Uticaj zeolita na hemijski sastav mleka kod krava muzara domaće šarene rase

Milk yield and milk chemical composition are largely affected by the quality of dairy cattle diet. The chemical composition of milk is dependent upon a large number of factors, including breed, diet, care, housing system, stage of lactation, etc. Milk composition is primarily a breed-specific trait. This study was conducted over a period of 15 months, involving Serbian Spotted dairy cattle. The experimental animals were assigned to three groups, each receiving different levels of supplemental zeolite. The control group comprised cows that received no zeolite supplement. Experimental Groups I and II were fed compound feeds supplemented with 4% and 2% zeolite, respectively. Milk samples were analysed for the contents of milk fat, proteins, fat-free solids and lactose, and density. The results obtained suggest that zeolite supplementation affects milk chemical composition, depending on the zeolite level present in livestock feed.Najveći sadržaj mlečne masti u mleku je izmeren kod krava I-O grupe 4,62%, zatim kod K-grupe 4,28% i najmanji kod II-O grupe 4,26%. Statistički signifikantnih razlika u sadržaju mlečne masti među grupama je bilo (P (lt) 0,05). Nivo proteina u mleku krava bio je u intervalu od 3,34% kod krava II-O grupe do 3,51% kod krava kontrolne grupe. Krave K-grupe imaju najveći prosečni sadržaj proteina u mleku ali i najveće varijacije u ovoj osobini. Na osnovu sadržaja proteina u mleku statistički značajnih razlika između grupa nije bilo (P>0,05). Prosečne vrednosti gustine mleka bile su u opsegu od 31,21% kod krava IIO grupe do 33,00% kod krava K-grupe. Kao i kod prethodne osobine i ovde je najmanja prosečna vrednost merene osobine bila kod krava II-O grupe (31,21), sa isto tako, najmanjim koeficijentom varijacije među grupama (3,01). Kod ove osobine uočene su statistički značajne razlike među grupama (P (lt) 0,05). Najveći sadržaj SMBM u mleku imale su krave K-grupe sa iznosom od 9,56%, a najmanju krave II-O grupe 9,11%. Najveće variranje ove osobine je kod krava K-grupe, a najmanje kod krava I-O grupe sa iznosom od 2,51%. Sadržaj SMBM u mleku pokazao je statistički značajne razlike (P (lt) 0,05). Sadržaj laktoze u mleku krava bio je u intervalu od 5,01% kod krava II-O grupe do 5,26% kod krava K-grupe. Krave I-O grupe imale su količinu laktoze koja se nalazila između ove dve grupe. Sadržaj laktoze u mleku krava između grupa pokazao je statistički značajne razlike (P (lt) 0,05). Dodavanje zeolita ('Tufozel') imalo je uticaja na hemijski sastav mleka kod ispitivanih krava muzara

Zeolit kao faktor poboljšanja nekih proizvodnih osobina kod krava muzara

Milk yield and milk chemical composition are largely affected by diet quality. Natural zeolite has been successfully used in livestock production as a feed supplement for some types and categories of domestic animals. This experiment was conducted over a period of 15 months involving Domestic Spotted dairy cattle. The test animals were assigned to three groups, each receiving different levels of supplemental zeolite. The control group comprised cows that received no zeolite supplement. Experimental groups I and II were fed compound feeds supplemented with 4% and 2% zeolite, respectively. The production traits studied included the following milk performance traits: whole lactation length, milk and fat yields over whole lactations, milk and fat yields over standard lactations. The results obtained suggest that zeolite supplementation affects some production traits, depending on the zeolite level present in livestock feed.Kontrolna grupa krava imala je prosečno trajanje laktacije od 312 dana, sa varijacijama od 300 do 360 dana. Ova grupa se po dobijenim rezultatima nalazi između ostale dve grupe krava. Statističke razlike u trajanju celih laktacija među grupama su značajne (P (lt) 0,05). Najniža proizvodnja mleka u celim laktacijama zabeležena je kod krava Kgrupe (6395,20 kg), viša kod krava I-O grupe (6714,13 kg) i najviša kod krava II-O grupe (6934,13 kg) koja je dobijala 2% zeolita preko krmnih smeša. Statističke razlike u proizvodnji mleka u celim laktacijama među grupama su vrlo značajne (P (lt) 0,01). Najmanja prosečna produkcija mleka zabeležena je kod krava K-grupe (6342,33 kg). Znatno veća proizvodnja je bila kod krava koje su dobijale zeolit. Krave I-O grupe dobijale su 4% zeolita i postigle su prosečnu mlečnost od 6690.86 kg. Krave II-O grupe dobijale su 2% zeolita i postigle su najveću prosečnu mlečnost od 6711.80 kg. Krave II-O grupe imale su najveću prosečnu proizvodnju mleka u standardnim laktacijama i najniži koeficijent varijacije među grupama. Statističke razlike u proizvodnji mleka u standardnim laktacijama među grupama su vrlo značajne (P (lt) 0,01). Krave K-grupe imale su najmanju prosečnu priozvodnju mlečne masti u mleku, a krave II-O grupe najveću. Statističke razlike u količini mlečne masti u celim laktacijama među grupama su vrlo značajne (P (lt) 0,01). Takođe su vrlo značajne (P (lt) 0,01) i statističke razlike među grupama u količini mlečne masti u standardnim laktacijama

