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1.
Garippa G 《Parassitologia》2006,48(3):419-422
Gastrointestinal strongylosis are the dominant parasitic infections of sheep and goats. The successful control of these parasites cannot be done exclusively with anthelmintics, but the first step is an integrated program for environmental prophylaxis. The correct planning of the prophylaxis program has to be preceded by the analysis of the related problems: (1) the parasitological status of farm livestock; (2) knowledge of the farm management; (3) hydrogeological, pedological and climatic-environmental aspects. The environmental control strategies can be resumed as follows: avoiding animals from different farms to share the same pasture; avoiding animals of different age classes to graze together; parcel the pastures to permit a rational rotation; rotational grazing of pastures according to the seasonal development of parasites; stocking rate; young animals grazing ahead of the older animal ones; crop management practices (draining, ploughing, harrowing, scrub clearing, fertilizing, etc.). These measures make the habitat less suitable for the free-living stages of gastrointestinal strongyles, reducing the potential of infection of the same pastures.  相似文献   

2.
The formation of mixed-species social groups, whereby heterospecifics form and maintain either transient or stable groups with each other, can confer substantial fitness benefits to individuals. Such benefits may arise via multiple mechanisms associated with both predation avoidance and foraging efficiency. In fishes, mixed-species shoaling reportedly occurs where displaced tropical species (known as “vagrants”) interact with resident temperate species, although little is known about the nature and frequency of such interactions. To investigate this phenomenon, we used displaced tropical Indo-pacific Sergeant Abudefduf vaigiensis settling in temperate south-eastern Australia as a model system. Underwater visual surveys revealed shoal composition and size differed significantly between open-water and reef habitats, with shoals in open habitats being larger and more speciose. Shoals containing A. vaigiensis were mainly mixed-species, and larger and more speciose in open habitats than nearer to reef. Since both foraging efficiency (via access to plankton) and predation threat likely increase with increasing distance from reef habitat, we suggest that mixed-species shoaling mitigates predation risk whilst allowing increased foraging opportunities for A. vaigiensis in open areas. These findings provide support for the importance of mixed-species shoaling to the persistence of tropical reef fishes in temperate regions.  相似文献   

3.
The establishment and reversibility of cross-species attachments were studied in sheep and goats taken from their mothers at birth and reared in same- or cross-species pairs until 12 months of age. Species affinities were determined at eight to nine months of age by time spent proximate to stimulus herds of sheep and goats housed in separate enclosures within a larger pasture. Sheep reared with goats spent significantly more time with the stimulus goats than did controls (sheep reared with sheep). Likewise, goats reared with sheep spent a significantly greater percentage of time with the stimulus sheep than did control goats. At approximately 13 months of age the sheep were segregated from the goats in separate pastures and were retested, as before, for species affinities after 34 to 90 days of exposure to conspecifics. Experimental subjects demonstrated a significant reversal of species preferences. However, the reversal was more complete for subjects housed for 57 to 90 days in same-species groups than for those tested after 34 to 56 days of exposure to conspecifics. It was concluded that species affinities of sheep and goats are basically learned and that relatively long-standing cross-species social attachments can be reversed by approximately 60 to 90 days of same-species cohabitation.  相似文献   

4.
Questions: What are the relative roles of abiotic and grazing management factors on plant community distribution in landscapes? How are livestock type and stocking rate related to changes in vegetation structure and composition? Location: Sub‐alpine grasslands in the central and eastern Pyrenees. Methods: Multivariate analysis and variance partitioning methods were used to evaluate the relative roles of environmental factors in structuring vegetation composition and diversity patterns in three surveys on differently managed grasslands. Results: Vegetation composition within a region was affected by environmental factors hierarchically, changing first according to abiotic factors and then to grazing management. At landscape scales, abiotic factors explained two‐fold more variation in vegetation composition than grazing factors. Within landscape units, cattle grazing increased vegetation heterogeneity at landscape and patch scales, while sheep grazing favoured the presence of a specific set of species with high conservation value. Species composition was highly responsive to management variables compared to diversity components. Conclusions: The combination of sheep and cattle grazing at various stocking rates is an effective tool to preserve the diversity of plant species and communities within a region with a long tradition of livestock management, through the scaling up of effects by local processes occurring in patches at smaller scales.  相似文献   

