High Livestock Density Research Articles

Overstocking in the trans-Himalayan rangelands of India

High livestock densities in rangelands can result in reduced animal production due either to overgrazing or reduced per caput food availability, yet evidence for reduced animal production due to overstocking is scarce. Here simple animal production models establish the occurrence of overstocking in a traditional agropastoral system in the Spiti Valley of the Indian Trans-Himalaya. Empirical data show that fecundity of adult female livestock is related to total livestock biomass density (S) as a negative linear function of S. Total herd production is modelled as a quadratic function of S, thereby calculating an optimum livestock biomass density (Sop), at which total herd production is maximized. A sample of 40 villages showed that over 83% of Spiti's rangelands may be overstocked with values of S > Sop. Overstocking seems to be a classic case of the tragedy of the commons, as livestock is individually owned while the land is communally grazed. Recent socio-economic changes have probably contributed to high levels of overstocking. Even areas within wildlife reserves are overstocked. Conservation management needs to focus on creation of grazing free areas and management of livestock densities.

Livestock sustaining intensive smallholder crop production through traditional feeding practices for generating high quality manure-compost in upland Java

Information is needed on the biophysical and economic rationale for labour-demanding (and therefore, expensive) backyard animal rearing systems on smallholdings in the uplands of Java where livestock have been an integral part of highly intensive agriculture for centuries. The occurrence of high densities of ruminant livestock is counter-intuitive considering the extent and continuous nature of cropping on densely populated islands such as Java where little land remains suitable for grazing. As a consequence, livestock are permanently housed in backyards and fed indigenous forages cut from field margins and roadsides. Although cut-and-carry feeding is labour-intensive, it is surprising that farmers collect quantities of forage greatly in excess of the requirements of their livestock. In an experiment, indigenous forage was fed to sheep at increasing rates: 25, 50 or 75 g DM kg −1 liveweight daily. The results showed that although DM intake and liveweight gain rose with increasing offer-rate, the incremental improvements from 50 to 75 were non-significant ( p<0.05) and <25 to 50. It is unlikely that farmers justify their excess-feeding strategies on the basis of these marginal gains in animal productivity alone. The rationale for excess-feeding also lies in the production of manure-composts. Group-interviews, involving preference-ranking and matrix scoring exercises, indicated that in upland areas, farmers have an extensive knowledge regarding organic fertiliser quality and use. Farmers place value on the inclusion of animal wastes, particularly urine, into composts. In rain-fed areas, manure production ranked similar to meat production in importance as outputs from the sheep enterprise. The research demonstrates how livestock are traditionally used to produce high quality compost and provides evidence to support the hypothesis that integration of livestock into Javanese agriculture is essential to sustaining some of the world’s most intensive smallholder farming systems.

Food habits and livestock depredation of two Iberian wolf packs (Canis lupus signatus) in the north of Portugal

AbstractTwo Iberian wolf Canis lupus signatus packs were studied in the north of Portugal during spring and summer 1996. The study areas are located in two mountainous areas close to the Spanish border. Both regions presented a very low density of wild ungulates and intensive livestock production. The food habits and the livestock depredation of the wolves were considered. The study material included 87 dropping samples, interviews with shepherds, carcass investigation and government reports of livestock depredation. Prey preference was measured in both areas. Wolves fed exclusively on livestock, especially goats. Wolf attacks on goats affected mostly large flocks of &gt; 100 heads, but where there were horses, wolves preyed preferentially on horses. In both study areas, sheep was recorded as a regular prey by the government reports but never appeared in the scat analysis results. This apparent contradiction will be discussed. The wolf's dependence on livestock can be explained by the scarcity of wild prey and the high density of livestock. Conservation of wolves in such impoverished areas depends on an efficient livestock depredation management plan and the reintroduction of native prey species.

