1945 Onderstepoort Journal of Veterinary Science and Animal Industry, Volume 20, Number 2, 1945

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

CONTENTS

*Volume 20: Number 2*

Section I: Virus Diseases

The manufacture of anti-rinderpest spleen vaccine under field conditions in Tanganyika Territory	Mitchell, DT & Peevie, WGG	123

Immunization of cattle against heartwater and the control of the tick-borne diseases, redwater, gallsickness and heartwater	Neitz, WO & Alexander, RA	137

An electrophoresis apparatus for the rapid routine analysis of sera and other protein solutions	Polson, A	159

Section II: Parasitology

Ticks in the South African Zoological Survey Collection. Part III. The ornate aponommas	Theiler, G	165

Ticks in the South African Zoological Survey Collection. Part IV. The inornate aponommas	Theiler, G	179

Ticks in the South African Zoological Survey Collection. Part V. Three African haemaphysalids parasitic on domestic stock	Theiler, G	191

Section III: Physiology

Studies on the alimentary tract of merino sheep in South Africa. XIII. The role of prussic acid in the aetiology of acute bloat	Clark, R & Quin, JI	209

Section IV: Nutrition

The nutritive value of mixed proteins. The biological value of the proteins of a mixture of yellow maize seed and grape seeds, and a mixture of yellow maize seed and camelthorn pods (Acacia giraffae)	Myburgh, SJ	213

Section V: Solar Radiation Survey

The absorptivity for solar radiation of different coloured hairy coats of cattle	Riemerschmid, G & Elder, JS	223

