Genetic parameters of milk fat-to-protein ratio in first three lactations of Polish Holstein-Friesian cows

Alicja Satoła , Ewa Ptak


The aim of the study was to estimate the genetic parameters of milk fat-to-protein ratio in the first three lactations of Polish Holstein-Friesian cows. Data included 104 875 test-day records of 6299 cows calving from years 2000–2012. Genetic parameters were estimated with a multitrait random regression model using the Bayesian method via Gibbs sampling. The linear model for fat-to-protein ratio and milk traits (milk yield, lactose percentage, milk urea concentration) included fixed herd-test-day effect, fixed regressions within age at calving by season of calving subclasses, and random regressions for additive genetic and permanent environmental effects. All regressions were modelled using fourth-order Legendre polynomials. The average daily heritability of fat-to-protein ratio ranged from 0.24 to 0.31. Fat-to-protein ratio was negatively genetically correlated with milk yield for almost every day in milk in each lactation, with means of −0.52, −0.24 and −0.05 in the first, second and third lactations, respectively. Average genetic correlations of fat-to-protein ratio with lactose percentage and milk urea concentration were rather low or close to zero (−0.08 to 0.10) except for the genetic correlation with milk urea content in the second lactation (0.32). The results suggest that fat-to-protein ratio is a heritable trait and might be used in the selection of Polish Holstein-Friesians assuming that the relationship between fat-to-protein ratio and economically important traits will be investigated
Author Alicja Satoła (FoAS / DoGaAIM)
Alicja Satoła,,
- Department of Genetics and Animal Improvement Methods
, Ewa Ptak (FoAS / DoGaAIM)
Ewa Ptak,,
- Department of Genetics and Animal Improvement Methods
Journal seriesJournal of Animal and Feed Sciences, ISSN 1230-1388, (N/A 40 pkt)
Issue year2019
Publication size in sheets0.6
Keywords in Polishwydajność mleczna, mocznik, laktoza, dziedziczalność, korelacja genetyczna, bilans energetyczny
Keywords in Englishmilk yield, urea, lactose, heritability, genetic correlation, energy balance
ASJC Classification1103 Animal Science and Zoology; 1106 Food Science
Internal identifierWHiBZ/2019/31
Languageen angielski
LicenseJournal (articles only); author's original; Uznanie Autorstwa - Użycie Niekomercyjne (CC-BY-NC); after publication
Genetic parameters of milk fat-to-protein ratio in first three lactations of Polish Holstein-Friesian cows of 25-06-2019
1,28 MB
Score (nominal)40
Score sourcejournalList
Publication indicators WoS Citations = 0; Scopus SNIP (Source Normalised Impact per Paper): 2018 = 0.439; WoS Impact Factor: 2018 = 0.875 (2) - 2018=0.906 (5)
Citation count*
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FinansowanieThis research was financed by the Ministry of Science and Higher Education of the Republic of Poland (DS 3254)
Udział procentowyAlicja Satoła: 75%, Ewa Ptak 25%
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