Livestock grazing has minimal effect on the species richness and diversity of semi-arid shrubland in the Western Little Karoo,South Africa

The Succulent Karoo, one of two arid biodiversity hotspots in the world, is known for its high plant species richness, but little is known about the influence of topography and how it mediates the potentially deleterious effects of grazing. Changes in vegetation species composition, cover and species diversity were examined along piosphere gradients on northerly slopes, bottomlands and low-lying plains on 45 farms. Landscapes differed in the plant speciesand life-form composition, species richness and cover, with the more species-rich, heterogeneous grassy northerly slopes distinct from the plains and bottomlands, which were dominated by Pteronia pallens, Psilocaulon junceum and Drosanthenum spp. with more annual and ephemeral species. Overall, species richness declined linearly with decreasing rangeland condition. A weak grazing effect was detected only on the north-facing slopes, where shrubs and grass decreased with intense grazing. Years of overgrazing have resulted in the widespread dominance of P. pallens, especially on the plains and bottomlands, rendering them insensitive to grazing. The current condition of the northern slopes should be maintained and managed such that palatable species can spread to more degraded areas of the landscape.     

Co-infection with Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' in three cats from Brazil

The two most common haemotropic Mycoplasma of cats, Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' have been identified using molecular techniques in all continents, except Antarctica. We report the first molecular characterization in South America of a dual infection with M haemofelis and 'Candidatus Mycoplasma haemominutum' in three domestic cats. The 16S ribosomal RNA gene was amplified in three anaemic cats in which haemoplasma organisms were seen attached to the erythrocytes in the peripheral blood smear. Bands of the expected size for M haemofelis and 'Candidatus Mycoplasma haemominutum' were observed in all three cats. The 393 bp segment of one of the amplicons had a similarity value of 100% to M haemofelis, whereas the other amplicon, a 192 bp segment, was 100% similar to 'Candidatus Mycoplasma haemominutum'. After diagnosis, two cats received blood transfusion and they were all treated with doxycycline. All three cats recovered uneventfully.     

Epidemiological assessment of rinderpest surveillance and control in Uganda between 1990 and 1998

Based on passive and active data, we report on an epidemiological assessment of surveillance and control of rinderpest (RP) in Uganda between 1990 and 1998. Active data were collected by administration of questionnaires to animal health personnel and their auxiliaries and to stockowners in six selected districts of eastern and northeastern Uganda. Passive data were extracted from vaccination and seromonitoring reports, and from field and laboratory reports. RP events were classified as “confirmed outbreaks”, “suspected outbreaks” and “rumours”. The classification of 56% of the RP events as “suspected outbreaks” indicates the difficulty in investigating disease outbreaks in Uganda. Although vaccination coverage and seroprevalence were <85% (the recommended target), they nevertheless corresponded well-reflecting effective vaccination. However, because of the low seroprevalence, a sizable population of cattle in Uganda remained at risk of RP. The agreement between the local and national disease reporting systems was low-to-moderate (κ=0.39); this indicates inefficiency in disease reporting.

Risk factors for RP outbreaks were cattle raids and communal grazing. Based on overlaid thematic maps of seroprevalence, vaccination coverage and RP events, close spatial and temporal associations were observed between cattle raids, transhumance and outbreaks and rumours. The high-risk areas were in the eastern and northeastern parts of the country. The results of this study support a phase approach of following the OIE pathway.     

Emergency-culling and mortality in growing/fattening pigs in a large Hungarian "farrow-to-finish" production unit

The trial was carried out in a large Hungarian 2000 sow "farrow-to-finish" production unit. Out of a total number of 15,841 evaluated growing/finishing pigs, 1319 pigs died or were emergency-culled and were post-mortem routinely examined. For the purpose of this study the emergency-culling and mortality were recorded into the same category. The average annual emergency-culling/mortality rate was unusual high (8.62%). Five body condition related categories were registered. The majority of the mortality comprised animals of body condition "below average", representing 891 pigs (67.56%) and "average" (407 pigs = 30.85%). The rest of the examined animals comprised 17 pigs (1.29%) "emitted", 2 pigs "kachexia" (stunted pig) or "fat" (0.15% each). The overall study showed that gastrointestinal tract disorders (395 animals = 29.95%) were the most frequently recorded cause of emergency-culling or mortality. Both inflammatory disorders (7.66%) and rectal stricture (7.51%) were in this category the most frequent diagnosis followed by rectal prolapse (5.92%). Gastric ulcers comprised 4.55% of the necropsied animals. Torsion of abdominal organs and miscellaneous cases represented slightly more than 2% of the post-mortem examined pigs. Lesions which involved the respiratory system, comprised 14.85% of the necropsied pigs. Bronchopneumonia due to Mycoplasma hyopneumoniae occurred in 5.61%, embolic suppurative or necrotic pneumonia in 4.78% and pleuropneumonia due to Actinobacillus pleuropneumoniae in 3.1% of the cases. Diseases involving the urinary system were diagnosed in 21 cases (1.59%). Five cases of skin disorders were registered (0.38%). Cardiovascular disorders were represented by congestive heart failure (31 pigs = 2.35%), pericarditis (22 animals = 1.66%) or endocarditis (21 pigs = 1.60%). Cardiomyopathy was found in 15 (1.2%) animals. Lesions involved the locomotor system ranked second of all cases (15.92%). Claw lesions accounted 13.72%, arthritis 2.13% of the animals and luxation or fracture was diagnosed only in one case (0.07%). Systemic infections were reported in 96 cases (7.28%) including polyserositis (4.09%), erysipelas, edema disease or miscellaneous causes (each category slightly more than 1%). Genetic problems were involved in 8.19% of the fatal cases and social stress or cannibalism related culling or mortality comprised 37 animals (2.81%). In 161 cases (12.20%) of the mortality the causes of death were not established. Two or more lesions related to culling or mortality were found in 320 pigs (24.26%, p < 0.001). The most common diagnosed pathologic changes in association with other lesions were Mycoplasma hyopneumoniae caused bronchopneumonia (4.09%), embolic suppurative or necrotic pneumonia (4.55%), followed by inflammatory gastrointestinal problems (3.10%), gastric ulcer (2.35%), claw lesions (2.19%) and arthritis (1.14%). It appears from the presented study that a routine post-mortem examination of all emergency-culled or dead pigs over a long period of time gives a clear picture of causes of mortality enabling the management to plan management strategies as vaccination programs, genetic improvements and optimising environmental conditions.     

Prof. Dipl. Ing. Dr. Dr. h. c. Leo Tschermak zum Gedenken

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