INFLUENCE OF THE NUMBER OF PREVIOUS CAESAREAN SECTIONS ON LOWER UTERINE SEGMENT STATE

Determining the lower uterine segment (LUS) state before vaginal delivery and after Caesarean section, including pregnant women with more than one Caesarean section, may be an important step towards prevention from still high maternal and neonatal morbidity and mortality that follow uterine rupture. In pregnant women with one or more previous Caesarean sections, ultrasonic measuring of thickness and estimating the LUS integrity can objectively show the state of uterine scars. The aim of this study was to determine the influence of several previous Caesarean sections on the LUS state in term pregnant women. The prospective study included 62 pregnant women with one or more previous Caesarean sections – the examined group, and 50 pregnant women without Caesarean section – the control group, that after the 37th week of pregnancy had undergone the transvaginal ultrasonic measuring of the thickness of the LUS muscular tissue. In 57 pregnant women from the examined group delivered with another Caesarean section, we estimated, intraoperatively, the LUS integrity in the scar area. On the same occasion, in the scar area, the presence of defect – partial or complete was detected. The research pointed out that the average LUS thickness in the examined group – 1.92±0.95mm was statistically significantly lower compared to the control group – 2.68±0.97mm (p<0.001). The average LUS thickness in 52 examined women with one Caesarean section was 1.92±0.97mm, and in 9 women with two Caesarean sections the average thickness was lower – 1.78±0.82mm, which does not represent a statistically significant difference (p=0.85). In one pregnant woman with three Caesarean sections, the LUS thickness was 3.30mm. We registered the total of 13 pregnant women with a defect in the Caesarean section scar area (12 partial and 1 complete defects), in 12 women after one Caesarean section and in 1 woman after two Caesarean sections. The research results show that women with previous Caesarean section have significantly thinner LUS, compared to the group of pregnant women without scars. With the increasing number of previous Caesarean sections, the LUS thickness decreases, but the difference is not statistically significant. Intraoperatively, the presence of certain LUS classes compared to the number of previous Caesarean sections is not significantly different. Furthermore, the increase in the number of Caesarean sections does not involve a statistically significant increase in the frequency of Caesarean section scar defects, which is in accordance with other authors’ results

Odgovor akutne faze kod Wistar pacova posle kontrolisanog krvarenja

After injury the acute-phase response of the organism activates mechanisms which imply the release of cytokines, stress hormones, and mediators of pain and inflammation. The main function of the acutephase response is to hinder further damage of the injured tissue by activating reparative processes. The increase in the concentration of acute phase proteins and the concurrent decrease in albumins and prealbumins indicate that there is a strong link between the liver and the traumatized site. Considering bleeding to be a major injury it can be supposed that it can result in changes in acute phase proteins concentrations despite the fact that it is not directly related to inflammatory reactions. In order to confirm this presumption the concentration changes in negative and positive acute phase proteins in Wistar rats' blood plasma were measured during a 10 day period after controlled bleeding. The result of the therapeutic effects of transfusion on acute phase proteins was estimated in a group of rats in the so called 'hospital stage' at which the blood loss was recovered by citrate blood transfusions. At the end of the 10th day the rats were monitored for an additional 10 day period. The obtained results confirm that bleeding is an impressive trauma and the acute phase response results in a significant change in acute phase proteins. These changes arise quickly, the highest concentrations were achieved within the first 24 to 72h and thereon they slowly declined.Odgovor akutne faze organizma na povredu tkiva aktivira mehanizme koji podrazumevaju oslobađanje citokina, hormona stresa, medijatora bola i zapaljenja. Njegova glavna funkcija je sprečavanje daljeg i većeg oštećenja povređenog tkiva uz aktivaciju reparatornih procesa. Porast koncentracije proteina akutne faze i smanjenje albumina i prealbumina ukazuje da postoji veza između mesta povrede i jetre. Smatrajući da je hemoragija teška povreda, pretpostavili smo da ona može izazvati promene u koncentraciji proteina akutne faze bez obzira što primarno nije povezana sa inflamatornom reakcijom. U cilju dokazivanja ove pretpostavke tokom 10 dana su praćene promene 'negativnih' proteina akutne faze; albumina i 'pozitivnih'; fibrinogena, α-2 makroglobulina i haptoglobina, kao i β-1 globulina i γ-globulina u plazmi Wistar pacova koji su bili podvrgnuti kontrolisanom iskrvarenju. Za potrebe ovog eksperimenta konstruisan je i novi model kontrolisanog krvarenja, koji je jedinkama omogućio preživljavanje tokom sledećih 10 dana, u toku kojih se merila promena relativnih koncentracija akutno-faznih proteina. Ispitan je i uticaj terapijskog efekta transfuzije na stanje proteina akutne faze na grupi pacova koji su u tzv. 'hospitalnoj fazi' kao nadoknadu izgubljene krvi, dobili infuziju citrirane krvi. Po završetku eksperimenta nadgledano je opšte stanje životinja i praćen je letalitet tokom 10 dana. Rezultati našeg istraživanja potvrđuju pretpostavku da je krvarenje teška trauma za organizam pri čemu se odgovor akutne faze manifestuje značajnom promenom koncentracije odgovarajućih proteina, čije se maksimalne koncentracije registruju u prvih 24-72 časa nakon traume

