Application of veld management in South Africa ‐ an analysis of progress

The widespread deterioration of veld in South Africa necessitates an analysis of the reasons for this serious state of affairs. Although approximately 34 per cent of farms have the facilities to apply conservation farming, less than 10 per cent of farmers apply the recommended veld management systems. The reasons for poor acceptance of systems may be grouped as: (a) economic pressure, (b) complacency, (c) ineffective extension and (d) unacceptable recommendations. Evidence is presented which indicates that all of these factors play a role in the present veld management position.     

A stochastic model accommodating the FAMACHA© system for estimating worm burdens and associated risk factors in sheep naturally infected with Haemonchus contortus

A previously developed multiple regression algorithm was used as the basis of a stochastic model to simulate worm burdens in sheep naturally infected with Haemonchus contortus over five consecutive Haemonchus seasons (November to January/February) on a farm in the summer rainfall region in South Africa, although only one season is discussed. The algorithm associates haemoglobin levels with worm counts in individual animals. Variables were represented by distributions based on FAMACHA(?) scores and body weights of sheep, and Monte Carlo sampling was used to simulate worm burdens. Under conditions of high disease risk, defined as the sampling event during the worm season with the lowest relative mean haemoglobin level for a class of sheep, the model provided a distribution function for mean class H. contortus burdens and the probability of these occurring. A mean H. contortus burden for ewes (n=130 per sample) of approximately 1000 (range 51-28,768) and 2933 (range 78-44,175) for rams (n=120 per sample) was predicted under these conditions. At the beginning of the worm season when the risk of disease was lowest (i.e. when both classes had their highest estimated mean haemoglobin levels), a mean worm burden of 525 (range 39-4910) for ewes and 651 (range 37-17,260) for rams was predicted. Model indications were that despite being selectively drenched according to FAMACHA(?) evaluation, 72% of the ewes would maintain their mean worm burden below an arbitrarily selected threshold of 1000 even when risk of disease was at its highest. In contrast, far fewer rams (27%) remained below this threshold, especially towards the end of the worm season. The model was most sensitive to changes in haemoglobin value, and thus by extrapolation, the haematocrit, which is used as the gold standard for validating the FAMACHA(?) system. The mean class haemoglobin level at which there was a 50% probability of worm burdens being ≤ 1000 worms was 7.05 g/dl in ewes and 7.92 g/dl in rams.     

Tactical treatment with copper oxide wire particles and symptomatic levamisole treatment using the FAMACHA(©) system in indigenous goats in South Africa

Haemonchosis is considered to be the most economically important gastrointestinal disease of small ruminants in the tropics and subtropics. However, chemical anthelmintics, which were the mainstay of control, have been compromised by a high prevalence of resistance worldwide. Copper oxide wire particles (COWP) have been shown to have anthelmintic effects, but few studies have examined their use under field conditions. The use of COWP was therefore evaluated as a tactical anthelmintic treatment in indigenous goats raised under communal farming conditions in Bergville, KwaZulu-Natal Province, South Africa. At the beginning of the summer rainfall season (October 2007), the faecal egg counts of 172 female goats belonging to 15 farmers were determined and this sampling continued every four weeks until the second week of January 2008. The goats within each of the 15 herds were ranked according to their faecal egg counts for this week. The goats were sequentially paired off within each ranking starting with those goats with the highest counts. One goat from each pair was randomly allocated to a treated or control group. Two weeks later, a 4 g COWP bolus was randomly administered to each goat in the treated group. Faecal egg counts were carried out on the goats two weeks following treatment, and the sampling of the goats then proceeded every four weeks until October 2008. Except for the six-week period prior to the administration of the COWP, the goats were examined according to the FAMACHA^© system and symptomatically treated with 12 mg/kg levamisole when anaemic. The percentage reduction in faecal egg count due to the COWP treatment was 89.0%. Mean pre- and post-treatment faecal egg counts for the COWP-treated group (n = 73) were 2347 eggs per gram of faeces (epg) and 264 epg, respectively. The corresponding values for the untreated controls (n = 66) were 2652 epg and 2709 epg. The prevalence of Haemonchus spp. larvae in pre- and post-treatment faecal cultures was 72% and 46%, respectively. Symptomatic anthelmintic treatments in combination with mid-summer tactical treatments with COWP appear to be useful strategies for the control of Haemonchus contortus in indigenous goats in this farming system and this approach could have application in other similar agro-ecological zones.     

