Arnold Theiler, founder of Onderstepoort.
Explore the source record for details and available documents.
Academies and Institutes↗
Biomedical subjects
D R Osterhoff
Publications and source records attributed to D R Osterhoff.
Genetic markers in the blood of animals: a historical review.
In this review an attempt is made to list the most important events in the search for genetic markers in the blood of animals. In chronological order, blood groups, biochemical polymorphisms, lymphocyte antigens and DNA markers have been discovered and used in practice. Of all practical uses, parentage verification and exclusion are regarded as the most important, and it can be said with pride that the South African Stud Book is as infallible as any other stud book in the world.
Animal Population Groups↗
Comparison between Russian and South African Karakul sheep based on blood group markers.
Gene frequencies at 10 blood polymorphic loci have been used to compare Karakuls from Uzbekistan, Union of Soviet Socialist Republics with South African Karakuls and to evaluate the influence of local Blackhead Persian sheep on the genetic composition of South African Karakuls. The data clearly show that genetic difference between the 2 populations of Karakuls is significant. The proportion of Blackhead Persian genes in South African Karakuls is estimated to be 0.2745, to which a certain degree of gene flow from other fat-tailed sheep has possibly to be added.
Animals↗
Blood groups and biochemical polymorphism in the Namaqua sheep breed.
The Namaqua is an indigenous fat-tailed African breed of sheep which has remained relatively isolated and which at one time dwindled to near extinction. Frequency data are given for blood group antigens, red cell glutathione and potassium types, for electrophoretic variants of red cell haemoglobin, 'X' protein, nucleoside phosphorylase, NADH-diaphorase, lysine and carbonic anhydrase and of plasma esterase, transferrin and albumin. Of particular interest was the occurrence of the i blood group, a bimodal distribution in red cell glutathione concentrations and red cell potassium concentrations of around 57 mmol/l cells, i.e. neither typically LK nor HK type.
Animals↗
[Owner-dog relationships--a decade later].
The first cynological study in South Africa was done in 1976. To establish possible new tendencies in dog ownership, the study was repeated a decade later. The questionnaire included questions on breed, nutrition, care, reproduction, behaviour, training and replacement, and the information was gathered by door to door visits. External factors such as the need for specific breeds for specific situations (security, economics) in the country, availability of reading matter about dogs, the convenience of commercial dog foods, the growing tendency for mothers to enter into fixed employment, campaigns against undesired breeding, improved veterinary services, reports on canine heroism in the media, could all have influenced the patterns of dog ownership. The awareness of these tendencies could be of importance to the companion animal veterinarian.
Animal Welfare↗
The genetic relationship between the Döhne- and the Walrich-merino.
The Döhne- and the Walrich Sheep breeders' societies amalgamated in 1982 to form an enlarged Döhne Merino Breed Society. Both breeds are dual-purpose, polled breeds with high fertility as well as good wool and mutton characteristics. Apparently they have a similar genetic background, both being developed out of local Merino ewes and dual-purpose Merino-type sheep from Europe. Studies of biochemical polymorphisms in the blood of 224 Döhne and 204 Walrich Merino established a close relationship between these two breeds.
Animals↗
Different banding techniques for the study of bovine chromosomes.
The different banding techniques R-, Q-, C-, NOR- and G-banding allow the identification of individual chromosomes in cattle with greater accuracy than with undifferentiated Giemsa staining. These techniques show characteristic bands on each chromosome and are therefore very useful and reliable for the detection of chromosomal abnormalities.
Animals↗
Horse haemoglobin phenotyping by agarose gel isoelectric focusing comparison of Thoroughbreds with other Equidae.
By using isoelectric focusing in thin agarose slab gels 1049 Thoroughbred, 82 Nooitgedachter, 45 Percheron and 244 horses of other breeds were examined. The numbers of other Equidae tested were 107 donkeys, 50 mules, 4 common zebras (Equus burchelli boehmi) and 8 mountain zebras (Equus zebra hartmannae). Phenotypic data are presented for all tested animals and gene frequencies are calculated for the horses.
Animals↗
[South African biltong--another close look].
Twenty beef biltong samples from various commercial sources were investigated chemically and microbiologically. The biltong contained 5-10% NaCl, little sugar and nitrite but 10-860 ppm nitrate. The addition of nitrate apparently did not ensure stability, since spoiled biltong often contained much residual nitrate. Biltong was stable at the barrier combination of aw less than or equal to 0.77 and pH less than or equal to 5.5 because such samples did not spontaneously become mouldy. A high degree of contamination with moulds and yeasts was found indicating a real health hazard to which consumers might be exposed. Better control measures must be imposed to ensure a better product to the consumer.
Animals↗
Disproval of an apparent goat x sheep hybrid.
Samples of whole blood of a Boergoat buck (60,XY), and ewe (54,XX) and her heterosexual twins were cytogenetically examined. The female offspring had hair and seemed to be a cross between the two animals. However, both twins possessed 54 chromosomes, including 6 large submetacentric autosomes, whose R- and G-banding patterns were identical to those of the ewe.
Animals↗
Protein variation and its systematic implications for the South African Leporidae (Mammalia:Lagomorpha).
Analysis of 9 genetic loci by horizontal starch gel electrophoresis was performed on 203 specimens of South African representatives of the leporid genera Lepus and Pronolagus. Three loci were found to be polymorphic within samples of the various species of both genera: transferrin (Tf-I), esterase-1 (Es-I) and esterase-2 (Es-II). Only one system, carbonic anhydrase (CA-I), proved useful in species identification, this being restricted to the genus Lepus. Based on this system all Lepus specimens analysed would be assigned to one of two groups corresponding to the species L. capensis and L. saxatilis.
