Genetics of autochthonous Italian beef cattle breeds

This thesis has aimed to analyse both management aspects of performance testing traits in many Italian breeds, including Italian beef cattle breeds, to analyse and update heritability values in performance test traits of Italian beef cattle breeds and evaluate a possible implementation of slaughter data as selection tools for the three main diffused Italian beef cattle breeds (i.e, Chianina, Marchigiana and Romagnola breeds). The Introduction aims with all Italian cattle breeds, considering both beef, dual purpose and dairy breeds and describes the selection of Italian cattle breeds. In the 60’-70’ the management of the Herd Book, since that held by State, has been delegated to several National Cattle Breeder Association, which have been recognized, in addition to competence in genealogical records, including that relating to the assessments of morphological traits and breeding values. For each cattle breed exist a National Cattle Breeder Association that is established to promote and implement all type of initiatives aimed towards improving, developing and valorisation. After the report of the EAAP working group on performance testing for young bulls to be used in artificial insemination (AI) programs was to established a recommendations for performance testing of beef, dual purpose and dairy prior to their use in AI. The Performance test, as method of evaluation, has become the main selection tool for both dual purpose and beef cattle breeding programmes. Station performance testing allows for the comparison of beef bulls from different herds under standard conditions to identify genetically superior bulls for use in commercial herds. The second chapter encloses over that an extract of this report, the results of a survey to review the present Italian situation as regard to the specific activity on performance testing of young bulls across National Cattle Breeders Association. A specific form was designed to collect data on performance test and given to Italian cattle breeders associations across the period 2007-2009. Data collected concerned national herd books’ statistics (i.e., registered and controlled population), structures available at the genetic centres to know the main characteristics of performance testing and its organisation, traits analysed and selection indexes obtained on bulls tested. The third chapter regarding an explanation for breeding system of Italian Beef Cattle Marchigiana, Chianina and Romagnola and its evolution in the last 20 years and the estimate heritability and genetic correlations of main slaughter data (carcass weight, slaughter age and carcass average daily gain) of these breeds. After years of selection based on Bull Selection Index for the three Italian Beef Cattle Marchigiana, Chianina and Romagnola, Chapters four aimed to obtained new estimates of heritability for traits included in the Selection Index on test station in Perugia. The bull selection index (BSI) that is used a selection criteria at the end of test, account for genetic index of both average daily gain (ADG) measured till weaning and average daily gain realized during the test. Other trait computed in BSI is fleshiness at the end of test. Heritability for ADG in test showed higher value than ADG in pre performance, as expected, and more closer to values reported in literature. Heritability of fleshiness resulted more variable between breeds. Simple correlation analysis was carried out on ranks between previous performance test indexes and global index (BSI) and the newest obtained with the heritability estimates. The fifth chapter deals with the study of an new estimates of genetic parameters for Maremmana and Podolica breeds using performance test data, after about fifteen years from the beginning of the activity. For these breeds the bull selection index (BSI) used as selection criteria at the end of test, accounts for genetic index of both average daily gain (TADG) realized during the test, and morphological score at end of test. The study carried out in chapter five involved also fleshiness evaluated at the end of test, aiming to obtain genetic correlations among all considered traits. The analysis produces h2 estimates greater than those obtained for the three main breeds at test station as regard the daily gain. Positive genetic correlations among traits were estimated for Maremmana, although milder correlations were obtained for Podolica.