1940 Onderstepoort Journal of Veterinary Science and Animal Industry, Volume 14, 1940
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Item A study of the mineral content and feeding value of natural pastures in the Union of South Africa (Final report)(Pretoria : The Government Printer, 1940) Du Toit, P.J.; Louw, J.G.; Malan, A.I.; DuToit, P.J.(1) The chemical composition of grass pastures differs in many respects considerably from that of bush pastures. Especially is this the case in connection with the changes to which the composition of pastures are subject with changing meteorological conditions from January to December. (2) Bush pastures are on the whole richer in all the constituents determined than are grass pastures. Another distinguishing feature in the two veld types is the difference in chemical composition between winter and summer pasturage: whereas the former type shows only minor fluctuations in the course of the year, the difference in the percentage contents of certain constituents during winter and summer are considerable in the case of grass pastures. (3) Qualitative differences in the pastures of specific regions within any one of the two main veld types are also encountered. (4) Expressed as percentages of the dry matter the phosphorus content of grass pastures is 0.12-0.17 during summer and 0.05-0.07 during winter. In the pastures composed mainly of bushes this constituent varies between 0.11 and 0.20 per cent. Crude protein values of the grass pastures fall from 7.0-9.0 per cent. in summer to 3.3-4.0 per cent. in winter, while the percentage of this constituent in those pastures composed mainly or wholly of bushes varies between 7.0 and 10.0 in the course of the year. (5) Calcium and magnesium values show only minor seasonal variations. Differences in the percentage contents of these constituents are, however, appreciable in the pastures of one region as against those of another. Expressed as an annual mean the variation in the calcium and magnesium contents of grass pastures in different regions are 0.25-0.48 per cent. and 0.12-0.21 per cent., respectively. Similarly, the calcium and magnesium averages for bush pastures are 0.60-1.05 per cent. and 0.21-0.37 per cent., respectively, depending on the region. (6) Maximum potassium and chlorine values occurring during summer in the grass pastures are 1.32-2.31 per cent. and 0.32-0.59 per cent., respectively. During winter the former constituent varies between 0.29 and 0.63 per cent. and the latter between 0.06 and 0.22 per cent. in the grass pastures of different regions. Sodium average figures fall from a maximum of 0.08 per cent. to a minimum of only 0.01 per cent. in some grass pastures while in others these values vary between 0.10 and 0.25 per cent. in the course of the year. (7) The percentage potassium remains comparatively high throughout the year in most bush pastures. Values seldom are below 1.00 per cent., while most figures fluctuate between 1.40 and 2.00 per cent. Sodium and chlorine averages are exceptionally high in some of the pastures composed mainly of bushes. Thus, for the greater part of the year figures for sodium are 1.00-1.86 per cent., and chlorine values exceed 0.70 per cent. (8) Crude fibre averages are lowest in pasture at the younger stages of growth, the mean annual variation is 34.6-37.2 per cent. for grass pastures and 32.0-35.0 per cent. for bush pastures. (9) Calcium-phosphorus ratios ranging from 2.00:1 to 11.60:1 occur in the dry matter of South African pastures. (10) Judged by the estimated requirements of cattle and sheep for growth all South African natural pastures, composed mainly or wholly of grasses are deficient in phosphorus, crude protein and, in certain areas, sodium for a period ranging from five to nine months of the year, depending on the area. There are indications that in certain of these regions the pasture may be deficient in phosphorus throughout the year. Furthermore, on the basis of the average values for phosphorus these grass pastures contain at no time of the year sufficient of this nutrient to provide in the requirement for an additional function (e.g., gestation or lactation) of the animal, superimposed on growth. (11) Provided sufficient food is available an intake of phosphorus, crude protein or sodium below the optimum requirements for growth will seldom occur on pastures composed mainly of bushes. (12) The requirements of calcium, magnesium and potassium for growth and moderate milk production will at all times be met by the amounts of these constituents present in South African pastures. Especially is the danger of a potassium and magnesium deficiency extremely remote. (13) The pastures of the Union are at no time deficient in chlorine. A cow producing two gallons of milk may, however, not ingest sufficient of this constituent on the winter pastures of some of the grassland regions.Item South African helminths. Part VII. Miscellaneous helminths, chiefly cestodes(Pretoria : The Government