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Association of bovine β‐casein protein variant I with milk production and milk protein composition
Author(s) -
Visker M. H. P. W.,
Dibbits B. W.,
Kinders S. M.,
van Valenberg H. J. F.,
van Arendonk J. A. M.,
Bovenhuis H.
Publication year - 2011
Publication title -
animal genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 81
eISSN - 1365-2052
pISSN - 0268-9146
DOI - 10.1111/j.1365-2052.2010.02106.x
Subject(s) - casein , haplotype , biology , lactation , composition (language) , population , gene , protein subunit , milk protein , genetics , genotype , food science , medicine , pregnancy , linguistics , philosophy , environmental health
Summary The aim of this study was to detect new polymorphisms in the bovine β‐casein ( β‐CN ) gene and to evaluate association of (new) β‐CN protein variants with milk production traits and milk protein composition. Screening of the β‐CN gene in genomic DNA from 72 Holstein Friesian (HF) bulls resulted in detection of 19 polymorphisms and revealed the presence of β‐CN protein variant I in the Dutch HF population. Studies of association of β‐CN protein variants with milk composition usually do not discriminate protein variant I from variant A2. Association of β‐CN protein variants with milk composition was studied in 1857 first‐lactation HF cows and showed that associations of protein variants A2 and I were quite different for several traits. β‐CN protein variant I was significantly associated with protein percentage and protein yield, and with α s1 ‐casein (α s1 ‐CN), α s2 ‐casein (α s2 ‐CN), κ‐casein (κ‐CN), α‐lactalbumin (α‐LA), β‐lactoglobulin (β‐LG), casein index and casein yield. Inferring β‐κ‐CN haplotypes showed that β‐CN protein variant I occurred only with κ‐CN variant B. Consequently, associations of β‐κ‐CN haplotype IB with protein percentage, κ‐CN, α‐LA, β‐LG and casein index are likely resulting from associations of κ‐CN protein variant B, while associations of β‐κ‐CN haplotype IB with α s1 ‐CN and α s2 ‐CN seem to be resulting from associations of β‐CN variant I.