Animal Grazing System Efficiency

Copyright © 2013 Springer Netherlands.

Effects of density versus size on grazing by a key exploited herbivore

Fishing decreases the biomass of target species via reduction in the numbers and/or size of individuals. In natural systems, the strength of biological interactions, including predator-prey dynamics, are often density or size-dependent. Hence, changes in the numbers or size of key taxa may be expected to influence biological interactions but their effects do not need to be identical. Here we compare the effects of biomass reduction in populations of the exploited limpet Patella candei. Biomass removal was experimentally achieved by either removing individuals (density reduction) or by replacing large by small individuals (size reduction), while controlling for total limpet biomass in a laboratory-based experiment. At the experiment’s termination, biomass reduction led to proportional changes in area grazed. However, there was no difference whether this was achieved via changes in density or in size. Furthermore, no discernible effects of treatments were evident on different components of the algal assemblage. A field survey also revealed that P. candei biomass explained a greater proportion in variation in the area free of algae than density alone. Our results suggest that loss of biomass in populations of P. candei has quantitatively and qualitatively similar effects on algal cover regardless of whether it is caused by an equivalent (biomass) reduction in the numbers or size of individuals.

A detecção remota e os SIG na produção animal - análise da contribuição e situação actual

Dissertação apresentada como requisito parcial para obtenção do grau de Mestre em Ciência e Sistemas de Informação Geográfica

Echinococcus granulosus sensu lato GENOTYPES IN DOMESTIC LIVESTOCK AND HUMANS IN GOLESTAN PROVINCE, IRAN

Cystic echinococcosis (CE) is a globally parasitic zoonosis caused by larval stages of Echinococcus granulosus. This study investigated E. granulosus genotypes isolated from livestock and humans in the Golestan province, northern Iran, southeast of the Caspian sea, using partial sequencing data of the cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase 1 (nad1) mitochondrial genes. Seventy E. granulosus isolates were collected from animals in slaughterhouses: 18 isolates from sheep, 40 from cattle, nine from camels, two from buffaloes and one from a goat, along with four human isolates (formalin-fixed, paraffin-embedded tissues) from CE patients of provincial hospitals. All isolates were successfully analysed by PCR amplification and sequencing. The sequence analysis found four E. granulosus genotypes among the 74 CE isolates: G1 (78.3%), G2 (2.7%), G3 (15%) and G6 (4%). The G1-G3 complex genotype was found in all of the sheep, goat, cattle and buffalo isolates. Among the nine camel isolates, the frequency of G1-G3 and G6 genotypes were 66.7% and 33.3%, respectively. All four human CE isolates belonged to E. granulosus sensu stricto. This study reports the first occurrence of the G2 genotype in cattle from Iran and confirms the previously reported G3 genotype in camels in the same country.

A longitudinal study on enteropathogenic infections of livestock in Trinidad

A longitudinal study was conducted on selected livestock farms to determine the prevalence of enteropathogens in diarrhoeic and non-diarrhoeic animals. The enteropathogens assayed from faecal samples and rectal swabs were bacteria (Escherichia coli, Campylobacter spp. Salmonella spp. and Yersinia enterocolitica), parasites (coccidia, gastrointestinal nematodes and Cryptosporidium spp.) and viruses (group A rotavirus and parvovirus). The prevalence of the enteropathogens in various animal species was related to age and month of the year. Generally, younger animals presented a higher prevalence of infection by enteropathogens than older animals while most infections occurred between the months of January and April.

Impact of livestock on a mosquito community (Diptera: Culicidae) in a Brazilian tropical dry forest

AbstractINTRODUCTION: This study evaluated the effects of cattle removal on the Culicidae mosquito community structure in a tropical dry forest in Brazil.METHODS: Culicidae were collected during dry and wet seasons in cattle presence and absence between August 2008 and October 2010 and assessed using multivariate statistical models.RESULTS: Cattle removal did not significantly alter Culicidae species richness and abundance. However, alterations were noted in Culicidae community composition.CONCLUSIONS: This is the first study to evaluate the impact of cattle removal on Culicidae community structure in Brazil and demonstrates the importance of assessing ecological parameters such as community species composition.

Manejo ganadero y restauración de ambientes montanos en relación a la biodiversidad, el suelo y la producción de agua. Livestock management and ecological restoration of mountain environments in relation to biodiversity, soil and water production.