Printer, 1940) Ortlepp, R.J.; DuToit, P.J.In the foregoing the writer discusses five species of Cestodes and one species of Nematode; of the cestodes three species are considered as new and the species from the Hoepoe is assigned to a new genus Biuterinoides closely related to the genus Biuterina Fuhrmann, 1902. The new species are Catenotaenia capensis from the Striped Mouse, Dilepis megacirrosa from the Golden Mole, Biuterinoides upupai from the Hoepoe and Ascaris suricattae from the Surricat. Another species of cestode from the Golden Mole is identified as Dilepis sphaerocephala (Rud. 1819) and its morphology is described. Materials from the Striped Mouse and the Gerbil are referred to Raillietina (Raill.) trapezoides (Janicki, 1904).Item Swine fever in South Africa(Pretoria : The Government Printer, 1940) De Kock, G.; Robinson, E.M.; Keppel, J.J.G.; DuToit, P.J.1. It is believed that various outbreaks of swine fever in South Africa have probably occurred since 1900. The disease in domestic pigs produced by the blood of warthogs resembled the European disease. Probably in swine fever, as in many virus diseases, more than one "strain" of virus exists. 2. Reference was made to the virulent nature of this disease in South Africa, and the fact that it does not progress as an enzootic as in European countries. A number of recovered animals harboured the virus for long periods. 3. It is quite likely that the virus in South Africa may also be maintained in a limited number of warthogs in certain areas of Northern Transvaal where domestic pigs occasionally become infected. That may explain the intermittent incidence of this disease in South Africa. 4. From the investigations carried out it would appear that the following may occur in South Africa: (a) Uncomplicated very acute form of swine fever without manifestations of "boutons", diphtheresis, hepatization of the lungs, etc. (b) Swine fever possibly complicated by such secondary infections as S. cholerae suis and B. suisepticus. (c) A septicaemic type of S. cholerae suis infection in an enzootic form and probably associated with such predisposing causes as bad hygiene, overcrowding, defective feeding, etc. 5. A description of the main pathological changes is given, and the value of the histological examination of organs for diagnostic purposes is discussed.Item A study of the mineral content and feeding value of natural pastures in the Union of South Africa (Final report)(Pretoria : The Government Printer, 1940) Du Toit, P.J.; Louw, J.G.; Malan, A.I.; DuToit, P.J.(1) The chemical composition of grass pastures differs in many respects considerably from that of bush pastures. Especially is this the case in connection with the changes to which the composition of pastures are subject with changing meteorological conditions from January to December. (2) Hush pastures are on the whole richer in all the constituents determined than are grass pastures. Another distinguishing feature in the two veld types is the difference in chemical composition between winter and summer pasturage: whereas the former type shows only minor fluctuations in the course of the year, the difference in the percentage contents of certain constituents during winter and summer are considerable in the case of grass pastures. (3) Qualitative differences in the pastures of specific regions within any one of the two main veld types are also encountered. (4) Expressed as percentages of the dry matter the phosphorus content of grass pastures is 0.12-0.17 during summer and 0.05-0.07 during winter. In the pastures composed mainly of bushes this constituent varies between 0.11 and 0.20 per cent. Crude protein values of the grass pastures fall from 7.0-9.0 per cent. in summer to 3.3-4.0 per cent. in winter, while the percentage of this constituent in those pastures composed mainly or wholly of bushes varies between 7.0 and 10.0 in the course of the year. (5) Calcium and magnesium values show only minor seasonal variations. Differences in the percentage contents of these constituents are, however, appreciable in the pastures of one region as against those of another. Expressed as an annual mean the variation in the calcium and magnesium contents of grass pastures in different regions are 0.25-0.48 per cent. and 0.12-0.21 per cent., respectively. Similarly, the calcium and magnesium averages for bush pastures are 0.60-1.05 per cent. and 0.21-0.37 per cent., respectively, depending on the region. (6) Maximum potassium and chlorine values occurring during summer in the grass pastures are 1.32-2.31 per cent. and 0.32-0.59 per cent., respectively. During winter the former constituent varies between 0.29 and 0.63 per cent. and the latter between 0.06 and 0.22 per cent. in the grass pastures of different regions. Sodium average figures fall from a maximum of 0.08 per cent. to a minimum of only 0. 