Koncentracija ureje u mlijeku holstein i simentalskih krava

Determining the urea concentration in milk is a useful indicator of the nutritional protein status of the organism as well as of the ratio between the energy and the protein in ruminant rations, with increasing practical usage. In addition to nutrition, milk urea concentration is influenced by a whole range of factors, for example: breed, stage and number of lactations, body weight, daily production and chemical composition of milk, somatic cell count, season and milking. The objective of this research was to determine the impact of the cow breed (Holstein and Simmental), the number of lactation (1st, 2nd, 3rd, 4th, 5th), milking time (morning-evening) and season (spring-summer and autumn-winter) on milk urea concentration. The following was determined for each breed: daily milk yield, milk fat, protein and lactose content, urea concentration and somatic cell count in milk. Statistical data processing was carried out by applying General Linear Model procedure, SAS system (1999). The cow breed had a significant influence on daily milk yield and log somatic cell count (P<0.001), lactose content in milk (P<0.01), milk fat content and milk urea concentration (P<0.05). The number of lactations significantly influenced daily milk yield (P<0.001), protein content (P<0.001 and P<0.01) and milk urea concentration, but only for Holstein breed (P<0.05). Milking time significantly influenced the fat and protein content (P<0.001) in the milk of Holstein cows, that is, lactose content (P<0.05) and urea concentration (P<0.05) in the milk of Simmental cows. The season significantly influenced the fat and protein content of milk (P<0.001), that is, urea concentration and log somatic cell count (P<0.01). Determining of urea concentration in cow milk should also be systematically conducted in the Republic of Croatia, in order to determine standard physiological values characteristical for a particular cow breed, aiming to determine the balance of energy and protein in rations.Određivanje koncentracije ureje u mlijeku koristan je pokazatelj opskrbljenosti organizma proteinima, kao i odnosa energije i proteina u obroku preživača, te ima sve veću praktičnu primjenu. Na koncentraciju ureje u mlijeku, osim hranidbe utječe niz čimbenika kao što su: pasmina, stadij i redoslijed laktacije, tjelesna masa, dnevna proizvodnja i kemijski sastav mlijeka, broj somatskih stanica, sezona i mužnja. Cilj istraživanja bio je utvrditi utjecaj pasmine krava (holstein i simentalska), redoslijeda laktacije (1., 2., 3., 4. i 5.), mužnje (jutarnja - večernja) i sezone (proljeće-ljeto i jesen-zima) na koncentraciju ureje u mlijeku. Za svaku pasminu utvrđena je dnevna količina mlijeka, udio mliječne masti, proteina, laktoze, koncentracija ureje i broj somatskih stanica u mlijeku. Statistička obrada podataka izvršena je primjenom procedure General Linear Model, programskog sustava SAS (1999). Pasmina krava značajno je utjecala na dnevnu količinu mlijeka i log broj somatskih stanica (P<0,001), udio laktoze u mlijeku (P<0,01), udio mliječne masti i koncentraciju ureje u mlijeku (P<0,05). Redoslijed laktacije značajno je utjecao na dnevnu količinu mlijeka (P<0,001), udio proteina u mlijeku (P<0,001 i P<0,01) te na koncentraciju ureje u mlijeku ali samo kod holstein pasmine (P<0,05). Vrijeme mužnje značajno je utjecalo na udio mliječne masti i proteina (P<0,001) u mlijeku holstein krava odnosno na udio laktoze (P<0,05) i koncentraciju ureje (P<0,05) u mlijeku simentalskih krava. Sezona je imala značajan utjecaj na udio mliječne masti i proteina u mlijeku (P<0,001) odnosno na koncentraciju ureje i log broj somatskih stanica (P<0,01). Određivanje koncentracije ureje u kravljem mlijeku trebalo bi sustavno provoditi i u RH, kako bi se utvrdile standardne fiziološke vrijednosti karakteristične za pojedinu pasminu krava, a u cilju procjene izbalansiranosti obroka energijom i proteinima

