental work of the author did not result in the production of chronic hydrocyanic acid poisoning in sheep. From the literature on the subject, available to the author, it is evident (1) that some authors .have produced chronic hydrocyanic acid poisoning in the form of injury to the central nervous system in rabbits and monkeys, and, ' (2) that other authors have demonstrated the goitrogenic activity of hydrocyanic acid in various combinations. It is shown, however, that the experimental conditions for the production of these forms of poisoning are such that it is very unlikely that they will occur naturally in stock.
Sheep blowfly research. VII. Investigations in the Cape winter-rainfall areas
(Pretoria : The Government Printer, 1944) Monnig, H.O.; Cilliers, P.A.; Du Toit, P.J.
Investigations in the winter-rainfall area were carried out with the object of obtaining a complete picture of the blowfly-sheep-carcase complex. The rainfall is well distributed over the whole year, the climate is mild and humidity is relatively high. Under these conditions sheep are susceptible during all seasons so that Lucilia cuprina causes strikes and breeds almost exclusively on live sheep throughout the year. It did not breed in sheep carcases at any time and only a few L. cuprina were obtained from four small carcases in winter. The sheep carcases produced mainly Chrysomyia chloropyga during the cooler months and C. albiceps and C. marginalis in summer. These flies were not found to strike sheep. The questions of competition between Lucilia and Chrysomyia and of the conditions under which C. chloropyga causes strike are briefly discussed. The latter question merits further investigation.
The tuberculin test in guinea-pigs and cattle. The allergic response of animals to tuberculin and to extracts of non-pathogenic acid-fast bacteria
(Pretoria : The Government Printer, 1944) Canham, A.S.; Du Toit, P.J.
1. In guinea-pigs a sufficient degree of infection with the organism of tuberculosis can be set up by artificial means so that reactions with tuberculin are given within from 24 to 30 days. This means that the period of 6-8 weeks usually elapsing before subjects injected with suspected tuberculin material are killed for diagnosis can be shortened by testing the subject and a control, with tuberculin in from 24 to 30 days, thus expediting results of tests. 2. Animals infected with Br. abortus may give strongly suspicious reactions when tested with tuberculin. 3. Reactions strongly suspicious of positive tuberculin reactions have been observed in cattle that were pregnant and' close to the time of parturition. A similar case was observed in a control guinea-pig. 4. Guinea-pigs infected with strains of non-pathogenic acid-fast organisms gave reactions in some cases when tested with tuberculin in a dilution of 1 to 100. More marked reactions to tuberculin were obtained when lower dilutions were used, viz., 1 to 10 to 1 to 40 dilutions. 5. Extracts prepared from non-pathogenic acid-fast organisms, in the same way as tuberculin is prepared, appear to contain some antigenic factor common to all members of this , group that gives rise to reactions when inoculated into small animals artificially infected with separate members of this group. 6. Extracts prepared on the lines of L'anaexo-Tuberculin may contain products that are specific for each member of the acid-fast group of organisms. 7. Cattle up to 2½ years of age can be sensitized by the subcutaneous inoculation of 10 mg. of strains of M. butyricum and M. phlei suspended in liquid paraffin. Larger amounts of the organisms do not appear to give rise to a greater degree of sensitivity. 8. Cattle sensitized by subcutaneous inoculation of strains of M. butyricum and M. phlei gave definite suspicious reactions when tested with tuberculin by the double intradermal method. 9. These same animals when tested with avian tuberculin showed no more marked suspicious reactions than when tested with standard tuberculin. 10. Thirteen and a half months after subcutaneous inoculation with strains of M. butyricum the non-pathogenic organism M. butyricum could be cultivated from pus obtained from the resultant lesion. 11. Sections cut from the lesions set up by these two organisms showed changes indistinguishable from those set up by tuberculosis. 12. Four months after the surgical removal of the lesions set up by the inoculation of the non-pathogenic acid-fast organisms the animals still gave definite positive reactions when tested against the corresponding extracts. 13. It is probable that some non-specific reactions shown by animals, when tested with tuberculin, may be due to these animals being sensitized naturally by a strain or strains of some non-pathogenic acid-fast organism. 14. This may also be an explanation for some of the "no lesion" reactors to the double intradermal tuberculin test.
A note on strains of tuberculosis from the Cape Kudu
(Pretoria : The Government Printer, 1944) Robinson, E.M.; Du Toit, P.J.
Several strains of M. tuberculosis isolated from cases of tuberculosis in the kudu were shown to be bovine in type, as judged by their growth characteristics and the results of inoculation of laboratory animals, cattle and goats.
Some remarks on black quarter vaccines
(Pretoria : The Government Printer, 1944) Scheuber, J.R.; Du Toit, P.J.
The experiments detailed here tend to the following conclusions:- (1) Slight persistent local reactions may sometimes be expected to follow inoculation with blackquarter vaccines precipitated by alum or aluminium hydroxide. (2) Blackquarter vaccines containing alum afford a very strong protection against the disease. (3) The immunity from the best vaccines at present in use becomes gradually reduced after six to twelve months. (4) There is probably some diminution in the efficiency of all types of blackquarter vaccine after 6-12 months, but a fairly good protection was still afforded by one-year-old vaccine.
The transmission of blue-tongue and horse-sickness by Culicoides
(Pretoria : The Government Printer, 1944) Du Toit, R.M.; Du Toit, P.J.
An account is given of an investigation into the transmission of blue-tongue and horse-sickness conducted at Onderstepoort during 1942 and 1943. Three positive infections with blue-tongue and one with horse-sickness, following the injection of emulsions of wild-caught Culicoides into susceptible animals, are recorded. The successful transmission of blue-tongue by the bites of Culicoides, which fed on experimentally sheep 10 days previously, is described. The identity of the diseases in question had been established clinically, by subinoculations into susceptible animals and by immunity tests with homologous strains of the particular virus where possible. The author is quite confident of the correctness of the diagnoses of the disease conditions produced. The special light trap used in the investigation for the trapping of Culicoides and the technique of handling and storing these insects are briefly described. It is concluded that certain species of the genus Culicoides are capable of becoming infected with and transmitting to susceptible animals by bite the virus of blue-tongue of sheep. From the evidence advanced it is anticipated that the transmitter or transmitters of horse-sickness will be found within the genus Culicoides.

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