Las áreas montanas brindan numerosos bienes y servicios a la humanidad cómo la provisión de agua. Asimismo, albergan una biota muy diversa y existe en ellas una actividad económica de considerable importancia centrada en la ganadería. En algunos casos las actividades asociadas a la ganadería pueden modificar los ecosistemas montanos y los bienes y servicios que brindan de forma drástica. Esto se debe a los cambios en la vegetación, y la pérdida y compactación de los suelos, que tiene repercusiones en la cantidad de agua captada, evapotranspirada y almacenada. También tiene repercusiones sobre la biodiversidad, tanto positivas como negativas. Aquí nos propusimos investigar cómo los cambios en la cobertura vegetal producidos por cuatro siglos de uso ganadero en el piso superior de las Sierras de Córdoba (Centro Argentino) han afectado a atributos del ecosistema como la diversidad vegetal, la integridad de los suelos y la capacidad de proveer agua a la población humana. A su vez, nos propusimos estudiar en detalle cómo las distintas opciones actuales de manejo pueden afectar a la cobertura vegetal y por ende a los atributos del ecosistema. De este modo, esperamos: (1) poder desarrollar un modelo espacialmente explícito que permita predecir la evolución del ecosistema ante distintos escenarios de manejo. (2) Más a largo plazo determinar los costos y los beneficios de los distintos manejos, en términos de la conservación de la biodiversidad, los suelos y la provisión de agua. El área de estudio cuenta un Sistema de Información Geográfica muy completo que incluye numerosas capas de información (vegetación, topografía, casas y caminos y otras). Además, existe en el área un Parque Nacional, con potreros bajo distintos manejos ganaderos (exclusión, cargas ganaderas moderadas continuas y estacionales), y una zona con herbivoría nativa de guanacos, que fueron reintroducidos recientemente en el Parque. Fuera del Parque, hay establecimientos con ganadería tradicional, con cargas ganaderas altas; así como un área donde se ha realizado una restauración modelo mediante reforestación y revegetación de zonas erosionadas. Estos escenarios representan una oportunidad muy especial para realizar estudios comparativos de la evolución de la fisonomía, composición florística, diversidad vegetal, integridad del suelo (erosión, tasa de infiltración, contenido de agua a lo largo del año) y el caudal de los arroyos en la estación seca. En este proyecto proponemos seguir con mediciones de la evolución de la vegetación bajo los distintos escenarios y seguir averiguando métodos de restauración de la vegetación. Además, proponemos empezar a realizar mediciones relacionadas al valor de los distintos tipos de cobertura vegetal, resultado de cuatro siglos de historia de disturbio, sobre la diversidad y los recursos hídricos. Por otro lado, realizaremos mediciones ecofisiológicas en las especies dominantes, para comprender sus efectos sobre el ciclo del agua.

Isolation and identification of mycobacteria from livestock specimens and milk obtained in Brazil

The prevalence of Mycobacterium bovis and other mycobacterial species in livestock specimens and milk was evaluated. An emphasis was placed upon the distribution of these organisms in milk that is readily available to the public that was either untreated, pasteurized, or treated using ultra high temperature. Twenty-two pathologic specimens from livestock (bovine, swine and bubaline) in five Brazilian states and 128 bovine milk samples from retail markets in the State of São Paulo were examined for mycobacteria. Identification was made by classical biochemical tests, thin layer chromatography of mycolic acids and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Mycobacteria were isolated from 15 (68.2%) caseous lesions and from 23 (18%) milk samples. Eleven isolates were identified as M. bovis, and the remaining 27 nontuberculous mycobacterial isolates were represented by five species and six unidentified rapidly growing mycobacterial strains. The data demonstrate that animal products in Brazil are frequent reservoirs of mycobacteria and may pose a risk to the public.

Stable carbon isotope composition of perirenal adipose tissue fatty acids from Engadine sheep grazing either mountain or lowland pasture

To provide further insights into ruminant lipid digestion and metabolism, and into cis9, trans-11 18:2 synthesis, 12 growing Engadine lambs grazing either mountain pasture (2,250 m above sea level; n = 6) or lowland pasture (400 m above sea level; n = 6) were studied. Both pastures consisted exclusively of C-3 plants. Before the experiment, all animals grazed a common pasture for 6 wk. Grasses and perirenal adipose tissues of the sheep were analyzed for fatty acids by gas chromatography. Stable C-isotope ratios (delta C-13 values in % vs. the Vienna Pee Dee Belemnite standard) were determined in the composite samples by elemental analysis-isotope ratio mass spectrometry. The delta C-13 of the individual fatty acids were measured by gas chromatography-combustion-isotope ratio mass spectrometry. The delta C-13 value of the entire mountain pasture grass was -27.5% (SD 0.31), whereas that of the lowland pasture grass was -30.0% (SD 0.07). This difference was reflected in the perirenal adipose tissues of the corresponding sheep (P < 0.05), even though the delta C-13 values were less in the animals than in the grass. The delta C-13 values for cis-9 16:1 and cis-9 18:1 in perirenal fat differed between mountain and lowland lambs (P < 0.05). The 16:0 in the adipose tissue was enriched in C-13 by 5% compared with the dietary 16:0, likely as a result of partly endogenous synthesis. The d13C values of cis-9, trans-11 18:2 (cis-9, trans-11 CLA) in the adipose tissue were smaller than those of its dietary precursors, cis-9, cis-12 18:2 and cis-9, cis-12, cis-15 18:3; conversely, the delta C-13 values of trans-11 18:1 were not, suggesting that large proportions of perirenal cis-9, trans-11 18:2 were of endogenous origin and discrimination against C-13 occurred during Delta(9)-desaturation. The same discrimination was indicated by the isotopic shift between 16:0 and cis-9 16:1 in the mountain grazing group. Furthermore, the delta C-13 values of cis-9, trans-11 18:2 were smaller relative to the precursor fatty acids in the mountain lambs compared with the lowland group. This result suggests a reduced extent of biohydrogenation in lambs grazing on mountain grass in comparison with those grazing on lowland grass. This was supported by the smaller cis-9, trans-11 18:2 concentrations in total fatty acids found in the adipose tissues of the lowland lambs (P < 0.001). The results of this study demonstrate that natural differences between delta C-13 values of swards from different pastures and the adipose tissue fatty acids could be used as tracers in studies of lipid metabolism in ruminants.

