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  • Author: Milorad Mirilović x
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Abstract

Bluetongue disease is an infectious non-contagious disease of domestic and wild ruminants, transmitted by hematophagous insects of the genus Culicoides. In endemic areas the disease has a seasonal character, occurs usually in summer when the population of vectors is at its peak. Culicoides are active at temperatures in the range from 13oto 35oC. The replication of the virus stops when the environmental temperature is below 13oC. It has been reported that the temperature and humidity of the environment affect to a great extent the biology of the vector and the survival of the virus in the reservoirs. During the summer, the number of infected cattle and sheep is directly dependent on the density of the population of the vector, the length of vectors’ life-span, the temperature of the environment and by precipitation, the affi nity of the vector to different hosts, and the ability of the vector to locate the host. Bluetongue has been spreading worldwide due to climatic changes and increasing average daily temperatures. The seasonal occurrences of the disease and the climate change have conditioned the need for adopting new strategies. The stochastic SEIRD mathematical model has been developed in order to simulate the transmission of the Bluetongue virus through the susceptible ruminant population on the territory of the Republic of Serbia, as well as to investigate the effect of climatic factors on the vector population and the magnitude of a possible epizootia. Besides the effects of climatic factors, we have analyzed a number of different approaches in the control of the disease based upon the vaccination of ruminants and control of vectors.

Abstract

Diflubezuron is increasingly used in areas where mosquito larvae developed resistance to other insecticides. In our community diflubenzuron is not used to control mosquito larvae. Two formulations of 1% diflubenzuron (on corn-cob EF-1, and zeolite EF-2) were tested on Culex pipiens L (larvae) on one canal in the Belgrade suburb area. The effect was followed for seven weeks after application of the formulations. Formulation EF1 achieved a reduction in mosquito L1L2 larvae between 23.9% and 89.4%. The change was statistically significant the 21st and 28th day (p<0.001), 35th and 42nd day (p<0.01) and 49th day (p<0.05). The maximal reduction obtained by formulation EF2 was 69.1%. The accomplished reduction was significant on the 28th and 42nd day (p<0.001), 35th day (p<0.01) and 21st (p<0.05). Both formulations have maintained a good residual effect on the lower developmental larval stages. Maximum reduction achieved by EF1 on L3L4 larvae was 97.4%. Reduction of larvae was high between the 7th and 42nd day (66.4 - 97%). Statistically significant values were recorded on the 21st, 28th and 35th day. Formulation EF2 achieved a reduction of 99.5%. A statistically significant reduction in the value of mosquito larvae was obtained on the 14th, 21st, 28th, 35th and 42nd day.

Between the two used formulations there was no significant difference in the number reduction of lower larval stages, but for the higher larval stages EF1 proved to be more efficient.

Abstract

Critical indicators of intensive production in hog raising are continuity of production, high level of produced series-tours, application of the most contemporary technological achievements without any turnover of capital, high merchandise turnover, and intensive usage of the reproduction potential of breeding material. Production of piglets represents one of the most essential phases in the production of pork meat. In spite of genetic factors, duration of interval wean-conception is one of the basic factors in determination of bringing forth indexes and number of piglets per litter. In order to recognize production costs of piglets completely we found nutrition costs for piglets and sows represent 61%, while other costs such as personal incomes, veterinary services, water, energy, losses, and amortization represent 39% of total costs. On the basis of cost price per feeding day of a sow and the number of piglets per litter, production costs of piglets older than 28 days with an average body weight of 7 kg were determined. Price cost per piglet after weaning, with 7 kg average body weight, and 146 days of reproduction process accounts for 21,78 EUR if there are 10 piglets in a litter. If the reproductive cycle would last exactly the same and if successful conception would be achieved 25 days after weaning, production cost per piglet would be 23,79 EUR.

Abstract

Bluetongue, a vector-born disease caused by the Bluetongue virus (BTV) and transmitted by Culicoides biting midges, is considered to be one of the most important diseases of domestic ruminants. The first outbreak of bluetongue in Serbia was reported in 2001, when BTV serotype 9 was identified in sampled materials. In 2014, outbreak of BTV-4 in Serbia caused considerable economic losses affecting sheep, cattle and goats. During this outbreak, BTV-4 was recorded in 644 outbreaks within 49 municipalities, part of 17 administrative regions. From the total number of sheep kept in areas affected by bluetongue (n=1 748 110), 2 083 cases (0.2%) were proven to be BTV-4 infected. Total of 206 infected cattle and 24 infected goats were reported during this investigation period, which represents 0.06% and 0.03% of the total number of cattle and goats kept in affected areas, respectively. The highest incidence of infected sheep, cattle and goats was recorded on the territory covered by veterinary institute of Nis. Recorded lethality in cattle, sheep and goats was 18.45% (n=38), 48.10% (n=1002) and 54.17% (n=13), respectively. The peak of the outbreak was in September and October when 94.43% of the confirmed positive cases, regardless of the species, was recorded. Monitoring of bluetongue disease in Serbia relies on active surveillance programmes aimed at: (i) identification and tracing of susceptible and potentially infected animals and (ii) detection, distribution and prevalence of insect vectors. Vaccination of sheep is planned to be implemented as a control measure against bluetongue in Serbia.