Estimation of laser-Doppler anemometry measuring volume displacement in cylindrical pipe flow

Laser-Doppler anemometry application in measurements of the 3-D swirl turbulent flow velocity in the cylindrical pipe, behind the axial fan, have been analysed. This paper presents a brief overview of uncertainty sources in the laser-Doppler anemometry measurements. Special attention is paid to estimation of laser-Doppler anemometry measuring volume positioning in cylindrical pipe flow due to optical aberrations, caused by the pipe wall curvature. The hypothesis, that in the central part of the pipe (r/R < 0.6) exists a small, or negligible pipe wall influence on laser- -Doppler anemometry measuring position, is investigate. The required corrections, for measurements of axial, tangential, and radial velocity components such: shift of measuring volume and its orientation are analyzed and determined for used test rig and for some other pipe geometries. [Projekat Ministarstva nauke Republike Srbije, br. TR 35046

Modern Approach to the Enigma of Bovine Respiratory Disease Complex: A Review

Research on bovine respiratory disease complex (BRDC) has strongly contributed to a better understanding of disease at both global and local levels. New agents have been identified and their nature has been better known since then, as well as all the factors that predispone the development of BRDC. Serious work in a number of researches has led to results that have proven significant synergistic interactions between viruses and bacteria that lead to the BRDC and complicate the prevention and treatment of the diseased cattle. Nowadays, it is necessary to apply the latest molecular and other techniques in order to examine in detail all of the specific causes, describe them accurately and provide effective prevention. This can primarily be accomplished by producing different types of vaccines, which are to be improved constantly. Serious progress has been made in researches on immunogenic properties and antimicrobial activity of various natural and synthetic substances in order to improve the production of more effective vaccines for control, as well as the development of a new generation of antibiotics to treat the disease. BRDC prevention programs have been successful, in which great importance was given to proper vaccinations and herd management practices. BRDC is still the most important disease of cattle from an economic point of view, since it causes great losses and expenses. (C) 2013 PVJ. All rights reserve

Efikasnost primene preparata na bazi zeolita u obrocima jagnjadi u tovu

The paper presents the results of a research on the impact of products based on natural zeolite on the production results of fattening lambs. The experiment involved two groups of lambs (the control - C and experimental - E groups), each consisting of 15 heads, for a period of 90 days. The meal was made from sheep milk, feed mixtures for fattening lambs and meadow hay. The test group lambs, unlike the ones from the control group, were given mixtures based on natural zeolite. Min-a-Zel S mixture (in the form of 25% composite) was fed to lambs from birth till their 14th day of life, directly into the mouth, once a day (before the morning feed), in the amount of 10 ml. Min-a-Zel Plus was given to them from their 15th day of life, together with the feed mixture (0.5%). Feeding was at will. The average weight of lambs at the end of the experiment, in accordance with the sequence of treatments (C:E) was 24.40:26.94 kg (P (lt) 0.01). Daily weight gain of lambs, during the experiment, was 229:256 g and in the experimental group it was by 27g or 11.79% higher (P (lt) 0.01). The test group lambs had a better utilization of dry matter, protein and energy, which justifies the use of products based on natural zeolite in fattening lambs.U radu su prikazani rezultati istraživanja o uticaju preparata na bazi prirodnog zeolita na proizvodne rezultate jagnjadi u tovu. Ogled je izveden na dve grupe jagnjadi (kontrolna - K i ogledna - O), po 20 jagnjadi u trajanju od 90 dana. Obrok se sastojao od ovčjeg mleka, krmne smeše za tov jagnjadi i livadskog sena. Iskorišćavanje preparata na bazi zeolita (Min-a-Zel S i Min-a-Zel Plus) pozitivno je uticalo na prirast, iskorišćavanje i efikasnost iskorišćavanja suve materije, proteina i energije. Prosečan dnevni prirast bio je veći kod jagnjadi ogledne grupe za 27 g ili 11,79 posto. Utrošak suve materije za kilogram prirasta u istoj gupi, bio je manji za 12,21 posto a proteina i energije za 10,58 posto. Manja učestalost javljanja proliva bila je kod jagnjadi ogledne gupe