Salmonella Brandenburg — emergence of a variant strain on a sheep farm in the South Island of New Zealand

AIM: To compare the rectal and I/V administration of tramadol in dogs, to assess both its pharmacokinetic properties and absolute bioavailability.

METHODS: After rectal administration via suppositories and I/V injection of tramadol (4 mg/kg), the concentration of tramadol and its main metabolites, O-desmethyl-tramadol (M1), N-desmethyl-tramadol (M2) and N,O-didesmethyl-tramadol (M5), were determined in plasma, using high-performance liquid chromatography (HPLC). A balanced cross-over study was used, involving six male Beagle dogs.

RESULTS: Plasma concentrations after rectal and I/V administration were fitted on the basis of mono- and bi-compartmental models, respectively. Following rectal administration tramadol was detected from 5 minutes up to 10 hours, in lesser amounts than M5 and M2, while M1 was detected in negligible amounts. Following I/V administration tramadol was detected up to 10 hours, M2 and M5 were detected at similar concentrations, and M1 was present at low concentrations. The area under the curve (AUC) of the three metabolites did not differ significantly after either route of administration of tramadol. The absolute bioavailability of tramadol via rectal administration was 10 (SD 4)%.

CONCLUSIONS: After rectal administration of tramadol suppositories, absorption of the active ingredient was rapid, but its metabolism quickly transformed the parent drug to high levels of M2 and M5.

CLINICAL RELEVANCE: In the dog, rectal pharmaceutical formulation of tramadol would have a different pharmacokinetic behaviour than in humans.     

Where to with reserve selection and conservation planning in South Africa?

A critical evaluation of the strengths and weaknesses associated with the ‘minimal set’ approach to designing an optimal reserve network tor vertebrate species is offered. Strengths are the rational and efficient manner in which full species representation is achieved, and the planning benefits that can be gained through its flexibility. Weaknesses include the inappropriateness of the ‘minimal set’ as a framework for a reserve network, and the frequent confusion between top-down relational species criteria and bottom-up site attributes. It is suggested that the distinct ‘top-down’ relational and ‘bottom-up’ representation approaches may act synergistically to form the basis of a National Biodiversity Conservation Strategy. These complementary approaches may require different forms of protection and monitoring, but could also be amalgamated to develop a conservation strategy for non-protected areas. Sufficient attention should also be paid to encouraging the free flow of information and to incorporating the principles of taxonomic and environmental uncertainty into future conservation policies.     

Evaluation of ‘best practice’ (SCOPS) guidelines for nematode control on commercial sheep farms in England and Wales

Parasitic diseases are a major constraint to optimum livestock production and are the major cause of economic loss in UK sheep flocks, with farmers remaining dependant on anthelmintics for control. In the UK, research and evidence based, “best practice” guidelines for sustainable control of parasites in sheep (SCOPS) were first produced in 2004 and have been regularly updated since. This study was designed to evaluate the effect of these best practice guidelines for worm control on lamb production and infection levels, compared with more traditional management. Sixteen farms were selected based on a 2 cube factorial design with 3 factors known to affect worm epidemiology: control regimen; farm type; and climatic region. A formalised plan for worm control using 7 potential resistance-delaying practices was prepared for each of the 8 best practice (SCOPS) farms, in conjunction with the farms veterinarians. The 8 farms in the traditional management group (CONTROL farms) were selected based on ongoing evidence of them using worm control strategies deemed to be “higher-risk”. A cohort of 40–50 study lambs at each farm was monitored from birth to finishing, allowing evaluation of lamb productivity, worm infection levels and for comparison of numbers of anthelmintic treatments. Birth and mid-season weights were used to calculate daily live-weight gain. Birth and finish dates were used to calculate time to finish and finish weights were also compared. Faecal egg counts, larval culture and species differentiation were undertaken throughout the year to assess the impact of the control strategies on worm burdens. There was no significant difference in results for any of the 3 production responses when comparing predicted means accounting for the differences in birth weight. In fact SCOPS farms had, on average, a higher daily weight gain and finish weight than CONTROL farms when comparing observed means. Statistical analysis of infection levels clearly showed no significant effect according to farm type (p = 0.71) or treatment (p = 0.81). In contrast the effect of region (p = 0.08), although not significant, had a much larger effect size (standardised mean difference) with lower parasite burdens based on faecal egg counts on Northern farms compared to Southern farms. For both ewes and lambs, significantly fewer treatments were carried out on the SCOPS farms. The data collected from this study suggests that farms implementing SCOPS principles use less anthelmintic than other farms, without loss of animal performance or increased worm burden.     

