[Relation of lactose levels in milk and indicators of mammary gland health in the first third of lactation].
A total of 662 bucket milk samples from cows of two breed groups were examined: red and white breed = Bohemian Pied cattle with different genetic proportions of Ayrshire and Red Holstein improvement breeds; black and white breed = Black and White Lowland breed and different degree of absorptive crossing with a genetic proportion of the Holstein breed. Samples of daily milk yields were taken in the first three months of lactation once a month within a year. A possibility of using lactose content as an auxiliary indicator for detection of the mammary gland secretion disorders in the initial lactation stage was evaluated. The average values of the different indicators and their variability are summarized in Tab. I showing also the significance in a statistical model of included effects. Lactose content (L) was 4.88 +/- 0.20%, chloride content (Cl-) 113.7 +/- 22.4 mg/100 ml, somatic cell (SC) count 474 +/- 805 thousand/ml, SC count log corresponds to the geometrical mean of 234 thousand/ml, titratable acidity (SH) 7.34 +/- 0.83 x 2.5 mmol/l, chloride-lactose ratio (ClL) 2.27 +/- 0.51, conductivity (gamma) 442.4 +/- 34.5 mS/m and mastitis test (MT-NK) 0.72 +/- 1.18. The efficiency of the used statistical model was highest for Cl- content (Tab. I, R2 = 0.41), and it was lowest for SC counts (R2 = 0.07), while it increased to the twofold value (R2 = 0.15) after logarithmic transformation of SC counts. The breed group exerted a significant effect on Cl-, SC, log SC, SH, ClL, gamma and MT-NK (Tab. I). The breed group of red and white cows (Tab. II) had higher component contents and better indicators of the udder health state (Cl-, SC, log SC, ClL, gamma and MT-NK). The month of lactation influenced significantly SC, log SC, SH and gamma (Tab. I). A decrease in SC counts with the accruing month of lactation was observed (Tab. II), the trend of gamma and SH was opposite. The effect of lactation number was found to be significant for L, SC, log SC, SH, ClL, gamma and MT-NK (Tab. I). A tendency of a gradual decrease with the lactation number was observed in these indicators: L, SH, proteins and solids-non-fat (Fig. 1), while Cl-, gamma and ClL showed an opposite tendency. The year season influenced significantly L, log SC, SH, ClL, gamma and MT-NK (Tab. I, Fig. 2).(ABSTRACT TRUNCATED AT 400 WORDS)
Hanus
O
O
Výzkumný ústav pro chov skotu, Rapotín.
Zvácková
I
I
Gencurová
V
V
Gabriel
B
B
D000818:Animals; D002417:Cattle; D005260:Female; D007774:Lactation; D007785:Lactose / Q000032:analysis*; D008414:Mastitis, Bovine / Q000175:diagnosis*; D008892:Milk / Q000737:chemistry*
D007785:Lactose
Vztah obsahu laktózy v mléce k ukazatelům zdravotního stavu mlécné zlázy v první tretinĕ laktace.