The milk protein genetic structure of the Reggiana dairy local cattle with remarkable milk quality properties was analysed and compared with the structure of Italian Friesian and Italian Brown cattle. A total of 1138 individual milk samples from the three breeds were typed by isoelectrofocusing. Polymorphism was found at the as1-casein (CSN1S1), b-casein (CSN2), K-casein (CSN3), and b-lactoglobulin (LGB) loci. High frequencies were observed for some casein alleles in Reggiana (CSN1S1*C, 25%; CSN2*B, (28%) with considerable differences to those observed in a survey carried out 30 years before. A great variation among breeds was observed for casein haplotype frequencies and high linkage disequilibrium was detected at the three polymorphic casein loci CSN1S1-CSN2-CSN3. The prevalent haplotypes were CA2B (23%; Reggiana), BA2A (48%; Italian Friesian) and BA2B (51%; Italian Brown). Higher GST values between breeds were observed when were considered instead of gene frequencies. In the Reggiana cattle, the occurrence of two casein alleles at a rather high frequency (CSN1S1*C, CSN2*B) allowed to estimate the effects of rare casein haplotypes on milk traits. The CA2B haplotype was associated with a significantly higher milk protein and fat content and a significantly higher protein per cent was found also for the BA1B haplotype.
|Titolo:||Genetic structure of milk protein polymorphisms and effects on milk production traits in a local dairy cattle|
|Settore Scientifico Disciplinare:||Settore AGR/17 - Zootecnica Generale e Miglioramento Genetico|
Settore AGR/19 - Zootecnica Speciale
|Data di pubblicazione:||2004|
|Digital Object Identifier (DOI):||10.1111/j.1439-0388.2003.00443.x|
|Appare nelle tipologie:||01 - Articolo su periodico|