Authors: KRZYSZTOF MLYNEK, BEATA GOWISKA, EWA SALOMONCZYK, JOLANTA TKACZUK, WOJCIECH STYS
Abstract: The present study investigated the effect of daily milk production on the content of crucial milk components, body condition, and the level of energy management parameters in the blood and milk in Holstein?Friesian (HF) and Simmental (SIM) cows. Within each breed, the animals were divided into two groups: the HF-L group was HF cows with daily milk production of ≤31 kg and the HF-H group was those with daily milk production of >31 kg. The SIM-L was SIM cows with daily milk production of ≤27 kg and the SIM-H group was those with daily milk production of >27 kg. The intensity of reserve fat accumulation was assessed by using body condition scoring. Samples of milk were taken every 30 days of lactation and the content of total protein, casein and ?-casein, fat, lactose, dry matter, and urea were determined. Blood samples were taken on days 10, 40, 70, 100 and 130 of lactation to determine the content of glucose and beta-hydroxybutyrate. The obtained results suggest that, in spite of the lower milk production, the Simmental cows had the more favorable energetic homeostasis of the organism. The values of casein and κ-casein indicate better suitability of the raw material obtained from Simmental cows for cheese processing. From a practical point of view, higher Holstein?Friesian cows? average daily yield and a relatively small difference in the content of the total protein compared to Simmental cows? milk suggest its use primarily as consumption milk.
Keywords: Milk production, milk composition, Holstein?Friesian, Simmental, body condition, energy management, correlation
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