Response of arthropod communities to plant-community rehabilitation efforts after strip mining on the semi-arid west coast of South Africa§

Strip mining in arid ecosystems causes extreme ecological destruction that may take decades to recover. The present study examined the effect of different plant-community rehabilitation treatments on arthropods after strip mining in the arid Namaqualand region of South Africa. Vegetation cover and plant species richness were significantly lower at all rehabilitated sites compared with those at a reference site. Arthropod species richness did not differ amongst the different treatments and the reference site. Except for the most recently rehabilitated site, arthropod abundance in all guilds was higher at all treatments compared with that of the reference site. Overall arthropod abundance was positively correlated to plant cover and negatively correlated to plant species richness, but these vegetation characteristics had no effect on arthropod species richness. This may be explained by a high cover of pioneer plants at the rehabilitated sites, which offer ample food for generalist arthropod taxa. Arthropod community composition differed significantly between treatments. We demonstrate that rehabilitation of ecosystem function after mining in arid systems is a lengthy process, even after implementation of intensive rehabilitation protocols. We also show that arthropod communities provide additional insights into the level of ecosystem recovery otherwise obscured when only considering plant community data.     

Environmental pollutants and diseases of sexual development in humans and wildlife in South Africa: harbingers of impact on overall health?

This study deals with disorders of sexual development in humans, wildlife and animals in an urban nature reserve (RNR) and a currently DDT-sprayed malarial area. High levels of oestrogenic chemical residues in water, sediment and tissue; skewed sex ratios; reduced biodiversity; gonadal malformations in sharptooth catfish and freshwater snails; intersex in catfish; and impaired spermatogenesis in catfish and striped mouse are of serious concern in the RNR. Persistent eggshell thinning in African darter eggs, intersex in male Mozambican tilapia, follicular atresia in females and impaired spermatogenesis in males following laboratory exposure of parent fish to environmentally relevant DDT and DDE concentrations, and abnormalities in freshwater snails were found in the DDT-sprayed area. Human studies related to DDT exposure indicated impaired semen quality, a weak association with sperm chromatin defects and higher risks for external urogenital birth defects in those who were born to mothers whose houses were sprayed and those who were homemakers (stay at home mother) instead of being employed. These findings indicate that diseases of sexual development occurred in both human and wildlife populations exposed to environmental endocrine disruptor chemicals in South Africa. The chemical mixtures, possibly related to disorders of sexual differentiation (DSD), were very different between the two. However, DSD occurred concurrently in the malarial area, possibly indicating that humans and wildlife shared exposures. Moreover, it emphasizes the importance of suspecting disease in the other when disease is found in either human or wildlife populations.     

Assessing the success of experimental rehabilitation on a coastal mineral sands mine in Namaqualand,South Africa§

The success of different rehabilitation treatments following surface mining on the arid west coast of South Africa was assessed. Treatments consisting of one or a combination of topsoil addition, plant translocation and seeding were applied to experimental rehabilitation sites in 2001, while the treatment of another site in 2008 combined all three techniques. Vegetation and species cover, species richness, diversity and evenness, and grazing capacity of rehabilitation sites were sampled during winter 2009 and summer 2010, and compared with a reference site. All rehabilitated sites achieved the objective to attain a minimum grazing capacity of 20 ha per small stock unit. Rehabilitation trials were successful in establishing a vegetation cover, but were unable to return species richness and diversity to reference levels and did not resemble the reference site in species composition. Common species in reference sites were absent or only occurred in low numbers. No treatment outperformed the others and further experimentation is needed to determine the most suitable combination. It is recommended that rehabilitation should be done in multiple stages in future to improve seedling survival and to return species that are unable to establish in the adverse conditions present at the onset of rehabilitation.     