Koncentracija ureje u mlijeku holstein i simentalskih krava

Determining the urea concentration in milk is a useful indicator of the nutritional protein status of the organism as well as of the ratio between the energy and the protein in ruminant rations, with increasing practical usage. In addition to nutrition, milk urea concentration is influenced by a whole range of factors, for example: breed, stage and number of lactations, body weight, daily production and chemical composition of milk, somatic cell count, season and milking. The objective of this research was to determine the impact of the cow breed (Holstein and Simmental), the number of lactation (1st, 2nd, 3rd, 4th, 5th), milking time (morning-evening) and season (spring-summer and autumn-winter) on milk urea concentration. The following was determined for each breed: daily milk yield, milk fat, protein and lactose content, urea concentration and somatic cell count in milk. Statistical data processing was carried out by applying General Linear Model procedure, SAS system (1999). The cow breed had a significant influence on daily milk yield and log somatic cell count (P<0.001), lactose content in milk (P<0.01), milk fat content and milk urea concentration (P<0.05). The number of lactations significantly influenced daily milk yield (P<0.001), protein content (P<0.001 and P<0.01) and milk urea concentration, but only for Holstein breed (P<0.05). Milking time significantly influenced the fat and protein content (P<0.001) in the milk of Holstein cows, that is, lactose content (P<0.05) and urea concentration (P<0.05) in the milk of Simmental cows. The season significantly influenced the fat and protein content of milk (P<0.001), that is, urea concentration and log somatic cell count (P<0.01). Determining of urea concentration in cow milk should also be systematically conducted in the Republic of Croatia, in order to determine standard physiological values characteristical for a particular cow breed, aiming to determine the balance of energy and protein in rations.Određivanje koncentracije ureje u mlijeku koristan je pokazatelj opskrbljenosti organizma proteinima, kao i odnosa energije i proteina u obroku preživača, te ima sve veću praktičnu primjenu. Na koncentraciju ureje u mlijeku, osim hranidbe utječe niz čimbenika kao što su: pasmina, stadij i redoslijed laktacije, tjelesna masa, dnevna proizvodnja i kemijski sastav mlijeka, broj somatskih stanica, sezona i mužnja. Cilj istraživanja bio je utvrditi utjecaj pasmine krava (holstein i simentalska), redoslijeda laktacije (1., 2., 3., 4. i 5.), mužnje (jutarnja - večernja) i sezone (proljeće-ljeto i jesen-zima) na koncentraciju ureje u mlijeku. Za svaku pasminu utvrđena je dnevna količina mlijeka, udio mliječne masti, proteina, laktoze, koncentracija ureje i broj somatskih stanica u mlijeku. Statistička obrada podataka izvršena je primjenom procedure General Linear Model, programskog sustava SAS (1999). Pasmina krava značajno je utjecala na dnevnu količinu mlijeka i log broj somatskih stanica (P<0,001), udio laktoze u mlijeku (P<0,01), udio mliječne masti i koncentraciju ureje u mlijeku (P<0,05). Redoslijed laktacije značajno je utjecao na dnevnu količinu mlijeka (P<0,001), udio proteina u mlijeku (P<0,001 i P<0,01) te na koncentraciju ureje u mlijeku ali samo kod holstein pasmine (P<0,05). Vrijeme mužnje značajno je utjecalo na udio mliječne masti i proteina (P<0,001) u mlijeku holstein krava odnosno na udio laktoze (P<0,05) i koncentraciju ureje (P<0,05) u mlijeku simentalskih krava. Sezona je imala značajan utjecaj na udio mliječne masti i proteina u mlijeku (P<0,001) odnosno na koncentraciju ureje i log broj somatskih stanica (P<0,01). Određivanje koncentracije ureje u kravljem mlijeku trebalo bi sustavno provoditi i u RH, kako bi se utvrdile standardne fiziološke vrijednosti karakteristične za pojedinu pasminu krava, a u cilju procjene izbalansiranosti obroka energijom i proteinima

Partitioning of Genetic Trends by Origin in Croatian Simmental Cattle

The objective of this study was to partition genetic trend for milk (protein yield) and meat (net daily gain) traits by the origin of selection in Croatian Simmental cattle. In order to evaluate overall genetic trend, breeding values were averaged by the year of birth and origin. Origin was defined as a country where animal was initially registered. Overall genetic trend for protein yield was positive. The relative effect of three origins on the overall genetic trend for protein yield was 43.5% for Germany, 33.9% for Croatia, and 22.1% for Austria at the end of analysed period. Genetic trend for net daily gain was also positive. The Croatian and German partitions had large contribution to the overall genetic trend, while small partition was attributed to the Austrian origin. At the end of analysed period, the relative effect of these three origins on the overall genetic trend for net daily gain was 57.0% for Croatia, 38.5% for Germany, and 4.5% for Austria. Selection work originated from Austria, Croatia, and Germany had effect on genetic trend in Croatia. Other origins did not contribute notably to the overall genetic trend of both traits

