Lactose content in milk and the evaluation of systematic effect
1996
Klopcic, M. | Monig, E.S. (Ljubljana Univ. (Slovenia). Biotechnical Fac., Zootechnical Dept.)
Subclinical mastitis of dairy cows causes great problems to milk producers because it leads to substantial financial losses, and at the same time it causes problems to dairies in milk processing. Lower lactose content can be one of the indicators for disturbances in the mammalian gland. Based on 83,420 records of AP milk recording in the period from October 1995 to September 1996 the average milk yield per milking day was 20.2 kg. There was an average of 3.26 % of protein, and 4.60 % of lactose content in milk. Data processing included the cows of all three breeds. Data on milk yield, protein and lactose content confirm the expected links with the lactation stage, with the age, breed of the cow, and with the month of the recording (season). The highest lactose content was noticed in Brown breed (4.68%), followed by Simmental (4.67 %) and Black-and-White breed (4.57 %). Further to these, the highest lactose content was observed in the first lactation (4.70 %), and the lowest in the 6th and higher lactations (4.50 %). Since the first lactation, the lactose content decreases, depending on the successive lactation or the age of a cow. In each lactation the highest values were established at the 2nd and 3rd recording (the peak of milk yield), being 4.69 %, then the lactose content gradually decreases. There is an effect of the season or the month of recording - the lowest lactose content was noticed in September (4.51 %), and October (4.52 %), and the highest in January (4.65 %).
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