Cappelloni, Manolo (2013) Sviluppo di metodi per la gestione di razze autoctone italiane. [Tesi di dottorato]
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The aim of this work is to give a review of official performance recordings performed by the Italian Breeders Association underlining the role of official recordings for all species and breeds of zoo-technical interest. Information and data collected with official performance recordings have allowed to analyze many aspects related to the conservation of autochthonous cattle breeds recorded at the Anagrafic Register of native cattle populations (R.A.B.), which are not subject to any national selection scheme, and to analyze some aspect of genetic improvement for autochthonous Herdbook breeds, focusing on the native Valdostana Red Pied breed. In the first chapter the Italian geographic distribution of heads and milk production has been described for year 2011. Evolution of productive and reproductive parameters are also analyzed for years 2004-2011 in large population breeds. A cluster analysis shows the degree of proximity between breeds recorded. This work concerns the identification of a (co)variance structure that allows a better interpretation of performance recording time series data by analyzing the phenotypic trend within breed in the period 2004-2011. Data show high concentration of official milk recording in the north of the country (79% herds and 86-87% of recorded cattle and milk production), the significant gap in milk production of Friesian over the other breeds, or in milk quality of Jersey, Brown Swiss and Valdostana Red Pied over the other breeds; whereas regarding to the fertility performances, Friesian has shown worst results, certainly due to its specialization in milk production. Focusing on cross breeding production and reproduction performance data, it can be noticed a similarity to Friesian performances, suggesting a most likely proximity to this breed than to other genetic types. The second chapter is a survey of the genetic variability of the sixteen autochthonous Italian cattle breeds recorded at the Anagrafic Register of native cattle populations (R.A.B.). The purpose was to analyze the genetic diversity of each population by the study of demographic and parentage index (i.e.: number of founders, number of ancestors, relatedness average between individuals, etc.) and the evaluation of inbreeding performance using a standard classification (Mc Parland, 2007). As a result, the effect of R.A.B. activity on autochthonous breeds conservation performed by the Italian Breeders Association was evaluated. A different scenario in pedigree completeness for different breeds has raised up from this work. In particular, Sardinian breeds (Sarda and Sardo Bruna breeds) and Agerolese have the most incomplete pedigrees while Tuscany breeds (Calvana, Garfagnina, Mucca Pisana e Pontremolese breeds), Varzese and Burlina breeds have deepest pedigrees. Regarding to the degree of relatedness average of each breed it can be seen that large size breeds (Sardo, Sardo Bruna, Sardo Modicana and Modicana breeds) have higher values of within herd average relatedness whereas have low values of within breed average relatedness (AR%), this is due to the rare use of artificial insemination and the infrequent exchange of bulls between farmers. The third chapter focuses on the development of a test-day model for genetic evaluation of autochthonous Valdostana Red Pied breed with the aim to review the current total lactation yield method versus a more sophisticated and accurate test-day yield method in order to give more efficient answers to selection needs. The work is a comparison of two different test-day models, one worked out by University of Padua and the other by the Research and Development office of Italian Breeders Association (A.I.A). In detail, the first comparison considered two different Repeatability TD models (below named as RP-TDm1 and RP-TDm2), afterwards the comparison has involved two different Random Regression TD models (below named as RR-TDm1 and RR-TDm2). The aim was to evaluate which model (1 Vs 2) and which method (RP Vs RR) were more appropriate for peculiar Valdostana Red Pied breed’s characteristics, and to build the best proposal to the Valdostana Red Pied National Breeders Association (A.Na.Bo.Ra.Va.). These comparisons were analyzed in terms of variance and covariance components estimation, then in terms of heritability for milk yield, fat percentage, protein percentage and somatic cell count and also in terms of Rank Correlation between the models. The work shows that random regression models can barely adapt to the reality of the Valdostana breed, which is characterized by a high level of calving seasonality and by the practice of summer pasture, which causes the rare number of test days in the tail of lactations. The two different methods (RP and RR) tested have both manifested a considerable difficulty in estimating the extremes of the lactation curve. Ali-Shaeffer model (RRm1), in fact, has produced a strong overestimation in early lactation phase for all traits, while the model based on Legendre’s polynomial (RRm2) produces a strong overestimation at the end of lactation phase. Instead, repeatability models (RPm) have produced comparable estimations between model 1 and model 2 and with results published in literature: milk yield 18-21% di h2, fat percentage 18% di h2, protein percentage 34-36% di h2 e SCS 10-12% di h2. The rank correlations of bulls or cows with greatest index accuracy were rather good for fat and protein indexes, the selection index IRC, which is based on the fat and protein indexes, has rank correlations between 87 and 94%. Rank correlations for milk genetic index were between 81 and 82%, these low values are worth of farther investigation.
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Lo scopo del presente lavoro è stato quello di approfondire diversi aspetti del panorama zootecnico nazionale focalizzando l’attenzione sul ruolo e l’importanza dei controlli funzionali svolti, su tutte le specie e razze di interesse zootecnico, dall’Associazione Italiana Allevatori. Le informazioni e i dati provenienti dai controlli funzionali hanno permesso poi di ampliare lo scenario dello studio analizzando da un lato gli aspetti riconducibili alla salvaguardia delle razze bovine autoctone iscritte al registro anagrafico (R.A.B.) e non sottoposte ad un piano nazionale di selezione e dall’altro le attività inerenti il miglioramento genetico delle razze autoctone dotate di Libro genealogico, soffermando l’attenzione sulla razza autoctona Valdostana Pezzata Rossa.
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