The Istrian (IS) and the Pag sheep (PS) are local Croatian breeds which provide significant income for the regional economy and have a cultural and traditional importance for the inhabitants. The aim ...of this study was to estimate some important population specific genetic parameters in IS (N = 1293) and PS (N = 2637) based on genome wide SNPs. Estimates of linkage disequilibrium effective population size (Ne) evidenced more genetic variability in PS (Ne = 838) compared to IS (Ne = 197), regardless of historical time (both recent and ancient genetic variability). The discrepancy in the recent genetic variability between these breeds was additionally confirmed by the estimates of genomic inbreeding (FROH), which was estimated to be notably higher in IS (FROH>2 = 0.062) than in PS (FROH>2 = 0.029). The average FROH2–4, FROH4–8, FROH8–16, and FROH>16 were 0.26, 1.65, 2.14, and 3.72 for IS and 0.22, 0.61, 0.75, and 1.58 for PS, thus evidencing a high contribution of recent inbreeding in the overall inbreeding. One ROH island with > 30% of SNP incidence in ROHs was detected in IS (OAR6; 34,253,440–38,238,124 bp) while there was no ROH islands detected in PS. Seven genes (CCSER1, HERC3, LCORL, NAP1L5, PKD2, PYURF, and SPP1) involved in growth, feed intake, milk production, immune responses, and resistance were associated with the found autozygosity. The results of this study represent the first comprehensive insight into genomic variability of these two Croatian local sheep breeds and will serve as a baseline for setting up the most promising strategy of genomic Optimum Contribution Selection.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The objective of this study was to estimate genetic parameters for daily
milk yield (DMY), fat (FC), and protein content (PC) using 329.022 test-day records of 23.756 Alpine does. Single trait ...repeatability animal model was applied. Parity, litter size, season, and lactation stage (Ali-Schaeffer’s curve) were fitted in the fixed, while herd, herd-test-day, permanent environment (within lactations) and additive genetic effect in the random part of the model. Variance components were
estimated using Residual Maximum Likelihood Method in the VCE-6 program. Additive genetic effect explained 23 %, 16 % and 25 % of DMY, FC and PC variability which is in general agreement with numerous previous reports for dairy goat breeds. Among the non-genetic effects, herd explained 24 %, 12 %, and 9 %, herd-test-day 17 %, 29 %, and 30 %, and permanent environment 16 %, 3 %, and 5 % of DMY, FC and PC variability, respectively. The estimated parameters and developed single
trait repeatability test-day models will serve as a basic tool in BLUP based genetic evaluation of Alpine breed in Croatia.
Cilj ovog istraživanja bio je procijeniti genetske parametre za dnevnu količinu mlijeka (DKM), udio mliječne masti (UM) i udio proteina u mlijeku (UP) temeljem 329,022 fenotipskih zapisa na dan kontrole mliječnosti koza pasmine Alpina (ukupno 23,756). Pri procjeni genetskih parametara za svako pojedino svojstvo korišten je model životinja s ponovljenim mjerenjima za jedno svojstvo (engl. single-trait repeatability animal model). U fiksnom dijelu modela korišteni su redoslijed laktacije, veličina legla, sezona laktacije i stadij laktacije (Ali-Schaeffer-ova krivulja). U slučajnom dijelu modela korišteni su utjecaji: stada, testnog dana unutar stada, trajnih okolišnih čimbenika unutar redoslijeda laktacije i aditivnih genetskih učinaka. Komponente varijance procijenjene su metodom REML u programu VCE-6. Udjeli aditivne genetske varijance u ukupnoj fenotipskoj varijanci DKM, UM i UP bili su redom 23 %, 16 % i 25 %, što je u suglasju s brojnim publiciranim heritabilitetima za ova svojstva kod mliječnih pasmina koza. Udio varijance negenetskih čimbenika za svojstva
DKM, UM i UP bili su redom 24 %, 12 %, i 9 % za utjecaj stada, 17 %, 29
%, i 30 % za utjecaj testnog dana unutar stada i 16 %, 3 % i 5 % za utjecaj trajnih okolišnih čimbenika unutar laktacije. Procijenjeni parametri i razvijeni statistički modeli biti će korišteni u rutinskom genetskom vrednovanju alpskih koza za svojstva mliječnosti u Hrvatskoj.
