Analysis of the relationships between production and longevity of cows
1991
Rehout, V. (Jihoceska Univ., Ceske Budejovice (CSFR). Zemedelska Fakulta)
The studied set of 1550 cows of the Bohemian Pied breed and crossbreds of this breed with the dairy breeds was characterized by an average performance of 3,020 kg of milk in the first lactation, by a lifelong milk yield of 10,575 kg of milk, a first-calving age of 891 days, 3.2 parturitions and other parameters. It follows from the analyzed spectrum of linear and quadratic dependences that age at first calving was negatively correlated to the lifelong milk performance for both standard lactations and all lactations, to the number of lactations, to the length of life and productive life, and to milk production per one day of life. The only parameters to which the age at the first calving was in a clearly positive relationship were those of performance at the first lactation. Another parameter that was in a negative relationship to longevity was performance in first lactation, except for milk yield for the maximum lactation and performance per one day of productive life. The correlations between milk yield at maximum lactation and the remaining parameters of output and longevity were positive. The results document the adverse effect exerted on the parameters of output and longevity by increased age at first calving as a complex trait comprising the realization factors setting in during the ontogenetic development of the future cow.
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