Biohemijske promene u krvnom serumu pasa tretiranih fenobarbitonom

Despite being described as the safest antiepileptic drug of first choice the presented literature data are much varied as far as dog blood serum biochemical parameters are considered. The aim of this study was to investigate the effect of phenobarbitone at different per os doses on the values of selected blood serum biochemical parameters in dogs during both short and long term application. The study was conducted on 30 dogs of different races, both sexes, ranging from 2 to 8 years of age. A total of 15 healthy and 15 dogs suffering from idiophatic epilepsy were observed. During the short term per os application of phenobarbitone (given at 3 week intervals) to the healthy population in varied doses a statistically significant increase in ALT and AP was recorded. Application of 16 mg/kg/day of phenobarbitone to the healthy population during 14 days resulted in a significant increase of ALT and AP. This increase was dependant on the duration of the treatment. During chronic application of phenobarbitone to dogs suffering from idiopathic epilepsy a significant increase in values of AP and ALT depending on the given dose was recorded. In two of the studied epileptic dogs treated with high therapeutic doses of phenobarbitone clinical signs of hepatotoxicity were recorded. Hepatotoxicity resulted in decreased albumin and total protein concentrations, as well as increased blood serum total bilirubin, AST, ALP and AP. The obtained results indicate that a long term application of phenobarbitone at high therapeutic doses can cause hepatotoxicity. However, there was no relationship between phenobarbitone dosage and duration of therapy and blood glucose, urea, creatinine, total proteins, albumins, total bilirubin, triglycerides and cholesterol.Iako označen kao antiepileptik prvog izbora i veoma bezbedan lek, u literaturi su prezentovani različiti podaci o uticaju fenobarbitona na vrednosti biohemijskih parametara krvnog seruma kod pasa. S obzirom na to, cilj ovog istraživanja bio je da se ispita uticaj fenobarbitona pri različitim per os dozama na vrednosti biohemijskih parametara krvnog seruma kod pasa, tokom kratkotrajne i dugotrajne aplikacije. Istraživanje je sprovedeno na 30 pasa različitih rasa, oba pola, starosne kategorije od dve do osam godina, od kojih su 15 bili zdravi psi a 15 psi oboleli od idiopatske epilepsije. Tokom kratkotrajne per os aplikacije fenobarbitona (intervali od po tri nedelje) zdravoj populaciji pasa pri različitim per os dozama, u krvnom serumu je registrovano značajno povećanje aktivnosti ALT i vrlo značajno povećanje aktivnosti AP u zavisnosti od doze leka. Aplikacija fenobarbitona u dozi od 16 mg/kg/dnevno tokom 14 nedelja zdravoj populaciji pasa ukazala je, na vrlo značajno povećanje aktivnosti ALT i AP u zavisnosti od dužine trajanja aplikacije. Tokom hronične aplikacije fenobarbitona psima obolelim od idiopatske epilepsije, ustanovljeno je statistički vrlo značajno povećanje aktivnosti AP i ALT u krvnom serumu u zavisnosti od doze leka. Kod dve jedinke u bolesnoj grupi pasa pri visokim terapeutskim dozama fenobarbitona registrovana je hepatotoksičnost, što je dovelo do statistički značajnog smanjenja koncentracije albumina i ukupnih proteina, statistički značajnog povećanja koncentracije ukupnog bilirubina, statistički značajnog povećanja aktivnosti AST i statistički vrlo značajnog povećanja aktivnosti ALT i AP u krvnom serumu Dobijeni rezultati ukazuju da dugotrajna aplikacija fenobarbitona, pri visokim terapeutskim dozama može izazvati hepatotoksičnost. Nije ustanovljeno postojanje veze između koncentracije glukoze, uree, kreatinina, ukupnih proteina, albumina, ukupnog bilirubina, triglicerida i holesterola u krvnom serumu pasa sa per os dozom fenobarbitona, niti sa dužinom trajanja terapije