Implications of Dutch ammonia policy on the livestock sector

The Dutch livestock sector is responsible for large emissions of ammonia, resulting in an ammonia deposition that greatly exceeds the critical loads for nitrogen and acidifying compounds in a large part of the country. Based on critical loads and technical possibilities for emission reduction, targets for the deposition of ammonia have been defined. According to plans for the Netherlands, in the year 2000 the deposition of ammonia should be reduced to a maximum of 1000 mol c ha -1 yr -1. In 2010 the target is to further reduce the ammonia deposition to 600 mol c ha -1 yr -1. This study examines the consequences of this environmental policy for the Dutch livestock sector. The scenario’s are also applicable to regions outside the Netherlands with high livestock density and high levels of ammonia emission and deposition. In most parts of the Netherlands, planned policy measures to abate ammonia emissions are expected to achieve the ammonia deposition target of 1000 mol c ha -1 yr -1. However, extra measures are necessary in regions with non-calcareous sandy soils, which are sensitive to acidification and where livestock density is high. The deposition target can be reached in these regions (mostly in the central, eastern and southern part of the country) by a combination of extra adaptations of animal housing systems to reduce ammonia emissions, together with relocation of holdings to other regions. If the more stringent deposition target of 600 mol c ha -1 yr -1 is to be reached, more efforts from the livestock sector will be required. In most parts of the Netherlands housing systems with low emission rates should reduce the deposition sufficiently. In the central, eastern and southern parts it is impossible to reach the deposition target for ammonia of 600 mol c ha -1 yr -1 with just technical measures. To meet this target will require a radical contraction of the livestock sector in these regions. Additional to measures in the Netherlands, it is important that the import of ammonia from neighbouring countries also be reduced.

Phosphorus sorption capacities and saturation of soils in two regions with different livestock densities in northwest Germany

Abstract. Soils in areas with high livestock density contribute to the eutrophication of aquatic ecosystems through loss of nutrients, especially phosphorus (P). In order to identify the potential for P loss from such soils we determined phosphorus extracted by water (H2O‐P), by double lactate (DL‐P), and P sorption capacity (PSC) and degree of P saturation (DPS) in soil samples from two counties, one with low (Harle‐catchment) and the other with very high livestock density (Vechta). Both catchments are hydrologically connected with the tidal areas of the North Sea.The mean concentrations of H2O‐P (0.4mmol/kg) and DL‐P (3.9 mmol/kg) were lower in the Harle‐catchment than in the Vechta area (1.2 mmol/kg, 6.8mmol/kg). Although oxalate‐extractable Al (Alox) and Fe (Feox) and the derived PSCs varied according to soil type and to land use, the livestock density and the resulting high concentrations of oxalate‐extractable P (Pox) were shown to be the main reason for the very high DPS of up to 179% in the county of Vechta. These values exceeded DPS reported from other intensive pig feeding areas in western Europe and indicate the potential for significant P loss. Less than 40% of the variation in Pox could be explained by the routinely determined H2O‐Por DL‐P. Geostatistical analyses indicated that the spatial variability of Pox depended on manurial history of fields and Alox, showed still smaller‐scale variability. These were the major constraints for regional assessments of P losses and eutrophication risk from agricultural soils using available soil P‐test values, digital maps and geostatistical methods.

Prevalence, spread and control of caprine arthritis‐encephalitis virus in dairy goat herds in New South Wales

A study of the prevalence, spread and control of caprine arthritis-encephalitis virus (CAEV) in dairy goat herds in New South Wales (NSW) during 1986-1988 found that 56.8% of 1484 goats in 14 dairy herds were infected with CAEV. The prevalence of CAEV infection within most herds not implementing control measures increased during the study. At the end of the study, 59.7% of 1322 goats were infected. The prevalence of CAEV increased with age. Differences between breeds were less apparent. Within seven herds with a high standard of identification of goats, 149 of 812 goats seroconverted in an ELISA. Of these newly infected goats, 142 (95.3%) were > 1 yr of age and 96 (64.4%) were > 2 yr suggesting lateral spread of the virus. Most of the goats > 2 yr of age had been in the milking herd for a minimum of 3 to 6 months. The high seroconversion rate within the milking herd suggested that factors other than the ingestion of infected colostrum and milk before weaning were important for the spread of CAEV. Observations indicated that behaviour of goats, particularly reproductive behaviour among lactating does, and milking herd management practices are important in the spread of CAEV. A high density of livestock, poor livestock control and contamination of feed, water, equipment and personnel were implicated in transmission. Poorly functioning milking machines may also be involved. CAEV was eradicated from 3 herds by the implementation of strict control measures.

