Original scientific paper
https://doi.org/10.15567/mljekarstvo.2020.0306
Genetic parameters and breeding values for daily milk production of Holstein cows in terms of heat stress
Goran Vučković
; Rinderunion Baden-Württemberg, Herbertingen, Ölkofer Strasse 41, 88518 Herbertingen Germany
Tina Bobić
orcid.org/0000-0001-9975-1258
; University of J. J. Strossmayer in Osijek, Faculty of Agrobiotechnical Sciences Osijek, Department for animal production and biotechnology Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Pero Mijić
; University of J. J. Strossmayer in Osijek, Faculty of Agrobiotechnical Sciences Osijek, Department for animal production and biotechnology Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Mirna Gavran
orcid.org/0000-0002-9158-7825
; University of J. J. Strossmayer in Osijek, Faculty of Agrobiotechnical Sciences Osijek, Department for animal production and biotechnology Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Maja Gregić
orcid.org/0000-0001-7495-6329
; University of J. J. Strossmayer in Osijek, Faculty of Agrobiotechnical Sciences Osijek, Department for animal production and biotechnology Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Klemen Potočnik
; University of Ljubljana, Biotechnical Faculty, Department of Animal Science, Groblje 3, Domžale, Slovenia
Vladan Bogdanović
; University of Belgrade, Faculty of Agriculture, Belgrade, Serbia
Vesna Gantner
orcid.org/0000-0002-1962-3131
; University of J. J. Strossmayer in Osijek, Faculty of Agrobiotechnical Sciences Osijek, Department for animal production and biotechnology Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Abstract
In order to estimate the variance components as well as the breeding value for daily milk production of Holstein cows in terms of heat stress defined as different THI threshold values (68, 70, and 72) 1,275,713 test-day records from 90,159 cows were used. Temperature-humidity index (THI) calculated from ambient temperature and relative humidity recorded in the barns on the milk recording day was used as the measure of heat stress. Daily milk production was analysed as a bivariate variable, in the normal conditions (under the set THIthreshold value), and in terms of heat stress (above the set THIthreshold value) using a model that accounted variances due to lactation stage, calving season, age at calving, breeding region, parity, permanent environment, interaction between hear and year, and individual animal. The estimated high genetic correlations between the daily milk production in normal and heat stress conditions, as well as high correlations among the EBVs in normal and heat stress conditions, point out that Holstein cows with high productivity in normal condition will sustain an alike level of production even in terms of heat stress. These results indicate that the Holstein cows are very well acclimatized to the environmental conditions at dairy farms in Croatia. However, these findings should be taken with caution, given that measurements of microclimate parameters were conducted only once at a milk recording day, so the reliability of such measurements could be questionable. In conclusion, in order to realize a completely unambiguous conclusion, further studies that include multiple daily measurements of microclimatic parameters in the farms facilities are necessary.
Keywords
daily milk production; heat stress; genetic parameters; Holstein
Hrčak ID:
239298
URI
Publication date:
17.6.2020.
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