Egyptian Field Research Articles

Dissipation Pattern, Terminal Residues, and Risk Assessment of Flutriafol and Cyflufenamid in Grapes under Egyptian Field Conditions

Dissipation Pattern, Terminal Residues, and Risk Assessment of Flutriafol and Cyflufenamid in Grapes under Egyptian Field Conditions

Decline pattern and dietary risk assessment of spinetoram in grapes under Egyptian field conditions.

Spinetoram is one of the most extensively used insecticides globally and is a new spinosyn-based insecticide registered for direct treatment of Egyptian grapes. This work established and validated a developed methodfor determining spinetoram in grape berries and leaves using the QuEChERS coupled LC-MS/MS technique. The average recoveries ranged between 98.52-101.19% and 100.53-104.93%, with RSDs of 2.74-6.21% and 2.79-7.26% for grape berries and leaves, respectively. Spinetoram residues degraded in grape berries and leaves through a first-order kinetic, with an estimated half-life (t1/2) of 4.3 and 2.8 days in grape berries and leaves, respectively, and significant degradation (91.4-97.5%, respectively) after 14 days. Besides, the terminal residues of spinetoram detected in grape berries and leaves samples ranged between 0.017-0.077 mg‧kg-1 and 0.79-0.023 mg·kg-1, respectively, when applied two to three times at a single recommended rate, while it was varied between 0.026-0.44mg‧kg-1 and 0.79-0.023mg‧kg-1 when applied two to three times at a double recommended rate, respectively. A dietary risk assessment was conducted using scientific data from field trials, acceptable daily intake (ADI), and food consumption. It was determined that no noteworthy health hazards were connected to eating grape berries and leaves that had been treated with spinetoram since the risk quotients (RQs) were ≤ 0.4.

Dissipation pattern and dietary risk assessment of chlorfenapyr and methomyl in corn under Egyptian field conditions.

Corn is the second most widely farmed grain for human consumption. Low corn productivity due to damage caused by pests has led to using pesticides to control pest infestations. However, the uncontrolled application of pesticides on corn harms both environmental and human health. Accordingly, field experiments followed good agricultural practices to investigate the dissipation pattern and terminal residues of chlorfenapyr and methomyl in corn and compare the values with established safety limits. Gas chromatography-tandem mass spectrometer coupled with the quick, easy, cheap, effective, rugged, and safe technique was used to analyze residues of chlorfenapyr and methomyl in corn. The average recoveries varied from 94% to 105%, with relative standard deviations (RSDs) of 8%-13% for chlorfenapyr and from 99% to 111%, with RSDs of 10-16% for methomyl. Chlorfenapyr and methomyl residues degraded in corn following a first-order kinetic model, with an estimated half-life (t1/2) of 3.9 and 2.8days, respectively, and significant degradation (91.4%-98.1.5%, respectively) after 14 days. Although the maximum residue limits of chlorfenapyr and methomyl for corn are yet to be formulated in Egypt, the long-term dietary risk for those pesticides was acceptable, with arisk quotient < 100%, according to the national assessments. These findings are required to guide the correct and safe application of these insecticides in Egypt.

Sulfoxaflor residues and exposure risk assessment in grape under Egyptian field conditions.

Grapes are among the most popular fruits globally, and insecticides are commonly used on grape farms. Sulfoxaflor, a novel sulfoximine insecticide that works against various insect pests, is extensively used in Egypt. Our field trials assessed the dynamics and final residues of sulfoxaflor in grapes and grape leaves grown in Egyptian environments with different application rates, including worst-case scenarios. A QuEChERS-based method with LC-MS/MS was used to analyze residues of sulfoxaflor in grapes and grape leaves. The limit of quantification (LOQ) was validated at 0.01 mg‧kg-1. Sulfoxaflor residues are degraded in grapes and grape leaves according to a first-order kinetic model, with an estimated half-life (t1/2) of 7.04 and 7.7 days, respectively, and considerable degradation (74.68 and 72.16%, respectively) after 14 days. The final residues in grapes and grape leaves were below the Codex or EU maximum residue limit (MRL) (2 mg‧kg-1) after 3 days of the recommended and high application rates. The findings showed that grapes and leaves treated with sulfoxaflor at the recommended rate are safe for humans 3 days after two or three consecutive treatments with intervals of 14 days. The current study should pave the way for implementing safe and appropriate sulfoxaflor use in grapes and grape leaves in Egypt.

