Prof. dr. sc. Ivan Knežević (Osijek, 21. studenog 1940. - Osijek, 5. listopada 2023.)

Dana 5. listopada 2023. godine preminuo je naš dragi prof. dr. sc. Ivan Knežević, redoviti profesor u miru. Utihnulo je srce velikog čovjeka, znanstvenika i profesora. Svoju profesorska osobnost na poseban način znao je dijeliti s radnim kolegama, a naročito s mlađim suradnicima. Krasile su ga dobrota, blagost, kreativnost, motivacija, odlučnost i pozitivnost

Lacto-corder - a new measurement device for cow milk productivity control

Lacto-Corder je mjerni uređaj za kontrolu proizvodnosti i izuzimanje uzorka mlijeka krava, službeno priznat od strane ICAR-a (Internacional Committee for Animal Recording). Uređaj se sastoji od dva dijela: hidrauličkog koji obuhvaća put mlijeka kroz mjerno područje i elektronoskog dijela koji obuhvaća upravljačko područje gdje se unose i spremaju podatci. Proizvođač je posebnu važnost dao muznim svojstvima (prosječnom i maksimalnom protoku mlijeka), kao i grafičkom prikazu svih faza mužnji (pripremnoj, glavnoj, slijepoj i naknadnoj). Početna ulaganja u kupnju opreme su velika. Međutim, sve informacije do kojih možemo doći ovim uređajem brzo bi opravdale uložena sredstva. Na Poljoprivrednom fakultetu u Osijeku u tijeku je znanstveno istraživanje s Lacto-Corderom čiji je cilj detaljnije proučavanje muznih svojstava i njihova povezanost sa zdravljem vimena krava.LactoCorder is a new measurement device for cow milk productivity control and sample isolation. As a measurement device it has been recognized by ICAR (Internacional Committee for Animal Recording) and is used as an official control device in a German province – Bavaria, The device is composed of two parts: hydraulic one including milk flow through the measuring area and electronic part comprising operational area where data is input and stored. Producer paid special attention to milking traits (average and maximun milk flow) as well as graphicall display of each part of the milking phase: preparation, basic, blind and additional one. Initial equipment purchase investments are large ones. However, taking into account available information obtained by this device invested means would be profitable wery soon. The Faculty of Agriculture in Osijek has been started a scientific – investigation project aimin at study milking traits and their correlation with cows udder health

Use of internet in agriculture

Internet je skup računalnih mreža koje po određenom protokolu omogućuju komunikaciju velikog broja računalnih sustava širom svijeta. Čovjek u svakodnevnom radu teži proširiti informacije korisne za svoje usavršavanje i obrazovanje. Internet, kao globalna svjetska računalna mreža, pruža novu kvalitetu u mogućnostima komuniciranja i razmjene podataka. Posebno vrijedan izvor brzo dostupnih i točnih inforamcija smatraju se on-line baze podataka, koje su važne i u poljoprivrednim istraživanjima.Internet is a group of computer nets, which by certain protocol enables the communication of a large number of computer systems all over the world. Man in his daily work tries to widen information useful for his improving and education. Internet, as a global world computer net, gives a new quality to communication possibilities and data exchange. A very valuable source of quickly accessible and accurate information are on-line databases, which can be very significant in research work in agriculture

Različitosti u muznim, mliječnim i zdravstvenim svojstvima kod krava u proizvodnji mlijeka ovisno o rednom broju laktacije

The aim of this study was to determine the differences in milkability, milk and health traits in Holstein and Simmental dairy cattle due to parity. Following traits were analysed: milkability (duration of milking, MT; milk yield per milking, MYM; maximal, MMF and average milk flow, AMF), milk traits (daily milk yield, DMY; daily fat content, DFC; daily protein content, DPC; daily lactose content, DLC; urea, UREA) and health traits (logarithmic somatic cell count, SCClog and teatend hyperkeratosis, TEH). Significant (p<0.05; p<0.01; p<0.0001) differences between parity in MYM, DMY, MMF, DPC and DLC was determined. Also, significant (p<0.0001) difference in the teat-end hyperkeratosis score were found between cows in 1st and 2nd as well as between cows in 1st and ≥3rd parity. The cows in 1st and 2nd parity had similar SCClog, while significant (p<0.05) difference was found between SCClog in cows in 1st and cows in ≥3rd parity. The obtained results indicate that the parity significantly affect the milkability, milk and health traits. Since the hyperkeratosis level is highly correlated to the mastitis incidence risk, the regular teat-end scoring should be used in order to ensure quality machine milking and to minimize mastitis incidence risk.Cilj rada bio je utvrditi različitosti u muznim, mliječnim i zdravstvenim svojstvima krava simentalske i holstein pasmine ovisno o rednom broju laktacije. Analizirana su sljedeća svojstva: muzna (trajanje mužnje, MT; količina mlijeka po mužnji, MYM; maksimalni, MMF i prosječni protok mlijeka, AMF), svojstva mlijeka (dnevna količina mlijeka, DMY; dnevna količina masti, DFC; dnevna količina proteina, DPC; dnevna količina laktoze, DLC; urea, UREA) i zdravstvena svojstva (logaritmirani broj somatskih stanica, SCClog; hiperkeratoza vrhova sisa, TEH). Utvrđen je visoko signifikantan (p<0,05; p<0,01; p<0,0001) razlika u: MYM, DMY, MMF, DPC i DLC između svih laktacija. Također je utvrđena visoko značajna (p<0,0001) razlika u hiperkeratozi vrhova sisa između krava u 1. i 2., te između krava u 1. i ≥3. laktaciji. Krave u prvoj i drugoj laktaciji imale su približno isti broj SCClog, međutim značajnost (p<0,05) je utvrđena između SCClog kod krava u prvoj i krava u trećoj i ostalim laktacijama. Rezultati istraživanja ukazuju na to da redni broj laktacije značajno utječe na muzna, svojstva mlijeka i zdravstvena svojstva. Budući da je razina hiperkeratoze jako povezana s rizikom od nastanka mastitisa, potrebno je redovito ocjenjivati vrhove sisa kako bi se osigurala kvalitetna mužnja a ujedno i smanjio rizik od nastanka mastitisa