5.
The opinions of seven respondent groups about the relative importance of different practices pertaining to the welfare of Australian beef cattle, sheep and goats were surveyed. Respondent groups comprised farmers, livestock transportation representatives, veterinarians, meat processors, animal welfare advocates, animal welfare scientists and government officers. The survey consisted of a web-based adaptive conjoint analysis questionnaire, which was administered to a sample population that was selected randomly for large respondent groups and comprehensively for small groups. The hierarchy of opinion concerning the importance of the different beef cattle practices was: stockmanship > ground (road and rail) transport > spaying > food supply > dehorning > stunning > shelter > identification > pretransport food and water deprivation > castration > sea transport > mustering > confinement. For sheep/goat practices the hierarchy was: parasite control > mulesing > shelter > stockmanship > tail docking > ground transport > feeding > predation > stunning > castration > pretransport food and water deprivation > sea transport > mustering. The method of performing invasive procedures was perceived as less important than the provision of pain relief. Differences in opinion were evident between respondent groups, with animal welfare advocates tending to focus on painful procedures more than those with direct involvement in the industry.  相似文献   

6.
Domestic sheep (Ovis spp.) grazing is emerging as an integrated pest management tactic for alfalfa weevil, Hypera postica (Gyllenhal), management and a degree-day model is needed as a decision and support tool. In response to this need, grazing exclosures with unique degree-days and stocking rates were established at weekly intervals in a central Montana alfalfa field during 2008 and 2009. Analyses indicate that increased stocking rates and grazing degree-days were associated with decreased crop levels of weevil larvae. Larval data collected from grazing treatments were regressed against on-site and near-site temperatures that produced the same accuracy. The near-site model was chosen to encourage producer acceptance. The regression slope differed from zero, had an r2 of 0.83, and a root mean square error of 0.2. Crop data were collected to achieve optimal weevil management with forage quality and yield. Differences were recorded in crude protein, acid and neutral detergent fibers, total digestible nutrients, and mean stage by weight. Stem heights differed with higher stocking rates and degree-days recording the shortest alfalfa canopy height at harvest. The degree-day model was validated at four sites during 2010 with a mean square prediction error of 0.74. The recommendation from this research is to stock alfalfa fields in the spring before 63 DD with rates between 251 and 583 sheep days per hectare (d/ha). Sheep should be allowed to graze to a minimum of 106 and maximum of 150 DD before removal. This model gives field entomologists a new method for implementing grazing in an integrated pest management program.  相似文献   

7.
Species distribution models (SDMs) are increasingly used to predict species ranges and their shifts under future scenarios of global environmental change (GEC). SDMs are thus incorporating key drivers of GEC (e.g. climate, land use) to improve predictions of species’ habitat suitability (i.e. as an indicator of species occurrence). Yet, most SDMs incorporating land use only consider dominant land cover types, largely ignoring other key aspects of land use such as land management intensity and livestock. We developed SDMs including main land use components (i.e. land cover, livestock and its management intensity) to assess their relative importance in shaping habitat suitability for the Egyptian vulture, an endangered raptor linked to livestock presence. We modelled current and future (2020 and 2050) habitat suitability for this vulture using an organism-centred approach. This allowed us to account for basic species’ habitat needs (i.e. nesting cliff) while gaining insight into our variables of interest (i.e. livestock and land cover). Once nest-site requirements were fulfilled, land use variables (i.e. openland and sheep and goat density) were the main factors determining species’ habitat suitability. Current suitable area could decrease by up to 6.81% by 2050 under scenarios with rapid economic growth but no focus on environmental conservation and rural development. Local solutions to environmental sustainability and rural development could double current habitat suitability by 2050. Land use is expected to play a key role in determining Egyptian vulture's distribution through land cover change but also through changes in livestock management (i.e. species and stocking density). Change in stocking densities (sheep and goats/km2) becomes thus an indicator of habitat suitability for this vulture in our study area. Abandonment of agro-pastoral practises (i.e. below ∼15–20 sheep and goats/km2) will negatively influence the species distribution. Nonetheless, livestock densities above these values will not further increase habitat suitability. Given the widespread impacts of livestock on ecosystems, the role of livestock and its management intensity in SDMs for other (non-livestock-related) species should be further explored.  相似文献   