On the effective shear modulus of composite honeycomb sandwich panels

U radu je određen efektivni modul klizanja kompozitnog panela sa saćastom ispunom. Ovaj elastični koeficijent predstavlja veoma važnu karakteristiku kompozitnih panela, naročito kod kompozitnih konstrukcija koje su izložene uvijanju kao i kombinovanom uvijanju sa savijanjem. Analizirane strukture u ovom radu sastoje se od gornje i donje kompozitne ploče (različitih tipova karbonskih vlakana, T300, AS4 u epoksidnoj matrici) kao i saćaste ispune (HexWeb EC engineered core). Polazeći od klasične teorije lamine, efektivni modul elastičnosti klizanja je određen za svaki sloj u kompozitnoj ploči. Ovi slojevi su spojeni u jedinstveni kompozitni sloj za različita usmerenja vlakana kao i debljine lamina. Elastični koeficijenti saćaste ispune HexWeb središnjeg sloja kompozitnog panela su izračunati koristeći teoriju Master Evans u cilju dobijanja ekvivalentnih vrednosti. Za proveru predloženog pristupa korišćen je metod konačnih elemenata, u cilju dobijanja polja pomeranja, deformacija i napona u kompozitnim pločama i saćastoj ispuni. Dva tipa numeričkih modela su upoređena: početni model, pri čemu su svi slojevi ploče modelirani sa svojim karakteristikama i drugi model kod kojeg su spojeni u jednu celinu sa svojim ekvivalentnim karakteristikama. Zaključeno je da se ekvivalentni metod određivanja modula klizanja kompozitnih panela sa saćastim ispunama može efikasno primeniti u slučajevima kada su gornja i donja kompozitna ploča simetričnog slaganja ili uopšte kvaziizotropna.In the presented paper the effective shear modulus of composite plates with honeycomb core is determined. This elastic coefficient represents one very important property, especially in constructions subjected to torsion and combined bending - torsion. The structures investigated in this research consisted of top and bottom plates (of different types of carbon fibers, T300, AS4 in epoxy matrix) and honeycomb core (HexWeb engineered core). Starting from classical lamination theory, the effective shear modulus of top and bottom plates was determined for each ply in the stack up sequence. These plies were 'lumped' into a single composite layer for different fiber orientations and plies thicknesses. Elastic coefficients for the HexWeb engineered core were obtained using Master and Evans relations for the equivalent properties of honeycomb cores. To verify this approach, finite element method was used to determine the displacement, stress and strain field on composite plates with honeycomb core. Two types of models were compared: the initial model where all the material components, plates and the core were modeled with their intrinsic properties and 'lumped' model with calculated effective elastic coefficients. It was found that the method of effective shear modulus calculation can successfully be used in situations where top and bottom plates are symmetric or quasi isotropic in general

Efikasnost različitih insekticida u poljskim uslovima u suzbijanju repičinog sjajnika (Meligethes aeneus F.) u usevima ozime uljane repice