Cattle migration and stocking densities in relation to tsetse-trypanosomiasis challenge in The Gambia.

The local migration of village N'Dama cattle between two study sites, Niamina East and Bansang, 40 km apart in the inland region of The Gambia, West Africa, is described. The consequences of seasonal variations in local stocking densities on the epidemiology of African animal trypanosomiasis are reported. Tsetse abundance at each study site was monitored throughout the study period from trap catches, and cattle censuses at each site were carried out on a monthly basis. Detailed ecological, productivity and health data, including dietary intake and trypanosomiasis prevalence, were collected from selected study herds resident at the two sites and from a third group of (four) herds that migrated annually between the two areas to spend the late dry season period in Niamina East. It was shown that the migration strategy allowed migrants to maintain a high level of green grazing in the diet throughout the year. Cattle were moved to the area of highest tsetse density in the region to obtain this grazing, but it appeared that individual risk of trypanosome infection was diminished by a dilution effect created by locally high livestock densities. Trypanosomiasis prevalences in resident cattle at Niamina East were best correlated with the tsetse catch/trap/day 2 months previously, once this index of tsetse abundance had been corrected to allow for changes in relative stocking density.

Volatile emissions of housing systems for cattle

In regions with high livestock density, deposition of ammonia can have a serious impact on the environment, especially natural vegetation and groundwater. In the Netherlands roughly 15% of the total ammonia emission originates from cattle houses and storage of cattle manure. This paper describes the experiences and results of research carried out in order to develop housing systems with a reduced emission of ammonia. Though manure is the main source of ammonia, it has become evident that not only manure storage but also the cattle house floor is an important source of ammonia evaporation. The work thus far has not resulted in a complete picture of the ammonia evaporation, nor in the development of an applicable housing system with reduced emission. The emission from outside storage tanks can be reduced by 70–90% by covering the tank. The different factors which have an effect are discussed. The emission of ammonia coincides with the emission of odours. Though ammonia hardly contributes to the odour sensation, the control of both emissions can often be combined. H 2S is a very odorous compound, but the low emission of H 2S as such does not cause severe pollution, but together with CH 4, it complicates measures to prevent ammonia emission.

Pollution by animal production in the Netherlands : solutions

Provided that the application rates of manure do not exceed the crop uptake of nutrients, pollution by animal production is mainly caused by nitrogenous substances. Applying manure outside the growing season causes pollution of groundwater and surface water due to leaching and runoff. In regions with a high livestock density, the evaporation of ammonia has a serious impact on the environment. It contributes to acidification and causes a nutrient imbalance in natural vegetation. The prevention of nutrient losses from manure is unprofitable. The environmental impact is not caused by the individual farmer but is a result of the sum of activities in a region. This means that legislation is necessary to impose limits in order to arrive at production without pollution. Within this framework, the farmer should optimise the utilisation of minerals from manure by more efficient animal nutrition and better handling of the manure. One of the most difficult problems is the prevention of ammonia evaporation. A reduction of these losses generally also has a favourable effect on odour emissions. A new development is the processing of manure surpluses into a dried manure of sufficient quality to compete on the fertiliser market. As is usually the case with pollution control, these measures raise the costs of livestock production.