8.
Individuals of many quite distantly related animal species find each other attractive and stay together for long periods in groups. We present a mechanism for mixed-species grouping in which individuals from different-looking prey species come together because the appearance of the mixed-species group is visually confusing to shared predators. Using an artificial neural network model of retinotopic mapping in predators, we train networks on random projections of single- and mixed-species prey groups and then test the ability of networks to reconstruct individual prey items from mixed-species groups in a retinotopic map. Over the majority of parameter space, cryptic prey items benefit from association with conspicuous prey because this particular visual combination worsens predator targeting of cryptic individuals. However, this benefit is not mutual as conspicuous prey tends to be targeted most poorly when in same-species groups. Many real mixed-species groups show the asymmetry in willingness to initiate and maintain the relationship predicted by our study. The agreement of model predictions with published empirical work, the efficacy of our modelling approach in previous studies, and the taxonomic ubiquity of retinotopic maps indicate that we may have uncovered an important, generic selective agent in the evolution of mixed-species grouping.  相似文献   

9.
This paper aims to explore farmers’ preferences for sheep or goats based on feeding practices, animal and flock performances and economic benefits of sheep and goats in different agro-ecological zones in Central Java, Indonesia. In total, 150 smallholder farmers were selected from three agro-ecological zones: the lowlands, the middle zone, and the uplands. Feeding and performance parameters were estimated through weekly farm visits and farm records, from September 2001 to August 2003. In the lowlands, small ruminants were fed mainly with field grass and crop residues, whereas in the middle zone and uplands feeds fed were mainly field grass and leaves. Sheep were given more opportunities to graze than goats, however, grazing was not a major component in the diets. In the lowlands and the middle zone the differences in feed intakes, ADG and reproductive performances between sheep and goats were small. In all zones, does had significantly larger litters than ewes. In the uplands, goats had a significantly higher DMI, grew slightly faster, and had a higher weaning rate than sheep. Consequently, in the uplands, the total economic benefits from goat flocks were 25% higher than from sheep flocks. The major differences in agro-ecological conditions that affect the choice for sheep or goats were the availability of cassava peels in the lowlands, favouring a choice for sheep, and the abundance of leaves in the middle zone and uplands, which favours keeping goats. The promotion of goats by the government, the family tradition of keeping sheep or goats, the preference for sacrificing sheep for religious festivities, and the high initial investment needed to buy goat breeding stock could be other important motives to keep sheep or goats. Sheep fattening based on rice bran supplementation could be a feasible innovation in the lowlands. In the middle zone and uplands goat breeding could make a positive contribution to rural livelihoods.  相似文献   

10.
The use of viral vectors is a method for introducing foreign genes into various animal species. Vectors based on retro-, adeno-, flavi-, and parvoviruses have been used for research in animal species of agricultural importance, such as chickens, quail, swine, cows, goats, sheep, fish, crustaceans, and mollusks. Viral vectors allow for efficient transgenic integration into host genome or for transient expression of the transgenic construct in somatic tissues. Because of that, viral vectors are important tools for research and potentially other biotechnology applications such as improving animal production qualities and introducing disease resistance, thus improving food quality and safety. Other uses may include generating animal models of human diseases and using animals as bioreactors for production of therapeutic proteins. Each vector type provides a unique set of advantages and limitations, which are in some cases specific to an animal species or a method of introduction. This article discusses viral vector characteristics and potential applications in agriculturally important animal species. It discusses advantages and disadvantages of using viral vectors in genetic engineering of agricultural animals.  相似文献   