Seismic Reprocessing Overcomes Uncertainty in Offshore Egyptian Field

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214066, “Seismic Reprocessing Leads to New Breakthroughs—A Successful Case in the ASH Field, AG Basin in Egypt,” by Mohamed Elokr and Ahmed Lotfy, Kuwait Energy Egypt, and Wei Xing, United Energy Group, et al. The paper has not been peer reviewed. _ The ASH oil field is in the eastern portion of the AG Basin in Egypt. The Lower Cretaceous Alam El Bueib is the main oil-producing formation. Because of the high heterogeneity of the Abu Roash succession, in addition to the influence of thick limestone of the Upper Cretaceous and the influence of multiple complex faults, the quality of seismic data is very poor, requiring seismic reprocessing. Two key techniques were used to achieve the goal: New vertical seismic profile (VSP) well data were acquired to adjust the velocity model, and common reflection angle migration (CRAM) prestack depth migration (PSDM) was used for reprocessing. Introduction The ASH field produces oil from the Aptian Lower Cretaceous reservoir. The ASH structure is interpreted as an elongated east-northeast/west-southwest anticline with intensive breaching on the downthrown side of northwest/southeast to west-northwest/east-southeast-oriented normal faults with obvious signature of synsedimentary activities. The entire area was subject to a series of tectonic events affecting the Western Desert, which led to a complex fault regime clearly recognized in the ASH structure by a series of horizontal displacement across the northwest/southeast faults. Strike/slip to oblique-slip faults also are observed from thicknesses of the cretaceous formations, creating significant difficulty in fault definition. The 3D seismic data acquired in 2007 suffered from losing amplitude of the Lower Cretaceous and deep Jurassic reflectors because of the complex structure. The strong carbonate markers disappear north of the field, where high, dense fault intersection is present closing from the main bounding fault. Loss of seismic amplitude could have severe effects on of the future economics of the field. The seismic survey was reprocessed two times without significant enhancement of the fault imaging. PSDM was run without velocity control, resulting in an uncertain velocity model with inaccurate fault imaging and a mismatching between actual and prognosed depths of the drilled wells of greater than 50 m. This contradiction in reservoir mapping meant that the northern portion of the field remained unexplored. Acquiring VSP in the recently drilled well encouraged reprocessing of the 3D seismic survey using well velocity as a control point in adjusting the seismic velocity model, and application of CRAM technology to improve fault imaging and appraise the uncertain area of the ASH field. CRAM Methodology CRAM was developed as a type of beam migration. Asymptotic ray tracing is performed, assuming that one-way diffraction rays from the subsurface image point to the surface sources and receivers. The takeoff angles from the image point are measured around a given local normal to a background reflection surface for each source ray and receiver ray. A system of source and receiver ray pairs is formed, and the recorded seismic data can be mapped into a local angle domain based on the reflection angles at the subsurface image points.​​​​

The efficacy of simultaneous successive classic and variant infectious bronchitis virus vaccines versus circulating variant II Egyptian field virus.

