Behaviour of goats,sheep and cattle and their selection of browse species on natural pasture in a Sahelian area

A study was conducted in the Sahelian zone of Burkina Faso of the behaviour of cattle, sheep and goats on natural pasture and their preference for browse species. Concurrently, a survey was undertaken on a sample of farmers (herders, women and livestock owners) in the study area to estimate the indigenous knowledge of browse species and their utilisation by ruminants. A herd of cattle and flocks of sheep and goats belonging to farmers were followed on pasture, each species during three consecutive days each month, from May 2003 to April 2004, and their activities were recorded regularly every 15 min, as well as the browse species selected and the height reached while browsing. The farmers had good knowledge of the browse species present in the area and their preferential classification depended on the availability of the species, their nutritive value and also other ways of utilising the species concerned. However, some divergence existed in the knowledge of farmers compared to the result from the behaviour study, e.g. some species were mentioned by farmers but not found in the inventory. There was a decline in the feeding activities of all animal species from rainy to dry season, while resting and ruminating activities were increasing at the same time. This decline in time spent feeding was more important for cattle (from 72 to 39% of total time) as they relied on the herbaceous biomass for feeding, while sheep and goats made a shift in the feeding activities from grazing to browsing when the herbaceous biomass decreased. Cattle browsed (leaves and litter) during all the study period for around 4.5% of the time spent on pasture. Sheep and goats showed a peak in browsing activity in the dry season, 28 and 52% of the time, respectively. During the whole observation period, cattle browsed 10 species, with Guiera senegalensis most often selected, with 59, 54 and 84% of browsing time, respectively, in the rainy, post rainy and dry season. G. senegalensis, Combretum micranthum and Balanites aegyptiaca were the most important species browsed by sheep among the 20 browse species selected. Goats browsed more than 20 species daily but the most preferred species were Acacia senegal, B. aegyptiaca and Pterocarpus lucens. The mean height reached by goats when browsing was higher (1.65 m) than that of cattle (1.47 m) and sheep (0.87 m). The result from this study can be used to select species for regeneration and to advice farmers on the importance of herd composition.     

Role of self-sufficiency,productivity and diversification on the economic sustainability of farming systems with autochthonous sheep breeds in less favoured areas in Southern Europe

Traditional mixed livestock cereal- and pasture-based sheep farming systems in Europe are threatened by intensification and specialisation processes. However, the intensification process does not always yield improved economic results or efficiency. This study involved a group of farmers that raised an autochthonous sheep breed (Ojinegra de Teruel) in an unfavourable area of North-East Spain. This study aimed to typify the farms and elucidate the existing links between economic performance and certain sustainability indicators (i.e. productivity, self-sufficiency and diversification). Information was obtained through direct interviews with 30 farms (73% of the farmers belonging to the breeders association). Interviews were conducted in 2009 and involved 32 indicators regarding farm structure, management and economic performance. With a principal component analysis, three factors were obtained explaining 77.9% of the original variance. This factors were named as inputs/self-sufficiency, which included the use of on-farm feeds, the amount of variable costs per ewe and economic performance; productivity, which included lamb productivity and economic autonomy; and productive orientation, which included the degree of specialisation in production. A cluster analysis identified the following four groups of farms: high-input intensive system; low-input self-sufficient system; specialised livestock system; and diversified crops-livestock system. In conclusion, despite the large variability between and within groups, the following factors that explain the economic profitability of farms were identified: (i) high feed self-sufficiency and low variable costs enhance the economic performance (per labour unit) of the farms; (ii) animal productivity reduces subsidy dependence, but does not necessarily imply better economic performance; and (iii) diversity of production enhances farm flexibility, but is not related to economic performance.     

Financial compensation for biodiversity conservation in Ba Be National Park of Northern Vietnam

Terrestrial biodiversity is seriously threatened by an increasing deforestation rate. Financial incentives can stimulate local people to participate in biodiversity conservation. A common approach to derive financial compensation is estimating the opportunity costs arising from the adoption of conservation-friendly land-use practices. Assuming that farmers are risk averse, we used a decision-making under uncertainty approach to derive financial compensation for local people living in and around Ba Be National Park, Vietnam. Moderately risk-averse farmers need US$ 228 ha⁻¹ year⁻¹ financial compensation for the protection of natural forests in the Ecological Rehabilitation and Buffer Zones, whereas the required compensation reaches US$ 334 ha⁻¹ year⁻¹ in the Strict Protection Zone. These compensation payments were derived by comparing financial returns from natural forests with those of the most profitable land-use (maize). Compensation amounts decrease to US$ 130 ha⁻¹ year⁻¹ in the Ecological Rehabilitation and Buffer Zones and to US$ 218 ha⁻¹ year⁻¹ in the Strict Protection Zone, when considering diversification strategy. Derived financial compensations assume that farms comprise 20% croplands and 80% forest. We conclude that compensation amounts vary with farmers’ risk preferences, whether or not diversification strategy is considered, and the level of protection of a given area.     

