Flock Growth Research Articles

Investigation of ash removal from fine grain coal-water suspension by hydrophobic flocculation using Taguchi (L16) experimental design

ABSTRACT In this study, it was aimed to remove ash from fine-grained coal-water suspensions and a series of hydrophobic flocculation experiments were performed using the Taguchi (L16) experimental design to determine the experimental optimum conditions. Five different controllable process variables such as amount of sodium silicate, suspension pH, amount of waste vegetable oil, flock growth time, and precipitation time, which are effective in hydrophobic flocculation of coal, and four different levels of each variable were investigated. Optimum conditions were determined as amount of sodium silicate 1 mL, pH = 3, amount of waste vegetable oil 4 mL, flock growth time 7 min and precipitation time 1 min. According to the optimization results obtained, the high calorific value (5450 kcal/kg) clean coal with 15.46% ash content and 100% combustible recovery was obtained with 57.52% ash removal. In addition, the contributions of each factor to hydrophobic flocculation of coal were determined with one way variance analysis (ANOVA). The most influential factor was determined as the pH value with a contribution of 61.34%.

Seroprevalence of avian leukosis virus in local chickens in five live bird markets, Kaduna metropolis, North-western Nigeria

Avian leukosis virus is recognized as an important viral pathogen in the poultry industry, resulting in salient severe economic losses due to reduced production, uneven flock growth rates, reduced growth, and immunosuppression which predispose affected birds to other infections. This study examined the seroprevalence of avian leukosis virus (ALV) in local chickens (LC) in 5 different live bird markets (LBMs) in Kaduna Metropolis. A total of 276 sera were tested for ALV p27 antigen using enzyme-linked immunosorbent assay (ELISA). An overall seroprevalence of 28.3% (78/276) was recorded in the study. At the market level, the seroprevalence of 35% (21/60), 30% (18/60), 32% (16/50), 28.6% (16/56), and 14% (7/50) were recorded for Sabon Tasha, Central market, Railway station, Kawo and Sokoto Road LBMs respectively. With regards to sex, female LC showed a significantly higher prevalence of 30.5% (46/105) compared to male chickens 26.9% (46/171) with no significant difference (P > 0.05) observed. This study established the presence of antigen to ALV in local chickens sold in LBMs. We recommend surveillance and further studies on the isolation, molecular characterization and pathogenicity of ALV in the study area.

Metagenomic Analysis of the Respiratory Microbiome of a Broiler Flock from Hatching to Processing

Elucidating the complex microbial interactions in biological environments requires the identification and characterization of not only the bacterial component but also the eukaryotic viruses, bacteriophage, and fungi. In a proof of concept experiment, next generation sequencing approaches, accompanied by the development of novel computational and bioinformatics tools, were utilized to examine the evolution of the microbial ecology of the avian trachea during the growth of a healthy commercial broiler flock. The flock was sampled weekly, beginning at placement and concluding at 49 days, the day before processing. Metagenomic sequencing of DNA and RNA was utilized to examine the bacteria, virus, bacteriophage, and fungal components during flock growth. The utility of using a metagenomic approach to study the avian respiratory virome was confirmed by detecting the dysbiosis in the avian respiratory virome of broiler chickens diagnosed with infection with infectious laryngotracheitis virus. This study provides the first comprehensive analysis of the ecology of the avian respiratory microbiome and demonstrates the feasibility for the use of this approach in future investigations of avian respiratory diseases.

The First Whole Genome Sequence and Characterisation of Avian Nephritis Virus Genotype 3.