Being a ubiquitous, highly contagious virus with a continuous mutation and a large number of evolutions worldwide, the infectious bronchitis virus (IBV) continues to wreak problems among Egyptian chickens and generate economic losses. The commonly applied IBV vaccination protocols in broilers include alternatives to classic and/or variant attenuated live virus vaccines. The current study targeted to assess the protective efficacy of concurrent and successive Ma5 and 4/91 vaccine strain regimens against the field variant II IBV strain (IBV-EGY-ZU/Ck-127/2021) in chickens. Commercial broiler chickens were vaccinated with Ma5 and 4/91 strains simultaneously at 1 and 14 days of age. The evaluation parameters included clinical protection and humoral and early innate immunity aspects in the renal tissues of vaccinated and infected birds. The vaccine regimen ameliorated the clinical and histopathological lesions against variant II IBV and enhanced body gain as well as succeeded in preventing tracheal shedding and minimizing cloacal shedding of the field virus. The IL-1β mRNA gene expression was evident as early as 24 hours, with highly significant upregulation at 48 hours post vaccination and 24 hours post challenge (PC) in vaccinated birds. Remarkable upregulation was observed in oligoadenylate synthetases (OAS) expression 48 hours PC in vaccinated and unvaccinated infected birds. The vaccinated birds developed a significant antibody titer of 704.0 ± 111.98 at 28 days of age, with a consistent antibody titer increase after the challenge. Overall, a combination of heterologous protectotype commercial vaccines achieved good protection against the Egyptian variant II IBV strain. This vaccine program could be an effective protocol against the threat posed by IBV viruses circulating in the Egyptian field.

Identification and genetic correlation of avian reoviruses to the currently used vaccines in Egypt

A variety of illnesses, including arthritis, tenosynovitis, stunted growth, and malabsorption syndrome, are caused by Avian Reoviruses (ARVs), which have become more prevalent in Egypt during recent years and resulted in significant economic losses. This study investigated 27 suspected samples collected from 14 broiler breeders and 13 broilers suffering from immunosuppression, decreased body weight, and diarrhea. Fourteen samples tested positive based on RT-PCR, and the virus could be isolated from ten samples in Specific Pathogen Free (SPF) embryonated chicken eggs. Ten isolates were subjected to molecular and genetic analysis of the S1 gene (sigma C) and S2 gene (sigma A). The amino acid identity of the S1 gene revealed that these viruses are closely related to the viruses that were identified in Israel during 2020 (91.8%-97.2% identity) and belonged to the genetic cluster 5 (genotype 5), which also includes some viruses that are circulating in the United States and Canada. They also showed weak similarity (48.9%-50.2%) with the available vaccine strains in the Egyptian field that belong to cluster 1, genotype 1. The S2 gene showed amino acid homology of 91.7%-98.2% with the current vaccine used in Egypt. However, the Egy-Reo-7-2021 virus had the lowest similarity (84.2%-87.6%) to the available vaccine. It is hypothesized that the difference between field and vaccine strains may have contributed to the failure of current vaccinations to produce protective immunity against current ARV strains circulated in Egypt, which made the disease a problem to the poultry industry. Developing homologous vaccines and evaluating their potency and efficacy are required in Egypt.

