PREDICTION OF SERVICE PERIOD DURATION OF COWS ACCORDING TO MILK YIELD AND COMPOSITION IN EARLY LACTATION

Ciljevi su ovoga istraživanja bili determinirati značajne utjecaje na trajanje razdoblja od teljenja do koncepcije (servis razdoblje), zatim utvrditi povezanost između trajanja servis razdoblja i svojstava rezultata provedbe kontrole mliječnosti te razviti sustav predviđanja trajanja servis razdoblje temeljem rezultata kontrole mliječnosti na početku laktacije (prve dvije kontrole) u populaciji holstein i simentalske pasmine krava. Statističkom obradom metodom analize preživljavanja i metodom logističke regresije obuhvaćeno je 14.864 krave holstein pasmine, s ukupno 29.278 zapisa rezultata kontrole mliječnosti, te 18.708 krava simentalske pasmine, s ukupno 37.416 zapisa rezultata kontrole mliječnosti. Vrijednosti koeficijenata korelacija između trajanja servis razdoblja i svojstava rezultata provedbe kontrole mliječnosti kretale su se unutar raspona ±0,00 do ±0,20 što upućuje na njihovu zanemarivu povezanost. Veća vjerojatnost koncepcije po svim razredima trajanja servis razdoblja u simentalske u odnosu na holstein pasminu utvrđena je analizom kretanja krivulje preživljavanja trajanja servis razdoblja. Provedbom logističke regresije izrađena su dva statistička modela. Model 1., koji uključuje varijable rezultata provedbe kontrole mliječnosti zasebno za svaku pasminu i svaki kontrolni dan. Model 2., koji, pored varijabli iz prvoga modela, uključuje i utjecaje regije, sezone i veličine stada, sezone koncepcije i sezone teljenja. Ispitivanje snage modela za predviđanje događaja prikazano je pomoću indeksa konkordacije, koji predstavlja sukladnost slaganja registriranih i predviđenih podataka unutar svakog modela. Utvrđeno je povećanje vrijednosti indeksa konkordacije za svaki model s većim rednim brojem u odnosu na početni model, kao i povećanje vrijednosti indeksa konkordacije za kontrolni dan 2. u odnosu na kontrolni dan 1. kod obje promatrane pasmine.The objectives of this research were to determine significant effects on the duration of the period from calving to conception (service period), the relationship between the duration of the service periods and the traits recorded during the milk recording and develop a system of predicting the duration of service period based on the milk recording results in early lactation (the first two controls) in Holstein and Simmental cows population, which would consequently increase competitiveness and financial performance of the farm. Statistical analysis using survival analysis and logistic regression method included 14,864 Holstein cows with a total of 29,278 milk recording records and 18,708 Simmental cows with a total of 37,416 milk recording records. Correlation coefficient values were within the range ±0.00 to ±0.20 indicating a negligible correlation between the service periods duration and the traits recorded during the milk recording. Higher conception probability at all classes of service periods duration in the Simmental compared to the Holstein breed was determined using the analysis of movement survival curves for service period duration. Based on the results of logistic regression two statistical models were created. Model 1 includes traits recorded during the milk recording separately for each breed and each test day. Model 2, besides traits from model 1, also included effects of region, season of recording, herd size classes, season of conception and calving season. The power testing of the models for prediction of incident was shown using the concordance index representing the compliance agreement of recorded and predicted data within each model. The increase of the concordance index value was determined for each model with a higher number in comparison to the initial model. Additionally, the increase of the concordance index value was determined for control day 2 compared to the control day 1 for both analysed breeds

Varijabilnost potencijala oporavka krava s obzirom na sezonu kontrole mliječnosti

