Milk yield and milkability traits of Lithuanian black and white cows with a different degree of Holstein blood

Abstract

The objective of this research was to evaluate milk yield and milk ability traits of Lithuanian black and white cows and to estimate their dependence on genotype according to the Hosltein breed degree. The research was carried out on 505 Lithuanian black and white cows with a different degree of Holstein blood. The degree of Holstein blood of cows has been estimated according to the records of cows with complete 3 ancestor's generations pedigree infarmation. Four groups of cows were selected according to the level of Hosltein breed genes in the genotype of cows as follows: I group - from 0.01 to 25 percent, II group - from 25.01 to 50 percent, III group - from 50.01 to 75 percent and IV group - from 75.01 and more. The milk yield and milk ability traits (milking speed (MS), high milk flow (HMF), milking time (MT) were estimated every day during morning and evening milkings by using electronic milk testers (DeLaval) installed at the milking parlour. Obtained data of milking characteristics was processed by DeLaval "ALPRO™ Windows" program. Descriptive statistics (mean, standard error, P-value) were calculated by using R 2.1.0" package (http://www.r-project.org/). The results considered to be reliable at P≤0.05. The highest milk yield was estimated in a I group of cows (P<0.025) and the lowest - in a II group of cows (P<0.005) [...].