The aim of the study was to determine the influence of parity and litter size on dairy traits in Istrian ewes. The following traits were analysed: lactation milk yield (LMY), daily milk yield (DMY), ...fat yield (FY), fat content (FC), protein yield (PY), protein content (PC), lactose yield (LY), and lactose content (LC). Lactation records (n=6481) collected on 2786 ewes were analyzed using a statistical model adjusted for unbalanced data structure accounting for all the available sources of phenotypic variability. Parity had a statistically significant effect on all the investigated traits (P<0.01, P<0.001). LMY DMY, PY and LY peaked in third, FY, FC, and PC in fourth, and LC in second lactation. The estimated differences between parities with maximum and minimum production for LMY, FY, PY, and LY were 21.6 kg, 1.1 kg, 1.25 kg, and 0.98 kg, respectively. Litter size had a significant effect on all the investigated traits (P<0.01, P<0.001) except the FC (P<0.05). Multiple litters led to higher yields but to lower contents of dry matter components in the milk. The results of the study should contribute to better understanding of the phenotypic variability of some economically very important dairy traits in ewes.
Starting from the assumption that the climatic conditions determine the quantity and quality of available forage on the pastures which is the largest source of nutrients of meal of sheep reared in ...coastal and island of Croatia, the aim of this research was to determine the seasonal variations of milk production and quality of Pag and Istrian sheep during three consecutive years – lactations (2012 – 2014) with extremely hot weather conditions. Regular monthly milking controls (using the AT4 method) included 30 flocks of Pag sheep and 19 flocks of Istrian sheep. In total, 29674 daily test records were collected in Pag sheep, and in Istrian sheep 12304 daily test records including the daily milk yield, the chemical composition of milk (content of milk fat, protein, lactose and dry matter) and number of somatic cells in milk. Significant (P<0.001) effect of the year on the daily milk yield of Istrian sheep was found, while unexpectedly, the average daily milk yield of Pag sheep, although predominantly kept in semi-extensive production system, has been uneven between the studied years (P>0.05). Significant variations of the daily milk yield of Pag sheep (P<0.001) and Istrian sheep (P<0.01) due to the season were established, as well as significant (P<0.001) seasonal variations of the content of all analysed milk constituents of Pag and Istrian sheep. Significant (P<0.001) phenotypic correlations were found between the daily milk yield and contents of all analysed components of Pag and Istra sheep milk.
In the light of increasingly rapid climate change worldwide, one of the primary goals is to reduce financial losses of dairy farmers and to enable the sustainable farming. In order to realize those ...goals, the necessity of implementation of breeding values for heat resistance in breeding strategies, have become more and more pronounced. Estimation of breeding values requires determination of temperaturehumidity index (THI) threshold value. Therefore, the objective of this research was to determine the THI threshold value for the first parity Holsteins in environmental conditions in Eastern Croatia. With that purpose individual test-day records of the first parity Holsteins with records of ambient temperature and relative humidity in the barns were analysed. Data were collected in regular milk recording from January 2006 to December 2012. The THI threshold values for daily milk yield were determined by least square analyses of variance for each given THI value (from 65 to 76) using the PROC MIXED (SAS). The THI< 68 did not cause significant change in daily milk production of the first parity Holsteins. Significant decrease of daily milk yield was observed at THI ≥ 68 with estimated drop from 0.240 to 0.716 kg milk/day (THI from 68 to 76). The THI=68, as the lowest value at which significant decrease in daily milk yield was determined, was taken as the threshold value for the first parity Holsteins in Eastern Croatia.