Animals↗
An investigation of five genetic loci controlling polymorphic variants in the red cells of goats.
Results of a joint study carried out in South Africa and England to search for new genetic markers in the blood of goats are presented. Haemoglobin (Hb) phenotypes were reinvestigated with the technique of isoelectric focusing; frequencies in different goat breeds are given. Anaemic Hb type A, AB and B goats all produced a Hb C with an identical electrophoretic pattern. All goats tested had identical carbonic anhydrase (CA) types, but showed polymorphism of 'X' protein. Preliminary results indicated that nucleoside phosphorylase (NP) may be polymorphic.
Alleles↗
Horse lymphocyte cell synchronization: improved technique for chromosome analysis.
A method using methotrexate for horse lymphocyte cell synchronization and thymidine for incorporation into DNA replication is described. This method provides a powerful technique for the study of chromosomal abnormalities and detailed analysis of chromosomal replication patterns. The determination of horse karyotypes with many similar chromosomes needs a special method which reveals the numerous and informative stages of the cell cycle. Horse lymphocyte cell cultures treated with colcemid (20 min) and harvested 6 hours after the release of the 17 hour-block with methotrexate show the best results for exact identification and analysis of horse chromosomes.
Animals↗
Biochemical polymorphisms in South African freshwater fish. Isoenzyme patterns in fish of the families Cyprinidae and Salmonidae.
Isoenzyme patterns were studied in local populations of the carp (Cyprinus carpio) and the bream (Sarotherodon mossambicus) of the Cyprinid family, and in the trout (Salmo giardneri) of the family Salmonidae. Homogenates of heart muscle extracts were used in the identification of PGI, NADP-IDH, PGM and 6-PGD. Polymorphisms found and gene frequencies obtained are discussed separately for each enzyme and species or population. In the bream, variation was found only at the PGI locus. In the carp only the PGM locus was polymorphic whereas both PGM and IDH showed variation in the trout. The variation at the PGM locus in the trout cannot support the three locus model suggested elsewhere and clearly indicates a single locus for the monomeric enzyme. The large variety of NADP-IDH types in trout not only illucidates the complexity of this locus but confirms a disomic mode of inheritance. Genetic differences in the trout populations could be related to possible advantages for management purposes.
Animals↗
Genetic markers in south african thoroughbred stallions.
Genetically controlled markers are ideal for the identification of individual animals, and throughout the world laboratories have been established whose chief function is to provide a blood-typing service for animals including horses. In order to achieve the aim of improved recording of foals almost all South African sires at stud were tested and their blood type identification completed. The genetic markers included in this survey were 14 blood group factors, transferrin, plasma esterase, haemoglobin, carbonic anhydrase, 6-phosphogluconate dehydrogenase, phosphoglucomutase and phosphohexose isomerase. Gene frequency calculations were performed and comparisons made with similar surveys in Thoroughbreds overseas. The results indicate that the strict selection for speed in Thoroughbred racing horses has resulted in a high degree of genetic uniformity between South African and overseas racing Thoroughbreds.
Animals↗
Biochemical polymorphisms in the South African springbok (Antidorcas marsupialis).
An attempt was made to use polymorphic markers in the genetic taxonomy of springbok populations. Three independent free ranging springbok populations could be identified on the basis of albumin and transferrin gene frequencies. Even if most of the enzyme markers appeared to be monomorphic it can be stated that in any comparative study of this kind, cryptic genetic markers are of greater use than other environmentally sensitive taxonomic criteria. From the given data and others mentioned it can be stated that little support exists for the continued application of the subspecific status in the species Antidorcas marsupialis. It is shown that the use of environmentally sensitive parameters in the springbok are both misleading and highly unsatisfactory. Biochemical polymorphism can be utilized better than other parametres but here also there are several limitations. Basically, only the albumin and transferrin types can be used when blood samples are available and only IDH and 6-PGD polymorphisms are of value when liver samples can be utilized for the genetic differentiation.
Animals↗
[The genetic value of embryo transfer in South Africa (author's transl)].
The different applications of embryo transfer from the animal improvement, scientific and commercial point of view are outlined. The most important application in South Africa is the production of the next generation's dairy A.I. bulls out of elite cows after superovulation, inseminations with the best available semen and embryo transfer to many foster mothers. The specific difficulties of running breeding programmes with small active breeding populations are discussed, and it is suggested that elite cows should be brought to special farms or government stations during the period of superovulation and transfer. In this way the disadvantage of small breeding populations could to a certain extent be overcome by embryo transfer.
Animals↗
Ethology and animal welfare.
Much scientific information concerning animal behaviour has become available only recently and it continues to increase rapidly. There is evidence indicating that the behavioural needs of animals have sometimes been neglected when natural life-style are replaced by artificially contrived ones. More attention to and study of animals' social and other behavioural requirements would be mutually beneficial to both man and beast. If those needs can be met more adequately, animals will be easier to handle, stress will be reduced and productivity improved. Animal welfare legislation in different countries is mentioned and ethological research as basis for new legislation discussed. The development in this critical field of Ethology and Animal Welfare is advancing fast and the South African Veterinarian must be aware of the new movement from Animal Science to Animal Rights.
Animals↗