Analyse of relationships between freezing point and selected indicators of udder health state among cow, goat and sheep milk

Abstract

Milk freezing point (MFP) is important quality indicator. Aim was to analyse the relationships of MFP to selected udder health milk indicators (Mis) by comparison between cows (reference), goats and sheep. Bulk milk samples came from 3 herds of Czech Fleckvieh (B, n 93) and 1 goat herd and sheep flock (White short-haired, W, n 60; Tsigai, C, n 60). Animal nutrition was performed under the typical country conditions. Mis which were investigated: DM, dry matter; SNF, solid non fat; L, lactose (all in %); SCC, somatic cell count (10 3ml-1); EC, electrical conducthrity (mS cm-1); MFP (°C); Na and K (in mgk-1). W MFP was -0.5544 ± 0.0293, B -0.5221 ± 0.0043 and C -0.6048 ± 0.0691°C. The B MFP was related to L (-0.36; P < 0.01), W was not related to L (-0.07; P > 0.05) and C was related to L (0.40; P <0.01). These facts could be explainable by worse SCC geometric averages for used W(3,646 lO3ml-1) and C (560 103ml-1) milk as compared to B (159 10 ml -1). Only 0.5 and 10.5% of variations in MFP were explainable by variations in DM and SNF in B, 32.7 and 12.8% in W but already 49.4 and 45.0% in C. Higher C values were caused by high MFP variability 11.8% (C) versus 0.8% (B). There is possible to derive the more reliable MFP qualitative limits for more efficient monitoring rules of milk quality problems in B, W and C.