In this perspective analysis, we strive to answer the following question: how can we advance integrative biology research in the 21st century with lessons from animal science? At the University of Ljubljana, Biotechnical Faculty, Department of Animal Science, we share here our three lessons learned in the two decades from 2002 to 2022 that we believe could inform integrative biology, systems science, and animal science scholarship in other countries and geographies. Cultivating multiomics knowledge through a conceptual lens of integrative biology is crucial for life sciences research that can stand the test of diverse biological, clinical, and ecological contexts. Moreover, in an era of the current COVID-19 pandemic, animal nutrition and animal science, and the study of their interactions with human health (and vice versa) through integrative biology approaches hold enormous prospects and significance for systems medicine and ecosystem health.

The aim of this study was to estimate perinatal and neonatal mortality rates from day 2 to day 30 in Slovenian Holstein Friesian population and to assess risk factors for increased losses. Data from 420,556 calves of Holstein Friesian cows born in Slovenia in the period from January 2005 to December 2016 were analysed. Data were obtained from the Central register of bovine animals. The average perinatal calf mortality, including abortions and stillbirths, was 8.24% and neonatal mortality from day 2 to day 30 4.28%. The most important effects on perinatal calf mortality rate were the number of calves at calving and the age of dam at calving, while herd size and calving season were the most influential in the neonatal period from day 2 to day 30.

Twenty indigenous Cika and 20 young Simmental bulls (slaughtered at 560–718 days) were finished on two diets (extensive vs semi-intensive). When fed similar rations, Cika bulls at a ‘suitable’ finished level, had a significantly higher dressing percentage (+2.5%), more total fat (+13.7%), a lower percentage of tendons (–22.7%) and bones (–7.7%), a higher lean meat to bones ratio (+8.1%) and a greater percentage of intramuscular fat (+45.9%) than the Simmental bulls. Their meat also had a significantly lower pH (–4.0%), higher redness (+13.74%), yellowness (+15.0%) and drip loss (after 2 days, +28.3%) and a more intense flavour (+6.1%). Cika fat contained higher proportions of saturated fatty acids (+6.86%) and less polyunsaturated fatty acids (–30.8%) than Simmental fat. However, it appears that the main difference between these two breeds were the slower growth rate of the Cika and their lower weight but greater age when a finished state was reached relative to the Simmental.

The aim of the present study was to evaluate the effect of different production systems on fatty acids (FA) composition of three beef muscles (longissimus thoracis, semitendinosus and diaphragmae). The first group (MGSC) included 8 bulls of Slovenian Brown breed that were fattened with maize, grass silage and concentrates. The second group (MCS) included 8 bulls of Slovenian Simental breed that were fattened with maize silage, ensiled corn grain and concentrates. The third group (GS) included 6 Limousine × Simmental crossbreed bulls that have been fattened on pasture in cow-calf production system until slaughter. In fourth group (G) 8 bulls of Slovenian Simmental breed were fattened on pasture from spring to autumn when they were slaughtered. Bulls from MSC and MGSC had similar carcass weight (316 kg, 308 kg, respectively), whereas bulls from GS had the lightest (215 kg) and bulls from G the heaviest carcass weight (371 kg). Carcass fatness was similar for bulls in MSC, MGSC and G groups and slightly lower in GS group. The percentage of saturated FA differed among groups only in semitendinosus muscle. Bulls from G and GS had lower percentage of monounsaturated FA (MUFA) and higher percentage of polyunsaturated FA (PUFA) in all three muscles. Bulls from grazing production systems had higher n-3 PUFA values in all muscles and higher n-6 PUFA values in semitendinosus and diaphragmae. Bulls fattened on pasture had lower n-6/n-3 ratio in all three muscles. Bulls from GS had a higher percentage of conjugated linolenic acid in comparison to MGSC and MCS groups in all muscles except in semitendinosus where percentage of CLA was higher only from MGSC group.