Author index		235

Subject index		236

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Subject index
(Published by The Government Printer, Pretoria, 1945) Anonymous; Du Toit, P.J.
Author index
(Published by The Government Printer, Pretoria, 1945) Anonymous; Du Toit, P.J.
The absorptivity for solar radiation of different coloured hairy coats of cattle
(Published by The Government Printer, Pretoria, 1945) Riemerschmid, G.; Elder, J.S.; Du Toit, P.J.
1. The mean effective absorptivity for solar radiation of the hairy coats of cattle was determined. It was found that the colour of the hair is the most important characteristic in effecting the total percentage of radiation absorbed. 2. The mean effective absorptivity was found to be 49 per cent. for the hairy coat of a white Zulu, 78 per cent. for that of a red Afrikaner and 89 per cent. for that of a black Aberdeen Angus. 3. The difference in absorption due to the direction of the hair in relation to the direction of the incoming solar beam was found to be not more than 4 per cent. (usually 1 to 2 per cent.). 4. No appreciable difference was found between the absorptivity of an autumn and a winter coat of two Afrikaner beasts. The mean absorptivity of a Sussex winter coat was not more than 2 per cent. higher than that of a Sussex summer coat. 5. A comparison of the absorptivity of an Afrikaner autumn coat with the hair smoothed down and with the hair standing up showed no appreciable difference. 6. After clipping a long-haired Sussex winter coat to about ½ inch in length, the mean effective absorptivity was found to be 2 per cent. lower than on the unclipped curly hair. This smaller absorption was probably due to the slightly lighter colour of the clipped hair. 7. The comparison of six hairy coats of different shades of red and of different grades of smoothness showed that the mean effective absorptivity varied between 78 per cent. and 83 per cent. The above findings show that the colour is the most important factor effecting the absorptivity of hairy coats for solar radiation, and that direction of the hair, its smoothness or curliness and seasonal changes in the character of the coat are of secondary importance.
The nutritive value of mixed proteins. The biological value of the proteins of a mixture of yellow maize seed and grape seeds, and a mixture of yellow maize seed and camelthorn pods (Acacia giraffae)
(Published by The Government Printer, Pretoria, 1945) Myburgh, S.J.; Du Toit, P.J.
1. Feeding camelthorn pods (13 per cent. crude protein) with maize to rats does not improve the nutritive value of the maize proteins. When the camelthorn pods are mixed with maize seed in the proportion 1 to 3, the biological value is slightly higher than that of the maize alone, but due to a lower true digestibility, the nett percentage utilization of the nitrogen in the mixture was decidedly lower. 2. Again, a mixture of grape seeds and maize seeds in the proportion of 1 to 3, yielded a higher biological value than the maize alone, but here also a lower true digestibility of the mixture resulted in a lower nett utilization of the nitrogen. 3. In these cases the biological value as an index of the nutritive value of the proteins, without considering the digestibilities, gives a somewhat misleading result. The nett utilization, calculated from both the biological value and the true digestibility yield a more accurate result and gives a better reflection of the nutritive value of the proteins. 4. The mixture of grape seeds and maize seeds proved to be superior to the mixture of camelthorn pods and maize seeds.
Studies on the alimentary tract of merino sheep in South Africa. XIII. The role of prussic acid in the aetiology of acute bloat
(Published by The Government Printer, Pretoria, 1945) Clark, R.; Quin, J.I.; Du Toit, P.J.
It is shown that more than four times the amount of KCN is required to cause ruminal paralysis in sheep during active fermentation of lucerne in the forestomach than after a fast of 14 hours. This increased tolerance to KCN after feeding is explained on the basis of an accelerated elimination of HCN from the lungs resulting from the greater respiratory exchange, which in turn is caused by the absorption of carbon dioxide from the alimentary tract during fermentation. Similar results are reported by the artificial introduction of carbon dioxide into the rumen. Sheep showing paralysis of the rumen, caused by KCN, are able to eructate two litres of gas per minute introduced through the ruminal fistula. These observations, therefore, afford no evidence for incriminating the cyanogenetic factors in plants as being associated with the aetiology of acute bloat in ruminants.
Ticks in the South African Zoological Survey Collection. Part V. Three African haemaphysalids parasitic on domestic stock
(Published by The Government Printer, Pretoria, 1945) Theiler, Gertrud; Du Toit, P.J.
1. The descriptions of the adults of H. aciculifer, H. parmata and H. silacea and of the immature stages of H. parmata are brought up to date. 2. The larvae and nymphae of H. aciculifer and of H. silacea are described for the first time. 3. The discontinuous distribution of H. aciculifer in the Union is shown to be due to the facts (a) that this is an introduced tick, (b) that the introduced cattle distributed from dispersal centres, were only sent where they were needed and not to all farms in any given region, (c) the tick only managed to maintain itself in those areas where conditions were favourable. Cold and frost seem to be the factors limiting its distribution. 4. H. silacea is shown to be confined to the Fish River Bush, so characteristics of certain parts of the Eastern Province of the Cape Colony.
