The relationship between freezing point of milk and milk components and its changes during lactation in Czech Pied and Holstein cows

Abstract

CHLáDEK, G., ČEJNA,V.: The relationship between freezing point of milk and milk components and its changes during lactation in Czech Pied and Holstein cows. Acta univ. agric. et silvic. Mendel. Brun., 2005, LIII, No. 5, pp. 63-70 The freezing point of milk (FPM) is an instant indicator of violated technological quality of raw milk, especially of dilution. FPM can also vary due to numerous effects associated with changes in milk composition and milk characteristics. Beside the effect of season, phase of lactation, breed, milk yield, subclinical mastitis etc. the impacts of nutrition and dietary or metabolic disorders are the most significant and the most frequent (GAJDŮŠEK, 2003). FPM is a relatively stable physical characteristic and due to osmotically active elements it ranges from -0.510 to -0.535 °C (HANUŠ et al., 2003b). Recently ŠUSTOVá (2001) studied the freezing point of milk in pool samples; she observed seasonal changes in FPM of mixed milk and the effect of different diets on FPM values. KOLOŠTA (2003) looked into the effect of grazing season on FPM. HANUŠ et al. (2003a) analysed possible effects of handling of milk components on FPM. The aim of this work was to describe the relationship between FPM and milk components and the impact of breed, number and phase of lactation on FPM. We analysed 328 milk samples in total, out of which 137 samples were of Czech Pied cows and 191 samples of Holstein cows. The effect of number and phase of lactation was evaluated for both breeds together. The greatest coefficients of correlation in total were found between FPM and lactose content (r = 0.600) and solids non fat (r = 0.523). Lower coefficients of correlation were found between FPM and milk fat content (r = 0.235), milk protein content (r = 0.260) and urea concentration (r = 0.256). These coefficients were considerably lower in Holstein cows than in Czech Pied cows. The coefficients of correlation between FPM and number and phase of lactation and somatic cells count were insignificant. The total mean value of FPM was -0.534 °C. Breed statistically significantly (P<0.01) affected FPM (+0.006 °C in C breed) and milk fat content (+0.19 % in H breed). Breed highly significantly (P<0.001) affected daily milk yield (+4.9 kg milk in H), milk protein content (+0.27 % in C) and solids non fat (+0.37 % in C). On the contrary, breed had no significant effect on lactose content, urea concentration and somatic cells count. Variability of FPM was greater in Czech Pied cows (5.9 %) than in Holstein cows (0.9 %). Number of lactation had no significant effect on FPM (maximum difference between lactations was 0.008 °C). Phase of lactation had no significant effect on FPM either. Our study revealed the fact that FPM was most of all affected by lactose content and solids non fat. However, the decrease of lactose content was compensated by a tendency of mammary glad to keep Ročník LIII 7 Číslo 5, 2005 63

Chosen biotic factors influencing raw cow milk freezing point

“…The milk urea concentration enhancement improves the FPD value according to expectation. These our new results are in accordance with our previous fi nd (Macek et al, 2005) in terms of tendency and with discoveries and opinions of other authors (Walstra , 1984;Buchberger, 1997;Kirchnerová and Foltys, 2005;Chládek and Čejna, 2005;Kirchnerová et al, 2009), too. The dependence of the FPD on free fatty acid concentration in milk was quite low and varied from 0.0095 (r = 0.10; P < 0.01) in November up to 0.0127 (r = 0.11; P < 0.01; Tab.…”

“…Our fi ndings about the relationships between the FPD values and the lactose and SNF contents are comparable to our previous results (Macek et al, 2005) and to the results which were published by some other authors (Demott, 1969;Brouwer, 1981;Walstra and Jenness, 1984;Koops et al, 1989;Buchberger and Klostermeyer, 1995;Buchberger, 1994;Crombrugge, 2003;Chládek and Čejna, 2005), as well. On the contrary, the relationships All differences between groups are statistically significant, P < 0.001…”

“…Proofs and reasoning about diff erent aspects of milk FPD problem were shown as follows: -FPD essence and its relationships to milk composition and its osmotic pressure (Freeman and Bucy, 1967;Demott, 1969;Brouwer, 1981;Walstra and Jenness, 1984;Buchberger, 1990Buchberger, a, b, 1991Buchberger, , 1994Buchberger, , 1997Wiedemann et al, 1993;Hanuš et al, 2003 b;Crombrugge, 2003;Kirchnerová and Foltys, 2005;Kovářová et al, 2005;Chládek and Čejna, 2005;Hanuš et al, 2005Hanuš et al, b, 2010Macek et al, 2008); -principles of various FPD analytical measurements (Koops et al, 1989;Bauch et al, 1993;Buchberger, 1994;Buchberger and Klostermeyer, 1995;Crombrugge, 2003); -infl uences of mammal species, cattle breed and height of the dairy cow milk yield on FPD value (Buchberger, 1990 andHanuš et al, 2003Hanuš et al, , 2009Hanuš et al, , 2010Macek et al, 2008;Genčurová et al, 2008;Janštová et al, 2007);impacts of the nitrogen matter/energy and mineral element balance in the dairy cow nutrition on the FPD (Buchberger, 1990(Buchberger, , 1991(Buchberger, and 1997Hanuš et al, 1998Hanuš et al, , 2010Kološta, 2003); -eff ects of production disorder occurrence including milk secretion disorders and SCC (mastitis) on FPD variation (Eisses and Zee, 1980;Buchberger, 1990 and…”

Selected abiotic factors that influence raw cow milk freezing point depression

“…Possible effects of automatic milking systems on FPD deterioration have been published (Rasmussen and Bjerring 2005). However, there are other additional reasons for milk FPD variations beside AFW (Wiedemann et al 1993;Buchberger 1994; Crombrugge 2003;Chládek and Čejna 2005). Average milk FPDs differ significantly among breeds and species of farm mammals, -0.5320 ± 0.0050 and -0.5221 ± 0.0043, -0.5544 ± 0.0293 and -0.6048 ± 0.0691 °C in Holstein and Czech Fleckvieh cattle, White short-haired goat and Tsigai sheep, respectively Macek et al 2008).…”

The effects of sample fat value manipulation on raw cow milk composition and indicators

“…FPD is investigated along the dairy chain as part of milk quality control in the dairy developed countries quite regularly (Crombrugge, 2003). The original raw milk freezing point is infl uenced in particular by the milk chemical composition and by the other milk physical properties (Brouwer, 1981;Walstra and Jenness, 1984;Koops et al, 1989;Wiedemann et al, 1993;Chládek and Čejna, 2005) as well. Of course, there are also secondary technological eff ects which infl uence the raw milk FPD such as the incidental foreign water addition during milking (Buchberger, 1990(Buchberger, a, b, 1994Crombrugge, 2003) or next milk manipulations via collecting, transport and other treatments such as pasteurization too (Rohm et al, 1991;Janštová et al, 2007).…”