Impact of Different Milk Yields on Milk Quality in Bohemian Spotted Cattle

Abstract

Hanuš O., J. Frelich, L. Janů, A. Macek, I. Zajíčková, V. Genčurová, R. Jedelská: Impact of Different Milk Yields of Cows on Milk Quality in Bohemian Spotted Cattle. Acta Vet. Brno 2007, 76: 563-571.The milk yield (MY) is a significant economic and health factor. MY influences the health state of dairy cows, their reproduction performance, longevity and milk indicators (MIs). Differences within MIs between 2 higher (1; 8 348 kg per lactation; 240 individual milk samples) and 2 lower yielding herds (2; 7 344; 239) of Bohemian Spotted dairy cows (B) were tested. Sampling was carried out during summer and winter feeding seasons. Lactation factors were well balanced. Group 1 was on a higher genetical level, had better nutrition and higher MY by 13.7% (P < 0.001). All herds were milked twice a day. Twenty-three MIs were examined and 39.1% (9 of 23; 30.4% it was formerly in Holstein (H) with higher MY by 30%) were influenced (P < 0.05) by relatively smaller difference in MY: fat; log somatic cell count; urea (U); acetone (AC); alcohol stability; time for enzymatic coagulation; whey volume; ratio of urea nitrogen in nonprotein nitrogen (URN); fat/protein content ratio. It shows a higher susceptibility of B cows to the impact of higher MY on lactation physiology than H. Most changes were in more important MIs, usually with higher differences compared with H. The whole milk protein spectrum was not influenced (P > 0.05). The U was higher (5.707 > 4.365 mmol·l Dairy cow, Bohemian Spotted cattle, milk yield, milk composition, milk properties, health status indicatorsDecisions on many aspects of cattle keeping (breeding, feeding and milking technologies) are necessary for a good farmer strategy. Additional information about processing capacities or situation on the milk market are essential for competent decisions. These facts are of paramount importance for the milk yield (MY) and consequently its economic efficiency both under extensive and intensive production systems. High MY is preferred because of higher milk income. However, high MY is also under criticism because of the suspected negative impact on animal health, poor reproduction performance and propensity of cows to production disorders and reduced longevity. A poor reproduction performance and longevity were found under a long protein over-loading of dairy cows metabolism by nutrition to ensure high MY. This was connected with high urea concentrations in their body fluids (Piatkowski et al. 1981;Butler et al. 1996;Ropstad and Refsdal 1987; Říha and Hanuš 1999ab;Hanuš et al. 2001). Despite this fact, most breeding programmes focus on the genetical improvement (GI) of MY beside the desirable increase of milk components, particularly protein content. The average MY has increased by more than 40% in the Czech Republic during the last fifteen years. The MY efficiency depends on numerous external and internal factors. The question is, what MY level is still efficient? There is no general answer to this question. The MY is increased by GI in most dairy herds a...

Chemical, physical and technological properties of milk as affected by the mycotoxin load of dairy herds

“…The analytical procedures were described in the previous studies of Hanuš et al (2007) or Janů et al (2007). Briefly, composition and physical-chemical and technological properties of milk were carried out according to the following methods:…”

“…Hanuš et al, 2007;Janů et al, 2007) without differences apparent at first glance that could have been caused by the exposure of cows to various levels of dietary mycotoxins.…”

Analysis of calibration results for casein determination via indirect method of infrared spectroscopy

“…I. Průměrné hodnoty kaseinu sad vzorků od 2,49 do 2,7 s průměrem průměrů sad 2,61 ± 0,155 % dobře odpovídají kravskému mléku v porovnání k dřívějším výsledkům (Broutin, 2006;Janů et al, 2007;Hanuš et al, 2007;Sojková et al, 2010;Kopunecz a Stachelberger, 2010). Průměrný variační obor kalibračních (referenčních) sad vzorků činil 0,561 ± 0,164 (od 0,27 do 0,89) %.…”

“…Variabilita byla od 1,4 do 1,5 % relativně, tedy velmi nízká. Tyto hodnoty variability kaseinového čísla bazé-nových vzorků mléka, v souladu s Bulletinem IDF (Broutin, 2006), naznačují možnost poměrně spolehlivé analýzy kaseinu nepřímými metodami MIR a zejména MIR-FT, zatímco uvedené, při vyšší variabilitě (Broutin, 2006;Hanuš et al, 2007;Janů et al, 2007;Sojková et al, 2010), nemusejí nutně plně souhlasit u analýz individuálních vzorků mléka. Zmí-něná argumentace platí obecně, ale vztahuje se nesporně silněji k metodě MIR než MIR-FT, již podle závěru z dříve zmíněných výsledků v Tab.…”

“…Zejména sýraře přirozeně zajímá obsah kaseinu a kaseinové číslo. Podle nedáv-ných výsledků se aktuální hodnoty kaseinového čísla u obou dojených plemen skotu v České republice pohybují kolem 79 ± 3 % Hanuš et al, 2007). Také obsah čistých bílkovin je z výše naznačených důvodů výtěžnosti mlékárenských vý-robků metodicky zajímavý pro mlékárenské pracovníky (Barbano et al, 1991).…”