Integrated Farm/Livestock Management Demonstration Program, 2002

Farm/Livestock Management Demonstration Program produced by Iowa Departmment of Agriculture and Land Stewardship

Livestock Revenue Insurance, November 2000

This study outlines several possible structures for livestock revenue insurance. The policies take the form of an exotic option—an Asian basket option. The actuarially fair premiums for these policies are equal to the prices of the options they represent. Due to the complexity of pricing Asian basket options, we have combined two techniques for pricing options to reach the actuarially fair premiums. Projected premiums, producer welfare, and program efficiency are evaluated for the insurance products and existing market tools. Using efficiency ratios and certainty equivalent returns, we compare the insurance policies to strategies involving existing futures and options.

High incidence of childhood hemolytic uremic syndrome in Switzerland is associated with indicators of livestock farming intensity

Background: Hemolytic-uremic syndrome (HUS) is a multisystem disorder associated with significant morbidity and mortality. Typically, HUS is preceded by an episode of (bloody) diarrhea mostly due to Shiga-toxin (Stx) producing Escherichia coli (STEC). The main reservoir for STEC is the intestine of healthy ruminants, mostly cattle, and recent studies have revealed an association between indicators of livestock density and human STEC infection or HUS, respectively. Nationwide data on HUS in Switzerland have been established through the Swiss Pediatric Surveillance Unit (SPSU) [Schifferli et al. Eur J Pediatr. 2010; 169:591-8]. Aims: Analysis of age-specific incidence rate of childhood HUS and possible association of Shiga-toxin associated HUS (Stx-HUS) with indicators of livestock farming intensity. Methods: Epidemiological and ecological analysis based on the SPSU data (1997-2003) and the database of the Swiss Federal Statistical Office (data on population and agriculture). Results: One hundred-fourteen cases were registered, 88% were ≤5 years old. The overall annual incidence rate was 1.42 (0.60-1.91) and 4.23 (1.76-6.19) per 100000 children ≤5 and ≤16 years, respectively (P = 0.005). Stx-HUS was more frequent compared to cases not associated with STEC (P = 0.002). The incidence rate for Stx-HUS was 3.85 (1.76-5.65) in children ≤5, compared to 0.27 (0.00-0.54) per 100'000 children 5-16 years (P = 0.002), respectively. The incidence rate of cases not associated with STEC infection did not significantly vary with age (P = 0.107). Compared to data from Scotland, Canada, Ireland, Germany, England, Australia, Italy, and Austria the annual incidence rate of HUS in young children is highest in Switzerland. Ecological analysis revealed strong association between the incidence rate of Stx-HUS and indicators of rural occupation (agricultural labourer / population, P = 0.030), farming intensity (livestock breeding farms / population, P = 0.027) and cattle density (cattle / cultivated area, P = 0.013). Conclusions: Alike in other countries, HUS in Switzerland is mostly associated with STEC infection and affects predominantly young children. However, the incidence rate is higher compared to countries abroad and is significantly correlated with indicators of livestock farming intensity. The present data support the impact of direct and indirect contact with animals or fecal contaminants in transmission of STEC to humans.

Final Report for the Iowa Livestock Industry Waste Characterization and Methane Recovery Information Dissemination Project, 2003

The Iowa livestock industry generates large quantities of manure and other organic residues; composed of feces, urine, bedding material, waste feed, dilution water, and mortalities. Often viewed as a waste material, little has been done to characterize and determine the usefulness of this resource. The Iowa Department of Natural Resources initiated the process to assess in detail the manure resource and the potential utilization of this resource through anaerobic digestion coupled with energy recovery. Many of the pieces required to assess the manure resource already exist, albeit in disparate forms and locations. This study began by interpreting and integrating existing Federal, State, ISU studies, and other sources of livestock numbers, housing, and management information. With these data, models were analyzed to determine energy production and economic feasibility of energy recovery using anaerobic digestion facilities on livestock faxms. Having these data individual facilities and clusters that appear economically feasible can be identified specifically through the use of a GIs system for further investigation. Also livestock facilities and clusters of facilities with high methane recovery potential can be the focus of targeted educational programs through Cooperative Extension network and other outreach networks, providing a more intensive counterpoint to broadly based educational efforts.

Integrated Farm/Livestock Management Demonstration Program, 2004

Farm/Livestock Management Demonstration Program produced by Iowa Departmment of Agriculture and Land Stewardship

Integrated Farm/Livestock Management Demonstration Program, 2001

Farm/Livestock Management Demonstration Program produced by Iowa Departmment of Agriculture and Land Stewardship