Agriculture, Vol. 11 No. 2, 2005.
Original scientific paper
ANALYSIS OF THE RELATIONSHIP BETWEEN FIRST THREE LACTATIONS OF HOLSTEIN COWS
Vesna Gantner
Sonja Jovanovac
K. Kuterovac
Abstract
The objective of this study was to evaluate relationship between milk yield in the first three lactations regarding levels of milk yield in the first lactation and levels of age at the first calving. Prediction of milk yield in later lactation based on milk yield in the earlier one was also carried out. The data used in this study were 5743 lactation yields collected from 1995 to 2003. All cows finished the first three lactations. Mean value of milk yield in the first lactation was 5283.5 kg, 6033.5 kg in the second and 6338.4 kg the third one. The milk yield estimation coefficients between the first and second lactation was 1.164, between the first and third was 1.231, and 1.079 between the second and third. The levels of milk yield in the first lactation highly significant influenced the value of estimation coefficient between first three lactations, while the age at first calving influenced less significantly. Determination coefficient (R2) values for models used in prediction ranged from 0.348 to 0.396.
Keywords
Holstein breed; lactation; milk yield; estimation coefficients; statistical models
Hrčak ID:
11947
URI
Publication date:
20.12.2005.
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