Th e aim of this study was to estimate the perinatal and neonatal mortality rates from day 2 to 30 in Slovenian calves and to evaluate risk factors for increased losses. We analysed data on 1,333,765 calves of diff erent dam breeds, born in Slovenia in the period from January 1 to December 31st 2012. Data were obtained from the Central register of bovine animals. Th e average perinatal calf mortality, including abortions and stillbirths, was 5.57% and 2.68% from day 2 to 30. Th e most signifi cant eff ects on perinatal calf mortality rate were the number of calves at calving, age of the dam at calving, the herd size, while herd size and calving season were the most infl uential in the following neonatal period from day 2 to 30. Calves from Holstein Friesian dams showed much higher perinatal and neonatal mortality rates than calves from Simmental, Brown and other dam breeds. With increased herd size, the perinatal and neonatal mortality rate increased. Th is increase was more pronounced in Simmental, Brown and other dam breeds than in Holstein Friesian dams.

1 University of Ljubljana, Biotechnical faculty, Department of Animal Science, Jamnikarjeva 101, SI-1000 Ljubljana, Slovenia, e-mail: mojca.voljc@bf.uni-lj.si 2 Same address as 1, e-mail: marko.cepon@bf.uni-lj.si 3 Same address as 1, e-mail: silvo.zgur@bf.uni-lj.si ABSTRACT In the present study, the carcass quality of organically and conventionally fattened cattle slaughtered between the years 2008 and 2015 were compared. Slaughtered animals were classified in different categories according to age and sex . The recorded data included hot carcass weight (HCW), slaughter age, net daily gain (NDG), EUROP conformation and fatness. Bulls and heifers older than 12 months from conventional fattening system had better HCW, NDG and conformation in comparison with organically fattened animals. Fatness was higher in bull and heifer carcasses from conventional fattening system compared to organic ones. On the contrary, calves from organic system younger than 12 months had better carcass quality compared to that from conventional system. Organically fattened calves had higher HCW, NDG and conformation, while no differences in fatness were found.

In the present study, the carcass quality of organically and conventionally fattened cattle slaughtered between the years 2008 and 2015 were compared. Slaughtered animals were classified in different categories according to age and sex . The recorded data included hot carcass weight (HCW), slaughter age, net daily gain (NDG), EUROP conformation and fatness. Bulls and heifers older than 12 months from conventional fattening system had better HCW, NDG and conformation in comparison with organically fattened animals. Fatness was higher in bull and heifer carcasses from conventional fattening system compared to organic ones. On the contrary, calves from organic system younger than 12 months had better carcass quality compared to that from conventional system. Organically fattened calves had higher HCW, NDG and conformation, while no differences in fatness were found.

In 2007, the EUROP 15-point scale of carcass conformation and fatness classification system was introduced in Slovenia and replaced existing 5-point scale. Data (carcass weight, carcass conformation and fatness) from Slovenian commercial slaughterhouses were collected from January 2005 to December 2013. In total, data from 374,122 animals were used. The analysis was conducted for the category of young bulls from 12 to less than 24 months of age. In the first year after the transition, the classifiers preferentially used o classes in classification of carcass conformation and carcass fatness as well. In period 2008 - 2009 the classifiers adapted the new scale and started to use + and - subclasses more frequently. The distribution of conformation and fatness subclasses was brought near normal distribution.

The aim of the study was to determine fatty acid composition in meat of Cika and Simmental bulls from two different fattening technologies. The herd of 39 young bulls was housed during the winter time and fed the same total mixed ration diet (TMR) based on corn and grass silage with a limited amount of concentrates. In the spring bulls of both breeds were divided into two subgroups. Bulls in the first subgroup (10 Cika, 9 Simmental; S-INT) were fattened indoors with the semi-intensive TMR. Bulls in the second subgroup (10 Cika, 10 Simmental; G+S-INT) were put on all-day grazing in the pasture. After grazing period bulls were housed under the same conditions as the first subgroup. Samples of M. longissimus dorsi were collected from the right carcass side to determine the total fat content and the fatty acid composition. The breed significantly influenced fatty acid composition in meat. The beef of Simmental bulls resulted in higher percentage of PUFA and lower percentage of SFA and MUFA. Higher percentage of n-3 and n-6 PUFA was determined in meat of Simmental bulls but the n-6/n-3 ratio was lower in Cika bulls meat. The fattening technology had less effect on FA composition in meat. The second grazing period produced higher percentage of SFA, beneficially lower values of n-6/n-3 ratio and higher values of long-chain C20-22n-3 PUFA. Higher CIA percentage was determined in beef from S-INT group.