11.
Polyspecific associations are commonly observed in social animals, including primates, and have been interpreted as adaptations either to improve access to resources or to provide protection against predators. Mixed‐species associations between Wied's marmosets (Callithrix kuhlii) and golden‐headed lion tamarins (Leontopithecus chrysomelas) have been documented, and are unique among Atlantic forest primates. Both species are endemic to southern Bahia where part of the forest has been converted into cacao agroforests, which have been subjected to management intensification. Tree density and canopy connectivity decrease in more intensively managed agroforests, potentially increasing predation risk and the frequency of mixed‐species groups between these primates. Here, we test this hypothesis using a standardized, large spatial‐scale data set obtained from camera‐trapping in 30 sites across an agroforestry landscape mosaic. As expected, the frequency of mixed‐species groups increased in more intensively managed agroforests, but only relative to the total number of records of tamarins. Our results highlight that the benefits of mixed‐species groups can be asymmetrical among species and variable across the landscape. They corroborate that predation avoidance is an important advantage of mixed‐species groups in callitrichids, especially for conspicuous species living in smaller groups, such as the tamarin. Despite the importance of agroforests to conservation, our results indicate that management intensification can increase predation risk for species of conservation concern. To maintain the conservation value of agroforests, management practices should be planned to avoid any loss of canopy connectivity, taking into account the biodiversity vs. productivity trade‐off associated with shade management.  相似文献   

12.
The European Centre for the Validation of Alternative Methods (ECVAM) has restructured its services by directly targeting the animal tests that need to be replaced. In view of the short time-lines for making available and implementing validated methods, ECVAM is offering to steer the process by bringing together the inputs of stakeholders and encouraging the early involvement of regulators. In essence, steering groups formed by ECVAM senior staff, and complemented with external experts, will carry out the project management and will coordinate the various inputs.  相似文献   

13.
This study investigated the relation between zookeeper-nonhuman animal distance and the undesirable behavior goats and sheep exhibited toward visitors of Zoo Atlanta's contact yard. It hypothesized that a close distance between keeper and animal would be associated with a lower rate of undesirable behavior than would a distant keeper-animal distance. The study recorded rate of undesirable behavior exhibited, number of visitors in the yard, and number of times visitors touched an animal under near and distant keeper-animal distances. Seven African pygmy goats (Capra hircus) and 4 Romanov sheep (Ovis aries) were the subjects. The study used linear regression methods to analyze approximately 48 hr of behavioral data collected using a focal sampling technique. Findings indicated a familiar animal keeper nearby was not associated with lower rates of undesirable behavior toward visitors. Higher rates of undesirable behavior occurred when keepers were nearby than when they were distant. The study also found that undesirable behavior increased as visitors' touching of the animals increased. Applying the study's findings may improve human-animal interactions and increase animal well-being in a contact yard through animal management techniques.  相似文献   

14.
Ticks and their pathogens cause significant disease and economic loss in many animal populations. Despite this, experiments that test the impact of ticks and tick-borne diseases on wild animal populations are rare. Here, we report on an experiment assessing the effect of ticks on red grouse productivity and chick growth in relation to other causes of poor recruitment at two sites in the Scottish uplands during 2005. Treated hens received two leg bands impregnated with the acaricide permethrin, while controls hens were untreated. Chicks were captured at c.2 weeks of age and fitted with a metal patagial tag, and chicks from treated hens also received a permethrin-impregnated strip. Mean tick burdens in treated chicks were close to zero compared with a mean of around 12 in the control group. Although treatment reduced tick infestations, it did not increase brood size. Growth rates in chicks from control and treated hens were similar during the first 10 days and comparable with chicks fed an ad-lib invertebrate-based diet. These results suggest that in this case, neither ticks (and the tick transmitted louping-ill virus) nor food shortages was the main cause of chick mortality. However, mortality in the adult hens was around 35 %, and predation accounted for 62 % of these losses before broods fledged. Our results indicate that on our study sites, predation may have a more important impact on grouse population dynamics than ticks and tick-borne disease. We suggest that it may be more cost effective to determine the causes of poor grouse population performance before implementing popular but expensive tick control measures such as the culling of alternative hosts and running acaracide treated sheep ‘tick-mop’ flocks.  相似文献   