Avian nephritis virus (ANV) is classified in the Avastroviridae family with disease associations with nephritis, uneven flock growth and runting stunting syndrome (RSS) in chicken and turkey flocks, and other avian species. The whole genome of ANV genotype 3 (ANV-3) of 6959 nucleotides including the untranslated 5′ and 3′ regions and polyadenylated tail was detected in a metagenomic virome investigation of RSS-affected chicken broiler flocks. This report characterises the ANV-3 genome, identifying partially overlapping open reading frames (ORFs), ORF1a and ORF1b, and an opposing secondary pseudoknot prior to a ribosomal frameshift stemloop structure, with a separate ORF2, whilst observing conserved astrovirus motifs. Phylogenetic analysis of the Avastroviridae whole genome and ORF2 capsid polyprotein classified the first complete whole genome of ANV-3 within Avastroviridae genogroup 2.

A longitudinal survey of the gut virome of commercial broiler chickens from prehatch to slaughter

Uneven flock growth (UFG) occurs when a broiler flock exhibits a wide range of bodyweights at slaughter. Automated chicken processing plants operate on an average bodyweight for the flock being processed so UFG can cause disruption to the processing flow that requires manual remediation. It is known that enteric virus infections of young broiler flocks lead to varying degrees of growth restriction that range from runts at hatch and severe early stunting, which are generally culled, to poor flock performance and UFG. In order to investigate the make-up of communities of enteric viruses (virome) associated with poor growth and also their infection timings and persistence in broiler flocks, a longitudinal survey of 7 commercial broiler flocks of varying performance over 3 successive broiler crops was undertaken with gut and faecal samples collected from 50 birds at each of 12 timepoints from pre-hatch to slaughter. The samples were pooled for each timepoint, then processed to enrich for viruses by removing host cells and bacteria. The RNA was extracted from each timepoint sample, amplified by whole transcriptome amplification followed by whole genome library preparation for the Illumina MiSeq platform and libraries multiplexed. Bioinformatics analysis used ViromeScan which facilitates metagenomic studies of quality-trimmed sequencing reads. The presence of diverse viral families was seen including the known major enteric viruses of the astrovirus, picornavirus, reovirus and parvovirus families. A greater diversity of viruses was observed in the flocks of poorer performance than in those flocks of good performance.

An Image-Assisted Rod-Platform Weighing System for Weight Information Sampling of Broilers

Abstract. The average weight and flock uniformity of broilers in group housing is important information that allows producers to know the flock growth conditions and determine the selling time. However, gathering weight information of chickens is not only labor-intensive for humans but also frightening for the birds. In this study, an image-assisted rod-platform weighing system was developed to automatically monitor the average weight and flock uniformity of broilers in chicken houses. This weighing system consists of a computer and several weighing scales. Each weighing scale contains a rod-platform weighing module and a surveillance camera module. The principle of the automated weighing system is to estimate population weight information using samples. The design of the rod-platform weighing module was based on the perching habit of birds to attract more broilers to stand on the rod platform and thus get more weight samples. The surveillance camera module is used to detect the number of broilers on the rod using image processing technology. A data processing method called PORWI, which includes elimination of redundant records and trim of non-redundant records, was designed to optimize the results of chicken number identification from images to improve the accuracy of the results. An experiment was done in two small groups of broilers with approximately 100 chickens and 8.58 m2 of area for each group. A weekly weighing was conducted, and three kinds of weight information were obtained, which included manual population weight information (MPWI), manual sample-based weight information (MSWI), and automated sampling weight information (ASWI). Each weight information set comprised the group average weight and flock uniformity, which were then used to evaluate accuracy. The perching rate of chickens using the rod platform reached an average of 60 times h-1, and the rate was retained with increasing age. Compared with the MPWI obtained by individual weighing, the manual sample-based measurement method provided results with errors of 0% to +5%, while our automated weighing system achieved accuracies within ±2% for average weight and ±1.5% for flock uniformity. Keywords: Automatic weighing, Average weight, Broiler, Chicken detection, Uniformity.

Multiple Applications of Sodium Bisulfate to Broiler Litter Affect Ammonia Release and Litter Properties.

