Associations between milk production level, calving interval length, lactation curve parameters and economic results in Holstein cows

Abstract

The objective of work was to evaluate effects of milk production level (MY1≥9500 kg, n=23; MY2 = 8000-9499, n=28; and MY3≤7999 kg, n=29) and calving interval length (CI1≥440 days, n=22; CI2 = 400-439 days, n=33; and CI3≤399 days, n=25) on the lactation curve parameters calculated using MilkBot® Model and economic profitability of Holstein dairy cow breeding. Data were obtained from 80 Holstein cows on 1st to 4th parity calved between January and August 2012 on the dairy farm of the Czech University of Life Sciences Prague in Czech Republic. Lactation curve parameters differed more in relation with milk production level compared to calving interval length. Lactation curve in cows with the highest MY was characterized with significantly higher overall magnitude (scale parameter) of milk production (P<0.01), higher peak yield (P<0.01) which occurred later (P<0.05) and higher persistence (P<0.05). Due to combination of higher persistence and total yield, average milk yield per day of calving interval was significantly (P<0.05) higher in cows with middle CI than in short CI. Optimal calving interval length should be assessed in relation with lactation persistence and milk production level. The highest individual profitability was reached by cows in MY1 and CI2 group.