The influence of ordinal number and stage of lactation on milkability traits in Holstein cows

Muzna svojstva goveda imaju sve veću važnost u suvremenoj govedarskoj proizvodnji mlijeka, iako su sekundarno selekcijsko obilježje. Strojna mužnja krava ukazala je da ne postoji potpuna usklađenost između muznog uređaja i životinje, što dovodi do produžene mužnje ili narušavanja zdravlja vimena. Zato je cilj rada bio istražiti utjecaj stadija i redoslijeda laktacije na sljedeće muzne parametre: ukupna količina mlijeka po mužnji (KMM), maksimalni protok mlijeka (MPM), prosječni protok mlijeka glavne faze mužnje (PPM), vrijeme trajanja startnog protoka (tS500), trajanje uzlazne faze mužnje (tUFM), trajanje plato faze mužnje (tPFM), trajanje silazne faze mužnje (tSFM) i trajanje glavne faze mužnje (tGFM), te iste preporučiti za selekcijski rad. Istraživanje je uključilo 322 krave holstein pasmine od prve do treće laktacije, raspoređene u tri stadija (prvi od 50. do 90. dana, drugi od 91. do 135. dana i treći od 136. do 180. dana laktacije). Rezultati istraživanja pokazali su kako je redoslijed laktacije značajno (P<0,01) utjecao na KMM i MPM, te na PPM i tGFM (P<0,05). U drugoj laktaciji značajan utjecaj (P<0,05) stadija uočen je za MPM, tS500 i tUFM. Značajan utjecaj stadija laktacije na KMM zabilježen je u prvoj i drugoj laktaciji (P<0,05) odnosno u trećoj laktaciji (P<0,01). Utvrđen je značajan pozitivan utjecaj KMM (P<0,05) na MPM, tPFM, tSFM i tGFM (r = od 0,22 do 0,52). Utvrđena je negativna korelacija MPM (P<0,05) s pojedinim dijelovima vremenskog trajanja faza mužnji (r = od -0,14 do -0,47). Dobiveni rezultati ukazuju na činjenicu da postoji mogućnosti za selekcijski rad na poboljšanju muznosti krava, što se može pozitivno odraziti na ekonomičnost utroška vremena prilikom mužnje, te indirektno popraviti zdravlje vimena.Milkability traits have an increasing importance in modern cattle production, although they are the secondary selective trait. The machine milking of cows has indicated that there is no complete alignment between the machine and the animals, what lead to increasing duration of milking and disturbances in health of udder. Because of that, the aim of this study was to investigate the influence of the ordinal number of lactation and stage of lactation on milkability traits (amount of milk per milking (KMM), maximum milk flow rate (MPM), average milk flow rate (PPM), duration of the start of milk flow (tS500), duration of the ascending phase of milking (tUFM), duration of the plateau phase of milking (tPFM), duration of the descending phase of milking (tSFM), duration of the main phase of milking (tGFM)), and recommend the same for the selection work. The study was done on 322 Holstein cows in the period from the first to third lactation, arranged in three stages of lactation (the first of the 50-90 day, the second stage of the 91-135 day and a third of 136-180 day of lactation). The results showed that the ordinal number of lactation had a highly statistically significant influence (P<0.01) on KMM and MPM, and on the PPM and tGFM (P<0.05). Statistically significant influence of the stage of lactation on the KMM was recorded in the first and second lactation (P<0.05) respectively in the third lactation (P<0.01). Was recorded a significant positive influence of KMM (P<0.05) on the MPM, tPFM, tSFM and tGFM (r = from 0.22 to 0.52). The negative correlation of the MPM (P<0.05) was recorded with some parts of the milking phase duration (r = -0.14 to -0.47). The results indicate that there are opportunities for selection work to improve milkability traits, which can have a positive impact on the economy of expenditure of time during milking, and indirectly improve the health of the udder

Nehranidbeni čimbenici sadržaja uree u mlijeku Holstein krava s velikih farmi u Hrvatskoj