Ammonia (NH) emissions from animal manures can cause air and water quality problems. Poultry litter treatment (PLT, sodium bisulfate; Jones-Hamilton Co.) is an acidic amendment that is applied to litter in poultry houses to decrease NH emissions, but currently it can only be applied once before birds are placed in the houses. This project analyzed the effect of multiple PLT applications on litter properties and NH release. Volatility chambers were used to compare multiple, single, and no application of PLT to poultry litter, all with and without fresh manure applications. A field component consisted of two commercial broiler houses: one had a single, preflock PLT application, while the other received PLT reapplications during the flock using an overhead application system. In the volatility chambers, single and reapplied PLT caused greater litter moisture and lower litter pH and , relative to no PLT. After 14 d, NH released from litter treated with reapplied PLT was significantly less than litter with both single and no applications. Furthermore, total N in litter was greatest in litter treated with reapplied PLT, increasing its fertilizer value. In the commercial poultry houses, PLT reapplication led to a temporary decrease in litter pH and , but these effects did not last because of continued bird excretion. Although one preflock PLT application is currently used as a successful strategy to control NH during early flock growth, repeat PLT application using the overhead reapplication system was not successful because of problems with the reapplication system and litter moisture concerns.

TURKEY CORONAVIRUS: AN UPDATED REVIEW

Turkey coronavirus (TCoV) causes acute atrophic enteritis and uneven flock growth in turkey farms leading to economic loss. Since 1990's, turkey flocks have kept experiencing coronaviral enteritis sporadically in the United States, Canada, Europe, and Brazil. Poult enteritis and mortality syndrome (PEMS) caused by the co-infection of TCoV, astrovirus, and other viruses or bacteria resulted in significantly high mortality. Diagnosis of TCoV depends on reverse transcription polymerase chain reaction (RT-PCR), quantitative real-time PCR, immunohistochemistry (IHC), immunofluorescent antibody assay and virus isolation (VI). Genomic organization of TCoV is as follows: 5′ UTR-1a-1b-S-3a-3b-E-M-5a-5b-N-UTR 3′. Genomic analysis suggests the emergence of TCoV from infectious bronchitis virus (IBV) through the recombination of spike (S) gene. Both TCoV and IBV belong to species Avian coronavirus in genus Gammacoronavirus and have a single stranded RNA genome with a size about 27 kb. High similarity of S genes has been found between TCoV isolates in contrast to low similarity between IBV strains. TCoV infection induced strong humoral and cellular immune responses, characterized by high levels of antibody and interferon gamma. The fragment containing neutralizing epitopes in the S protein has been identified. Vaccines conferring protection against TCoV have not been developed and used in the fields but live attenuated, killed, DNA, and fowlpox virus vectored vaccines have been generated and their efficacies were evaluated. Molecular epidemiology of TCoV in recent outbreaks sheds more information on the evolution and transmission of TCoV, which will aid in developing effective vaccines or treatment to prevent, control, or eliminate TCoV infection.

Financial analysis of brucellosis control for small-scale goat farming in the Bajío region, Mexico

Brucellosis is an endemic disease in small-scale goat husbandry systems in Mexico. It is a zoonosis and the economic consequences can be large, although estimates are not available for the Mexican goat sector. Our objective was to conduct a financial analysis of brucellosis control in a prominent dairy goat production area of the Bajío region, Mexico. We used three models: (1) a brucellosis transmission model at village flock level (n=1000 head), (2) a flock growth model at smallholder flock level (n=23 head) using output of model 1 and (3) cost–benefit analysis of several brucellosis control scenarios based on output of model 2. Scenarios consisted of test-and-slaughter or vaccination or a combination of both compared to the base situation (no control). The average net present values (NPV) of using vaccination over a 5-year period was 3.8 US$ (90% CI: 1.3–6.6) and 20 US$ (90% CI: 11.3–28.6) over a 10-year period per goat. The average benefit-cost ratios over a 5-year period and 10-year period were 4.3 US$ (90% CI: 2.2–6.9) and 12.3 US$ (90% CI: 7.5–17.3) per goat, respectively. For the total dairy goat population (38,462 head) of the study area (the Bajío of Jalisco and Michoacán) the NPV's over a 5-year and 10-year period were 0.15 million US$ and 0.8 million US$. However, brucellosis prevalence was predicted to remain relatively high at about 12%. Control scenarios with test-and-slaughter predicted to reduce brucellosis prevalence to less than 3%, but this produced a negative NPV over a 5-year period ranging from −31.6 to −11.1 US$ and from −31.1 to 7.5 US$ over a 10-year period. A brucellosis control campaign based on vaccination with full coverage is economically profitable for the goat dairy sector of the region although smallholders would need financial support in case test-and-slaughter is applied to reduce the prevalence more quickly.