Since pollen beetle, M. aeneus, is usually controlled by insecticides, the efficacy of several compounds with different modes of action against adult beetles was studied in a threeyear field study. The selected insecticides were: three pyrethroids (lambda-cyhalothrin, alpha-cypermethrin and bifenthrin), an oganophosphate (pirimiphos-methyl), a combination of an organophosphate and a pyrethroid (chlorpyrifos + cypermethrin) and a neonicotinoid (thiacloprid). The insecticides were applied at label rates to winter rapeseed crops at the moment of visible but still closed flower buds (BBCH 55-57). In all experiments, the efficacy of pyrethroids and the organophosphate ranged from 90-100%, while the efficacy of the neonicotinoid was 85-95%. Therefore, they can be recommended for control of pollen beetle in Serbia.S obzirom da gajenje uljane repice za sobom povlači i primenu insekticida za suzbijanje repičinog sjajnika kao najštetnije insekatske vrste, u radu je tokom trogodišnjih poljskih ogleda (2008-2010. godina) na tri lokaliteta (Kovin, Smederevo i Požarevac) ispitana efikasnost insekticida različitih mehanizama delovanja: piretroida (lambda-cihalotrin, alfa-cipermetrin, bifentrin), organofosfata (pirimifos-metil), kombinacije organofosfata i piretroida (hlorpirifos + cipermetrin) i neonikotinoida (tiakloprid) za imaga M. aeneus. Komercijalne formulacije insekticida su primenjivane u preporučenim dozama u usevima ozime uljane repice u vreme vidljivih cvetnih pupoljaka, ali još zatvorenih (BBCH 55-57). Efikasnost piretroida i organofosfata je tokom svih ogleda bila 90-100%, a neonikotinoida 85-95%, pa se zbog ispoljene visoke efikasnosti može preporučiti njihova primena u Srbiji

Pojava deformacije ekstremiteta krava simentalske rase u različitim tipovima ležišta

Problems with legs and various forms of lameness of cows, in intensive milk production, are the third significant problem occuring in this production, after mastitis and reproductive disorders, both globally and in our country. The paper analyzes the incidence of the deformation of legs of 145 cows of the Simmental breed in the Kolubara region, and the influence of paragenetic factors (housing/holding and type of stall/bedding and lactation) on the incidence of deformations. The obtained results show that, of the total number of cows assessed, 3.45% had 'X' position of the front legs, 14.8% had a 'X' position of the hind legs. The convergent position of the front legs was recorded in 35.86%, and divergent in 8.28% of animals. The convergent position of the hind legs was observed in 16.55% of cows, and divergent in 2.76%. The outward position of the front legs was observed in 4.14% of cows, inward position in 11.03%, and broad position in 4.14% of studied cows. Also, 17.24% of the cows had a so called sable like position of hind legs, and 7.59% showed steap angle of hind legs. The pronounced soft front leg pasterns were observed in 7.59% of the cows, and the soft pasterns of the hind legs in 33.79% of the total number of observed cows. The observed changes in the ankles in the shape of swelling were recorded in 1.38% of cattle on the carpal joint and 2.76% on the tarsal ankle. The damaged shoulder and body joint (scabbed shoulder) was observed in 43.45% of the total number of cows evaluated. Scores for the front and hind legs front, back and side views, varied at different levels of significance under the influence of the type of stall/bedding, while the scores for the condition of the hind leg pasterns varied highly significantly (p lt 0.001) under the influence of the type of stall/bedding. The scores for the front leg pasterns and scores for shoulder and body joint were not significant (p> 0.05) depending on the type of stall/bedding and the method of housing/holding of cows.Problemi sa nogama i različiti oblici šepavosti krava, u intenzivnoj proizvodnji mleka su treći problem po značaju posle mastitisa i reproduktivnih poremećaja, kako u svetu tako i u našoj zemlji. U radu su analizirane pojava deformacije stavova nogu 145 krava simentalske rase na području Kolubarskog okruga, i uticaj paragenetskih faktora (način držanja i tip ležišta i laktacija po redu) na pojavu deformacija. Od ukupnog broja ocenjenih krava 3,45 % je imalo 'X' stav prednjih nogu, 14,8% je imalo 'X' stav zadnjih nogu. Konvergentan stav prednjih nogu imalo je 35,86%, a divergentan 8,28%. Konvergentan stav zadnjih nogu imalo je 16,55% krava, a divergentan 2,76%. Isturen stav prednjih nogu imalo je 4,14% krava, podvučen 11,03%, a širok stav 4,14%. Sabljast stav zadnjih nogu imalo je 17,24% krava, a stubast 7,59%. Izražene mekane kičice prednjih nogu imalo je 7,59% krava, a mekane kičice zadnjih nogu imalo je 33,79% od ukupnog broja ocenjenih krava. Uočene promene na zglobovima u vidu otoka imalo je 1,38% krava na karpalnom zglobu i 2,76% na tarzalnom zglobu. Narušen spoj lopatice i tela (odvaljena plećka) imalo je 43,45% od ukupnog broja ocenjenih krava. Ocene za stavove prednjih i zadnjih nogu posmatrano spreda, otpozadi i sa strane varirale su na različitom nivou značajnosti pod uticajem tipa ležišta, dok ocene za stanje kičica na zadnjim nogama su vrlo visoko značajno (p lt 0,001) varirale pod uticajem tipa ležišta. Ocene za kičice prednjih nogu i ocene za spoj lopatice i trupa, nisu značajno (p>0,05) zavisile od tipa ležišta i načina držanja krava