Evaluation of strategies to enhance biosecurity compliance on poultry farms in Québec: effect of audits and cameras

Biosecurity compliance is generally poor in all types of animal production systems around the world. Therefore, it is essential to define strategies to improve the implementation of biosecurity measures. This study evaluated the value of audits and visible cameras on compliance with biosecurity measures required when entering and exiting poultry barns on 24 poultry farms in Québec, Canada. Short term (first two weeks) and medium term (six months later) compliance were determined. Application of biosecurity measures was evaluated using hidden cameras. Video viewing revealed a total of 2748 visits by 259 different individuals. Results showed that bimonthly audits did not have any impact on medium term compliance. Visible cameras had a significant impact on changing boots (OR=9.6; 1.9-48.4) and respecting areas (contaminated vs. clean) during the visit (OR=14.5; 1.2-175.1) for the short term period. However, six months later, compliance declined and was no longer significantly different from controls. Duration and moment of the visit, presence of the grower or an observer, barn entrance design, number of barns, number of biosecurity measures requested, type of boots worn, gender and being a member of a grower's family were significantly associated with biosecurity compliance.     

Effect of phentolamine mesylate on regression of lidocaine–epinephrine epidural anaesthesia in sheep

ObjectiveTo determine the impact of epidural phentolamine on the duration of anaesthesia following epidural injection of lidocaine–epinephrine.Study designBlinded randomized experimental study.AnimalsA group of 12 adult ewes weighing 25.7 ± 2.3 kg and aged 8–9 months.MethodsAll sheep were administered epidural lidocaine (approximately 4 mg kg^–1) and epinephrine (5 μg mL^–1). Of these, six sheep were randomized into three epidural treatments, separated by 1 week, administered 30 minutes after lidocaine–epinephrine: SAL: normal saline, PHE1: phentolamine (1 mg) and PHE2: phentolamine (2 mg). The other six sheep were administered only epidural lidocaine–epinephrine: treatment LIDEP. Each injection was corrected to 5 mL using 0.9% saline. Noxious stimuli were pinpricks with a hypodermic needle and skin pinch with haemostatic forceps to determine the onset and duration of sensory and motor block. Heart rate, noninvasive mean arterial pressure (MAP), respiratory rate and rectal temperature were recorded.ResultsThe onset times were not different among treatments. Duration of sensory block was significantly shorter in SAL (57.5 ± 6.2 minutes), PHE1 (60.7 ± 9.0 minutes) and PHE2 (62.0 ± 6.7 minutes) than in LIDEP (81.7 ± 13.4 minutes) (p < 0.05). Duration of motor blockade was significantly shorter in PHE1 (59.4 ± 5.4 minutes) and PHE2 (54.3 ± 4.0 minutes) than in SAL (84.8 ± 7.0 minutes) and LIDEP (91.5 ± 18.2 minutes) (p < 0.01). MAP in PHE2 was decreased at 10 minutes after administration of phentolamine (p < 0.05).Conclusion and clinical relevanceEpidural administration of 5 mL normal saline after epidural injection of lidocaine–epinephrine reduced the duration of sensory but not motor block in sheep. Epidural administration of phentolamine diluted to the final volume of 5 mL diminished both the duration of sensory and motor block in sheep administered epidural lidocaine–epinephrine.     

A preliminary report on the occurrence of maedi‐visna in sheep in Morocco

Summary

A small scale serological survey for antibodies to maedi‐visna virus among 15 flocks of sheep in Morocco revealed the infection in one flock. Infection appeared to be related with imported sheep. In addition, two abattoir surveys yielded, 0.1% lungs with gross and histological lesions suggestive of maedi.     