Downsizing, Use of Dummy and Venturi Valves Enhance Gas Lift Performance

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 213975, “Gas Lift Performance Enhancement Strategies by Downsizing and Using Dummy and Venturi Valves: A Paradigm Shift in Gas Lift Systems Management Philosophy,” by Wael F. Akeil, Ahmed M. El-Bohoty, and El-Sayed I. Abd El-Mawla, Gulf of Suez Petroleum Company, et al. The paper has not been peer reviewed. _ A mature offshore Egyptian field has entered a depletion phase. Most of its gas lift design bases were initiated during production startup and feature standardized sets of large gas lift valve port sizes with narrow spacing. Inconsistent well flow during reservoir depletion adds complications to the system. Therefore, a screenout model was created to select candidate wells for downsizing and for changing out with dummy and Venturi valves. After screening, 70 wells were selected for application of the new strategy. The complete paper discusses the effectiveness of smaller port sizes and the use of dummy and Venturi valves in enhancing gas lift performance and maximizing recovery. Field Background The field is divided into four main geographical quadrants, each with its own facilities. Total production currently is approximately 60,000 BOPD with an average water cut of 85%. Exploration and development of the field saw the drilling of more than 460 wells; half of these currently are experiencing reservoir pressure decline, drained reserves, or operational problems. Most wells are gas lifted, and the remainder either use electric submersible pump (ESP) installation or flow naturally. The facility consists of 73 offshore satellite platforms containing the wells—both oil producers and water injectors—connected to nine offshore complex platforms. As a part of continuous improvement trials, the operator reviewed the process of gas lift system management to introduce necessary improvements and recommend changes for long-term plans. The proposed amended management system was the result of monitoring, troubleshooting, and optimization activities outlined in the complete paper. Amended Gas Lift Management System Using Dummy Valves in Gas Lift System. Conceptual Phase. A dummy valve is a special gas lift valve shaped like solid metallic bar with upper and lower packings. They are installed to replace unloading valves that are no longer needed. Installing dummy valves instead of the unloading valves can reduce problems such as valve interference and deepens the point of gas injection. Redesign Procedure Based on the New Production Profile. This practice can be applied in two main cases: First, if reservoir pressure has declined and the well is producing with a lower rate but the surface injection pressure is still high enough to reach deeper valves; and, second, if the well is planned to be recompleted from one formation to another that has a higher reservoir pressure but with lower formation feed as the result of lower productivity. The main steps for redesign are provided in the complete paper.

Monitoring Resistance and Biochemical Studies of Three Egyptian Field Strains of Spodoptera littoralis (Lepidoptera: Noctuidae) to Six Insecticides

Spodoptera littoralis (Boisd.) is a prominent agricultural insect pest that has developed resistance to a variety of insecticide classes. In this study, the resistance of three field strains of S. littoralis, collected over three consecutive seasons (2018 to 2020) from three Egyptian Governorates (El-Fayoum, Behera and Kafr El-Shiekh), to six insecticides was monitored. Laboratory bioassays were carried out using the leaf-dipping method to examine the susceptibility of the laboratory and field strains to the tested insecticides. Activities of detoxification enzymes were determined in an attempt to identify resistance mechanisms. The results showed that LC50 values of the field strains ranged from 0.0089 to 132.24 mg/L, and the corresponding resistance ratio (RR) ranged from 0.17 to 4.13-fold compared with the susceptible strain. Notably, low resistance developed to spinosad in all field strains, and very low resistance developed to alpha-cypermethrin and chlorpyrifos. On the other hand, no resistance developed to methomyl, hexaflumeron or Bacillus thuringiensis. The determination of detoxification enzymes, including carboxylesterases (α- and β-esterase), mixed function oxidase (MFO) and glutathione-S-transferase (GST), or the target site of acetylcholinesterase (AChE), revealed that the three field strains had significantly different activity levels compared with the susceptible strain. Our findings, along with other tactics, are expected to help with the resistance management of S. littoralis in Egypt.

Molecular and pathological investigation of avian reovirus (ARV) in Egypt with the assessment of the genetic variability of field strains compared to vaccine strains.

Avian orthoreovirus (ARV) is among the important viruses that cause drastic economic losses in the Egyptian poultry industry. Despite regular vaccination of breeder birds, a high prevalence of ARV infection in broilers has been noted in recent years. However, no reports have revealed the genetic and antigenic characteristics of Egyptian field ARV and vaccines used against it. Thus, this study was conducted to detect the molecular nature of emerging ARV strains in broiler chickens suffering from arthritis and tenosynovitis in comparison to vaccine strains. Synovial fluid samples (n = 400) were collected from 40 commercial broiler flocks in the Gharbia governorate, Egypt, and then pooled to obtain 40 samples, which were then used to screen ARV using reverse transcriptase polymerase chain reaction (RT-PCR) with the partial amplification of ARV sigma C gene. The obtained RT-PCR products were then sequenced, and their nucleotide and deduced amino acid sequences were analyzed together with other ARV field and vaccine strains from GenBank. RT-PCR successfully amplified the predicted 940 bp PCR products from all tested samples. The phylogenetic tree revealed that the analyzed ARV strains were clustered into six genotypic clusters and six protein clusters, with high antigenic diversity between the genotypic clusters. Surprisingly, our isolates were genetically different from vaccine strains, which aligned in genotypic cluster I/protein cluster I, while our strains were aligned in genotypic cluster V/protein cluster V. More importantly, our strains were highly divergent from vaccine strains used in Egypt, with 55.09-56.23% diversity. Sequence analysis using BioEdit software revealed high genetic and protein diversity between our isolates and vaccine strains (397/797 nucleotide substitutions and 148-149/265 amino acid substitutions). This high genetic diversity explains the vaccination failure and recurrent circulation of ARV in Egypt. The present data highlight the need to formulate a new effective vaccine from locally isolated ARV strains after a thorough screening of the molecular nature of circulating ARV in Egypt.