Milk urea nitrogen concentration is a reliable indicator of protein energy balance in dairy cows. Concentration of milk urea nitrogen is mostly affected by nutritional factors, but also its concentration can be influenced by some non-nutritional factors. The aim of this research was to determine the effect of season, parity and stage of lactation on concentration of milk urea nitrogen, as well as its association with daily milk yield, milk fat and protein content and somatic cell count. For that purpose, milk control data were collected for 5061 Holstein dairy cows from four dairy farms during five-year period (between January 1999 and December 2005). When milk urea nitrogen was associated with season, the higher concentration was found in the summer and autumn period, while significantly lower concentration was found in the winter and spring period. Milk urea nitrogen was the lowest in first lactation (27.34 mg/dL) and significantly increased with parities. The highest milk urea nitrogen concentration was recorded during mid-lactation stage (100-200 days), while the lowest concentration was found during late lactation stage (>200 days). Daily milk yield increased notably until above 35.00 mg/dL concentration of milk urea nitrogen, and above that level daily milk yield decreased. Milk fat and protein, content and somatic cell count had negative relationship with milk urea nitrogen concentration. The highest value of milk protein (3.41 %) was recorded when milk urea nitrogen ranged from 15 to 25 mg/dL, while milk fat percentage was the highest (4.06 %) when milk urea nitrogen ranged from 15 to 20 mg/dL. Cows with milk urea nitrogen concentration <15 mg/dL had the highest mean somatic cell count (333x103/mL). Results of this study show significant influence of analyzed non-nutritional factors on milk urea nitrogen concentration. These results may be useful in improving the accuracy of models for controlling protein-energy balance in Holstein dairy cows.Sadržaj uree u mlijeku pouzdan je pokazatelj uravnoteženosti odnosa bjelančevina i energije u obroku mliječnih krava. Različiti hranidbeni, ali i neki nehranidbeni čimbenici utječu na udjel uree u kravljem mlijeku. Cilj ovog rada bio je utvrditi utjecaj sezone, redoslijeda i stadija laktacije na udjel uree u mlijeku, kao i povezanost između udjela uree, proizvodnje mlijeka, udjela mliječne masti i bjelančevina te broja somatskih stanica u mlijeku. U tu svrhu su provedene mjesečne kontrole mliječnosti na četiri velike farme mliječnih krava Holstein pasmine (ukupno 5061 krava u razdoblju od siječnja 1999. do prosinca 2005. godine). Sezona je značajno utjecala na udjel uree u mlijeku, čija je koncentracija tijekom ljeta i jeseni bila viša nego zimi i u proljeće. Udjel uree bio je najniži u prvotelki (27,34 mg/dL) te se značajno povećavao u krava višeg reda laktacije. Sredinom laktacije (100-200 dana) zabilježen je najveći, a krajem laktacije (>200 dana) najmanji prosječni sadržaj uree u mlijeku. Proizvodnja mlijeka znatno se povećavala do razine od 35,00 mg uree po 1 dL mlijeka, nakon čega je uslijedio pad. Udjel mliječne masti i bjelančevina te broj somatskih stanica u mlijeku bili su u negativnoj korelaciji sa sadržajem uree. Najviši udjel bjelančevina (3,41 %) zabilježen je u mlijeku s rasponom udjela uree od 15 do 25 mg/dL, dok je najviši udjel mliječne masti (4,06 %) zabilježen kad je urea bila u rasponu od 15 do 20 mg/dL. Najveći prosječni broj somatskih stanica (333x103 mL-1) utvrđen je u mlijeku sa <15 mg/dL uree. Rezultati ovog istraživanja upućuju na zaključak da analizirani nehranidbeni čimbenici značajno utječu na udjel uree u kravljem mlijeku. Na taj način dobiveni rezultati mogu poslužiti prilikom usavršavanja modela za kontrolu uravnoteženosti bjelančevina i energije u obroku mliječnih krava Holstein pasmine