Carcass quality of Cika (20) and Simmental (19) young bulls either semi-intensively fattened indoors or finished indoors after a previous (second) grazing period was studied. There was no difference between breeds for carcass weight, dressing percentage, EUROP conformation, carcass length as well as the proportion of fore-stomachs and head. Only, fatness score and pelvic/kidney fat percentage were higher in Cika bulls compared to Simmental, while chest depth was higher in Simmental bulls. Bulls which have been finished indoors after a previous grazing period had significantly lighter carcasses, lower dressing percentage, lower EUROP conformation and fatness score but higher empty reticulo-rumen percentage compared to bulls fattened indoors. Breed x fattening technology interaction was significant for carcass weight, conformation, fatness, chest depth and empty reticulo-rumen, while slaughter weight affected only carcass weight, conformation and carcass length. The difference in the lean meat percentage between Cika and Simmental bulls was not significant. Cika bulls expressed higher fat and lower bone percentage compared to Simmental bulls. However, fattening technology did not affect the tissue percentages in the carcasses. Cika young bulls had more red and more yellow beef compared to Simmental. Bulls fattened indoors had slightly darker beef than bulls finished indoors after a second grazing period. However, carcass traits of Cika bulls were similar to those of Simmental bulls and a second grazing period could be efficiently set up in the growing-fattening scheme.

This study aimed at comparing the effects of a traditional finishing roughage-based diet and a higher energy diet, on growth, carcass characteristics, and feeding behaviour of Slovenian Cika and Simmental bulls (20 per breed). The experimental diets were: extensive (EXT) based on grass silage, and semi-intensive (S-INT) in which a part of the roughage was replaced with maize silage and sunflower meal. Each diet was fed ad libitum to 10 Cika (547 days old) and 10 Simmental (442 days old) bulls housed in group pens of five animals each. Growth performance was similar in both breeds, but Cika reached commercial finishing 1 month earlier than Simmental (139 vs 167 days; P = 0.016). Bulls fed S-INT had higher final weight (645.3 vs 590.1 kg; P = 0.05), average daily growth (1.05 vs 0.83 kg; P = 0.026), and feed intake (11.7 vs 10.6 kg dry matter (DM)/day; P < 0.001) than EXT bulls. Regardless of breed and diet, bulls ate 77–80% of the daily DM in the first 8 h after feed delivery. Bulls fed EXT showed longer standing (406.4 vs 355.8 min; P < 0.001) and eating (217.2 vs 155.3 min; P < 0.001) and shorter ruminating (77.5 vs 92.9 min; P < 0.001) times than S-INT bulls during the first 8 h of feed delivery. Cika bulls had lower full reticulo-rumen weights relative to slaughter weights (8.7 vs 10.7%; P = 0.002) than Simmental. The positive findings obtained with Cika cattle should encourage farmers to finish their young Cika male stocks for beef production, thus contributing to the maintenance of this animal genetic resource, and also to increase the energy density of the grass-based finishing diets by feeding supplements.