Effect of Long‐term Application of Farmyard Manure on Growth and Quality of Sugar Beet

AbstractField trials were conducted for two years on two farms which differed in long‐term application of pig slurry in order to study the effects of long‐term organic manuring, timing of slurry application (no slurry, slurry autumn, slurry spring) and additional doses of mineral N‐fertilizer (0, 80, 160, 240 kg N/ha) on growth and quality of sugar beet. The results can be summarized as follows:1. The effect of slurry application on growth of sugar beets varied markedly with the long‐term differences in farm management. On the “arable farm” yield of beet roots increased substantially after slurry application and could not be replaced by higher doses of mineral N fertilizer. It is concluded therefore that “special effects” of farmyard manure are involved. On the “livestock farm”, however, highest beet yields were obtained on plots without slurry. Additionally slurry application caused a significant decrease in beet yields.2. Sugar beets without slurry treatment always developed higher sugar contents and lower concentrations of alpha‐amino‐N, sodium and potassium as compared to beets from plots with slurry application.3. Despite the decline in sugar content, sugar yield greatly increased by slurry application on the “arable farm”. The average increase in sugar yield was 10 dt/ha (=8%) with slurry application in autumn and amounted to 16 dt/ha (=14%) with spring application. On the livestock farm however, additional applications of slurry caused a decline in sugar yields in both years because of lower sugar contents and decrease in beet yields.4. The utilization rate of slurry‐N, depending mainly on time of application, annual rainfall and soil N mineralization, varied from 6–41%. On the “livestock farm” the utilization of slurry‐N was only half of the rate obtained on the “arable farm”.5. The application of small doses of slurry may cause a significant yield increase on farms without or only less livestock, while on farms with intensive livestock production continous slurry application needs to be considered as an expensive form of waste disposal. Therefore farms with high livestock density are advised to sell slurry to neighbouring farms without or only low animal production at a fair price for their mutual advantage.

Grassland communities on the central plateau of Shewa, Ethiopia

A floristic-sociological and production study of the grassland vegetation on the central plateau of Shewa, Ethiopia, is described. Six communities are distinguished and interpreted as expressions of variation in moisture status of the soil, grazing conditions, agronomic activities and altitude. The study indicates that the prevailing poor grassland conditions on the central plateau of Ethiopia with production levels ranging from 73.4–839.7 g/m2 are largely due to high livestock density, and other related problems rather than adverse physical conditions.

Utilisation of liquid manure from large animal farms in Poland

Because of the development in building farms with the litterless system of animal breeding, studies on the improvement of liquid manure utilisation are more and more intensive in Poland. An organisational basis for protection of the environment against the effects of a high density of livestock is provided by the instructions of the Ministry of Agriculture concerning the location of farms and liquid manure treatment and utilisation. From the experiments conducted in ten artificial treatment plants using three licenced technologies and a home technology it follows that these treatments are insufficient and uneconomical; hence utilisation of untreated manure for fertilisation purposes is prefered. Agricultural utilisation of liquid manure is based on the method of an optimum use of nitrogen—70–100% of the need of plants for this component is satisfied by manure. In this way the possibility of water pollution with the loads of BOD 5 and phosphorus from liquid manure is almost completely eliminated. The amount of nitrates that penetrate to underground waters is not greater tha n in the case of the application of mineral fertilisers.

The Hampshire epidemic of foot-and-mouth disease, 1967

An analysis was made of the spread of foot-and-mouth disease during the epidemic in Hampshire in January and February 1967. To explain the pattern of spread, it had to be postulated that virus was present seven days before the first outbreak was reported. It is suggested that the disease occurred initially in pigs fed on infected meat and that the virus was subsequently disseminated from the local abattoir, where the pigs were killed, to four farms by movement of animals, slaughterhouse waste, people or vehicles, and to fifteen by the airborne route. Subsequent spread from these farms was by movement in two instances and by the airborne route in five. The source and route of infection of the last farm in the outbreak were not determined.The risk of spread through movement was associated more with carriage of infected slaughterhouse waste, movement of animals, people or vehicles carrying animals than through collection of milk, artificial insemination or movement of other types of vehicles. Outbreaks of disease among pigs gave rise to more secondary spread than outbreaks in cattle. Secondary outbreaks attributed to airborne spread occurred only in ruminants. Most airborne spread was into areas of high livestock density and cattle in the larger herds became infected. Airborne spread could be correlated with wind direction and speed but not with rain. The reduction in the number of outbreaks at the end of the epidemic could be attributed to the elimination of the largest sources of virus, the control of movements and the fact that in all instances except two the wind was blowing virus over towns and out to sea, to areas of low stock density and to areas where animals had been killed.