Nutritional Quality of Corn Silage on Dairy Farms in the Republic of Croatia

Za potrebe vrjednovanja kvalitete kukuruzne silaže, u ovome je istraživanju analizirano 270 uzoraka na mliječnim farmama u dvanaest (12) županija. Pripremljeni uzorci analizirani su uz pomoć FT-NIR uređaju uz primjenu spektrometra AgriQuant-B1 (Model: QIA 1020), kojim su analizirane vrijednosti devet (9) nutritivnih, dva (2) pokazatelja fermentacije buraga te tri (3) pokazatelja fermentacije silaže kukuruza. Jedan fizički pokazatelj, distribucija veličine čestica silaže, određen je prosijavanjem preko sustava triju sita (Penn State Separator). Prosječne vrijednosti većine praćenih nutritivnih pokazatelja bile su zadovoljavajuće: suha tvar (ST) = 349 g kg-1, sir. protein = 65 g kg-1ST, sir. pepeo = 38 g kg-1ST, sir. vlakna = 180 g kg-1 ST, kisela deterdžentska vlakna (KDV) = 210 g kg-1ST, neutralna deterdžentska vlakna (NDV) = 387 g kg-1ST, kiseli deterdžentski lignin (KDL) = 17 g kg-1ST, škrob = 336 g kg-1ST, neto energija mlijeka = 6,76 MJ g kg-1ST. Značajnija odstupanja u Max. i Min. utvrđena su za vrijednosti ST (156 nesukladnih uzoraka), za sirovi protein utvrđen je čak 231 nesukladan uzorak, za kisela deterdžentska vlakna 90, a za škrob 233 uzorka. Pokazatelji fermentacije buraga kao prosječna probavljiva organska tvar (pOT) iznosila je = 75,6 %, a probavljiva neutralna deterdžentska vlakna (pNDV) = 52,8 %. Prosječna pH vrijednost je bila poželjnih 3,85, uz prosječnu koncentraciju mliječne (54,9 g kg-1ST) i octene (21,1 g kg-1ST) kiseline. Prosječne vrijednosti distribucije veličine čestica silaža, mjerene četirima frakcijama rezultirale su sljedećim vrijednostima: sito 1–5,7 %; sito 2–55,7 %; sito 3–26,1 % i posuda na dnu–12,6 %. Najjača pozitivna korelativna povezanost utvrđena je između sirovih vlakana u odnosu na KDV (r = 0,870), NDV (r = 0,959) i KDL (r = 0,790) te između NDV-a i KDV-a (r = 0,845). Korelativna povezanost negativnoga predznaka bila je najjača između KDL-a i pOT-a (r = -0,844), škroba u odnosu na sir. vlakna (r = -0,835) i NDV (r = -0,809), te pH i mliječne kiseline (r = -0,804). Navedene korelativne veze između pokazatelja bile su i statistički visoko značajne (p < 0,001).For the purpose of corn silage quality evaluation, 270 samples on dairy farms in twelve (12) counties were analyzed in this study. The prepared samples were subjected to the FT-NIR device using the AgriQuant-B1 spectrometer (Model: QIA 1020), which analyzed the values of nine (9) nutritional, two (2) indicators of rumen fermentation, and three (3) indicators of corn silage fermentation. One physical indicator, the silage particle size distribution, was determined by sieving through a three-sieve system (Penn State Separator). The average values of most of the monitored nutritional indicators were satisfactory: DM = 349 g kg-1, crude protein = 65 g kg-1 DM, crude ash = 38 g kg-1 DM, crude fiber = 180 g kg-1 DM, acid detergent fiber = 210 g kg-1 DM, neutral detergent fiber = 387 g kg-1 DM, acid detergent lignin = 17 g kg-1 DM, starch = 336.59 g kg-1 DM, net energy of milk = 6.76 MJ g kg-1 DM. Significant deviations in Max. and Min. were found for the DM values (156 non-compliant samples), as many as 231 non-compliant samples were found for crude protein, 90 noncompliant samples were detected for the acidic detergent fibers, and 233 for starch. The rumen fermentation indicators, expressed as average digestible organic matter (dOM), amounted to 75.6%, and those of digestible neutral detergent fiber (dNDF) amounted to 52.8%. The average pH value reached a desirable value of 3.85, with an average concentration of lactic acid (54.9 g kg-1 DM) and acetic acid (21.1 g kg-1 DM). The average values of silage particle size distribution, measured through four fractions, resulted in the following values: sieve 1 – 5.7%; sieve 2 – 55.7%; sieve 3 – 26.1% and bottom vessel – 12.6%. The strongest positive correlation was found between the crude fiber in relation to the ADF (r = 0.870), NDF (r = 0.959), and ADL (r = 0.790) and between the NDF and ADF (r = 0.845). Negative correlation was strongest between the ADL and dOM (r = -0.844), between the starch compared to the CF (r = -0.835) and NDF (r = -0.809), and between thepH and lactic acid (r = -0.804). These correlations between the indicators were also statistically highly significant (p<0.001)

Utjecaj genetskih i okolišnih parametara na broj somatskih stanica u mlijeku simentalske i holstein pasmine goveda