Vegetation responses to seasonal weather conditions and decreasing grazing pressure in the arid Succulent Karoo of South Africa§

The Succulent Karoo biome is a renowned centre of biodiversity and endemism in the arid winter rainfall region of South Africa that is threatened by climate change. On 20 permanently marked plots within a biodiversity observatory, species richness and cover were assessed annually from 2002 to 2017 during the growing season. We were interested, firstly, in whether the vegetation showed any trends in response to the strong decrease in grazing pressure, which occurred at the beginning of the monitoring period, and secondly, in the effect of seasonal climate on the vegetation. We analysed the responses of species richness and cover in four life forms to seasonal rainfall and the standardised precipitation–evapotranspiration index (SPEI) using linear mixed-effect models. Time had a positive effect on richness of annual species and a negative effect on cover of shrubs and annuals, which increased in response to SPEI and less strongly to rainfall during autumn and winter. Habitat did not have any effect and geophytes and perennial herbs did not show any significant response. The importance of SPEI during autumn and winter is discussed in relation to potential germination cues and the projected decrease in rainfall and increase in temperature during these seasons.     

Linear structures in the Karoo,South Africa,and their impacts on biota§

Linear structures include fences, roads, railways, canalised water ways and power lines, all man-made. Fencing as a way of managing livestock began in the late 1800s, and by the early twentieth century was almost fully implemented throughout the Karoo sensu lato. The advent of these fences, and now in many instances, ‘game proof’ (～2 m high) and electric fences have impacted native flora and fauna in various ways. Roads influence the quality and quantity of vegetation along corridors throughout the Karoo, with impacts on wildlife through increased mortality, but also provide foraging opportunities. Road-side structures, such as transmission poles, offer nest sites and perches in otherwise treeless landscapes, benefiting certain avifauna. Railway lines create similar corridors, carrying ungrazed vegetation along them. Their associated structures – culverts and (historically) steel frame bridges – provide nest sites for birds and some mammals. Transmission cables and pylons along power lines have mixed benefits to conservation, providing bird nest and perch sites, but can also cause bird mortalities. Unquestionably, these linear structures have had marked effects on the biota of the Karoo, through their effects on wildlife and livestock movement and mortality, plant demography and the spread of native and alien species.     

Assessment of producers’ response to Salmonella biosecurity issues and uptake of advice on laying hen farms in England and Wales

1. High standards of biosecurity are known to reduce the risk of disease outbreaks; however, uptake of advice and implementation of biosecurity measures are dependent on many factors.

2. This study assessed the uptake of targeted biosecurity advice by 60 laying hen farms provided during biosecurity audit visits. Advice was provided as bullet point cards focusing on specific areas identified as benefitting from improvement. These covered site entrance, site tidiness, vaccination, boot hygiene, hand hygiene, house tidiness, rodent control, fly control, red mite control and cleaning and disinfection between flocks. Background knowledge of Salmonella and biosecurity and farmers’ willingness and intent to implement additional measures were assessed.

3. About 50% of the principal decision-makers had basic background knowledge of Salmonella, with 22% considered well informed; almost all agreed that biosecurity could impact on Salmonella control and many appeared willing to implement additional biosecurity measures. Sixty-three per cent of study farms were categorised using the Defra Farmer Segmentation Model as Modern Family Businesses (MFBs), with 7–11% of farms being categorised as Custodian, Lifestyle Choice, Pragmatist or Challenged Enterprise; however, categorisation, did not determine uptake of advice. The most frequently used advice cards were boot hygiene, red mite control, hand hygiene, site entrance and cleaning and disinfection; uptake of advice ranged from 54 to 80% depending on the advice card.

4. Uptake of advice by the farmers was encouraging, especially considering it was being provided by people other than their usual source of biosecurity information. Those who did not implement the recommended measures cited cost, difficulty of enforcement and practicality as the main reasons. However, the positive uptake of advice and implementation of recommended measures by many farmers demonstrates that targeted advice, discussed face to face with farmers, on a small number of key areas, is a potentially effective method of providing biosecurity information to complement more lengthy formal advisory reports.     

