Smetko A.,University of Natural Resources and Life Sciences, Vienna |
Smetko A.,Croatian Agricultural Agency |
Soudre A.,University of Natural Resources and Life Sciences, Vienna |
Soudre A.,University of Koudougou |
And 12 more authors.
Frontiers in Genetics | Year: 2015
Trypanosomosis is a serious cause of reduction in productivity of cattle in tsetse-fly infested areas. Baoule and other local Taurine cattle breeds in Burkina Faso are trypanotolerant. Zebuine cattle, which are also kept there are susceptible to trypanosomosis but bigger in body size. Farmers have continuously been intercrossing Baoule and Zebu animals to increase production and disease tolerance. The aim of this study was to compare levels of zebuine and taurine admixture in genomic regions potentially involved in trypanotolerance with background admixture of composites to identify differences in allelic frequencies of tolerant and non tolerant animals. The study was conducted on 214 animals (90 Baoule, 90 Zebu and 34 composites), genotyped with 25 microsatellites across the genome and with 155 SNPs in 23 candidate regions. Degrees of admixture of composites were analyzed for microsatellite and SNP data separately. Average Baoule admixture based on microsatellites across the genomes of the Baoule-Zebu composites was 0.31, which was smaller than the average Baoule admixture in the trypanosomosis candidate regions of 0.37 (P=0.15). Fixation index FST measured in the overall genome based on microsatellites or with SNPs from candidate regions indicates strongdifferentiation between breeds. Nine out of 23 regions had FST ≥ 0.20 calculated from haplotypes or individual SNPs. The levels of admixture were significantly different from background admixture, as revealed by microsatellite data, for six out of the nine regions. Five out of the six regions showed an excess of Baoule ancestry. Information about best levels of breed composition would be useful for future breeding ctivities, aiming at trypanotolerant animals with higher productive capacity. © 2015 Smetko, Soudre, Silbermayr, Mueller, Brem, Hanotte, Boettcher, Stella, Mészáros, Wurzinger, Curik, Mueller, Burgstaller and Sölkner.
Estimation of genetic parameters and environmental effects on somatic cell count in Simmental and Holstein breeds [Utjecaj genetskih i okolišnih parametara na broj somatskih stanica u mlijeku simentalske i holstein pasmine goveda]
Ivkic Z.,Croatian Agricultural Agency |
Spehar M.,Croatian Agricultural Agency |
Bulic V.,Croatian Agricultural Agency |
Mijic P.,Josip Juraj Strossmayer University of Osijek |
And 2 more authors.
Mljekarstvo | Year: 2012
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 Restricted 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.
Van Der Zee R.,Netherlands Center for Bee Research |
Brodschneider R.,University of Graz |
Brusbardis V.,Latvian Beekeepers Association |
Charriere J.-D.,Swiss Bee Research Center |
And 16 more authors.
Journal of Apicultural Research | Year: 2014
This article presents results of an analysis of winter losses of honey bee colonies from 19 mainly European countries, most of which implemented the standardised 2013 COLOSS questionnaire. Generalised linear mixed effects models (GLMMs) were used to investigate the effects of several factors on the risk of colony loss, including different treatments for Varroa destructor, allowing for random effects of beekeeper and region. Both winter and summer treatments were considered, and the most common combinations of treatment and timing were used to define treatment factor levels. Overall and within country colony loss rates are presented. Significant factors in the model were found to be: percentage of young queens in the colonies before winter, extent of queen problems in summer, treatment of the varroa mite, and access by foraging honey bees to oilseed rape and maize. Spatial variation at the beekeeper level is shown across geographical regions using random effects from the fitted models, both before and after allowing for the effect of the significant terms in the model. This spatial variation is considerable. © IBRA 2014.