Water,land and carbon footprints of sheep and chicken meat produced in Tunisia under different farming systems

Meat production puts larger demands on water and land and results in larger greenhouse gas emissions than alternative forms of food. This study uses footprint indicators, the water, land and carbon footprint, to assess natural resources use and greenhouse gas emissions for sheep and chicken meat produced in Tunisia in different farming systems in the period 1996–2005. Tunisia is a water-scarce country with large areas of pasture for sheep production. Poultry production is relatively large and based on imported feed. The farming systems considered are: the industrial system for chicken, and the agro-pastoral system using cereal crop-residues, the agro-pastoral system using barley and the pastoral system using barley for sheep. Chicken meat has a smaller water footprint (6030 litre/kg), land footprint (9 m²/kg) and carbon footprint (3 CO₂-eq/kg) than sheep meat (with an average water footprint of 18900 litre/kg, land footprint of 57 m²/kg, and carbon footprint of 28 CO₂-eq/kg). For sheep meat, the agro-pastoral system using cereal crop-residues is the production system with smallest water and land footprints, but the highest carbon footprint. The pastoral system using barley has larger water and land footprints than the agro-pastoral system using barley, but comparable carbon footprint.     

Empirical evaluation of sustainability of divergent farms in the dryland farming systems of India

The present study argues that there are heterogeneous farm systems within the drylands and each farm system is unique in terms of its livelihood asset and agricultural practice, and therefore in sustainability. Our method is based on household survey data collected from 500 farmers in Anantapur and Kurnool Districts, in Andhra Pradesh State of India, in 2013. We carried out principal component analysis (PCA) with subsequent hierarchical clustering methods to build farm typologies. To evaluate sustainability across these farm typologies, we adopted a framework consisting of economic, social and environmental sustainability pillars and associated indicators. We normalized values of target indicators and employed normative approach to assign different weights to these indicators. Composite sustainability indices (CSI) were then estimated by means of weighted sum of indicators, aggregated and integrated into farm typologies. The results suggested that there were five distinct farm typologies representing farming systems in the study area. The majority of farms (>70%) in the study area are small and extensive (typology 1); marginal and off farm based (typology 2). About 20% of the farms are irrigation based and intensive (typology 3); small and medium and off farm based (typology 4) and irrigation based semi-intensive (typology 5). There was apparent variability among farm typologies in terms of farm structure and functions and composite sustainability indices. Farm typologies 3 and 5 showed significantly higher performances for the social and economic indices, while typologies 2 and 4 had relatively stronger values for environment. These discrepancies support the relevance of integrated farm typology- and CSI approaches in assessing system sustainability and targeting technologies. Universally, for all farm typologies, composite sustainability indices for economic pillar was significantly lower than the social and environment pillars. More than 90% of farmers were in economically less-sustainable class. The correlations between sustainability indices for economic and environment were typology specific. It was strong and positive when aggregated for the whole study systems [all samples (r = 0.183; P < 0.001)] and for agriculture dependent farm typologies (e.g. typologies 1 and 3). This suggests the need to elevate farms economic performance and capacitate them to invest in the environment. These results provide information for policy makers to plan farm typology–context technological interventions and also create baseline information to evaluate sustainability performance in terms of progress made over time.     