0 per cent. in some grass pastures while in others these values vary between 0.10 and 0.25 per cent. in the course of the year. (7) The percentage potassium remains comparatively high throughout the year in most bush pastures. Values seldom are below 1.00 per cent., while most figures fluctuate between 1.40 and 2.00 per cent. Sodium and chlorine averages are exceptionally high in some of the pastures composed mainly of bushes. Thus, for the greater part of the year figures for sodium are 1.00-1.86 per cent., and chlorine values exceed 0.70 per cent. (8) Crude fibre averages are lowest in pasture at the younger stages of growth, the mean annual variation is 3.6-37.2 per cent. for grass pastures and 32.0-35.0 per cent. for bush pastures. (9) Calcium-phosphorus ratios ranging from 2.00:1 to 11.60:1 occur in the dry matter of South African pastures. (10) Judged by the estimated requirements of cattle and sheep for growth all South African natural pastures, composed mainly or wholly of grasses are deficient in phosphorus, crude protein and, in certain areas, sodium for a period ranging from five to nine months of the year, depending on the area. There are indications that in certain of these regions the pasture may be deficient in phosphorus throughout the year. Furthermore, on the basis of the average values for phosphorus these grass pastures contain at no time of the year sufficient of this nutrient to provide in the requirement for an additional function (e.g., gestation or lactation) of the animal, superimposed on growth. (11) Provided sufficient food is available an intake of phosphorus, crude protein or sodium below the optimum requirements for growth will seldom occur on pastures composed mainly of bushes. (12) The requirements of calcium, magnesium and potassium for growth and moderate milk production will at all times be met by the amounts of these constituents present in South African pastures. Especially is the danger of a potassium and magnesium deficiency extremely remote. (13) The pastures of the Union are at no time deficient in chlorine. A cow producing two gallons of milk may, however, not ingest sufficient of this constituent on the winter pastures of some of the grassland regions.Item Subject index(Pretoria : The Government Printer, 1940) Anonymous; DuToit, P.J.Item Author index(Pretoria : The Government Printer, 1940) Anonymous; DuToit, P.J.Item Anatomical studies no. 64: Anomalous course of the left phrenic nerve in a donkey(Pretoria : The Government Printer, 1940) Jackson, Cecil; Viljoen, W.C.; DuToit, P.J.Item Anatomical studies no. 63: an abnormal bovine heart(Pretoria : The Government Printer, 1940) Cloete, J.H.L.; Steyn, H.P.; DuToit, P.J.Item Conjunctivitis of the domestic fowl and an associated Rickettsia-like organism in the conjunctival epithelium(Pretoria : The Government Printer, 1940) Coles, J.D.W.A.; DuToit, P.J.An apparently new form of conjunctivitis of the domestic fow1 has been described. No doubt the disease has been seen before and called “ocular roup”. The condition is confined to the structures of the eye. Transmission experiments have led to the successful reproduction of a disease, similar in all aspects to that found in nature. The conjunctivitis is associated invariably with the presence of Rickettsia-like organisms in the conjunctival epithelial cells. Almost identical inclusions have been found in cases of ophthalmia of the sheep, ox, goat, and pig. These fowl parasites have been described an the name, Rickettsia conjunctivae galli, proposed for them. Reasons have been advanced for suggesting that R. conjunctivae galli is the true cause of the conjunctivitis.Item The origin of sulphur in wool. III. An improved cuprous mercaptide method for the determination of cystine in material low in cystine(Pretoria : The Government Printer, 1940) Rossouw, S.D.; DuToit, P.J.Cystine is determined as cysteine in hydrolysates of plant or biological material of low cystine content. This method is an improvement and also more accurate than the previous one described.Item Chemical blood studies VIII. A rapid spectroscopic method for (A) the quantitative determination of haemoglobin in blood and (B) its application for the quantitative estimation of haemoglobin in milk, urine, serum or plasma and faeces(Pretoria : The Government Printer, 1940) Roets, G.C.S.; DuToit, P.J.A spectroscopic method for the quantitative determination of the haemoglobin content of blood is described. The haematin is converted into pyridine haemochromogen and a comparison of the intensity of the 555 absorption band made against a known standard. Haemoglobin can be quantitatively estimated in milk, urine, serum, plasma or faeces.Item The Senecio alkaloids. Part 2: hydrogenation, hydrolysis and structural results of isatidine(Pretoria : The Government Printer, 1940) De Waal, H.L.; DuToit, P.J.In the first paper of this series (de Waal, 1939) the isolation and chemical properties as well as the results of the preliminary hydrolysis and of the hydrogenation of the alkaloid isatidine were recorded. This alkaloid is the active principle particularly of Senecio