DETECTION OF RECESSIVE MUTATIONS (CVM, BLAD AND RED FACTOR) INHOLSTEIN BULLS IN SLOVENIA

Detection of recessive mutations that causes complex vertebral malformation (CVM) and bovine leukocyte adhesion defi ciency (BLAD) in Holstein cattle is especially required for bulls, which are used for artifi cial insemination (A.I.); these enable elimination of carriers from the A.I. programs and therefore prevent transmission of unwanted mutations to a large number of offspring. Some breeders are also interested in the identifi cation of carriers of recessive allele for red and white coat colour (Red factor). Here, we performed genetic tests for detection of mutations associated with CVM, BLAD and Red factor using methods previously reported or modifi ed methods. Analysis of Holstein bulls, which were recommended for A.I in Slovenia in the years 2007 and 2008, revealed four (10 %) carriers of CVM, and two (5.4 %) carriers of red gene, while all bulls were non-carriers of BLAD

DOLOČANJE RECESIVNIH MUTACIJ (CVM, BLAD IN ALEL ZA RDEČO BARVO) PRI BIKIH ČRNO-BELE PASME V SLOVENIJI

Detection of recessive mutations that causes complex vertebral malformation (CVM) and bovine leukocyte adhesion defi ciency (BLAD) in Holstein cattle is especially required for bulls, which are used for artifi cial insemination (A.I.); these enable elimination of carriers from the A.I. programs and therefore prevent transmission of unwanted mutations to a large number of offspring. Some breeders are also interested in the identifi cation of carriers of recessive allele for red and white coat colour (Red factor). Here, we performed genetic tests for detection of mutations associated with CVM, BLAD and Red factor using methods previously reported or modifi ed methods. Analysis of Holstein bulls, which were recommended for A.I in Slovenia in the years 2007 and 2008, revealed four (10 %) carriers of CVM, and two (5.4 %) carriers of red gene, while all bulls were non-carriers of BLAD.Pri bikih, ki so namenjeni za osemenjevanje, je zaželena detekcija mutacij povezanih s CVM (prirojena kompleksna vretenčna anomalija) in BLAD sindromom (odsotnost sposobnosti obrambe levkocitov), ker s pravočasnim izločanjem nosilcev, lahko preprečimo prenos nezaželenih mutacij na veliko število potomcev. V interesu nekaterih rejcev je tudi identifi kacija nosilcev recesivnega alela za rdeče-belo barvo dlake (Red factor). V tem delu smo izvedli detekcijo mutacij povezanih s CVM in BLAD oz. rdečo-belo barvo dlake (Red factor) z genetskimi testi po že znanih metodah oz. s spremenjenimi metodami. Rezultati analize vzorcev plemenskih bikov črno-bele pasme, ki so bili priporočeni za osemenjevanje v Sloveniji v letih 2007 in 2008 so bili naslednji: štirje biki (10 %) so nosilci mutacije, ki povzroča CVM, dva bika (5,4 %) sta nosilca alela za rdečo barvo, medtem ko so vsi biki prosti mutacije, ki povzroča BLAD

MULTIPLE TRAIT ANALYSIS OF GENOTYPE BY ENVIRONMENT INTERACTION FOR MILK YIELD TRAITS IN SLOVENIAN CATTLE

The objective of the study was to evaluate genotype by environment interaction (GxEI) for yield traits in Holstein, Simmental and Brown breed cattle in Slovenia using multiple trait analysis. Data from Slovenian milk-recording scheme was used. The lactation records on cows having first to third calving in the period 1990-2004 and milk, protein and fat yield in 305 days were studied. The variables used to characterize the environment were herd-year averages of each trait. The multiple trait analysis was done using the highest and lowest quartiles of the environments. To study the GxEI, animal model methodology and the genetic correlation between the traits were used. GxEI was generally smaller for fat and milk yield than for protein yield. The lowest genetic correlations between high and low environments were estimated for protein yield, especially in Simmental (0.81) and in Brown (0.86) breed. In Holstein the correlation was higher, 0.94. The genetic correlations for fat yield were 0.95 for Brown and Simmental breed and 0.96 for Holstein. For milk yield the estimated genetic correlations were 0.88, 0.92 and 0.96 in Brown, Simmental and Holstein breed, respectively. Differences between variance components obtained in low and high quartile result in the rank of heritabilities from 0.04 to 0.12 in low and from 0.12 to 0.22 in high quartile