Abstract

The purpose of this study was to assess the effects of various dietary meal compositions on production, economic performance and meat quality of the rainbow trout (Oncorhynchus mykiss). Experimental group (0-I) was fed with a mixture containing 30% fish meal, 35% soybean meal, 30% sardines and 5% fish oil. Experimental group 0-II was fed with a combined meal consisting of 75% of fish food pellets and 25% of sardines. The control group (C) was fed with a standard complete pelleted feed. The best result was obtained in group 0-II, while group C achieved results common for local food quality and farming conditions in Serbia. Group 0-I had less productive results compared to group C and group 0-II. Feed used in group 0-II has its own nutritional, biological and economic justification.

Use of different fish meals had no significant influence on trout meat chemical composition, except the fat content which was significantly higher in group 0-II. Considering current market prices of fish feed and fish as a final product, the best economic results were achieved by using the combined feed in group 0-II.

Abstract

Histopathological examination, grading, immunohistochemical staining and molecular genetic examinations are the proposed criteria that should be used for cutaneous mast cell tumors (CMCTs) classification. The presence of aberrant CD117 expression and mutations of the c-kit proto-oncogene could be an indicative parameter for final histological grading. Determination of the connection between the localization of KIT receptor expression and the histological grade of CMCTs without c-kit proto-oncogene mutations was the main goal of this study. The study included twenty four CMCTs and six control skin samples from 30 dogs of different ages, breed and sex. Formalinfixed and paraffin-embedded tissue samples were stained with hematoxylin-eosin and toluidine blue and immunohistochemically tested for CD117 expression. DNA was extracted from the same paraffin blocks and subsequent polymerase chain reaction amplification was performed using PE1 and PE2 primers. Degree of malignancy was determined based on the presence of mitotic figures, multinucleated cells, bizarre nuclei and karyomegaly in 10 high power fields. Based on histological features, fourteen of 24 CMCTs were of a high histological grade, while ten were classified as a lowgrade malignancy. CD117 cytoplasmic expression was observed in nine of fourteen high-grade malignancy CMCTs, which confirms the link between the aberrant CD117 expression and increased cell proliferation.

Abstract

In this investigation, the genotoxic properties of mestranol were examined in vitro. Human lymphocyte cultures were exposed for 72 h to mestranol at concentrations of 7.5, 15 and 30 µg/g. The genotoxic effects of the chemosterilant were assessed by numerical and structural chromosome aberrations.

Mestranol induced certain genotoxic effects in human lymphocytes. There was a dose-dependent significant (p<0.01) increase in the number of numerical aberrations in comparison to the control, but without significant differences (p>0.05) between the doses applied. Further, structural aberrations increased significantly (p<0.01) in the presence of mestranol, being most frequent in cultures exposed to the highest mestranol dose.

The frequency of Robertsonian translocations increased significantly only in cultures treated with mestranol at concentration of 30 µg/g in comparison both with the control (p<0.01) and the lowest chemosterilant dose (p<0.01).

There were significant differences (p<0.01) in the levels of chromosome gaps and fragments compared to Robertsonian translocations, whilst the frequencies between gaps and fragments were not significantly different (p>0.05).

Abstract

The aim of our study was to investigate if the thyroid axis of newborn calves is affected by prenatal application of propylthyouracil (PTU). The study included 20 late pregnant Holstein cows. One group (n=10) was treated with PTU (4 mg/kg of BW daily) from day 20 before expected calving until the day of calving. The other group (n=10) was non-treated. Placental samples of dams were obtained for measuring mRNA expression of iodothyronine deiodinases type I (D1), type II (D2) and type III (D3). After parturition calves were separated from the dams and included in the study. Blood samples were taken daily from each calf starting on the day of birth until day 7 of age. Blood T3, T4 and TSH concentrations were measured. PCR analysis of the placental tissue revealed an abundance of all three types of placental deiodinases in non-treated cows, and a significant elevation of mRNA levels for all three types of deiodinases after PTU treatment. Calves that originated from dams treated with PTU had significantly lower T3 and T4 and significantly higher TSH concentrations compared to non-treated calves during the first 2 days of life. Starting from day 4 until day 6 of life the opposite effect was observed meaning that calves prenatally exposed to PTU had significantly higher T3 and T4 and slightly lower TSH. Our study, for the first time, provides information related to iodothyronine deiodinases mRNA expression in bovine placenta, and confirm that PTU treatment of pregnant dams provokes depression of thyroid function in newborns during the first days of life.