Caseous lymphadenitis in sheep flocks of the state of Minas Gerais,Brazil: Prevalence and management surveys

Corynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis, which is a serious, economically important problem for sheep production. We examined the seroprevalence of infection by C. pseudotuberculosis and possible risk factors associated with caseous lymphadenitis in sheep herds of the state of Minas Gerais, Brazil. Samples were collected from 642 sheep from 97 farms. Sera of all of the sheep were tested with ELISA for antibodies against C. pseudotuberculosis. A questionnaire was applied to gather data on the farm, the sheep herd, the farmer, and individual animal data (breed, sex and age). This is the first sero-epidemiological survey for caseous lymphadenitis in sheep herds in Minas Gerais. We found a high real prevalence, much higher than that suggested from information obtained with the questionnaire, which points to the scarcity of vaccination against caseous lymphadenitis in the sample evaluated. Only a small proportion of the farmers declared that cases of this disease were present in their flocks. The frequency of seropositive sheep varied significantly with breed (χ² test, P = 0.021). Age group also significantly affected the percentage of seropositivity (χ² test, P = 0.049), the highest frequency being found in adult animals (more than 12 months old), when compared to the 5–12 months old group (χ² test, P = 0.021). The prevalence of infection with C. pseudotuberculosis in sheep in the state of Minas Gerais was estimated to be 70.9% (95% confidence interval (CI): 64.7–77.0%) and the prevalence of infected flocks being 95.9% (95% CI: 89.8–98.9%). We concluded that C. pseudotuberculosis infection is widely disseminated in sheep flocks in Minas Gerais and that caseous lymphadenitis control and eradication programs are necessary in this state.     

Estimates of economic values for traits of Arabic sheep in village system

A deterministic bio-economic model was used to estimate the economic values of different traits in Arabic sheep native to the Khuzestan province of Iran. In the studied system, variable costs accounted for about 98.5% of the total costs and among variable costs, feed costs had the highest proportion with 70.7%. Revenue sources included meat, wool, and manure, where meat was the most important one and formed 95.5% of total revenues. Economic value for a trait was estimated as the amount of change in the profit of system as its mean increased by one unit, while the means of other traits were constant. The most important trait in this system was litter size, followed by ewe survival, dressing percentage, and wool weight, respectively. Birth weight had a negative economic value but weight at older ages especially weaning weight and 12-month weight had positive economic values. The sensitivity of economic values of traits was investigated by changing feed and non-feed costs, meat and wool prices by ±10%. Results showed that economic values for dressing percentage and wool weight are not sensitive to change in costs. In addition, changes in marketing and management costs had no effect on the economic value for traits related to body weight in different ages. In general, the economic value for traits which showed sensitivity to the changes of costs, except ewe survival, decreased due to an increase in costs. The economic value for all traits, except birth and wool weight, changed because of a change in meat price. Increasing meat price meant a higher economic importance. Among different factors, meat price fluctuations had the most effect on the economic value of traits.     

Estimates of economic values for traits of Arabic sheep in village system

A deterministic bio-economic model was used to estimate the economic values of different traits in Arabic sheep native to the Khuzestan province of Iran. In the studied system, variable costs accounted for about 98.5% of the total costs and among variable costs, feed costs had the highest proportion with 70.7%. Revenue sources included meat, wool, and manure, where meat was the most important one and formed 95.5% of total revenues. Economic value for a trait was estimated as the amount of change in the profit of system as its mean increased by one unit, while the means of other traits were constant. The most important trait in this system was litter size, followed by ewe survival, dressing percentage, and wool weight, respectively. Birth weight had a negative economic value but weight at older ages especially weaning weight and 12-month weight had positive economic values. The sensitivity of economic values of traits was investigated by changing feed and non-feed costs, meat and wool prices by ±10%. Results showed that economic values for dressing percentage and wool weight are not sensitive to change in costs. In addition, changes in marketing and management costs had no effect on the economic value for traits related to body weight in different ages. In general, the economic value for traits which showed sensitivity to the changes of costs, except ewe survival, decreased due to an increase in costs. The economic value for all traits, except birth and wool weight, changed because of a change in meat price. Increasing meat price meant a higher economic importance. Among different factors, meat price fluctuations had the most effect on the economic value of traits.     

