Analyses of influencing factors on milk composition and quality

English. A detailed evaluation of the indicators of milk composition and quality at six different milk production farms was researched in the time period from July to the November, 2006. 2768 milk samples were analyzed for their fat, protein, casein and lactose content (%), as well as urea level mg dlE-1. Analyses of the results show that all the indicators of milk composition and quality were very variable during the research (p is less than 0.05). With multi-factorial analyses, it was shown that the composition and quality of cows' milk differed significantly depending on the farms and research months (p is less than 0.001). The age of the cows had significant influence on the milk yield, fat, lactose and urea content (p is less than 0.001, p is less than 0.01). The factor day of lactation had significant influence on milk yield, fat, protein, casein and lactose content (p is less than 0.001). It was shown that milk yield had a low negative phenotypic correlation with fat, protein and casein rp= -0.182 to - 0.347 content, but a positive correlation with lactose content rp=0.330. Milk yield correlation with the level of urea was low positive rp=0.190. Urea content correlation was low negative with fat content rp=-0.138. The higher correlation was between protein and casein contents rp=0.990 (p is less than 0.01).

Latvian. Pētījuma mērķis - noskaidrot kāda sastāva un kvalitātes govju pienu iegūstam Latvijā, kādi ir galvenie faktori, kas to ietekmē. Pētījumu veicām, sešās, atšķirīgās piena ražošanas saimniecībās, laika periodā no 2006. gada aprīļa līdz oktobrim. Saimniecības izvēlētas ar mērķi pārstāvēt piesieto un brīvo govju turēšanas tehnoloģiju, Melnraibo un Sarkano govju grupu, kā arī bioloģisko un konvencionālo saimniekošanas metodi. Piena paraugi analizēti akreditētā piena kvalitātes kontroles laboratorijā SIA Piensaimnieku laboratorija. Tauku, olbaltumvielu un laktozes saturs (%) noteikts saskaņā ar standarta ISO 9622 : 1999 prasībām. Kazeīna satura (%) un urīnvielas satura (mg dlE-1) noteikšanai izmantotas neakreditētas testēšanas metodes: MET 006 un MET 003. Pētījuma laikā kopā analizēti 2768 piena paraugi. Izslauktā piena daudzuma analīzei izmantojām SIA Lauksaimniecības datu centrs (LDC) informāciju. Datu matemātiskā apstrāde veikta, izmantojot aprakstošo statistiku.