Dynamics of Sheep Production in Brazil

Sheep production is present on all continents and has been practiced in Brazil since the colonization. In this study, the multitemporal dynamics of sheep production in Brazil is examined using official government data (Brazilian Institute for Geography and Statistics-IBGE) from 1976 to 2010. Maps of flock growth rates and growth acceleration maps by municipality were elaborated. The Southern states are seen to show a reduction in production mainly due to the wool crisis in the 1970s and 80s. The Northeast is seen to be important for meat production. More recently, centerwest and northern states have shown an increase in growth rates but this is still incipient. The maps of growth, acceleration and midpoint for sheep production showed a noticeable return to an increase in production in the South in recent years. The midpoint of production flow was in the northeast direction, which has stagnated. There was great dynamics in sheep production over the whole Brazilian territory, which affected supply chains due to the expansion of domestic and foreign markets. Areas with higher fluctuations in production are more vulnerable in terms of investment policies.

The Effect of Kaolin Concentration on Flock Growth Kinetics in an Agitated Tank

This paper reports on an investigation of the effect of initial solid particle concentrationon flock growth and flock shape characterized by the fractal dimension Df2. The experiments werecarried out in a baffled tank agitated by a Rushton turbine at mixing intensity 64W/m3 and constantdimensionless flocculant dosage DF/ck0 = 4.545 mg/g. The model wastewater (a suspension of tapwater and kaolin) was flocculated with Sokoflok 56A organic flocculant (solution 0.1% wt.). The size and shape of the flocks were investigated by image analysis. The flock growth kinetics was fitted according to a semi-empirical generalized correlation proposed by the authors. The dependences Af = 100.35ck01.532, df,eq,max = 1.0474ck0-0.311 and (NtF)max = 1622ck0-0.393 were found. The fractal dimension Df2 was found to be independent of flocculation time and initial kaolin concentration, and its value Df2 = 1.470 ± 0.023 was determined as an average for the given conditions.

Flock Growth Kinetics for Flocculation in an Agitated Tank

Flock growth kinetics was investigated in baffled tank agitated by a Rushton turbine at mixing intensity 40 W/m3 and kaolin concentration 0.44 g/l. The tests were carried out with a model wastewater (a suspension of tap water and kaolin). The model wastewater was flocculated with organic Sokoflok 56 A flocculant (solution 0.1 % wt.). The flock size and flock shape were investigated by image analysis. A simple semiempirical generalized correlation for flock growth kinetics was proposed, and was used for data treatment. The flock shape was characterized by fractal dimension Df2. Using the statistical hypothesis test, the fractal dimension was found to be independent of flocculation time, and the value Df2 = 1.442 ± 0.125 was determined as the average value for the given conditions.

Livestock Subsidies and Rangeland Degradation in Central Crete

Lorent, H., R. Sonnenschein, G. M. Tsiourlis, P. Hostert, and E. Lambin. 2009. Livestock subsidies and rangeland degradation in central Crete. Ecology and Society 14(2): 41. https://doi.org/10.5751/ES-03229-140241