The purpose of the study was to investigate how different milk recording seasons affected the prevalence of mastitis and the potential for cows to recover from it. After conducting logical data validation, a total of 3,953,637 test-day records of Holstein cows obtained during the milk recording period from January 1, 2005, to December 31, 2022, were used. The findings revealed that mastitis was most prevalent in the autumn season, and during this period, there was a lower total increase in milk production. On the other hand, the prevalence of healthy cows was maximum in summer and winter, while the winter season showed the highest overall increase in milk production. These results suggest that the prevalence of mastitis and the potential for recovery in cows are significantly influenced by the season, and the values may vary considerably. During the winter season, which is characterized by lower temperatures and humidity levels, the animals have the maximum likelihood of recuperation and regaining their production capacity in a manner that is consistent with their genetic potential.Cilj istraživanja bio je utvrditi utjecaj sezone kontrole mliječnosti na prevalenciju mastitisa i mogućnost oporavka krava nakon mastitisa. Nakon provedbe logičke kontrole podataka, analizirano je ukupno 3.953.637 zapisa na kontrolni dan krava holstein pasmine prikupljenih u razdoblju od 1. siječnja 2005. do 31. prosinca 2022. Utvrđeni rezultati su pokazali da je prevalencija mastitisa najviša u jesenskom razdoblju te je u tom razdoblju manji ukupni porast proizvodnje mlijeka. S druge strane, prevalencija zdravih krava bila je najveća tijekom ljetnog i zimskog perioda, dok je najveći ukupni porast proizvodnje mlijeka utvrđen tijekom zime. Nadalje, ovi rezultati sugeriraju da su prevalencija mastitisa i potencijal oporavka krava pod značajnim utjecajem sezone, te vrijednosti mogu značajno varirati. Tijekom zimske sezone, koju karakteriziraju niže temperature i niža relativna vlaga u proizvodnim objektima, krave imaju maksimalnu vjerojatnost oporavka i ponovnog uspostavljanja proizvodnog kapaciteta u skladu s njihovim genetskim potencijalom

Nutritional and energy value of corn silage on dairy farms in Eastern Croatia

Cilj ovog istraživanja je bio utvrditi kvalitetu kukuruzne silaže kao dominantne komponente u hrani mliječnih krava u tri županije Istočne Hrvatske; Brodsko-posavske, Osječko-baranjske i Vukovarsko-srijemske. Praktični dio istraživanja obuhvatio je 25 mliječnih farmi u svakoj Županiji u kojima je uzorkovana i potom analizirana kukuruzna silaža. Praćeni nutritivni, fermentativni i fizički pokazatelji izraženi kao prosječne vrijednosti bili su dobri. Pokazatelji kemijskog sastava: suha tvar (ST)=349 g/kg, sirove bjelančevine=71 g/kg ST, sirovi pepeo=39 g/kg ST, sirova vlakna=186 g/kg ST, kisela deterdžent vlakna=212 g/kg ST, neutralna deterdžent vlakna=393 g/kg ST, kiseli deterdžent lignina=17 g/ kg ST, škrob=325 g/kg ST, energetska vrijednost izražena u neto energiji za laktaciju (NEL, MJ/kg ST)=6,78, prosječna probavljivost organske tvari=75,8% i probavljivost neutralnih deterdžent vlakana=53,7%. Pokazatelji fermentacije silaže uključili su mjerenje prosječne pH vrijednosti koja je iznosila 3,86, koncentraciju mliječne kiseline=56,37 g/kg ST i octenu kiselinu 20,68 g/kg ST. Fizički pokazatelj, određivanje distribucije veličine čestica silaže (sustav tri sita) zabilježio je; sito 1=7,1%; sito 2=56,3%; sito 3=24,8% i kutija na dnu=11,7%. S obzirom na utvrđene statističke značajnosti testiranih razlika prosječnih vrijednosti kod devet pokazatelja hranjive i energetske vrijednosti silaže kukuruza između županija, moguće je potvrditi da je kvaliteta silaže bila bolja u Osječko-baranjskoj i Brodsko-posavskoj županiji u odnosu na Vukovarsko-srijemsku. Na temelju značajnijih odstupanja u minimumu i maksimumu te utvrđivanjem većeg broja nesukladnih uzoraka kod nekih pokazatelja od prosječnih vrijednosti, navodi na zaključak o neujednačenoj kvaliteti silaže kod pojedinih proizvođača.The aim of this study was to determine the quality of corn silage as the dominant component in the diet of dairy cows in three counties of Eastern Croatia; Brod-Posavina, Osijek-Baranja, and Vukovar-Srijem. The practical part of the research included 25 dairy farms in each County in which corn silage was sampled and then analyzed. The monitored nutritional, fermentative, and physical indicators expressed as average values were satisfactory. Indicators of chemical composition: dry matter (DM) = 349 g/kg, crude protein = 71 g/kg DM, crude ash = 39 g/kg DM, crude fiber = 186 g/kg DM, acidic detergent fiber (ADF) = 212 g/kg DM, neutral detergent fiber (NDF) = 393 g/kg DM, acidic detergent lignin (ADL) = 17 g/kg DM, starch = 325 g kg DM, energy value expressed in net energy for lactation (NEL, MJ/kg DM) = 6.78, average digestibility of organic matter (dOM) = 75.8% and digestible neutral detergent fibers (dNDF)= 53.7%. Indicators of silage fermentation included the measurement of an average pH of 3.86, a concentration of lactic acid = 56.37 g/kg DM, and acetic acid of 20.68 g/kg DM. Physical indicator, determination of silage particle size distribution (three sieve system) recorded following values: sieve 1 = 7.1%; sieve 2 = 56.3%; sieve 3 = 24.8% and box at the bottom = 11.7%. Given the established statistical significance of the tested differences in average values for nine indicators of nutritional and energy value of corn silage between counties, it is possible to confirm that the quality of silage was better in OsijekBaranja and Brod-Posavina counties than in Vukovar-Srijem County. Based on significant deviations in the minimum and maximum, and by determining a larger number of non-compliant samples in some indicators than the average values, it leads to the conclusion of uneven quality of silage in some producers

