ANIMAL-RELATED AND SOME ENVIRONMENTAL EFFECTS ON DAILY MILK PRODUCTION > OF DAIRY COWS UNDER THE HEAT STRESS CONDITIONS
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Authors
Micic, NenadStanojevic, Dragan
Samolovac, Ljiljana

Petričević, Veselin

Stojiljković, Nenad

Gantner, Vesna
Bogdanovic, Vladan
Article (Published version)
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The study aimed to determine the effect of different fixed factors (breed, region, calving year,
calving season, parity and lactation stage) on daily milk production (yield and content) of four
dairy cattle breeds under the heat stress conditions (THI≥72). The research was conducted
on a set of test-day records of four dairy cattle breeds (Simmental, Holstein-Friesian, Red
Holstein and Brown Swiss) reared in the Republic of Serbia (Region of Mačva, Podunavlje and
Šumadija). The statistical analysis included test-day records collected in the period from the
beginning of the year 2012 to the end of the year 2019. Based on the performed analysis, it
could be demonstrated that all the effects included in the statistical model (breed, region,
calving year, calving season, parity and lactation stage) statistically highly significant (p<0.001)
affected daily milk production (yield and content) of cows reared in the terms of the heat stress
conditions. The highest daily milk producti...on was determined in the region of Podunavlje, and
by the Holstein-Friesian breed. Furthermore, dairy cows calved during the spring season, in the
third lactation and from the 61st to the 120th day of lactation, had the highest milk production
during the summer period in an environment characterised by heat stress. Also, daily milk yield
of cows in a heat stress environment decreased in the period from June to September. The
results obtained indicate different animals’ responses to heat stress concerning the animal’s
breed, rearing region, calving year, calving season, parity and lactation stage.
Keywords:
dairy cows; cattle breeds; milk production; heat stress; test-day recordsSource:
Mljekarstvo: journal for dairy production and processing improvement, 06-10-2022, 72, 4, 250-260Publisher:
- MLJEKARSTVO