The aim of the study was to determine chemical and fatty acid composition in meat of Cika bulls fattened in two production systems. Eight bulls were semi-intensively fattened with a total mix ratio (TMR), while ten were grazed without cereals supplementation. Housed bulls were slaughtered at the age of 20.0 months while grazed bulls were slaughtered at the age of 23.5 months. Samples of M. longissimus dorsi located between the 7th and 8th rib were used to determine the chemical and fatty acid composition. Data were analysed using the GLM procedure of the SAS/ STAT. Model 1 was used to test the effect of production system on the chemical composition of meat. Model 2 was used to test the effects of production system and the intramuscular fat content nested within the production system as linear regression on the fatty acid composition. Significant differences were determined in intramuscular fat (14.54 vs. 8.57 g/kg, P = 0.015) and in dry matter content (231.85 vs. 239.49 g/kg, P = 0.032) in beef meat of TMR fed and in grazed bulls, respectively. Beef meat of grazed bulls contained significantly lower palmitic acid (19.87 vs. 21.03 wt.%, P = 0.002), oleic acid (26.18 vs. 30.01 wt.%, P = 0.007) and MUFA (29.88 vs. 33.80 wt.%, P = 0.010) and higher α-linolenic (3.33 vs. 1.45 wt.%, P = 0.014), EPA (1.40 vs. 0.57 wt.%, P = 0.002), DPA (1.84 vs. 1.06 wt.%, P = 0.001), PUFA (21.42 vs. 19.43 wt.%, P = 0.047) and n-3PUFA (6.80 vs. 3.24 wt.%, P = 0.001) compared to TMR fed bulls.

In 2002, it was discovered that several Cika cattle in the mountain areas of Slovenia had escaped the official policy of cross-breeding. Here, we report a genetic characterization to assess their status as autochthonous breed. We compared genotypes for 14 microsatellite markers in 150 Cika cattle individuals with data from 16 Central European cattle breeds. We show that Cika cattle are genetically as diverse as other Eastern Alpine breeds, are more diverse than Austrian Simmental but less than the Balkan Busha cattle. STRUCTURE analysis showed Pinzgauer admixture in several individuals but also indicated a unique genetic identity for Cika. This analysis also allowed a selection of the most genetically pure Cika individuals as assessed by the panel of microsatellites. These original Cika cattle form an Eastern Alpine breed cluster together with Pinzgauer and Pustertaler cattle. Cika cattle should be considered as an authentic and valuable genetic resource, which offers clear opportunities for sustainable agriculture and landscape conservation in marginal and mountain areas.

The objective of this study was to estimate genetic parameters for milk traits (daily milk, fat, and protein yield) for a joint genetic evaluation in Holstein breed in Croatia and Slovenia and to compare results from the joint and national evaluation systems. Test-day records from Croatian (CRO) and Slovenian (SVN) routine genetic evaluation in May 2012 were used. A joint data set included 1, 840, 816 CRO and 2, 680, 001 SVN test-day records of 111, 218 CRO and 127, 774 SVN cows. The total number of animals included in the joint pedigree was 382, 991. Genetic parameters for milk traits were estimated using bivariate model. SVN data were evaluated with a model which included fixed effects of calving season and stage of lactation fitted by the Ali-Schaeffer’s lactation curve nested within parity. Random part of the model consisted of a common herd environment, direct additive genetic, and permanent environment effect within lactation. In addition to these, fixed class effect of region and covariate age at the first calving were included in the model for CRO data. In the random part, the contemporary group was defined as an interaction between the herd and year of testing for CRO data and as herd effect in SVN data. The estimated heritabilities of daily milk, fat, and protein yield were 0.19, 0.15, and 0.17 for CRO and 0.23, 0.19, and 0.21 for SVN data. Genetic correlation between countries was medium to high (0.78, 0.64, and 0.63) indicating some differences between countries. Correlations between inferred breeding values from the joint and national evaluations were high (0.997 for CRO and 0.999 for SVN evaluation). On SVN scale, genetic trend obtained from the joint evaluation was higher compared to the national evaluation. On CRO scale, the national genetic trend for daily protein yield was similar to the trend from joint model.

Cooperation in the fields of local breeds of farm animals in neighboring countries is particularly important. In the scientific field for such collaboration more or less there, but they are more sporadic than systematic. In the field of conservation autochthonous breeds and study their properties can deepen cooperation on many levels; on scientific research, the technical and technological and practical work. All this would help by sharing experience contribute to better understanding and promotion of our autochthonous breeds of farm animals and contribute to more effective conservation of these. In particular, we can improve breeding programs for those breeds that are bred in several countries-the so-called transboundary breeds.