isatideus, but was also found to be present in very much smaller quantities in S. retrorsus D.C. It was then found that when isatidine was hydrogenated in the presence of platinum dioxide four molecules of hydrogen were consumed, which at the time could not be explained. Continuous efforts have since led to the repeated and facilitated isolation of the reduced compound in the crystalline form, and this as well as some other structural results on isatidine are now reported upon.Item The carotene content of some South African feeds(Pretoria : The Government Printer, 1940) Myburgh, S.J.; DuToit, P.J.1. Carotene values are given for six well-known grasses, cut monthly from established plots under natural climatic conditions at Onderstepoort from August, 1938, to August, 1939. 2 . If the average bovine (800 lb. body weight) requires 9 milligrams carotene per day, then there exists no actual Vitamin-A deficiency for the season in question. 3. Carotene values are given for grasses cut at one-monthly up to four-monthly periods during the growth stage. 4. The average intakes of carotene from these grasses are well above the minimum requirements of stock. 5. Carotene values are given for veld grasses cut on the veld from the areas Vryburg, Bechuanaland and Ermelo on the Highveld of the Transvaal during the years 1935 and 1936, and analysed shortly afterwards. 6. Here for the period in question, there is a strong indication of a likely Vitamin A deficiency during the dry months.Item The utilization by sheep of the proteins contained in the natural grazing during different seasons of the year(Pretoria : The Government Printer, 1940) Smuts, D.B.; Marais, J.S.C.; DuToit, P.J.By means of controlled metabolism experiments it was shown that the biological value of the proteins in the natural grazing of the Transvaal varies according to the season of the year. During April the average biological value is 82, and during July the value obtained is 83. When the nitrogen content of the pasture increases, the biological value decreases. In October the average biological value is 62, and in January 74. It has been shown by means of the above data that there is a protein deficiency in the pasture during the entire winter, starting in April and concluding round about August or September.Item The dry matter consumption of sheep on natural grazing in the Transvaal(Pretoria : The Government Printer, 1940) Smuts, D.B.; Marais, J.S.C.; DuToit, P.J.From a study on the dry matter consumption of sheep under natural conditions of grazing, it is evident that the quantity consumed is not a factor in the loss of weight in sheep during winter. It appears from these data that the decline in weight is specifically due to a rapid depletion of n nutritive elements from summer to winter grazing. It has further been shown that the dry matter consumption of sheep is correlated with the weight of the animals and that it can be predicted with success from the following equation DM = 56Wº·⁷⁵, where DM equals dry matter in grams and W weight in Kilograms.Item Further studies on the amino acid deficiencies of plant proteins(Pretoria : The Government Printer, 1940) Marais, J.S.C.; Smuts, D.B.; DuToit, P.J.By means of paired feeding tests, it has been shown that sesamemeal is deficient in cystine and that cottonseedmeal is not deficient in this amino acid. Bran and coprameal are apparently not deficient in lysine, while the supplementation of peanutmeal with methionine did not enhance its growth-promoting properties. Tryptophane does not appear to be a secondary amino acid deficiency in either soyabeans or linseed meal. By means of nitrogen balance studies, it was shown that the increased weights obtained by the supplementation of sesamemeal with cystine are due to a better utilization of the sesamemeal nitrogen. The unsupplemented biological value previously determined by Smuts and Malan was 71 and the supplemented biological value as determined in this paper 80. In the case of cottonseed supplemented by cystine, the biological value of 84 is only slightly higher than 81, and does not signify a significantly better utilization of nitrogen of the supplemented over the unsupplemented cottonseedmeal.Item A procedure for the micro determination of fluorine(Pretoria : The Government Printer, 1940) Van der Merwe, P.K.; DuToit, P.J.A method of the micro determination of fluorine based on the bleaching effect of the fluorine ion towards the thorium lake of the anthraquinone dyes sodium alizarin sulphonate and alizarin Bordeaux is described. This procedure is not concerned with the determination of more than 100 micrograms of fluorine per 200 ml. distillate. 1. Neutralization of the acid distillate is avoided, the total acidity in both standards and samples being controlled equivalent to 2 ml. 0.05 N acid (hydrochloric or perchloric acid) per 43 ml. volumes. The pH of the medium is 2.74. 