The objective of this study was to estimate genetic parameters and environmental effects on somatic cell count in Croatian dairy cows. Data consisted of 861,417 test-day records for Simmental and 656,272 for Holstein cows. For Simmental breed, number of animals in pedigree was 123,199, while pedigree file for Holstein breed included 94,294 animals. A single-trait repeatability fixed regression test-day model was used to estimate genetic parameters. Fixed effects in the model were parity and calving season. Days in milk was fitted using Ali-Schaeffer lactation curve nested within parity. Age at first calving was modelled as quadratic regression. Direct additive genetic effect, herd, herd-test-date, and permanent environmental effect of cow within parity were included in the model as random effects. Variance components were estimated using Residual Maximum Likelihood method as implemented in the VCE-6 program. Estimated heritabilities were 0.21 for Simmental and 0.15 for the Holstein breed. Permanent environmental effect explained 19 % of phenotypic variation in Simmental and 20 % in Holstein breed. Herd and herd-test-date accounted for another 9 % and 5 % of variability for Simmental breed. The effects of herd and herd-test-date explained 10 % and 5 % of phenotypic variance in Holstein breed.Cilj ovog rada bio je ispitati i ocijeniti utjecaj okolišnih čimbenika na varijabilnost broja somatskih stanica u mlijeku i procijeniti komponente varijance. Ukupno je analizirano 861.417 dnevnih zapisa krava simentalske i 656.272 dnevna zapisa krava holstein pasmine. Porijeklo simentalske pasmine uključuje 123.999, a porijeklo holstein pasmine 94.294 životinje. Za procjenu genetskih parametara korišten je model dnevnih zapisa s fiksnom regresijom. Fiksni dio modela je uključivao utjecaj rednog broja laktacije i sezone teljenja. Stadij laktacije je opisan Ali-Schaefferovom funkcijom ugniježđenom unutar rednog broja laktacije, dok je dob kod prvog teljenja opisana kvadratnom regresijom. Slučajni dio modela je određen stadom, interakcijom stado-dan testiranja, direktnim aditivnim genetskim i stalnim okolišnim utjecajem. Procijenjeni heritabilitet za broj somatskih stanica u mlijeku krava iznosio je h2= 0,21 za simentalsku pasminu, a za holstein pasminu h2=0,15. Stalnim utjecajem okoliša je pojašnjeno 19 % varijabilnosti za simentalsku, te 20 % za holstein pasminu. Utjecajem stada i interakcije stado-dan kontrole za simentalsku pasminu je pojašnjeno 9 % odnosno 5 % od ukupne varijabilnosti broja somatskih stanica. Za holstein pasminu je utjecaj stada i interakcije stado-dan kontrole pojasnio 10 % odnosno 5 % varijabilnosti

Procjena genetskih parametara za svojstvo protoka mlijeka kod holstein pasmine goveda u Hrvatskoj

