The relationship between milk production in the first three lactations of Holstein cows
2002
Chladek, G. | Kucera, J. (Mendelova Zemedelska a Lesnicka Univ., Brno (Czech Republic). Ustav Chovu Hospodarskych Zvirat)
Milk yields of 7,878 Holstein (H) and crossbred dairy cows with at least 87.5 % of Holstein breed (CH) were evaluated during the first three lactations according to the breed, lactation number and milk yield. First lactation cows were divided into 3 groups according to their milk yield as follows: MI - up to 3,999 kg, MII - between 4,000 and 6,399 kg, MIII - above 6,400 kg. Milk yield of H cows was higher (by 477.3 kg, 590.9 kg, and 675.0 kg) than that of CH cows in all lactations. The mean estimation coefficient calculated for the whole dataset was 1.175 between the first and second lactation, 1.297 between the first and third lactation, and 1.119 between the second and third lactation. The values of estimation coefficients decreased with increasing milk yield in the first lactation. There was a significant effect of milk yield in the first lactation (MI to MIII) on calculated estimation coefficients, while the effect of breed (H and CH) was not significant.
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