Water use and feeding patterns of the marsupial western grey kangaroo (Macropus fuliginosus melanops) grazing at the edge of its range in arid Australia,as compared with the dominant local livestock,the Merino sheep (Ovis aries)

Western grey kangaroos (Macropus fuliginosus melanops) are large, foregut fermenting herbivores common to Australia's southern woodlands and shrublands, but they extend well into semiarid habitats at the north-eastern edge of their range. At this range boundary, western grey kangaroos occupy open chenopod (saltbush) shrubland, along with Australia's other large native kangaroos, as well as with extensive pastoral stock, primarily the wool-breed merino sheep. In this habitat, within a large naturally vegetated enclosure (16 ha), western grey kangaroos grazing sympatrically with merino sheep spent much of the day resting under shade trees, and fed mainly during the evening and early morning, mainly on grasses and flat-leaved chenopods. On this diet, western grey kangaroos had water turnovers similar to those of red kangaroos, at 1.1 L d⁻¹. Sheep, however, used 7.7 L of water each day. Thus, although the sheep were twice the average body mass of kangaroos, the sheep used more than seven times as much water. This level of water use by sheep was almost half that previously reported for sheep at the same site feeding mainly on salt-laden chenopods (ca. 12 L d⁻¹), but was consistent with other studies showing lower water usage by sheep feeding on trees and low-salt shrubs; foregut (rumen) contents of our sheep comprised 35% tree browse. Overall, our data do not support suggestions that western grey kangaroos are limited mainly by water at this arid range-boundary. Notably, the western grey kangaroos’ feeding behaviours were consistent with those of other arid-zone kangaroos, highlighting distinctive differences in the ecological physiology of the foregut fermenting kangaroos and the ruminant sheep.     

Analysis of different effects on longevity in four sheep breeds of northern Germany

The lifetime performance of female sheep is one of the most important economic traits in sheep husbandry. In this investigation, a Weibull model was used to study the effects of ‘breed’, ‘number of lambings’, ‘age at first lambing’, ‘type of birth’ and ‘farm’ on the length of productive life (LPL). The data included records of 5191 female sheep of four different breeds on 236 breeding farms in northern Germany. The observation period in which the sheep were born or were removed from the farm ranged from January 2003 to December 2007. About 12% of the records were right-censored. All variables had a significant effect on LPL at a level of p < 0.001 except ‘type of birth’. The German Blackheaded Mutton breed showed the lowest risk ratio with 0.77 (SE = 0.17), while the Texel had the highest hazard rate (1.00). The relative culling risk initially decreased from the first (5.73, SE = 0.09) to the seventh lambing (0.36, SE = 0.12), and then increased until lambing number nine. The highest relative culling risk was calculated at an age of 395 to less than 455 days at first lambing (1.00). Animals younger than 395 days at first lambing showed the lowest risk ratio (0.56, SE = 0.05). The culling risk for the effect ‘farm’ ranged from 0.3 to 3.1. A differentiation of environmental, housing or management effects was not feasible with this data. But the results offer some interesting options for further studies.     

Water footprint assessment of sheep farming systems based on farm survey data

Water scarcity is among the main challenges making vulnerable the livestock farming systems in drylands. The water footprint (WF) indicator was proposed as a metric to measure the impacts of livestock production on freshwater resources. Therefore, this study aimed to assess water use in five different Tunisian sheep production systems using the Water Footprint Network methodology. The primary data were obtained from 1050 sheep farms located in 13 Tunisian provinces. A multivariate analysis was performed to characterize the different farming systems. A validation step of the WF modeled values of sheep meat was conducted in 12 sheep farms belonging to two different farming systems. This was done through year-round monitoring of on-farm practices using water metres and recording equipment’s taking into account the direct and indirect water use. The typology analysis came up with five sheep farming systems that are the mixed sheep-cereal (MSC), the agro-sylvo-pastoral (ASP), the agro-pastoral (AP), the extensive agro-pastoral (EAP) and the mixed sheep-olive tree farming systems. The WF of sheep meat produced under the target farming systems ranged from 8654 to 13 056 l/kg live weight. The evaluation of WF of five different sheep production systems figured out that sheep raised under the EAP farming system had the greatest WF per ton of live animal. However, the ASP farming system exhibited the lowest WF. Water used to grow feedstuffs for sheep production accounts for 98% of the total WF of sheep. The green WF accounts for more than 92% of the total WF in all farming systems. Results of monitoring water use at farm scale show that the modeled values of WF are overestimated by an average of 23.3% and 24.1% for the selected farms assigned to the MSC and AP farming systems, respectively. Water use for sheep production is high in most of the Tunisian farms. Therefore, the general assumption that ‘meat production is a driver of water scarcity’ is supported and should be considered as an important focal point in agricultural and water policies. Particular attention should be given to forage crops with low WFs and high contribution to dry matter to provide ration with low WF. The efficient use of green water along the meat value chain is essential to minimize the depletion of blue water resources and to reduce the economic dependency on virtual water through the import of feedstuffs.     