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)

ESTIMATION OF PREVALENCE, EFFECT AND COST OF MASTITIS ON SIMMENTAL DAIRY FARMS OF DIFFERENT SIZES

Mastitis, a production disease highly prevalent in dairy farming, poses a significant challenge to farmers. It is responsible for decreased milk production, reduced milk quality, and increased treatment costs. Thus, early detection and prompt treatment are essential to prevent the infection and minimize the mastitis impact. This study aimed to determine how farm size affects the prevalence, effect, and cost of mastitis. Therefore, a total of 4,922,751 test-day records for dairy Simmental cows collected in the period 2005-2022 were analysed. Results showed that mastitis was most prevalent among small farms, which also exhibited a lower total increase in milk production. In contrast, the highest prevalence of healthy cows was observed at large farms, with the highest total increase in milk production

Prediction of service period duration of cows according to milk yield and composition in early lactation

Ciljevi su ovoga istraživanja bili determinirati značajne utjecaje na trajanje razdoblja od teljenja do koncepcije (servis razdoblje), zatim utvrditi povezanost između trajanja servis razdoblja i svojstava rezultata provedbe kontrole mliječnosti te razviti sustav predviđanja trajanja servis razdoblje temeljem rezultata kontrole mliječnosti na početku laktacije (prve dvije kontrole) u populaciji holstein i simentalske pasmine krava. Statističkom obradom metodom analize preživljavanja i metodom logističke regresije obuhvaćeno je 14.864 krave holstein pasmine s ukupno 29.278 zapisa rezultata kontrole mliječnosti, te 18.708 krava simentalske pasmine s ukupno 37.416 zapisa rezultata kontrole mliječnosti. Vrijednosti koeficijenata korelacija između trajanja servis razdoblja i svojstava rezultata provedbe kontrole mliječnosti kretale su se unutar raspona ±0,00 do ±0,20 što upućuje na njihovu zanemarivu povezanost. Veća vjerojatnost koncepcije po svim razredima trajanja servis razdoblja u simentalske u odnosu na holstein pasminu utvrđena je analizom kretanja krivulje preživljavanja trajanja servis razdoblja. Provedbom logističke regresije izrađena su dva statistička modela. Model 1. koji uključuje varijable rezultata provedbe kontrole mliječnosti zasebno za svaku pasminu i svaki kontrolni dan. Model 2. koji pored varijabli iz prvog modela uključuje i utjecaje regije, sezone i veličine stada, rednog broja teljenja, sezone koncepcije i sezone teljenja. Ispitivanje snage modela za predviđanje događaja prikazano je pomoću indeksa konkordacije koji predstavlja sukladnost slaganja registriranih i predviđenih podataka unutar svakog modela. Utvrđeno je povećanje vrijednosti indeksa konkordacije za svaki model s većim rednim brojem u odnosu na početni model kao i povećanje vrijednosti indeksa konkordacije za kontrolni dani 2. u odnosu na kontrolni dan 1. kod obje promatrane pasmineThe objectives of this research were to determine significant effects on the duration of the period from calving to conception (service period), then the relationship between the duration of the service periods and the traits recorded during the milk recording and develop a system of predicting the duration of service period based on the results milk recording in early lactation (the first two control) in a population of Holstein and Simmental cows, which would consequently increase competitiveness and financial performance of the farm. Statistical analysis using survival analysis and logistic regression method included 14,864 Holstein cows with a total of 29,278 milk recording records, and 18,708 Simmental cows with a total of 37,416 milk recording records. Correlation coefficient values were within the range ± 0.00 to ± 0.20 which indicates a negligible correlation between the duration of the service periods and the traits recorded during the milk recording. Higher conception probability at all classes of duration of service periods in the Simmental compared to the Holstein breed was determined using the analysis of movement survival curves for duration of service period. Based on results of logistic regression two statistical models were created. Model 1 includes traits recorded during the milk recording separately for each breed and each test day. Model 2 besides traits from model 1 also included effects of region, season of recording, herd size classes, parity, season of conception and season of calving. The power testing of models for prediction of incident was shown using the concordance index which represents the compliance agreement of recorded and predicted data within each model. The increase of the concordance index value was determined for each model with a higher number in comparison to the initial model. Additionally, the increase of the concordance index value was determined for control day 2 compared to the control day 1 for both analysed breed