The Impact of Wheat Yellow Rust on Quantitative and Qualitative Grain Yield Losses under Egyptian Field Conditions.

The Impact of Wheat Yellow Rust on Quantitative and Qualitative Grain Yield Losses under Egyptian Field Conditions.

Interval inversion of multiwell logging data for estimating laterally varying petrophysical parameters and formation boundaries

The present paper introduces a Legendre polynomials based interval inversion method for processing multi-borehole logging data. The method allows the determination of lateral changes of the layer-thicknesses together with the vertical and lateral variations of petrophysical parameters along a 2D cross-section of several boreholes. The method is assessed using noisy synthetic measurements of a petrophysical model made of two-layers structure related to hydrocarbon bearing formations. The numerical experiments aided to investigate the stability and convergence of the 2D interval inversion procedure. To ensure the accuracy and reliability of the inversion results, the misfit of data and model distance are tested, beside the calculation of estimation errors and correlation coefficients. A large amount of input data relative to the number of unknowns results in a high overdetermined ratio, consequently more precise estimates are obtained in stable and convergent procedure than in conventional local (1D) inversion schemes. The feasibility of the 2D interval inversion method is shown by analysing in-situ well logging data acquired in four wells situated in an Egyptian hydrocarbon field.

Artificial Neural Network Modeling for Water Saturation Determination in Shaly Sandstone Reservoirs: Case Study Egyptian Oil Field

Artificial Neural Network Modeling for Water Saturation Determination in Shaly Sandstone Reservoirs: Case Study Egyptian Oil Field

Pharaohs and Playwrights between Fiction and Reality: Controversies in the Egyptian Cultural Field

Going through the controversies involving pharaohs as fictive characters, this article focuses on the life and works of four Egyptian playwrights (Yaʿqūb Ṣanūʿ, ʿAlī Aḥmad Bākaṯīr, Alfred Faraǧ and Tawfīq al-Ḥakīm). Deeply engaged in the politics of their time, playwrights’ experiences with ‘pharaohs’ are studied here with the aim of highlighting the different perceptions of the character of the pharaoh in Egypt and in the West, retracing the implications of the common pairing of pharaohs with presidents, as well as showing how literature can affect politics and how the collocation of pharaohs in the Egyptian cultural field remains problematic, but is changing.

Dissipation profile of sulfoxaflor on squash under Egyptian field conditions: a prelude to risk assessment

ABSTRACT The neonicotinoid insecticide sulfoxaflor is widely used in Egypt. This work assessed the safety of using sulfoxaflor in squash to consumers, along with the residue behaviour. Supervised field trials were conducted to investigate the dynamics and terminal residues of sulfoxaflor in squash under Egyptian field conditions for several agricultural practices, including worst-case scenarios. A QuEChERS-based protocol coupled with LC-MS/MS was employed to measure residues in squash fruits; the limit of quantitation was successfully validated at 0.01 mg/kg. Sulfoxaflor residues reduce in squash fruits via a first-order decay process, with a calculated half–life (t1/2) of 6.13 days and significant degradation (88.5%) after 14 days. During harvest, the terminal residues of sulfoxaflor were ranged from 0.365 to 1.611 mg/kg and from 0.576 to 1.865 mg/kg on sampling days of 3, 7 and 14 days when applied 2-3 times at single or double recommended dose, respectively. A consumer risk assessment was performed employing the FAO/WHO approach; the risk quotients (RQs) were ≤0.0102, and hence; no significant health risks associated with consumption of squash treated with sulfoxaflor were identified.

