Evaluation of cow fertility on profitability of milk production

Objectives of this study were to evaluate effects of milk production level and calving interval, resp. days open period length on the lactation curve parameters and milk production profitability. Data were obtained from Holstein dairy farm. From our results can be stated, that cows with the longest days open period length reached significantly the highest lactation persistence. Due to their ability to maintain high milk productivity after peak day, average daily milk yield was not in these cows, despite long lactation, lower than in cows with shorter lactations. From the economic point of view, milk production profitability with calving interval length decreased and with milk production level increased. Low profitability in cows with long days open period caused high replacement and fertility costs. Feeding costs despite expectations didn´t differ between these groups. All early lactating cows are fed with the same expensive concentrated feeding ration, thats why there is not possible to save feeding costs in high persistent cows with low milk production increase after calvin