Cfd simulations of thermal comfort in naturally ventilated primary school classrooms

The purpose of thermal comfort is to speck the combinations of indoor space environment and personal factors that will produce thermal environment conditions acceptable to 80% or more of the occupants within a space. Naturally ventilated indoors has a very complex air movement, which depends on numerous variables such as: outdoor interaction, intensity of infiltration, the number of openings, the thermal inertia of walls, occupant behaviors, etc. The most important mechanism for naturally ventilated indoors is the intensity of infiltration and thermal buoyancy mechanism. In this study the objective was to determine indicators of thermal comfort for children, by the CFD model based on experimental measurements with modification on turbulent and radiant heat transfer mathematical model. The case study was selected on school children of 8 and 9 years in "France Presern" primary school in Belgrade. The purpose was to evaluate the relationships between the indoor environment and the subjective responses. Also there was analysis of infiltration and stack effect based on meteorological data on site. The main parameters that were investigated are: operative temperature, radiant temperature, concentration of CO2, and air velocity. The new correction of turbulence and radiative heat transfer models has been validated by comparison with experimental data using additional statistical indicators. It was found that both turbulence model correct and the new radiative model of nontransparent media have a significant influence on CFD data set accuracy

Cfd simulations of thermal comfort in naturally ventilated primary school classrooms

The purpose of thermal comfort is to speck the combinations of indoor space environment and personal factors that will produce thermal environment conditions acceptable to 80% or more of the occupants within a space. Naturally ventilated indoors has a very complex air movement, which depends on numerous variables such as: outdoor interaction, intensity of infiltration, the number of openings, the thermal inertia of walls, occupant behaviors, etc. The most important mechanism for naturally ventilated indoors is the intensity of infiltration and thermal buoyancy mechanism. In this study the objective was to determine indicators of thermal comfort for children, by the CFD model based on experimental measurements with modification on turbulent and radiant heat transfer mathematical model. The case study was selected on school children of 8 and 9 years in "France Presern" primary school in Belgrade. The purpose was to evaluate the relationships between the indoor environment and the subjective responses. Also there was analysis of infiltration and stack effect based on meteorological data on site. The main parameters that were investigated are: operative temperature, radiant temperature, concentration of CO2, and air velocity. The new correction of turbulence and radiative heat transfer models has been validated by comparison with experimental data using additional statistical indicators. It was found that both turbulence model correct and the new radiative model of nontransparent media have a significant influence on CFD data set accuracy

Uticaj kukuruzne silaže u obroku krava muzara na sadržaj kalcijuma, fosfora i magnezijuma u krvnom serumu

The amount of calcium, phosphorus and magnesium in milking cows, blood was tested and it is one of indicators that cows were fed with these substances. The average amount of calcium, phosphorus and magnesium in blood of milking cows was tested and it is one of indicators that cows were fed with these substances. The average amount of calcium in tested cows, blood is 2.82 mmol/l, the average amount of phosphorus is 1.66 and the average amount of magnesium is 1.29 mmol/l. Cows, were fed by corn silage, alfalfa hay, along with concentrate of standard mineral composition.Ispitivan je sadržaj kalcijuma, fosfora i magnezijuma u krvnom serumu krava, kao jednog od indikatora obezbeđenosti životinja ovim elementima. Prosečan sadržaj kalcijuma u krvnom serumu ispitivanih krava iznosio je 2.82 mmol/l, fosfora 1.66 mmol/l i magnezijuma 1.29 mmol/l seruma. Krave su hranjene kukuuznom silažom, senom lucerke i krmnom smešom za krave muzare