Ticks in the South African Zoological Survey Collection. Part IV. The inornate aponommas
(Published by The Government Printer, Pretoria, 1945) Theiler, Gertrud; Du Toit, P.J.
1. The description of the various stages of Aponomma latum is brought up to date and its known hosts and geographical distribution listed. 2. Donitz's contention, that A. laeve capensis Neumann 1901 is a synonym of A. latum is upheld by the study of Neumann's type material. 3. The revised synonymy is given. 4. Attention is drawn to the possible synonymy of A. pseudolaeve Schulze 1935 and of A. politum, Neumann 1899.
Ticks in the South African Zoological Survey Collection. Part III. The ornate aponommas
(Published by The Government Printer, Pretoria, 1945) Theiler, Gertrud; Du Toit, P.J.
1. The full colour pattern of Aponomma exornatum is described, and the range of variations within the species discussed. 2. A. arcanum and A. neglectum are put into the synonymy of A. exornatum. 3. The conclusion is drawn that the varanids are the normal hosts, with the crocodile as a second choice. All others are but accidental hosts. 4. The descriptions are given of the two ticks parasitic on Varanus griseus; A. crassipes and A. fraudigerum; of the tick parasitic on Mabuya striata; A. ochraceum; and their affinities are discussed.
An electrophoresis apparatus for the rapid routine analysis of sera and other protein solutions
(Published by The Government Printer, Pretoria, 1945) Polson, A.; Du Toit, P.J.
An electrophoresis apparatus is described which was found suitable for the rapid analysis of sera and other protein mixtures. A method for identification of protein components in the migrating column is given.
Immunization of cattle against heartwater and the control of the tick-borne diseases, redwater, gallsickness and heartwater
(Published by The Government Printer, Pretoria, 1945) Neitz, W.O.; Alexander, R.A.; Du Toit, P.J.
1. A record of the number of cases of tick-borne diseases in a herd of adult cattle rather less than 1,000 in number over a period of four years is given, viz., 8 cases of anaplasmosis of which 3 were fatal, 9 of redwater of which 2 were fatal, and 79 of heartwater, of which 44 were fatal. 2. In a control group of 196 grade Angus animals under observation from birth for a period of 3½ years there occurred 48 cases of heartwater (37 fatal), 2 redwater (no deaths) and 2 gallsickness (1 death). The alarming rate at which the animals were contracting heartwater compelled the Company to deplete the herd after 3½ years for economic reasons by the sale of 125 oxen. Of the remaining 32 control animals 10 cases of heartwater (7 deaths), 2 redwater (no deaths) and 2 gallsickness (no deaths) occurred. 3. In a comparable group of 89 animals immunized against heartwater the record shows 1 case of gallsickness which was fatal, no cases of redwater, and 24 cases of heartwater of which only 11 were fatal. 4. In a grade herd 53 calves out of 1,374 = 3.9 per cent. ddied as a direct result of immunization. 5: In the immunized herd (1,321 grades) there were 30 cases of redwater of which 15 were fatal, 18 cases of gallsickness of which 2 were fatal and 121 cases of heartwater of which 66 were fatal. 7. There was no mortality amongst 27 adult purebred Aberdeen Angus cattle varying from 1 months to 5 years and 9 months in age as a result of immunization against heartwater and there was no subsequent mortality over a period of three years. 8. Immunization of a mixed group of purebred Afrikaner cattle showed that the Afrikaner is no more resistant to heartwater than the Aberdeen Angus or Hereford. 9. Heartwater is the chief cause of mortality under ranching conditions in the Northern Transvaal. 10. The control of tick-borne diseases is discussed and a system of animal husbandry suggested.
The manufacture of anti-rinderpest spleen vaccine under field conditions in Tanganyika Territory
(Published by The Government Printer, Pretoria, 1945) Mitchell, D.T.; Peevie, W.G.G.; Du Toit, P.J.
Although the method described served its purpose it is considered that the technique is too complicated. The reduction of the spleen tissue to a very fine pulp is important if blockage of needles with consequent delay and considerable annoyance in the field is to be obviated. This might be accomplished by leading the pulp through a second mincer prior to delivery into pulp tank. A more thorough mincing might make a second filtration unnecessary in spite of the large amount of fibrous tissue in the spleen particularly if a more efficient method of filtration in the pulp tanks was devised. Too many metal taps were used in setting up the apparatus. These taps clog easily and are difficult to clean and sterilize. It is suggested that all connections should be rubber and glass which are far more easily cleaned. Although the use of hypertonic saline subsequently brought back to normality by the addition of 9 times the volume of water may be regarded almost as a standard laboratory procedure a detailed investigation is desirable to determine whether it is actually effective in bringing about rupture of the tissue cells, more particularly when 50 per cent. glycerine water is used as the final diluting fluid. The technique was introduced because if it did not actually assist in the process it did not in interfere with it. In the "open" method glass beads were shaken up with the vaccine to disintegrate the tissue. The sterilization plant was totally inadequate to cope efficiently with the constant demands made upon it. It is essential to have large capacity autoclaves heated by paraffin burners to deal with bottles, corks and other portions of the equipment.

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