15.
The mean fibre diameter (MFD) of wool is the primary determinant of price, processing performance and textile quality. This study determines the primary influences on MFD as Saxon Merino sheep age, by allometrically relating MFD to fleece-free liveweight (FFLwt). In total, 79 sheep were grazed in combinations of three stocking rates and two grazing systems (GS: sheep only; mixed with Angora goats) and studied over 3 years. Measurements were made over 14 consecutive periods (Segments), including segments of FFLwt gain or FFLwt loss. Using shearing and liveweight records and dye-bands on wool, the FFLwt and average daily gain (ADG) of each sheep were determined for each segment. The mean and range in key measurements were as follows: FFLwt, 40.1 (23.1 to 64.1) kg; MFD, 18.8 (12.7 to 25.8) μm. A random coefficient restricted maximum likelihood (REML) regression mixed model was developed to relate the logarithm of MFD to the logarithm of FFLwt and other effects. The model can be written in the form of β(A) is a random animal effect, γ(Segment.Plot) a random effect associated with Segment.plot combinations, and κ a constant that depends on GS, random animal effects, random Segment.plot combination effects, Segment and ADG. Thus, MFD was allometrically related to the cube root of FFLwt over seasons and years for sheep, but to the square root of FFLwt for sheep grazed with goats. The result for sheep grazed alone accords with a primary response being that the allocation of nutrients towards the cross-sectional growth of wool follicles is proportional to the changes in the skin surface area arising from changes in the size of the sheep. The proportionality constant varied systematically with ADG, and in sheep only grazing, was about 5 when sheep lost 100 g/day and about 6 when sheep gained 100 g/day. The proportionality constant did not systematically change with chronological age. The variation in the allometric coefficient between individual sheep indicates that some sheep were more sensitive to changes in FFLwt than other sheep. Key practical implications include the following: (a) the reporting of systematic increases in MFD with age is likely to be a consequence of allowing sheep to increase in size during shearing intervals as they age; (b) comparisons of MFD between sheep are more likely to have a biological basis when standardised to a common FFLwt and not just to a common age; (c) wool quality (MFD, staple strength) are most likely to be optimised in management systems that maintain constant FFLwt of adult sheep within and between years.  相似文献   

16.
Livestock grazing is known to influence carbon (C) storage in vegetation and soil. Yet, for grazing management to be used to optimize C storage, large scale investigations that take into account the typically heterogeneous distribution of grazers and C across the landscape are required. In a landscape-scale grazing experiment in the Scottish uplands, we quantified C stored in swards dominated by the widespread tussock-forming grass species Molinia caerulea. The impact of three sheep stocking treatments (‘commercial’ 2.7 ewes ha?1 y?1, ‘low’ 0.9 ewes ha?1 y?1 and no livestock) on plant C stocks was determined at three spatial scales; tussock, sward and landscape, and these data were used to predict long-term changes in soil organic carbon (SOC). We found that tussocks were particularly dense C stores (that is, high C mass per unit area) and that grazing reduced their abundance and thus influenced C stocks held in M. caerulea swards across the landscape; C stocks were 3.83, 5.01 and 6.85 Mg C ha?1 under commercial sheep grazing, low sheep grazing and no grazing, respectively. Measured vegetation C in the three grazing treatments provided annual C inputs to RothC, an organic matter turnover model, to predict changes in SOC over 100 years. RothC predicted SOC to decline under commercial sheep stocking and increase under low sheep grazing and no grazing. Our findings suggest that no sheep and low-intensity sheep grazing are better upland management practices for enhancing plant and soil C sequestration than commercial sheep grazing. This is evaluated in the context of other upland management objectives.  相似文献   

