Effect of milking frequency on DHI performance measures

Area of Science:

• Dairy Science
• Animal Husbandry
• Reproductive Biology

Background:

• Increasing milking frequency (MF) is a strategy dairy producers use to enhance milk production.
• Understanding the effects of MF on various herd performance metrics is crucial for effective dairy management.

Purpose of the Study:

• To examine the effects of milking frequency (MF) on dairy herd performance.
• To investigate interactions between MF, herd size, and geographical region on production and health indicators.

Main Methods:

• Analysis of Dairy Herd Improvement (DHI) Holstein herd summary records from 1998-2000 (n > 10,000 herds per year).
• Classification of herds by milking frequency (2X vs. 3X), herd size (small <250 cows, large >=250 cows), and region (North vs. South).

Main Results:

• Herds on 3X milking showed 15-16% higher rolling herd average milk production compared to 2X herds.
• 3X milking resulted in lower milk fat and protein percentages, affecting energy-corrected milk yield.
• Herds on 3X milking had poorer reproductive outcomes (more days open, higher calving intervals, more services per pregnancy) but lower somatic cell scores.
• Higher herd turnover rates (cow entry and exit) were observed in 3X milking herds.

Conclusions:

• While 3X milking increases overall milk yield, it negatively impacts milk component percentages and reproductive efficiency.
• Regional differences exist, with Northern herds showing higher production under 3X milking.
• Management decisions regarding MF should consider trade-offs between production, reproduction, and herd dynamics.