Genetic aspects of longevity in cows - the effect of breed
1991
Rehout, V. (Vysoka Skola Zemedelska, Ceske Budejovice (CSFR). Fakulta Agronomicka)
A set of 1550 cows of a population negatively selected from breeding herds was investigated on two farms. The population was divided into five breeding groups: Bohemian Pied breed (C), crossbred cows with 50 per cent and 75 per cent blood proportions of the Black-Pied Lowland breed (N), crossbred cows with 25 to 50 per cent blood proportions of the Ayrshire breed (A) and crossbred cows with 25 to 50 per cent blood proportions of the Red Holstein-Friesian breed (R). Milk yield in the first lactation, number of lactations, milk yield per day of life and per day of productive life were evaluated as the parameters of production and longevity. The milk yield of cows, crossbreds with N and R breeds, was significantly higher in the first lactation than in the cows of C breed and crossbred cows with A breed. But the situation was quite different as to the number of lactations - the first group of genotypes reached on average only 2.5 lactations, the other 4.5 lactations. In the FCM production per day of productive life the group with the higher milking capacity was the best - in the same order on average 9.0 and 8.4 kg FCM. The effect of the higher milk yield per day of the whole life was compensated by higher longevity, and the group of cows with lower milking capacity yielded on average 0.6 kg FCM more (3.7 vs. 4.3 kg FCM). The results indicate that it is necessary to re-evaluate the one-sided orientation to cows with good milking capacity with respect to longevity because they are kept in the conditions which do not correspond to the requirements for the realization of their genetic pool.
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