The aim of this paper was to study the effects of breed, stage of lactation, season of kidding and parity on goat milk yield and composition. A total of 25255 records of daily milk production and ...25065 records of fat percentage, 25382 records of protein percentage and 24810 records of lactose percentage were obtained, at approximately monthly intervals, from 3702 Alpine and 411 Saanen goats in Croatia. The analysed data were recorded during 2006. Saanen breed had significantly (P<0.01) higher lactation and daily milk yield than Alpine breed (720 kg and 2.63 kg/day versus 577 kg and 2.08 kg/day, respectively). The contents of protein and lactose were similar between investigated breeds, while Alpine goats had significantly higher (P<0.05) milk fat content than Saanen goats (3.47 % versus 3.25 %, respectively). Least square analyses showed significant effects of stage of lactation, season of kidding and parity on almost all variables. Milk lactose content tended to decline as the lactation period progressed and milk yield decreased. Milk protein content tended to increase with the lactation period. The lowest content of milk fat was established in the mid stage of lactation, whereas the highest fat content was recorded at the end of lactation. The effect of parity on total lactation and daily milk yield shows an almost steady growing trend from first to fourth lactation. Goats kidding early in the year had better milking performances (longer lactation period, higher milk yield, higher content of milk fat) than goats kidding in the spring. In order to improve lactation performances of their animals, the goat farmers should apply earlier mating season and use the appropriate breeding programmes.
The study aimed to examine the effect of inbreeding on the birth weight (BW) of Saanen goat kids under the framework of the genetic animal model for maternal traits. The BW of the kids was analyzed ...as the inherent phenotypic trait of the kid, and not of their mothers (does) which means that the impact of the direct inbreeding (not maternal) was examined. The estimated ratios of variance components for direct genetic, indirect maternal genetic, maternal permanent environmental, and herd effects were 0.127, 0.026, 0.163, and 0.373, respectively. The average coefficient of inbreeding (F) was 2.5%, and 4.2% among the inbreds. The results of the preliminary conducted glm ANCOVA analysis implicated statistically significant inbreeding depression for BW (βF=-0.0076, P<0.001). However, when the genetic animal model for maternal traits was applied in the inferential statistical analysis, it turned out that there was no statistically significant effect of F on BW of kids in this population (βF= 0.0001; P>0.05).
The study involved determination of the freezing point of cow milk by a reference (thermistor cryoscopy) and an instrumental (infrared spectrometry) method. The aim of the study was to evaluate the ...possibility of milk freezing point determination in milk samples preserved with azidiol by using a reference and an instrumental method of analysis. Five hundred cow milk samples were analysed during three research periods. Samples were taken at milk collection points in north-western Croatia. Samples preserved with azidiol (0.3 mL azidiol/40 mL; 0.011 g sodium azide/40 mL) and without preservatives (control samples) were analysed. The freezing point of milk was determined in duplicate. Average freezing point results of azidiol preserved samples were lower compared to control samples. A statistically significant difference between the means of the results obtained for azidiol preserved and control samples was determined (P<0.05; P<0.01) in all research periods. The results revealed a significant influence of the preservative azidiol on milk freezing point determination regardless of the method of analysis applied, which could lead to wrong interpretation of the results.
The proximate composition and mineral content of light lambs muscle (derived from Istrian and Dalmatian Pramenka breeds) were studied. The M. Longissimus dorsi (MLD) samples of 30 carcasses were ...analysed and the effects of breed and sex were studied. Although lambs of investigated breeds were similar for slaughter age (2.5 months), Dalmatian Pramenka had significantly higher carcass weights (CW; P<0.05). Breed had a significant influence on moisture and fat contents, whilst mineral composition (with the exception of selenium) was scarcely affected by breed and sex. Fat and moisture contents were significantly correlated with cold CW. The magnesium, calcium, manganese and selenium contents were significantly correlated (r=0.50, -0.46, 0.44, 0.54; P<0.05 respectively) with CW. This study contributes to characterization of lamb carcasses from Istrian Sheep and Dalmatian Pramenka breeds and provides new data on the composition of the MLD of light lambs.
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.
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