Varijabilnost osobina fundamenta kod prvotelki simentalske rase

Visual evaluation and recognition of dairy traits of cows are preliminary indicators of milk yield, longevity, and reproductive ability of the individual animal, which is very important from the aspect of the economics of milk production. The deficiencies in the fundament traits lead to poor production, poor health and premature culling of cows from the herd. The paper examines the frequency of preferred scores of a certain trait in the first calving heifers according to the housing method (animals reared by individual agricultural producers and farm animals) and their origin (domestic and imported animals), as well as the impact of these two factors on the observed properties. Four fundament traits were analysed: the position of the hind legs, the development of the hocks/joints, the pastern joints and the height of the feet on a total of 954 first-calving Simmental heifers. Observed by the housing method, the higher frequency of the preferred scores for all of the fundament traits, was achieved by the farm cows, while according to the origin of the cows, the higher frequency of the preferred scores for all of the fundament traits was realized by imported animals in relation to domestic cows. The influence of the factors of the housing method and origin of animals examined by χ2 test on all the tested linear scores (frequency of scores) of the fundament traits was statistically very significant (p≤0.001), while the analysis of the variance (F test) determined high significance (p≤0.001) of the interaction between the origin and housing method on the height of the feet, as well as significant effect (p≤0.05) on the position of the hind legs, while on other linear scores of the fundament traits it did not exhibit statistical significance (p>0.05).Vizuelna procena i prepoznavanje mlečnih karakteristika krava su preliminarni pokazatelji mlečnosti, dugovečnosti, kao i reproduktivnih sposobnosti grla, što je veoma važno sa aspekta ekonomičnosti proizvodnje mleka. Nedostaci u osobinama fundamenta dovode do slabije proizvodnje, lošeg zdravstvenog stanja i preranog isključenja krava iz zapata. U radu je ispitivana učestalost poželjnih ocena određene osobine kod prvotelki podeljenih po načinu držanja (grla kod individualnih proizvođača i grla sa farme) i podeljenih po poreklu (grla domaćeg odgoja i grla iz uvoza), kao i uticaj ova dva faktora na posmatrane osobine. Analizirane su četiri osobine fundamenta: položaj zadnjih nogu, razvijenost skočnog zgloba, kičični zglobovi i visina papaka na ukupno 954 prvotelke simentalske rase. Posmatrano prema načinu držanja, veću frekvenciju poželjnih ocena za sve osobine fundamenta iskazane u ocenama ostvarile su krave sa farme, dok su prema poreklu krava, veću frekvenciju poželjnih ocena za sve osobine fundamenta iskazane u ocenama ostvarile krave poreklom iz uvoza u odnosu na krave domaćeg porekla. Uticaj faktora načina držanja i porekla grla ispitivani χ2 testom na sve isptitivane linearne ocene (frekvenciju ocena) osobina fundamenta bio je statistički vrlo visoko značajan (p≤0,001), dok je analizom varijanse (F test) utvrđena visoka značajnost (p≤0,001) interakcije porekla i načina držanja na visinu papaka, kao i značajnost (p≤0,05) na poziciju zadnjih nogu, dok na ostale linearne ocene osobina fundamenta nije ispoljila statističku značajnost (p>0,05)