Seasonal Trends in Holstein Milk Traits

The dairy industry acknowledges the seasonal nature of milk production and the fluctuations in milk component concentrations throughout the year. This variability in milk components, influenced by seasonal changes, assumes critical importance in light of the projected global population increase to 9.7 billion people within the next 20–50 years. Addressing the imminent need for major alterations in agricultural and livestock practices to accommodate this growth necessitates a comprehensive evaluation of all stages within the food production chain. An essential aspect of achieving sustainable agriculture involves identifying opportunities to reduce gaseous pollutants. This study aims to investigate how seasonal variations impact the specific properties of Holstein milk, with a focus on the daily milk yield, daily milk protein, daily milk fat, and urea content. Test-day records from Holstein dairy cows in Croatia, collected during routine milk assessments from January 2005 to December 2022, form the basis of this research. A meticulous process of logical scrutiny of milk recording data, compliant with the ICAR standards, and rectification of non-logical variable values ensured the inclusion of 5,164,920 Holstein test-day records in the refined database. Our analysis centers on the annual number of samples and the primary parameters of milk content (namely fat, protein, and urea). The examination of Holstein milk samples revealed recurring cyclical patterns, indicating higher values during winter and lower values in summer. These distinct variations likely correlate with the annual climatic fluctuations in Croatia. The implications of these findings warrant future research to monitor trends in the raw milk quality and assess the potential adverse effects of the identified changes on the milk properties

The Effect of Age of Cows on Variability in Mastitis Prevalence Risk and its Concomitant Impacts on the Successive Daily Milk Yield

The purpose of this study is to determine the effect of age of cows on variability in mastitis prevalence risk and its concomitant impacts on their successive daily milk yield by analyzing test-day records of dairy cows collected in the period 2005–2022. The results obtained indicate a correlation between the age and breed of cows enrolled in the study and mastitis prevalence risk alongside its concomitant impacts on their successive daily milk yield. The findings demonstrate a progressive increase in mastitis prevalence risk with the advancing age of cows, notably more pronounced in the Holstein breed than in the Simmental breed. The Simmental cows exhibited a lower increase in daily milk yield, experiencing a substantial decrease in overall yields (namely milk, fat, and protein) in contrast to the Holstein cows. The primiparous cows of both breeds displayed the highest total increase in daily milk yield. This study underscores the significance of monitoring dairy herd health as a pivotal component of successful dairy herd management. Moreover, the daily lactose content was found a valuable and cost-effective indicator for ensuring the economically and environmentally sustainable operations of dairy farms