Partial resistance to powdery mildew and leaf rust of wheat in Egyptian and CIMMYT genotypes

Powdery mildew caused by Blumeria graminis f. sp. tritici and leaf rust caused by Puccinia triticina are among the most important widespread diseases of wheat (Triticum spp.). Seedling and adult plant partial resistance were assessed for both diseases in 46 wheat genotypes, including 20 Egyptian cultivars and 26 CIMMYT genotypes, during two growing seasons (2018/19 and 2019/20) in Egypt. Four Egyptian cultivars (cvs), Misr-1, Misr-2, Misr-3, Giza-171 and eight CIMMYT genotypes, Jupateco-73-R, Pavon-F-76, Opata-85, Thew, Kiskadee-1, Chewink-1, Exchange, Quaiu-1 showed partial resistance to both diseases at the seedling stage. They recorded the longest incubation period (IP) and latent period (LP) for both diseases. Seven Egyptian cvs, Misr-1, Misr-2, Misr-3, Giza-168, Giza-171, Sids-13, Sids-14 and ten CIMMYT genotypes, Lee, Otane, Pavon-F-76, Opata-85, Tatara, Janz, Gatcher, Kenya-Sunbird, Exchange, Quaiu-1 appear to have consistently effective adult plant partial resistance to both diseases. They exhibited the lowest values of average disease index (ADI), average coefficient of infection (ACI), AUDPC, r-AUDPC. Strong inverse correlations observed between each of IP, LP and ADI, ACI and r-AUDPC indicate that seedling partial resistance traits (IP, LP) contribute to curbing the process of epidemic development under field conditions. Strong correlations observed between each of ADI, ACI and r-AUDPC imply that wheat breeders and pathologists may be able to assess their lines by a single scoring at an appropriate time. Cultivars with seedlings and adult plant partial resistance may be of value in breeding for durable resistance to powdery mildew and leaf rust under Egyptian field conditions.

Moringa water extract promising additive to prolong the activity of baculovirus under field-sunlight conditions in Egypt.

Baculoviruses are considered as effective bio pesticides except of being not active under sunlight conditions. The aim of this study is to evaluate the capability of moringa extract to prolong virus activity under Egyptian field conditions especially that Moringa proved to be strong protective material under previous investigation under laboratory conditions the addition of moringa filters were tested on tomato plant foliage. Results are based on leaf bioassay using Spodoptera littoralis test insect and its nuclepolyhedrovirus (SpliNPV) as standard materials. The Original Activity Remaining (OAR) and Lethal Infectivity Time to 50% (LIT50) were estimated after exposure to natural sunlight. cacao and green tea were tested as comparative materials, which proved to be effective as virus protective agent in earlier investigations. The results showed that moringa additive at 10% sustained 50% of virus activity for 193.53 hours and 62.05 and 23.023 hours post application for cacao and green tea; respectively. While virus alone treatment lasts for only 17.551 hours. Moringa generally available, relatively cheap; it also has been tested and proved to be non-toxic, safe, and friendly to the environment. The obtained results showed the activity of moringa water extract in prolonging the virus activity under field application.