The Analysis of Variability of Indicators Associated with Prevalence of Subclinical Ketosis/Acidosis in Dairy Cattle

Metabolic disorders of dairy cows, primarily ketosis and acidosis, are one of the most significant problems in dairy herd management. Numerous studies have shown that metabolic disorders induce economic losses for milk producers due to treatment costs, reduced milk production, impaired reproduction, and ultimately increased animal excretion rates. Given the above, and for the purpose of sustainable management of the dairy herd, it is extremely important to detect as early as possible the cows that are at risk of subclinical metabolic disorders and to prevent the development of the clinical form in time. On dairy farms, milk recording is performed every month, which includes the collection of data on the productivity of dairy cattle that are in the system of breeding and selection work. The results of milk recording together with the pedigree data, the basis for calculating the breeding value of cattle and for the implementation of selection in accordance with the breeding program of each breed, also allow the breeder to improve dairy herd management and timely detection of metabolic disorders in the subclinical phase using precision dairy farming technologies. The daily content of milk fat and protein represents the basis for estimating the prevalence, with the optimal values of the ratio of milk fat and protein being 1.1 - 1.5, while the deviation from the same indicates the prevalence of acidosis or ketosis. The aim of this study was to determine the prevalence of subclinical disorders of Simmental and Holstein cows depending on the season by applying precision dairy farming technologies- that is, the results of milk recording. Our logical control dataset consisted of over 1.6 million of test day records (Holstein cows: 805,247 records/ 69,368 animals/ 4,998 farms; and Simmental cows: 845,514 records/ 78,540 animals/ 7,242 farms). Conducted analysis indicated that daily milk production, stage of lactation, parity, age at first calving, milk recording, and cattle breed significantly affected daily fat and protein content as well as F/P ratio. Also, determined higher values of F/P ratio in winter period indicates higher ketosis prevalence risk, while lower values of F/P ratio in summer period indicates higher acidosis prevalence risk. Finally, in order to more precisely predict the ketosis / acidosis prevalence in dairy cows based on milk recording data, factor that significantly affects the variability of daily fat and protein content, and consequently the fat to protein ratio as well as the prevalence risk of metabolic disorders should be taken into account

Utjecaj vrijednosti temperaturno-humidnog indeksa na dnevnu proizvodnju mliječnih goveda

The objectives of this study were to determine the microclimatic conditions in stables in three climactic regions (East, Mediterranean, and Central) of Croatia as well as to evaluate the effect of temperature-humidity index (THI) values on the daily production of dairy cattle. With that purpose, 1675686 test-day records collected from January 2005 until April 2010 were extracted from HPA (Croatian Agricultural Agency) database. For estimation of the effect of THI on daily production of dairy cows fixed-effect model that took into account the effects of lactation stage, breed, calving season, measuring season, and THI group (T1 - THI≤72; T2 - THI>72) was used. Model was applied to each class of parity (P1, P2, P3, P4 and P5) and region. During the analysed period, the highest monthly averages of ambient temperature were determined in Mediterranean region, the highest monthly averages of relative humidity were observed in Central region, while the highest monthly mean values of temperature-humidity index (THI) were determined in Mediterranean region. Heat stress conditions indicated with mean daily values of THI>72 were determined during spring and summer season in all analysed regions. Absence of heat stress conditions during autumn and winter season also characterised all three regions. Highly significant (P72). Model je apliciran zasebno po razredima redoslijeda laktacije (P1, P2, P3, P4 i P5) te regije. Tijekom analiziranog razdoblja, najviše prosječne mjesečne vrijednosti ambijentalne temperature utvrđene su u mediteranskoj, najviše prosječne mjesečne vrijednosti relativne vlage utvrđene su u centralnoj, dok su najviše prosječne mjesečne vrijednosti temperaturno-humidnog indeksa (THI) utvrđene u mediteranskoj regiji. Toplinsko stresni uvjeti indicirani prosječnom dnevnom vrijednošću THI>72 utvrđeni su tijekom proljetne i ljetne sezone u svim analiziranim regijama. Odsustvo toplinsko stresnih uvjeta tijekom jesenske i zimske sezone karakteriziralo je sve tri regije. Visoko signifikantan (P<0.01) pad dnevne količine mlijeka te dnevnog sadržaja mliječne masti i bjelančevina uzrokovan povišenom vrijednošću THI utvrđen je u svih grla neovisno o redoslijedu laktacije te u svim klimatskim regijama. Nadalje, najizraženiji negativni utjecaj toplinskog stresa utvrđen je u istočnoj regiji. Tijekom razdoblja toplinskog stresa, s ciljem minimalizacije utjecaja istog, neophodna je prilagodba managementa u stadu mliječnih grla. Uzgajivačima su na raspolaganju različiti alati za borbu protiv toplinskog stresa. Na primjer, hlađenje okoliša omogućuje unos dostatne količine krmiva dok prikladan sastav obroka osigurava dostatan unos hranjiva. Navedeno omogućava održavanje optimalne proizvodnje mlijeka