Influences of Different Milk Yields of Holstein Cows on Milk Quality Indicators in the Czech Republic

Abstract

The milk yield (MY) is an important economic and health factor closely connected with the health status of dairy cows, their reproduction performance, longevity and milk composition and properties (MIs). The differences within MIs between high yielding herd (Group 1; 10 282 kg per lactation) and three herds with average MY (Group 2; 7 926 kg) were tested. The files with 96 and 290 milk samples were collected in summer and winter feeding seasons and well balanced in lactation factors. Group 1 had higher genetical value, better nutrition and was milked three times per day and its MY was higher by 30% (P < 0.001). among 23 milk indicators (MIs) under study only a few MIs (30.4%) were influenced (P < 0.05): somatic cell count (SCC); urea (U); acetone (aC); pH acidity; alcohol stability; curd firmness; the ratio of urea nitrogen in non-protein nitrogen (URn). Except for U, these changes were less important. Protein spectrum was not affected (P > 0.05). The U was probably higher due to higher loading of the nitrogen nutrition (4.27 > 3.57 mmol·l Dairy cow, Holstein cattle, milk yield, milk composition, milk properties, health status indicatorsIn dairy cattle, genetic improvement and well balanced nutrition are the main factors improving the milk yield (MY). Furthermore, feeding technology may help to fully exploit the genetic potential as evidenced in current Holstein (H) population. In general, a better use of these factors in dairy herds may enhance the lactation physiology and also the composition and milk properties of high yielding cows. The resistance degree to health disorders (e. g. mastitis) or stress may increase as well. These facts are interesting for milk producers, veterinarians and dairy operations because of impacts on farmer milk price, processing efficiency and product quality. Relevant changes are observed due to routine performance of milk recording in dairy herds. However, it is only possible for a limited number of milk indicators such as MY, fat, protein, lactose and urea contents and somatic cell counts. These are usually included in milk recording and dairy herd improvement programmes. Of course, interesting changes could be found in other milk components and properties as well. The genetic and nutritional improvements are in accordance with the basic equation phenotype = genotype + environment the main factors of cow MY increase. However, high MY is often a reason for breeder fears from its possible negative consequences. It could cause production health disorders as a result of impaired immunity decrease of cows including a shorter production age of dairy cows. Poor reproduction

Proteolysis in raw milk in relation to microbiological indicators

“…The respective medians showed similar values as the geometric means. SCC and chemical parameters were in accordance with the characteristics of Holstein breed in the Czech Republic (Janů et al 2007). The parameters MPE, TCMB, TCPB, and protein were important for the evaluation of results for sets III and IV (Table 2).…”

Effect of organic farming on selected raw cow milk components and properties

“…Generally the mentioned diff erences of O from C agriculture could aff ect the milk composition and properties, especially those that are infl uenceable by nutrition (Sehested et al, 2003;Janů et al, 2007;Pozdíšek et al, 2008;Sojková et al, 2010). Also an impact on selected health indicators such as protein, urea, acetone, or certain elements as Ca, Mg or I could be signifi cant (Hanuš et al, b, 2008.…”

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) %.…”

“…Prů-měrné kaseinové číslo Janů et al, 2007) se podle plemen pohybovalo v České republice od 79,37 do 79,50 % (České strakaté) a od 79,42 do 79,45 % (Holštýn, s nadprůměrnou a průměr-nou dojivostí). Průměry se mezi oběma hlavními dojenými plemeny skotu, jak patrno, lišily nepatrně a uvnitř plemen podle dojivosti nevýznamně (P > 0,05).…”

“…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.…”