Prevalence of Neospora caninum and Toxoplasma gondii in sheep and dogs from Guarapuava farms, Paraná State, Brazil

Sheep and dog blood samples were collected from nine farms in the county of Guarapuava, Paraná, Brazil. The indirect fluorescent antibody test (IFAT) was used to detect Neospora caninum and Toxoplasma gondii antibodies. Herein, serum samples from 305 sheep were evaluated, being 29 (9.5%) and 157 (51.5%) seropositives to N. caninum and T. gondii, respectively. Seven (29.1%) and five (20.8%) out of 24 dogs were seropositives to N. caninum and T. gondii, respectively. There were no differences among the sheep serology for N. caninum and reproductive problems, management and animal feeding variables, neurological problems and presence of other animals species on the farm (P>or=0.05). The simultaneous frequency of antibodies between N. caninum and T. gondii was 5.2% in the herds. Age, breed, farm size, semi-intensive activity, mineral salt supplementation, water origin, stage of the pregnancy when reproduction problems occurred, neurological problems in lambs, presence of rodents in the food room and pasture cat access were identified as associated factors for the occurrence of toxoplasmosis in sheep (P<0.05). There were no differences among the seropositivity in dogs for N. caninum and T. gondii and breed, age and sex (P>or=0.05). The present work is the first report on serum prevalence of N. caninum in sheep from the state of Paraná, Brazil.     

Drivers and trajectories of social and ecological change in the Karoo,South Africa§

This review article explores past, present and possible future drivers of change in Karoo social-ecological systems. Biogeographically, the Karoo comprises the arid Succulent Karoo and Nama-Karoo biomes covering significant portions of the Northern Cape, Eastern Cape and Western Cape provinces and a smaller part of the Free State. Despite the Karoo’s specific environment and spatial importance nationally (covering some 30% of South Africa), no government structures address its needs holistically. Today it is a politically and economically marginalised region; perceptions of it as a desert easily morph into perceptions of it as deserted and ripe for exploitation for the benefit of external constituencies, whether in the name of astronomy, shale-gas and uranium mining or renewable energy. To manage the Karoo better for present and future generations, it is clearly desirable for social and natural scientists to work collaboratively, yet there is relatively little interdisciplinary work to date. Against this background this review article provides an overview of social and ecological changes historically and in the present, and offers some cautious reflections concerning climate change, changing land use and governance as key drivers affecting trajectories of change into the future.     

Correction to: First confirmation of rabies in Zamfara State,Nigeria—in a sheep

Tropical Animal Health and Production - Unfortunately the Abstract was missing in the original version of this article. The Abstract is published below.     

Short‐term effects of cattle‐to‐sheep ratio and stocking rate on patch grazing in sour grassveld

Abstract

The short‐term effects of stocking rate (AUE ha^?1) and cattle‐to‐sheep ratio on the extent and severity of patch grazing and on patch size were evaluated. The extent of patch grazing was proportional to stocking rate, and livestock species had a small but significant effect. Patch size was also a function of stocking rate. Cattle and sheep had similar effects on patch size distribution when stocked at the same number of AUE ha^?1. The severity of grazing within a patch was influenced by both stocking rate and cattle‐to‐sheep ratio. Recommendations that cattle should be grazed together with sheep and that cattle should be in greater proportion (in terms of AUE ha^?1) than sheep, which are aimed at limiting the severity of grazing by sheep, are supported. However, severe grazing within patches is an inevitable consequence of sheep grazing irrespective of the stocking rate or cattle‐to‐sheep ratio applied.     

Breeding for resistance to footrot – the use of hoof lesion scoring to quantify footrot in sheep

So that genetic studies can be undertaken on footrot in sheep, it is necessary that a reliable and repeatable method to categorise the phenotype is available. This paper summarises the methods used and results obtained from 1600 hoof lesion scores of 100 mixed-age ewes independently scored twice by two trained operators. Using a 5-pont scale describing the severity of foot lesions, residual correlations were used to assess agreement between scorers and scoring occasions. Data were analysed using both zero-1 and continuous data methods. The average prevalence of any score >0 was 15%, and of scores >1 was 12%. The residual correlation between scorers for SUM_FR was 0.87 and between scoring occasions it was also 0.87, indicating high repeatability or agreement both within and between scorers. No significant differences were detected between scorers or between scoring occasions for any of the traits analysed, or different analytical methods used.