Genetic parameters of Conformation Traits in Brown, Simmental and Holstein Breed Calves in Slovenia

Conformation traits of Brown, Simmental and Holstein breed calves were studied to estimate the genetic and environmental parameters using data from two classification systems. Calves were classified in the period 2000 – 2010 between the age of one to 51 days. Beside the chest girth as a measurement in cm five traits were scored. At the beginning, the traits such as muscularity, form, body depth, body length and width were scored on the scale from 1 to 3 or 1 to 9 while in the year 2008 the system of classification changed to scores from 1 to 5 for all traits. Due to high variability of the data their thorough cleaning and homogenisation was required. Uni- and bivariate analyses using animal model methodology were performed. The effects of technician by year of classification, classification age class, birth season in months by years were treated as fixed and the herd by year of classification and additive genetic effect as random. Heritability estimates for data from the new classification system are rather higher (0.05-0.29) than those from the old system. Genetic correlations between estimates of two classification systems are very high, i. e. in a range from 0.74 to 0.97, which indicates a strong genetic relationship between the old and the new system of classification. The only exceptions were form and body depth in Simmental breed. In the chest girth the estimates of heritability from 0.16 to 0.27 were obtained

Breed assignment test of Slovenian cattle breeds using microsatellites

A population analysis of 1,474 non-related animals (563 Holstein, 548 Simmental, 168 Brown cattle and 195 crossbreeds) was carried out using 12 microsatellite markers. The real location of known individuals to their breeds of origin and the assignment of unknown individuals was tested. A STRUCTURE analysis of all individuals revealed three genetic clusters corresponding to three breeds while crossbreeds mostly clustered with Simmentals and to a lesser extent to Holstein. The assignment and Migrants Detection test was carried out using GeneClass. The results from the assignment test revealed that in purebreds >98% animals were assigned to the correct breed. The crossbreeds were assigned to Simmental (85%) and Holstein (15%) as expected. Individual assignment tests provided excellent assignment success in all three highly differentiated cattle breeds (FST between 0.076 and 0.095) and could prove very useful for numerous forensic applications

MULTIPLE TRAIT ANALYSIS OF GENOTYPE BY ENVIRONMENT INTERACTION FOR MILK YIELD TRAITS IN SLOVENIAN CATTLE

The objective of the study was to evaluate genotype by environment interaction (GxEI) for yield traits in Holstein, Simmental and Brown breed cattle in Slovenia using multiple trait analysis. Data from Slovenian milk-recording scheme was used. The lactation records on cows having first to third calving in the period 1990-2004 and milk, protein and fat yield in 305 days were studied. The variables used to characterize the environment were herd-year averages of each trait. The multiple trait analysis was done using the highest and lowest quartiles of the environments. To study the GxEI, animal model methodology and the genetic correlation between the traits were used. GxEI was generally smaller for fat and milk yield than for protein yield. The lowest genetic correlations between high and low environments were estimated for protein yield, especially in Simmental (0.81) and in Brown (0.86) breed. In Holstein the correlation was higher, 0.94. The genetic correlations for fat yield were 0.95 for Brown and Simmental breed and 0.96 for Holstein. For milk yield the estimated genetic correlations were 0.88, 0.92 and 0.96 in Brown, Simmental and Holstein breed, respectively. Differences between variance components obtained in low and high quartile result in the rank of heritabilities from 0.04 to 0.12 in low and from 0.12 to 0.22 in high quartile

Genotype x Climate interactions for protein yield using four European Holstein Populations

peer reviewedReaction norm models were applied to investigate genetic variation in heat tolerance of Holsteins across environments using long term protein milk yield test-day records and weather variables as proxy of climate change. Data represented four European regions characterized by different management systems and environments. Daily protein yield changed across the trajectory of temperature humidity index (THI) for all studied populations, pointing out negative associations between warm conditions and cow performance. For most regions, additive genetic variances for daily protein yield decrease when THI increases. Antagonistic relationships between level and intercept were relatively limited for Slovenia compared to the three other regions. Rank correlations of estimated breeding values for three proposed heat tolerance measures ranged from 0.56 (Spain and Slovenia) to 0.81 (Walloon Region of Belgium and Luxembourg), indicating a possibility of genotype by environment (G x E) for some pairs of regions.Projet de chargé de recherches "DairyHeatStress