Forty lambs (progeny of two different genotype sires and Jezersko-Solcava ewes) were used to evaluate the effect of slaughter weight, genotype and sex on non-carcass components, carcass characteristics, carcass cuts and meat quality of Longissimus dorsi. Twenty-eight lambs were progeny by improved Jezersko-Solcava (JSR) sire (JSR lambs) and twelve were progeny by Texel (T) sire (JSRT lambs). After 10 days of age lambs were fed with commercial concentrate and hay ad libitum. Lambs remained indoors with their dams until weaning at 60 days of age. Lambs were divided into three groups according to genotype/sire and slaughter weight. JSR lambs were divided into JSR-light group (6 males and 6 females) and JSR-heavy group (6 males and 10 females). All Texel sired lambs representing the third group of JSRT lambs (6 males and 6 females). JSR-light group was slaughtered at the average 29.5 kg of live weight, JSR-heavy group and JSRT group were slaughtered at the adjusted 44 kg of live weight. Slaughter weight had effect on all non-carcass components presenting JSR-heavy the highest percentage. JSR-heavy carcasses had higher carcass fatness and were longer and wider in shoulder and hindleg. Slaughter weight affected carcass cuts, having the JSR-heavy lower percentage of shoulder and hindleg, but higher percentage of rib with flank. JSR-heavy carcasses had redder meat than JSR-light. When comparing JSRT and JSR-heavy lambs, JSRT had lower percentage of liver and lungs and higher percentage of head and pelt. JSRT carcasses had lower fatness, better conformation score and better dressing proportion than JSR-heavy. The composition of hindleg showed that JSRT carcasses had higher percentage of muscle and lower percentage of bone in hindleg than JSR-heavy carcasses. Meat quality differ only in b* value with more yellow meat in JSRT than JSR-heavy. Sex had effect on liver, heart and head with higher percentages in males. Males had lower dressing percentage, lower carcass fatness and higher percentages of neck, chuck and shoulder and had lighter meat. It was concluded that progeny by Texel sire had better carcass characteristics especially dressing percentage, carcass fatness and carcass conformation. Slaughtering JSR lambs at 44 kg of live weight have as a result longer and wider carcasses with slightly higher carcass fatness score, greater muscle and lower bone percentage in hindleg than JSR lambs slaughtered at 29.5 kg of live weight.

Fifty veal calves were used to study the effect of wrapping carcasses in viscose foil on carcass and meat quality traits. Half of them were wrapped in viscose foil before they were exposed to chilling, and half of them served as a control. Veal calves were around 4 months old at slaughter and reached on average 84 kg warm carcass weight. After 24 hours of conventional chilling wrapped veal calves had for 0.45 kg or 0.5% lower (P 0.05) effect on meat colour of flenk muscle.

The aim of the present study was to estimate genetic parameters for growth traits of Charolais calves in Slovenia. Analysed traits included birth weight (BW), weight at the beginning (WB) and at the end of grazing season (WE), as well as yearling weight (WY). Data were collected on 340 Charolais calves. The total number of records, including pedigree data (parents and grandparents) was 401 animals. (Co)variance components were estimated by REML method for the animal model that included fixed effects of sex, parity and year of birth in the models for all traits. Age of calves at the beginning of grazing season was included as linear regression in models for all traits except for birth weight. The age of calves at the end of grazing season, and age at approximately one year were included as linear regression in the models for corresponding weights. Random effects included direct and maternal additive genetic effects. Direct heritabilities (h(a)(2)) were decreased from 0.74 at birth to 0.19 at yearling weight. Inversely, maternal heritabilities (h(m)(2)) were increased from 0.04 at birth to 0.12 at all other included weights. Direct-maternal genetic correlation (ram) was negative for all weights except for yearling weight (0.10).