Plisko M.,Creska 16 |
Prpic Z.,University of Zagreb |
Mioc B.,University of Zagreb |
Jurkovic D.,Croatian Agricultural Agency |
Vnucec I.,University of Zagreb
Journal of Central European Agriculture | Year: 2016
Istrian sheep has the highest milk yield among indigenous Croatian sheep breeds though originally belongs to a group of sheep of combined production traits. Since milk of Istrian sheep is traditionally processed into cheese and that processing possibilities of milk, among other things, are defined by its chemical composition and hygienic quality, the aim of this study was to determine the influence of some environmental factors (year, parity, stage of lactation, season (month) of lambing) on daily and lactation milk yield, lactation length, milk chemical composition and the somatic cell count (SCC) in the milk of Istrian ewes. A total of 83 purebred, dairy Istrian sheep, during three consecutive lactations (from 2012 to 2014), were involved in this research. Due to conditions of feeding, care and housing, all ewes were kept in identical (semi-intensive) farming conditions throughout the whole study period. During milking period of lactation regular milking controls were carried out (AT method) and, on these occasions, individual milk samples for chemical composition analysis and determination of somatic cell count were taken. During average lactation length of 206 days Istrian ewes produced on average 190.77 kg of milk, or1.1 kg of milk per day. Milk of Istrian ewes on average contained 6.81% fat, 5.90% protein, 4.32% lactose, 18.08% total solids and 11.31% non-fat solids. The geometric mean of SCC was 316*103*mL-1 of milk (log 5.50±0.02). A significant (P < 0.001) effect of the year is determined on the milk yield and the lactation length, as well as the chemical composition of milk (with the exception of protein) and SCC. Ewes in the fourth lactation achieved the highest average daily (P < 0.001) and lactation milk yield (P < 0.05), while the first-lambing ewes produced milk with the highest content of total solids, milk fat and proteins. Stage of lactation significantly (P < 0.001) affected the daily milk yield, milk chemical composition, as well as the somatic cell count in ewe’s milk. Ewes born in December produced significantly (P < 0.001) more milk than ewes born in January and February. There was a negative correlation between SCC (log10) and daily milk yield (P < 0.001), while the SCC (log10) was positively correlated (P < 0.001) with the contents of total solids, milk fat and proteins. © 2016, University of Zagreb - Faculty of Agriculture. All rights reserved.
Spehar M.,Croatian Agricultural Agency |
Stepec M.,University of Ljubljana |
Potocnik K.,University of Ljubljana
Acta Agriculturae Slovenica | Year: 2012
The objective of this study was to estimate genetic parameters for 39 (26 official and 13 new) scored type traits in Slovenian Brown Swiss cattle. Data set included records of 35 386 Brown Swiss cows scored from 2000 to 2011 using method 'System 97'. The studied type traits were scored on scale from 1 to 9 (29 traits), measured by stick or tape (five traits) or expressed in points from 60 to 90 (five traits). Multiple-trait analyses based on three models were used for estimates of genetic parameters. Fixed class effects in the models were: classifier and year of scoring interaction, calving season, and time from calving to scoring. Body condition score effect was additionally fitted as linear regression in the second model. The third model included time after milking as fixed class effect instead of condition. Direct additive genetic effect and herd were used in the models as random effects. Estimated heritabilities ranged from 0.13 to 0.46 for frame and from 0.03 to 0.22 for form traits. Low to intermediate heritabilities (from 0.10 to 0.25) were estimated for mammary system traits. The lowest heritability estimates, in range from 0.04 to 0.13, were obtained for foot and leg traits. The variance ratio for herd covered between 0.02 and 0.26 of phenotypic variation. Genetic correlations among type traits ranged from -0.41 between rear legs side view and legs overall to 0.99 between rump height measured by tape and rump height linearly scored for frame traits. High genetic correlations were estimated for the following pairs of traits: rump width measured and rump width linearly scored (0.92), central ligament and central ligament redefined (0.97), body depth measured and body depth linearly scored (0.86). Phenotypic correlations between pairs of traits were similar in direction but smaller in magnitude in comparison to genetic correlations. Measured type traits should be replaced with the scored one since genetic correlations between them were high. The replacement will lead to the same efficient but cheaper scoring system.