Polymorphism of k-casein and b-lactoglobuline in simmental cattle in Serbia

The objective of this study was to determine the frequency of the kappa-casein and beta-lactoglobulin genotypes in the Simmental cattle in Serbia and compare it with the frequency according to the Hardy-Weinberg equilibrium law. Blood samples were taken from a total of 157 cows of the Simmental breed in Toplica and Rasina districts. Of the 157 cows included in this study, the AA kappa-casein genotype was found in 53 cows, which makes a frequency of 33.80%, the AB genotype in 81 cows or 51.60% and the BB genotype in 23 cows or 14.60%. The allelic frequency A was 59.60%, while allele B had a frequency of 40.40%. In regard to the frequency of genotypes and beta-lactoglobulin alleles for the total studied population of cows obtained for AA, AB and BB genotypes for beta-lactoglobulin, was 33.10%, 49.70% and 17.20%, respectively, which means that 52 animals had genotype AA, 78 genotype AB and 27 genotype BB. The frequency of alleles A and B resulting from the incidence of genotypes was 58.00% for allele A and 42.00% for allele B. The specified frequencies for both protein fractions statistically differed significantly from the frequency according to the Hardy-Weinberg equilibrium law, which confirmed the absence of equilibrium in the examined population

Proizvodni potencijal prvotelki simentalske rase u Srbiji

Cattle production in Serbia, and especially milk production, contributes significantly to the value of total agricultural production (20%) and livestock production (45%). Achieved annual rate of milk yield increase of approx.100 kg per cow cannot adequately compensate for drastic decrease of number of dairy cattle which dropped by fifth over last decade. This is especially important from the aspect of assessment of future production quotas for milk as part of Serbia's preparation for EU accession. From the aspect of the genetic potential of dairy cattle, the most significant measure aimed at increase of milk performance in future will be execution of systematic selection-breeding work in the main population. Special attention should be directed in future to selection of parents of dairy herd, criteria for selection of heifers and their adequate rearing in sense of nutrition and housing. For the purpose of establishing of production potential of first calving Simmental cows in Serbia, data was analyzed for 37.171 Simmental cows with completed lactations in the period 2007 to 2010. Research results showed moderate trend of increase in milk performance in first calving cows - average milk production of 4.348 kg, milk fat content of 3.93% and milk fat yield of 171.1 kg. Milk performance of first calving cows in average was lower by 147 kg compared to cows in other lactations and by 1.169 kg compared to bull dams in the observed period. In analysis of bulls - most common sires of studied first-calvers, it was established that eight of ten bull sires had negative values for milk yield, which indicated the need for better cooperation and organization in work of all services which are included in selection-breeding activities in dairy cattle breeding.Govedarstvo Srbije a posebno proizvodnja mleka značajno učestvuju u vrednosti ukupne poljoprivredne (20%) i stočarske proizvodnje (45%). Postignutim tempom rasta prinosa mleka od oko 100 kg po kravi godišnje ne može se adekvatno kompenzovati drastičan pad broja mlečnih grla koji je u protekloj deceniji opao za petinu. Ovo je posebno značajno sa aspekta procena budućih proizvodnih kvota za mleko u priprema Srbije za ulazak u EU. Sa aspekta genetskog potencijala mlečnih krava, najznačajnija mera za povećanja prinosa mleka u narednom periodu je sprovođenje sistematskog odgajivačko-selekcijskog rada u matičnoj populaciji. Izboru roditeljskih parova budućih generacija mlečnog stada, kriterijumima odabira junica i njihovom pravilnom odgoju u smislu ishrane i uslova držanja treba posvetiti primaran značaj. U cilju utvrđivanja proizvodnog potencijala prvotelki simentalske rase u Republici Srbiji analizirani su podaci 37.171 simentalskih krava koje su svoje prve laktacije zaključile u periodu od 2007-2010 godine. Rezultati istraživanja pokazali su umereni trend porasta mlečnosti prvotelki sa ostvarenom prosečnom proizvodnjom od 4.348 kg mleka, sadržajem od 3,93% i prinosom od 171,1 kg mlečne masti. Mlečnost prvotelki u proseku je bila niža za 147 kg od mlečnosti krava u ostalim laktacijama i za 1.169 kg od mlečnosti bikovskih majki u posmatranom periodu. Analizom bikova - najčešćih očeva ispitivanih prvotelki, utvrđeno je da je osam od deset bikova-očeva imalo negativne vrednosti za prinos mleka što upućuje na neophodnost bolje saradnje i organizacije u radu svih službi koje obavljaju odgajivačko-selekcijski rad u mlečnom govedarstvu

