Genetic analysis of milk clotting aptitude in the Italian Holstein-Friesian
| Autor: | S. Chessa, O. Bulgari, R. Rizzi, L. Calamari, A.M. Caroli |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | ASPA 20th Congress, pp. 38–38, Bologna, June 11-13, 2013 info:cnr-pdr/source/autori:S. Chessa, O. Bulgari, R. Rizzi, L. Calamari, A.M. Caroli/congresso_nome:ASPA 20th Congress/congresso_luogo:Bologna/congresso_data:June 11-13, 2013/anno:2013/pagina_da:38/pagina_a:38/intervallo_pagine:38–38 |
| Popis: | The coagulation of milk is based on a series of physicochemical changes at the level of the casein micelle resulting in a gel formation. Milk coagulation properties (MCP) are known to be relevant for cheese quality and yield, important factors for the eco- nomic outcome of the dairy industry. In some instances, the MCP of herd bulk milk used to produce Protected Designation of Origin cheeses are periodically analyzed and the data used to reward or penalize producers. The economic importance of improving milk rennet clotting aptitude fully justifies the wish of taking this trait into account in the selection process. Thus, a pilot study was carried out on the possibility of including coagulation traits in the selection schemes of a dairy cattle breed. Milk clotting aptitude was evaluated in the Italian Holstein-Friesian by means of Fourier Transform mid-Infrared (FT-IR) spectroscopy on 1044 individual milk samples collected in 16 herds of Brescia province from daughters of 52 sires. Milk proteins were genotyped by isoelectric focusing and casein haplotypes (aS1-CN, ?-CN, aS2-CN, and k-CN) of the daughters, sires and dams were reconstructed. Data were analysed by an animal model in order to estimate: i. the heritability of milk rennet coag- ulation time (RCT, min), curd firming rate (k20, min), and curd firmness (a30, mm); ii. the breeding values (EBV) for these clotting variables; iii. the effect estimated of milk protein genotypes and casein haplotypes on the clotting aptitude of milk. Heritability of RCT (0.28) and k20 (0.30) were close to the average heritability described in literature (0.26 and 0.36 respectively), whereas the heritability of a30 was found to be higher (0.46 against an average value 0.27). The animal model was used to calculate the EBV for the milk rennet coagulation traits. The effects of ?-lactoglobulin genotype and casein haplotypes on the EBV were tested resulting statistically significant, as expected from the wide literature available on the subject. On the basis of the obtained results, the coagulation traits can be proposed as interesting phenotypes to be considered for addressing the selection strategies of the breed. |
| Databáze: | OpenAIRE |
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