17.
To meet rising demands for agricultural products, existing agricultural lands must either produce more or expand in area. Yield gaps (YGs)—the difference between current and potential yield of agricultural systems—indicate the ability to increase output while holding land area constant. Here, we assess YGs in global grazed‐only permanent pasture lands using a climate binning approach. We create a snapshot of circa 2000 empirical yields for meat and milk production from cattle, sheep, and goats by sorting pastures into climate bins defined by total annual precipitation and growing degree‐days. We then estimate YGs from intra‐bin yield comparisons. We evaluate YG patterns across three FAO definitions of grazed livestock agroecosystems (arid, humid, and temperate), and groups of animal production systems that vary in animal types and animal products. For all subcategories of grazed‐only permanent pasture assessed, we find potential to increase productivity several‐fold over current levels. However, because productivity of grazed pasture systems is generally low, even large relative increases in yield translated to small absolute gains in global protein production. In our dataset, milk‐focused production systems were found to be seven times as productive as meat‐focused production systems regardless of animal type, while cattle were four times as productive as sheep and goats regardless of animal output type. Sustainable intensification of pasture is most promising for local development, where large relative increases in production can substantially increase incomes or “spare” large amounts of land for other uses. Our results motivate the need for further studies to target agroecological and economic limitations on productivity to improve YG estimates and identify sustainable pathways toward intensification.  相似文献   

18.
Veneziano V 《Parassitologia》2004,46(1-2):245-250
Gastrointestinal (GI) parasitism are the most serious problem affecting sheep and goats worldwide. Economic losses caused by GI strongyles are related to decreased production, costs for treatment and prophylaxis and animal death. Effective control of internal parasites in small ruminants is one of the most difficult challenges encountered by veterinary in practice. For control of helminth parasites in grazing animals it is important knowledge of epidemiology of the parasite as it interacts with the host in a specific climatic, management and production environment. Sheep and goats are infected by many of the same GI nematodes, but feeding and management practices alter levels of parasitism between the two ruminants. The most commonly anthelmintics used for helminth control in small ruminants include three chemical groups: Imidazothiazoles/Pyrimidines (Im/Pm), Benzimidazoles/Probenzimidazoles (Bz/Pbz) and Macrocyclic Lactones (ML). The control of gastrointestinal strongyles infections in goats shows specific patterns. The use of anthelmintics in goats is based upon anthelmintics goats-suited dose rates taking into account the specific pharmacokinetics features of some anthelmintics in this species. Several types of control strategies: deworming programs, grazing management, biological control, supplementary feeding and breeding approaches are discussed.  相似文献   

19.
Because "odd" individuals often suffer disproportionately highrates of predation, solitary individuals should join groupswhose members are most similar to themselves in appearance.We examined group-choice decisions by individuals in armoredand nonarmored species and predicted that either (1) the oddityeffect would result in preference for conspecific groups forsolitary individuals of both species, or (2) individuals inthe armored species would prefer to associate with groups containingindividuals of the more vulnerable species. Armored brook sticklebacks(Culaea inconstans) and nonarmored fathead minnows (Pimephalespromelas) have the same predators and often occur together instreams. In mixed-species shoals, yellow perch (Perca flavescens)attacked minnows earlier and more often than sticklebacks. Wetested whether solitary minnows and sticklebacks preferred toassociate with conspecific or heterospecific shoals under conditionsof both low and high predation risk. When predation risk washigh, minnows preferred to associate with conspecifics overheterospecifics, as predicted by the oddity effect. In contrast,sticklebacks preferentially associated with groups of minnowsover groups of conspecifics when predation risk was high. Whenpredation risk was low, solitary individuals of both speciespreferentially associated with conspecific over heterospecificshoals. Stickleback shoal choices under low-risk conditionsmay have been influenced by interspecific competition for food.In feeding experiments, minnows were more efficient foragersthan sticklebacks, so it should benefit sticklebacks to avoidminnows unless predation risk is high. Therefore, for armoredprey, the benefits of associating with more vulnerable preyappear to override the costs of both the oddity effect and foodcompetition when predation risk is high.  相似文献   

20.
Historically, shooting has been a popular method for controlling foxes in Australia, but past research has shown it to be an ineffective method for significantly reducing fox population numbers. These past studies investigated shooting when conducted in isolated, one‐off programmes. In more recent years large, coordinated group fox management programmes has become popular in both agricultural and conservation areas. These landscape scale programmes give more chance of long‐term respite from predation damage by slowing down the immigration rates of foxes into the culled area. Studies have been conducted investigating the effectiveness of large‐scale group fox management programmes that primarily used 1080 baiting as the method of control to protect vulnerable livestock and small animal. This study investigated the potential of a large‐scale group programme that used shooting as the main form of control to reduce the impact of fox predation.  相似文献   

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