Özet:

This study was conducted with Holstein heifers imported from the United States (US), Germany, and the Czech Republic to a private dairy farm in Kırklareli/Lüleburgaz region in Turkey to evaluate their adaptation in terms of milk production and fertility performance. The first insemination age of the herd was 490.62 days, and the first calving age was 804.24 days. The number of inseminations required per pregnancy was calculated as 3.99, gestation length as 279.72 days, and service period as 213.99 days. The rate of abortion and twin births were higher in those of US origin. Increased first calving age was observed in heifers of German origin due to delayed insemination. The mean actual lactation milk yield in the first lactation periods was 11834.75 Lt, 305 days milk yield was 8573.31 Lt, lactation length was 419.61 days, the dry period was 63.02 days. Milk yield performance of Holsteins of US origin was higher in the first lactation period. In conclusion, milk production was profitable; however, the fertility performance of the herd was poor in general. Poor fertility performance was due to poor herd management and adaptation problems. Therefore, after the calving period, more attention should be paid to oestrus monitoring and insemination activities. In Turkey, the success of live animal imports should be well investigated; in particular, problems occurring during animal selection for importation should be evaluated, and short-/long-term national strategies should be developed.

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