Economics of sheep production

The aims of this paper are to give a brief overview of world sheep production at present and to describe in detail sheep production and profitability using New Zealand as a case example. Sheep numbers have been declining throughout the world over the last five years, resulting in decreased sheep meat production and a resultant shortage of supply. There is evidence that demand in the short-term will not be met by the major exporters (New Zealand and Australia). Although sheep numbers have declined in New Zealand, production has increased dramatically, with lambing percentages increasing from 98% in 1987 to 125% in 2008 and carcass weights from 14 to 17 kg, respectively. Despite this production increase, return on capital in the farming business has been around 1% per annum. However, property values have increased by around 10% offsetting the low return on capital from farming sheep. There are a number of challenges facing New Zealand's sheep farmers, namely changing land-use patterns, climate change and greenhouse gas mitigation, all of which will potentially impact on future profitability.     

Why household inefficiency? An experimental approach to assess spousal resource distribution preferences in a subsistence population undergoing socioeconomic change

Two disparate views of the sexual division of labour have dominated the representation of intra-household resource allocations. These joint and separate interests views differ in their interpretation of the relative roles of men and women, and make different predictions about the extent to which marriage promotes economic efficiency (i.e. maximized household production). Using an experimental “distribution task” stipulating a trade-off between household efficiency and spousal equality in allocating surpluses of meat and money, we examine factors influencing spousal distribution preferences among Tsimane forager-horticulturalists of Bolivia (n = 53 couples). Our primary goal is to understand whether and how access to perfectly fungible and liquid resources – which increases with greater participation in market economies – shifts intra-household distribution preferences. We hypothesize that greater fungibility of money compared to meat results in greater squandering of money for individual fitness gain at a cost to the family. Money therefore requires costly strategies to insure against a partner's claims for consumption. Whereas nearly all Tsimane spouses prefer efficient meat distributions, we find a substantially reduced efficiency preference for money compared to meat controlling for potential confounders (adjusted OR = 0.087, 95% CI: 0.02–0.38). Reported marital conflict over paternal disinvestment is associated with a nearly 13-fold increase in odds of revealing a selfish money distribution preference. Selfish husbands are significantly more likely than other husbands to be paired with selfish wives. Lastly, Tsimane husbands and wives are more likely than Western Europeans to prefer an efficient money distribution, but Tsimane wives are more likely than Western European wives to exhibit a selfish preference. In sum, preferences for the distribution of household production surplus support joint and separate interests views of marriage; a hybrid approach best explains how ecological-, family-, and individual-level factors influence spousal preferences through their effects on perceptions of marginal gains within and outside the household.     

Review: Precision livestock farming,automats and new technologies: possible applications in extensive dairy sheep farming

Precision livestock farming (PLF) technologies are becoming increasingly common in modern agriculture. They are frequently integrated with other new technologies in order to improve human–livestock interactions, productivity and economical sustainability of modern farms. New systems are constantly being developed for concentrated farming operations as well as for extensive and pasture-based farming systems. The development of technologies for grazing animals is of particular interest for the Mediterranean extensive sheep farming sector. Dairy sheep farming is a typical production system of the area linked to its historical and cultural traditions. The area provides roughly 40% of the world sheep milk, having 27% of the milk-producing ewes. Developed countries of the area (France, Italy, Greece and Spain – FIGS) have highly specialized production systems improved through animal selection, feeding techniques and intensification of production. However, extensive systems are still practiced alongside intensive ones due to their lower input costs and better resilience to market fluctuations. In the current article, we evaluate possible PLF systems and their suitability to be incorporated in extensive dairy sheep farming as practiced in the FIGS countries. Available products include: electronic identification systems (now mandatory in the EU) such as ear tags, ruminal boluses and sub-cutaneous radio-frequency identification; on-animal sensors such as accelerometers, global positioning systems and social activity loggers; and stationary management systems such as walk-over-weights, automatic drafter (AD), virtual fencing and milking parlour-related technologies. The systems were considered according to their suitability for the management and business model common in dairy sheep farming. However, adoption of new technologies does not take place immediately in small and medium scale extensive farming. As sheep farmers usually belong to more conservative technology consumers, characterized by an average age of 60 and a very transparent community, the dynamics do not favour financial risk taking involved with new technologies. Financial barriers linked to production volumes and resource management of extensive farming are also a barrier for innovation. However, future prospectives could increase the importance of technology and promote its wider adoption. Trends such as global sheep milk economics, global warming, awareness to animal welfare, antibiotics resistance and European agricultural policies could influence the farming practices and stimulate wider adoption of PLF systems in the near future.     