2. The need for controlling the indicator concentration at a constant throughout the series is emphasized by the variations observed in the titer of the thorium solution, at varying indicator concentrations. 3. A sodium fluoride of satisfactory purity may be prepared by the method of Reynolds and Hill (1939). 4. The use of a standard sodium fluoride solution for the determination of 20 micrograms of fluorine as silico fluoride may be accomplished at a pH 2.74 without the use of a buffer. 5. The use of sulphuric acid as final volatilizing agent cannot be recommended. Even under the most favourable conditions plus errors are caused due to the presence of the sulphate ion. 6. Blank distillates collected from perchloric acid exhibit a bleaching effect towards the alizarin compound. This bleaching effect is not due to fluorine, as added fluorine results in a decrease of this plus error. Neither is this apparent fluorine value due to partially volatilized perchloric acid. The magnitude of the apparent fluorine value is not influenced by treating the perchloric acid at 160°C. prior to distillation. 7. The introduction of the sodium ion is manifested by plus errors when the concentration of sodium chloride reaches 4.095 x 10⁻³ grams per 43 ml. in the absence of fluorine and 2.925 x 10⁻³ grams per 43 ml. in the presence of 10 micrograms of fluorine. The corresponding concentrations for sodium perchlorate are 3.063 x 10⁻³ and 1.839 x 10⁻³ grams per 43 ml. respectively. 8. The evaporation of the alkaline distillate in glass leads to a minus error of variable size. Quantitative recoveries are observed when evaporation is effected in platinum. 9. A method for the complete ashing of blood at low temperatures is described and the subsequent fluorine determination on the ash may be duplicated with a maximum error of 5 per cent . A low recovery of added fluorine to whole blood was encountered, presumably clue to the formation of acid resisting iron-fluorine complexes on ashing. Blood iron converted to ferric sulphate has no inhibitory effect on the volatilization of added fluorine.Item The significance of fluorine traces in natural waters and a proposed method to effect their removal(Pretoria : The Government Printer, 1940) Van der Merwe, P.K.; DuToit, P.J.1. Methods are described whereby the concentration of solute fluorides in water can be reduced to a safe level for human consumption, at a very low cost. 2. The active defluorinizing agent is derived from commercial superphosphate. The sulphate and fluorine compounds present in superphosphates are precluded from passing into solution. 3. By adopting the concentrate method of fluorine removal, it is estimated that 1 Kilogram of double superphosphate can remove from 9 to 10 grams of fluorine from solution. The figure obtained by Klein, Adler and Lindsay (1938), for tri-calcium phosphate in filter beds, amounts to 1.8 grams of fluorine per Kilogram tricalcium phosphate, for ten consecutive cycles. 4. The reaction between the defluorinizing agent and the fluorine in solution is apparently accelerated by heat. Suspensions boiled for 5 to 10 minutes leave a lower residual fluorine content than cold agitations over a 24 hour period. That the process of defluorinization is however a time reaction, culminating in a quantitative adsorption or precipitation of solute fluorides is proved by the fact that prolonged cold agitations result in an almost complete removal of the fluorine in solution. 5. The process of fluorine removal is concomitant with an improvement in the general nature of the water subjected to treatment. A reduction in total solids including a reduction in the concentration of metals forming insoluble secondary and tertiary phosphates, is encountered. 6. The chemical combination in which the fluorine compound is present in the water is of no importance as far as its removal is concerned, NaF, CaF₂ and silicofluorides being reduced with equal ease. 7. In significant traces of selenium, boron and arsenic were found in the concentrates, adopted in this investigation. 8. The possibility of utilizing the naturally occurring wavelite as defluorinizing agent, is indicated.Item Iodine in the nutrition of sheep. Final report(Pretoria : The Government Printer, 1940) Malan, A.I.; Du Toit, P.J.; Groenewald, J.W.; DuToit, P.J.1. Two groups of 10 merino ewes were fed the same adequate basal ration with the exception that one group received an addition of 0.05 gms. each daily of potassium iodide. 2. A slight depression of weight and greater irregularity in regard to the reproduction was shown by the group that received the iodine supplement. The detrimental effects, however, were not as marked as recorded in previous work where other deficiencies, especially vitamin A, undoubtedly exercised an aggravating influence on reproductive abnormalities. 3. The indiscriminate use of iodine supplements for sheep is not recommended.Item Marshallagia marshalli (Ransom, 1907) Orloff, 1933 and a new species of this genus from sheep in South Africa(Pretoria : The Government Printer, 1940) Monnig, H.O.; DuToit, P.J.