Flock dynamics of desert Barki sheep in relation to age structure

Reproduction data of 8689 ewe records spread over 40 years (from 1960 to 2000) representing 2952 breeding Barki ewes were used in this study. The flock belonged to the Desert Research Center in Egypt. Flock dynamics of nine age groups (2-10 yrs) were assessed. Two parameters were used to evaluate flock dynamics, net reproduction rate (R(o)) (number of ewe- lambs reaching joining age and produced by each ewe during its lifetime in the flock) and intrinsic rate of increase (r(m)) (flock growth when no resource is limiting). Age of ewe had a highly significant (P < 0.01) effect on number of ewes lambing per ewe joined (E(PJ)), number of lambs born per ewe joined (L(BJ)), number of lambs weaned per ewe joined (L(WJ)) and number of ewe lambs reaching joining age per ewe joined (L(EJ.J)). All estimates tended to increase with dams age up to four years and decreased thereafter. The results of R(o) and r(m) showed that the studied flock must consist of 5 age groups to maintain its size and replace itself. It may be recommended to cull the breeding ewe at the age of 6 years to accelerate genetic improvement.

Modeling the Productivity of a Breeding Sheep Flock for Different Production Systems

Individual production traits, such as reproduction and mortality rates, are partial measures, but may be used to evaluate the performance of different systems by comparing the rate of flock growth and potential offtake. The productivity of two existing sheep production systems, one extensive, one intensive, was compared with an alternative semi-intensive system. The future flock sizes, offtakes and structures were predicted based on the age structure of the flock and age-specific reproduction, mortality and growth rates. The measurements were illustrated with reference to growth of a sheep flock of different age and sex categories. The flock was in a so- called dynamic situation. During the dry period, the digestible organic matter intake of the animals in the intensive system and both extensive and semi-extensive systems was 36 and 20.1 g kg -0.75 d -1 , respectively. During the cold period, the digestible organic matter intake of the animals in extensive, intensive and semi-extensive systems was 34, 34.5 and 41 g kg -0.75 d -1 , respectively. During the dry period, the animals in the both extensive and semi-intensive systems lost in body weight at a rate of 19 g per day, but the rate of gain in body weight of the animals in intensive system was 57 g per day. During the cold period, the animals in extensive, intensive and semi- intensive systems gained in body weight at rates of 56, 67 and 97 g per day, respectively. The higher gain of animals during the cold period in the semi-intensive system was related to a sustained higher intake of low-quality roughage and more efficient use of the available feed. Compared to the intensive system, the annual concentrate input of the semi-intensive system was about 48% lower for each livestock unit. The productivity of the semi-intensive system was higher than that of the extensive system. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 5 : 606-612)

Sigmoid Model for the Evaluation of Growth and Production Curves in Laying Hens

The aim of this study was to choose the best predictive model for the accurate description of the average flock growth of laying hens and for the daily egg mass being produced by the layers during the productive period. The calculations were undertaken with the generalised data on the weight growth and daily egg mass, produced by the commercial flock of a Shaver White laying hens breed. The model, represented as the ratio of the polynomials of the third and the second powers, was deduced by the authors for the prediction of the growth and daily egg mass production curves. This Narushin–Takma model was tested for the accuracy of the results prediction in comparison with the following growth models: the logistic, the Gompertz, the von Bertalanffy, the Richards, the Weibull and the Morgan–Mercer–Flodin functions. The egg production model used for comparison were the Adams–Bell, the logistic-curvilinear, the compartmental and the Lokhorst functions. Fitting criteria were estimated as the coefficients of determination R 2 and the final loss L f of the loss function: sum of observed minus predicted data in the second power. The Narushin–Takma model was found to be the best in description of the both curves, values for R 2 of 0·9997 and for L f of 0·005 for the evaluation of the body growth data and values for R 2 of 0·996 and L f of 0·001 for the description of the egg mass producing function. The accuracy of the other models was high and almost the same for all functions. The order of the accuracy for the compared models was as follows: for the body growth curve — the Weibull model, the Gompertz, the von Bertalanffy, the Morgan–Mercer–Flodin, the logistic and the Richards functions; for the egg mass producing curve — the logistic-curvilinear model, the compartmental, the Lokhorst and the Adams — Bell functions.