The intake and digestion of a range of temperate forages by sheep and fibre-producing goats

The voluntary intake, digestibility and mean retention time of six temperate forages differing in their chemical composition by 12 adult castrated male Scottish blackface sheep, aged 15 months, and fibre-producing castrated male goats, aged 27 months, and of similar live weight, 40 kg, were described. The creation of a range of chemical compositions was effected through the use of barley straw, and a low- and high-digestibility hay, and the use of ammonia treatment of these forages. A wide range of voluntary intakes (42–78 g DM/kg W^0.75/day), digestibility of dry matter (0.46–0.60) and mean retention times of undigested residues (36–72 h) was achieved through feeding the six forages. Across all the forages fibre-producing goats had higher voluntary intakes, expressed on a metabolic live weight basis, and lower digestibility values than sheep, whereas the mean retention time of the undigested residues was similar for the two species. Within forages goats selected a diet of potentially higher nutritive value, as predicted from chemical composition, with a smaller particle size than sheep. It was concluded that the differences in intake and digestion of temperate forages between sheep and fibre-producing goats are broadly similar to those observed in other experiments between sheep and goats ingesting tropical forages.     

Farmers’ practices,motivators and barriers for adoption of treatments of digital dermatitis in dairy farms

This study aimed to catalogue the digital dermatitis (DD) treatment practices used by French dairy farmers and to identify the motivators and barriers to the adoption of these treatments. A semi-structured survey was conducted involving 65 farmers in the main dairy production areas of France in the spring of 2009. The different treatment modalities implemented by farmers since the first diagnosis of DD in their herds were described. The reasons for adopting or abandoning these treatments were then investigated based on criteria of perceived effectiveness, labour, time, cost and toxicity related to their use. For individual treatments, farmers used 30 different products, applied through three different routes, for 1 to 21 consecutive days. For collective treatments, farmers used 31 products, applied through four different routes, at a rate ranging from once a day to once a year. Several products, especially antibiotics, were used without observing the manufacturer's instructions. The principal criteria for the adoption of a treatment was the perceived effectiveness in healing DD lesions and in limiting recurrence, while the principal barriers to adopting a treatment were the time and labour required for its application, followed by cost. Topical oxytetracycline treatments applied individually were used and adopted the most. They were perceived to be effective in healing DD lesions. However, these treatments were judged labour and time consuming, particularly when many animals had to be treated. Collective treatments combining formalin and copper sulphate often were applied topically using walk-though footbaths. These treatments often were judged to be insufficiently effective in healing DD lesions, difficult to implement, labour and time consuming and costly. The plethora of DD treatment practices and the misuse of some treatments could suggest that there is a lack of guidelines available to farmers on the optimal use and expected effectiveness of treatments. Clinical trials should be conducted to develop recommendations based on scientific rather than empirical data, and to identify the DD control measures which consume the least amount of time and labour.     

Cystic echinococcosis in Sardinia: the current role of sheep

Cystic echinococcosis is one of the most widespread parasitosis in the Mediterranean region. Unfortunately this is also true for Sardinia for various reasons, among which is the close relationship between sheep and dogs in the farms. This work first epidemiologically analyses hydatidosis in sheep in Sardinia and then examines the most important causes of the persistence of these metacestodosis in sheep. The work looks at the factors which are responsible for the enormous quantity of illegal slaughtering and the widespread habit of abandoning the sheep carcasses in the grazing areas, as well as possible initiatives which may eliminate these practices. Such initiatives must include reducing the financial costs and bureaucracy involved when sheep are slaughtered in abattoirs, and also increasing the value of sheep meat. In conclusion new checks and controls are hoped for at a political level which will increase the financial support for the farmers and encourage the use of recombinant vaccines which have already been tested in Sardinia. These are extremely useful for effectively curbing cystic echinococcosis.     