Milking speed (MS) has a growing importance from a dairy management standpoint. Cows with slow MS require more labour, while cows with fast MS could be in greater risk for udder diseases. Although MS is considered as a trait of importance, little attention has been given to estimate genetic components for MS and its relationship with other traits. The objectives of this study were: 1) to estimate genetic parameters for MS in Croatian Holstein cattle; 2) to use them for the prediction of breeding values; and 3) to estimate proof correlations of MS with production and conformation traits in order to understand the interrelationships among traits. Data included 129,723 test-day records for 35,908 first calving cows taken from the central database of the Croatian Agricultural Agency. Pedigree file consisted of 85,605 animals. In order to improve the normality, logarithmic transformation for MS was used. Variance components where estimated by REML method using VCE 6 program. Statistical model included calving season, milking time, and milk yield class as fixed class effects, while age at first calving and days in milk were fitted as covariates. Random effects were: common herd-test day, permanent environmental and direct additive genetic effect. Common herdtest day and permanent environmental effect accounted 27 % and 15 % of variability. Direct additive genetic effect explained another 14 % of phenotypic variation for MS. Analysis of proof correlations between bulls and cows BV for MS with production and conformation traits showed low to mediate relationships. Most of these proof correlations were positive with an exception of teats length. Genetic evaluation for MS provide useful tool for breeding decisions due to moderate heritability of MS and the trait should be included in the total merit index in the future. In order to determine the appropriate economic weights for MS in the overall index, genetic correlations among MS and production and conformation traits should be estimated.Svojstvo protoka mlijeka (PM) ima sve veću važnost sa stajališta upravljanja proizvodnjom mlijeka. Kod krava sa sporim PM potrebno je više rada, dok krave s brzim PM mogu biti u većoj opasnosti od pojave bolesti vimena. Iako se PM smatra svojstvom od značaja, malo je pozornosti dano procjeni genetskih parametara za PM i njegovoj povezanosti s drugim svojstvima. Ciljevi ovog istraživanja bili su: 1) procijeniti genetske parametre za PM u populaciji holstein goveda u Hrvatskoj; 2) koristiti izračunate genetske parametre za procjenu uzgojnih vrijednosti (UV) za svojstvo PM; i 3) izračunati korelacije između UV za PM s proizvodnim i sa svojstvima vanjštine kako bi se utvrdili međuodnosi između navedenih svojstava. U analizu je bilo uključeno 129.723 zapisa na kontrolni dan za 35.908 prvotelki holstein pasmine, uzetih iz središnje baze podataka Hrvatske poljoprivredne agencije. Podaci o porijeklu sadržavali su zapise za 85.605 životinja. Logaritamska transformacija podataka za svojstvo PM izvršena je s ciljem dobivanja distribucije slične normalnoj. Komponente varijance procijenjene su REML metodom u programu VCE-6. Statistički model je uključivao sljedeće fiksne utjecaje s razredima: sezona teljenja, vrijeme mužnje i razredi količine mlijeka, dok su dob kod prvog teljenja i stadij laktacije korišteni kao kontinuirana varijabla. Slučajni utjecaji u modelu bili su: interakcija stado-kontrolni dan, stalni utjecaj okoliša i aditivni genetski učinak. Interakcija stado-kontrolni dan i stalni utjecaj okoliša su pojasnili 27 % i 15 % ukupne varijabilnosti PM. Aditivni genetski učinak je pojasnio dodatnih 14 % fenotipske varijabilnosti PM. Utvrđene su niske do srednje korelacije UV bikova i krava između PM i proizvodnih te PM i svojstava vanjštine. Izračunate korelacije bile su pozitivne s izuzetkom korelacije između UV za PM i duljine sisa. Genetsko vrednovanje za svojstvo PM pruža korisne informacije za donošenje uzgojnih odluka zbog umjerenog heritabiliteta te bi u budućnosti navedeno svojstvo trebalo uključiti u ukupan selekcijski indeks. Da bi se utvrdile odgovarajuće ekonomske težine za PM u ukupnom selekcijskom indeksu, potrebno je prethodno procijeniti genetske korelacije između PM i proizvodnih svojstava te svojstava vanjštine

Opportunities of implementing the genomic selection in small populations - the Croatian case

