Milk quality and processing in relation to polymorphism of capa casein at black and white Holstein cattle

Abstract

Capa casein genotyping was performed on 36 cows, bull dams, and based on the analysis of DNA from blood using PCR - REFL techniques. Served for the identification of allelesand genotypes capa casein. Using the identified allels (A and B) and genotypes (AA, AB and BB) capa casein evaluated their frequency in the examined population of cows. Frequency capa casein genotype were: 0,450 AA +0,494 AB + 0,056 BB = 1,00. Furthermore, the frequency of allels A and B which is derived from frequencies of genotypes was 0,66 for allele A and 0,34 for allele B. This reletionship expresses the preliminary information about presence of different genotypes capa casein in Holstein. The contribution capa casein and total casein genotype on milk coagulation rate, determined by LS method, model 1, the coagulation of milk was highly significant. Using model 2, the coagulation of milk, the amount of calcium present in milk had a high impact significantly and lactation order significant impact on the speed of milk coagulation. Physical and chemical composition of fresh milk casein genotypes of different hats, meets the current criteria for the quality of fresh milk. Acceptable rennet - coagulation properties of k-BB groups are reflected in a shortetime of coagulation of milk with rennet. In particular it is a significant relatioship that manifests increased content of casein and total protein in milk. The analysis showed that reflect the time making chesse milk k-BB group was almost three times faster than k-AA milk about 2 times faster than k-AB milk.