GENETIC ASSESSMENT OF LEAF RUST RESISTANCE IN SOME WHEAT VARIETIES

The experiments of this study were carried out through four growing seasons i.e., 2015/16 to 2018/19 at the farm of the faculty of Agriculture, Shibin El-Kom, Menoufia University.Using10 Egyptian wheat varieties,16 wheat promising lines from (CIMMYT) and 20 adult plant leaf rust resistance genes (Lr). lines Lr were used as (male) for crosses with the wheat cultivars (female) to obtain the F1 grains to produce F2 grains and perform genetic analysis. Recording final rust severity (FRS), rate of disease increase (r-value) and the area under disease progress curve (AUDPC) from varieties and lines to responses leaf rust resistance. While STS marker specific for Lr19 and Lr28 genes were performed on the ten wheat varieties and the sixteen promising lines. The responses of rust severity and infection type of the 20 Lr strains were divided into three groups; I resistant genes i.e., Lr17, Lr18, Lr28, Lr 38 and Lr42, II susceptible genes i.e., Lr2c, Lr9, Lr14b, Lr24, Lr34, Lr35, Lr36, Lr37, Lr44 and Lr45, and III genes with variable reactions i.e. Lr2a, Lr19, Lr29, Lr30 and Lr39. Results suggested that genes of group I are important for breeding for leaf rust resistance under Egyptian field conditions. The ten wheat cultivars exhibited low values of FRS and AUDPC except Sids1, and no variety has high rate of (r-value). These cultivars except Sids1 have a good level of adult plant resistance to leaf rust and can be used as resistance sources, 16 wheat promising lines gave lowest values of (FRS), (r-value) and (AUDPC), and consequently they can be used in breeding programs. Genetic analysis showed that Sids1 did not have any of genes under study. However, Gemmeiza 7, Gemmeiza 9, Gemmeiza 10, Gemmeiza 11, Gemmeiza 12, Misr 1, Misr 2, Giza168 and Giza 171 have several Lr genes. Using STS marker specific for Lr19 and Lr28 genes, Lr19 was identified in Gemmeiza 7 and Gemmeiza 11 and Lr28 detected in Gemmeiza 9 and Gemmeiza 10, while Lr19 detected in 13 promising lines, Lr28 found only in five of them. These results showed that molecular markers for Lr genes might be a useful tool in marker-assisted breeding (MAS) for developing Egyptian wheat cultivars.

THE IMPACT OF MANAGEMENT SYSTEMS ON CALVES PERFORMANCE

Records of 3691 growing Holstein Friesian calves, from birth up to weaning (born in a period from 2013 to 2019), belonging to commercial farm named El-Baiomy dairy farm located in Gamasa-Dakahlia Province- Egypt were used in this study. Data collected included management factors such as dam effect (dry period, parity, calving interval and previous milk production) and calves management (Housing system, suckling system, season and gender) and their effects on calves' performance (birth weight (kg), weaning weight (kg), weaning age (day) and daily gain (kg/day)). There were no significant effects in dry period length, parity, calving interval and previous milk production of dam on calf's performance. The lowest birth weight found to be in first parity cows (31.63 kg), while the heaviest one was found to be in third parity cows (33.00 kg). The lowest calves birth weight (30.40kg) was produced by high yielder cows (>11 ton). While it was been 31.71kg for calves belonging to cows with low (< 9 ton) milk production. There was significant effect (P ≤ 0.05) of housing system, suckling system and seasons of calving on weaning age and daily gain of calves. The lowest birth weight was been in winter (31.34 kg) however the heaviest one was been in winter (93.88 kg). The heaviest birth weight was been in male (32.93 kg) but female was 31.63 kg only. On the other hand weaning age found to be 81.31 and 79.14 days in female and male respectively. In addition, a supplementary study has been made to explain management systems of calves raised in some Egyptian villages using field survey. Data of 267 questionnaires (3458 Animals) have been recorded and analyzed to study calf's management systems in different farms located in Nile delta.

Joint Toxic Action of Spinosad with Fenpropathrin and Chlorpyrifos and its Latent Effect on Different Egyptian Field Populations of Spodoptera littoralis

Joint Toxic Action of Spinosad with Fenpropathrin and Chlorpyrifos and its Latent Effect on Different Egyptian Field Populations of Spodoptera littoralis