Tehnološki napredak i uvođenje genomske selekcije potaknuti globalizacijom i liberalizacijom tržišta rasplodnog materijala doveli su u pitanje održivost postojećih nacionalnih uzgojnih programa posebice u manjim državama. Cilj ovog rada je bio: opisati postupke pri uvođenju i provedbi genomske selekcije u malim populacijama simentalske (SIM) i holstein (HOL) pasmine goveda u Republici Hrvatskoj (HR); predstaviti rezultate uvođenja genomske selekcije; i prikazati perspektive koje genomika nudi za ove populacije. S ciljem unapređenja odabira SIM bikova, RH se pridružila sustavu genomskog vrednovanja Njemačke i Austrije u srpnju 2013. godine. Cilj uvođenja genomske selekcije za HOL populaciju temeljio se na odabiru potencijalnih bikovskih majki u ranoj dobi, a započeo je 2016. godine uključenjem u sustav njemačkog genomskog vrednovanja za HOL pasminu. Ukupno je 268 SIM i 96 HOL teladi odabrano, genotipizirano i za njih je bilo provedeno genomsko vrednovanje. Preporučeni kriterij za ulazak mladih SIM bikova u centre za umjetno osjemenjivanje je genomski optimizirana uzgojna vrijednost za ukupan selekcijski indeks iznad 130, a ujedno kandidati ne smiju ispoljavati genetske defekte niti biti nositelji istih. Na osnovi ovih kriterija, sedam je mladih bikova bilo uključeno u sustav umjetnog osjemenjivanja. Preporučeni kriterij za odabir ženskih grla HOL pasmine je ukupni selekcijski indeks iznad 150, a kandidatkinje ne smiju ispoljavati niti biti nositeljice genetskih defekata. Do sada niti jedno genotipizirano žensko grlo nije zadovoljilo ove standarde. Alternativa njemačkom sustavu genomskog vrednovanja je međunarodni projekt za male HOL populacije (IgHol) koji predstavlja mogućnost ekonomski prihvatljive genomske selekcije. Provođenje aktivnosti genomske selekcije u RH omogućilo je korištenje sjemena bikova iz nacionalnog uzgojnog programa. Provođenje genomske selekcije za ženski dio populacije predstavlja mogućnost odabira najboljih jedinki u ranoj dobi i tako pridonosi ekonomičnosti proizvodnog ciklusa.The implementation of genomic selection (GS) together with the changes caused by globalization and trade liberalization of breeding material often raise the question of sustainability of breeding programs in small cattle populations/countries. The objective of this study was to describe the steps in the implementation of GS in small populations of Croatian Simmental (SIM) and Holstein (HOL) breeds; to show the results of its implementation; and to present the perspectives of GS for these populations. In order to improve the selection of SIM bulls, Croatia joined the German-Austrian genomic evaluation system in July 2013. The main goal of the GS in HOL population was selection of bull’s dams at a young age which started in 2016 through the inclusion in German HOL genomic evaluation system. In total, 268 SIM and 96 HOL calves were selected, genotyped, and genomically tested until the end of 2017. The criterion for the entry of SIM bulls in the artificial insemination (AI) centres is the total merit index over 130 and candidates should not be carriers of specific monogenic defects or be recessive for them. Based on these criteria, seven young bulls were selected as for AI. The criteria for the selection of HOL females are the total merit index of 150, without monogenic defects and so far none of them reached these standards. The future perspective for HOL breed is international IgHol project for small HOL populations representing the possibility for cost-efficient solutions of GS. The implementation of GS brought opportunity to Croatian breeders to use semen of bulls from the national breeding program. Genomics for females becomes an attractive option to capitalise the benefits of using this technology

ESTIMATION OF GENETIC DIVERSITY USING PROBABILITIES OF GENE ORIGIN OF AUTOCHTHONOUS CATTLE BREED BUSHA

Registar izvorne pasmine goveda buša utemeljen je 2003. i danas broji 1020 grla. U cjelokupnom rodovniku utvrđeno je 329 foundera i 249 polufoundera. Broj foundera u referentnoj populaciji iznosi 285, polufoundera 219 i 255 ancestora, a 50% genetske varijabilnosti objašnjava 17 ancestora i 20 foundera. Najveći broj poznatih generacija predaka u rodovniku je pet, s prosječnim ekvivalentom kompletnih generacija 1,41 koji ukazuje na slabu informativnost i kompletnost rodovnika. Dio značajnih predaka je dao svoj doprinos genetskoj varijabilnosti kao founder, ali ne i kao ancestor, što ukazuje na gubitak dijela genetske varijabilnosti. Povećanje stupnja inbreedinga i povezanosti, omjeri pojedinih parametara porijekla gena (fe/fa, fg/fe, fe/f) i smanjenje doprinosa broja foundera u referentnoj populaciju u odnosu na cjelokupan rodovnik, ukazuju na gubitak genetske varijabilnosti u populaciji. Rezultati analize rodovnika ukazuju da je u cilju očuvanja genetske varijabilnosti, nužno i žurno dizajniranje kvalitetnog uzgojnog programa, plana pripusta i konzervacijske strategije, temeljenih na analizama rodovnika i metodama molekularne genetike (DNA).Register of autochthonous cattle breed busha was founded in 2003. and till today it is consisted of 1020 heads. In whole pedigree 329 founders and 249 half-founders are determined. The number of founders in reference population is 285, half-founders 219, and ancestors 255, and 50% of genetic variability explain 17 ancestors and 20 founders. The largest number of complete generations 1,41 which indicates poor informativity and completness of pedigree. Part of significant ancestors gave its contribution to genetic variability as founder, but not as ancestor which indicates loss of part of genetic variability. Increasing of inbreeding rate and connections, ratios of certain parameters of gene origin (fe/fa, fg/fe, fe/f) and decreasing of contribution of number of founders in reference population compared to the whole pedigree, indicate the loss of genetic variability in population. Pedigree analysis results indicate that in purpose of preservation of genetic variability, it is necessary and urgent creating of quality breeding progam, breeding plan and conservation strategy, based on pedigree analysis and method of molecular genetic