Determination of prediction equations for estimating body weight of Zulu (Nguni) sheep

Data on linear body measurements (LBM) of 403 sheep collected in three areas of KwaZulu-Natal were utilized to develop a prediction equation for live body weight of Zulu sheep. Data were collected on live weight (LW), heart girth (HG), wither height (WH) and scrotum circumference (SC) on sheep of all ages. The age of sheep was estimated by dentition. The analysis of variance showed that age and sex were important factors contributing to variation in LW of Zulu sheep. Phenotypic correlation coefficients and regression equations of LW on HG, WH and SC were computed within different age groups (milk set of teeth, one pair, two pairs and the three and four pairs of incisors). Low correlation coefficients (r = 0.21–0.48) between LW, HG and WH were found among the pregnant ewes. The relationship between LBM and LW was stronger (r = 0.66–0.86) for males than among females (r = 0.42–0.75). The cubic polynomial of HG was the best fit (R² = 0.76) for the live weight prediction of young sheep with milk set of teeth. The combination of HG and WH produced the best fit for the two tooth and above males and non-pregnant females. The LW prediction equations for pregnant females were not reliable (R² = 0.05–0.26). The SC was more precise (R² = 0.61–0.80) when estimating the live weight of young males (<15–22-month-old) than of the older rams (R² = 0.23–0.56). It was concluded that LW of Zulu sheep can be reasonably estimated using the HG and WH. A table could be constructed for the farmers to estimate the LW of their animals.     

Financial evaluation of different vaccination strategies for controlling the bluetongue virus serotype 8 epidemic in The Netherlands in 2008

Background

Bluetongue (BT) is a vector-borne disease of ruminants caused by bluetongue virus that is transmitted by biting midges (Culicoides spp.). In 2006, the introduction of BTV serotype 8 (BTV-8) caused a severe epidemic in Western and Central Europe. The principal effective veterinary measure in response to BT was believed to be vaccination accompanied by other measures such as movement restrictions and surveillance. As the number of vaccine doses available at the start of the vaccination campaign was rather uncertain, the Dutch Ministry of Agriculture, Nature and Food Quality and the Dutch agricultural industry wanted to evaluate several different vaccination strategies. This study aimed to rank eight vaccination strategies based on their efficiency (i.e. net costs in relation to prevented losses or benefits) for controlling the bluetongue virus serotype 8 epidemic in 2008.

Methodology/Principal Findings

An economic model was developed that included the Dutch professional cattle, sheep and goat sectors together with the hobby farms. Strategies were evaluated based on the least cost - highest benefit frontier, the benefit-cost ratio and the total net returns. Strategy F, where all adult sheep at professional farms in the Netherlands would be vaccinated was very efficient at lowest costs, whereas strategy D, where additional to all adult sheep at professional farms also all adult cattle in the four Northern provinces would be vaccinated, was also very efficient but at a little higher costs. Strategy C, where all adult sheep and cattle at professional farms in the whole of the Netherlands would be vaccinated was also efficient but again at higher costs.

Conclusions/Significance

This study demonstrates that a financial analysis differentiates between vaccination strategies and indicates important decision rules based on efficiency.     

Learning from science and history about black-backed jackals Canis mesomelas and their conflict with sheep farmers in South Africa

The black-backed jackal Canis mesomelas, henceforth jackal, has re-emerged as a threat to South African sheep farmers. This sparked contestation between farmers and conservationists over the reasons for their return and the relative merits of lethal and non-lethal approaches to protecting livestock. Three separate reviews of the scientific literature converged on the same broad conclusion that lethal control of jackals is probably ineffective, but that more scientific research is necessary, especially on farms. We draw on historic evidence and recent research across a range of disciplines to show that jackal diet and behaviour varies regionally and alter in response to changing threats and opportunities. More data will not support generalisable conclusions and have already been eclipsed by broad-scale changes in the political, economic and ecological landscapes of South Africa. Reduced government support for farmers, rising production costs and falling product prices, together with an increasing frequency of droughts, have conspired to weaken the collective management hand of farmers and, ultimately, contributed to a decline in the sheep farming industry. Many sheep farmers have sold their land to non-commercial ‘lifestyle' farmers or expanding nature reserves, creating a growing network of safer spaces for jackals to persist, from which their offspring can sink into neighbouring commercial farmland. When these landscape-level changes are combined with the wide phenotypic plasticity and catholic diet of the jackal, we should be neither surprised at their resurgence nor contented with suggestions that more ecological research is likely to facilitate any sustainable solutions.