Rezultati biološkog testa bikova simentalske rase u centralnoj Srbiji

Exceptionally important aspect in cattle production, from the aspect of production and economy, is ensuring normal and regular fertility. Every cattle breeder wants to have high-yielding animals which at the same time have good fertility. In proper cattle breeding this means that from each cow during single year one healthy calf is obtained. Use of artificial insemination has enabled that one breeding male is used as sire for several tens of thousands of progeny, however, there is always the risk that sires could be carriers of lethal and semi-lethal genes, which can cause huge losses of calves. In order to bring these undesirable occurrences to a minimum, so called bilogical test is included in the breeding and selection activities, i.e. bulls are tested through their progeny for presence of difficult calving (dystocia) abd calf losses caused by genetic anomalies. In Republic of Serbia, this test is carried out on ehtire Simmental population in an exchange of data produced by primary breeding organizations. Per each tested bull, it is necessary to have data on minimum 50 randomly selected calves. Calves are examined visually 65 days after the birth, at the latest. In the present study, the results of the biological testing of 35 Simmental bulls, sires of total 3572 calves on the territory of Central Serbia, in the period 2008-2009, are used. The effect of sires on parameters of biological test were studied: body mass of calves at birth, calf score and calving score. Also, bulls were ranked based on said parameters, male/female calves ratio and percentage of twins and still-born calves for each bull individually were determined. After the rank of bulls was established, the correlation between the rank and studied fertility traits was determined. Correlations were expressed using the Spearman coefficient. Research results show that the effect of bulls was very high p (lt) 0,001 on all three parameters of the biological test, and also that the percentage of still born calves for all bulls was within limits, with the exception of bulls Zahlo (HB 1497) and Woz (HB 1433) where it was above 5.Izuzetno važan aspekt u govedarskoj proizvodnji, gledano sa proizvodnog i ekonomskog stanovišta je obezbeđivanje normalne i redovne plodnosti. Svaki odgajivač goveda želi da ima grla koja su visoko proizvodna i istovremeno poseduju dobru plodnost. Za pravilno odgajivanje goveda to znači da se od svake krave u toku godine dobije po jedno zdravo tele. Upotreba veštačkog osemenjavanja omogućila je da jedan priplodnjak bude otac nekoliko desetina hiljada potomaka. Međutim, uvek postoji rizik da su očevi nosioci letalnih i semiletalnih gena, što može prouzrokovati velike gubitke teladi. Da bi se ove nepoželjne pojave svele na najmanju moguću meru u odgajivački i selekcijski rad uključeno je ispitivanje bikova po potomstvu na teška teljenja i gubitke teladi izazvane genetskim anomalijama, tzv. biološki test. Ovaj test se u Republici Srbiji vrši jedinstveno za čitavu populaciju simentalske rase, razmenom podataka između odgajivačkih organizacija. Po svakom biku koji se testira, neophodno je imati podatke za najmanje 50 slučajno odabrane teladi. Vizualni pregled teladi se obavlja najkasnije do 65 dana, od datuma rođenja teleta. U ovom istraživanju korišćeni su rezultati biološkog testa 35 bikova simentalske rase koji su bili očevi ukupno 3572 teladi na teritoriji centralne Srbije u periodu 2008. i 2009. godine. U radu je ispitivan uticaj očeva na parametre biološkog testa: telesnu masu teladi po rođenju, ocenu teleta i ocenu toka teljenja. Takođe je izvršeno rangiranje bikova na ove parametre, kao i utvrđivanje odnosa muške i ženske teladi, procenat bližnjenja kao i procenat mrtvorođene teladi za svakog bika posebno. Nakon utvrđenog ranga bikova izvršena je korelacija ranga ispitivanih osobina plodnosti. Korelacije su iskazane Spirmanovim koeficijentom. Rezultati istraživanja pokazali su da je uticaj bikova izuzetno visok p (lt) 0,001 na sva tri parametra u biološkom testu, kao i da je procenat mrtvorođene teladi kod svih bikova u dozvoljenim granica, osim bikova Zahlo (HB 1497) i Woz (HB 1433) gde je iznosio preko 5