Dynamics of Culling Risk of Holstein Cows in U.S Organic Dairy Herds

Project Director: Sushil Paudyal, Texas A&M University

Project Overview

Culling, the selective removal of specific individuals within a herd, is a common management practice within the dairy industry and can be important for maintaining healthy herds. Culled animals may be removed by a dairy farmers for several reasons, including low milk production or disease. Understanding how, when, and why cows are culled can improve herd health management decisions.

In the United States, over one-third of all dairy cows are culled annually, with previous research suggesting that culling rates may be lower in organic dairy herds, around 21%. However, more specific information about culling practices on organic dairy farms is needed. This study, led by researchers from Texas A&M University and Colorado State University, analyzed industry data from organic dairy farms to provide a detailed report of the management decisions behind organic dairy cow culling.

Farmer Takeaways

The average annual culling rate for U.S. organic dairy farms between 2018 and 2022 was 28.4%, slightly lower than reported annual culling rates for conventional dairy farms.
Reproductive failure (i.e., failure to conceive) was the leading reason for culling, responsible for >25% of annual cullings. Cow mortality and mastitis were the next most common reasons for culling.
Culling rates tended to be higher in low-yielding cows, cows with a parity of 4+, larger herds, cows calving during seasons with extreme temperatures, and during early lactation.
Reasons for culling differed depending on lactation stage.

Project Objectives and Approach

Examine the culling dynamics of cows in U.S organic dairy herds

Researchers at Texas A&M University and Colorado State University analyzed management data provided by a dairy industry recordkeeping software company.
- The records included information from 434 organic dairies across 31 states, representing nearly 288,000 calving records between January 2018 and December 2022.
- Data included culling date and reason, as well as calving information such as birth date, calving date, dam parity*, date of dry-off*, and milk yield.
  - - Dam parity: the number of times a dam has given birth
    - Date of dry-off: the date when milk production is intentionally stopped, usually 45 to 60 days before a cow’s next expected calving date. Allows for udder recovery.
Statistical models were created to test whether culling rates were associated with any particular herd- or cow-level factors.
- These tests were used to determine if any of the management data listed above were associated with annual culling rates, age distributions of culled cows, and specific reasons for culling.
- Reasons for culling included feet and leg issues, low milk production, reproductive problems, injury, death, mastitis, disease, and udder problems.
- The researchers also looked at whether broader factors like geographic location or time of year could be associated with culling.

Key Findings

Culling in U.S organic dairies is influenced by lactation stage, dam parity, milk production, herd-level characteristics, and calving season

The annual culling rate in U.S organic dairies between 2018 and 2022 was 28.4%, somewhat lower than reported culling rates on conventional dairy farms.
Reproductive failure was the most common reason for culling organic cows, responsible for 27% of culling. **Note: Reproductive failure rates tend to be higher in organic dairies, due to the restriction on using reproductive hormones.
Culling risk was associated with several factors, including lactation stage, dam parity, milk production, herd-level characteristics, and calving season.
- - Lactation Stage: Culling rates tended to be particularly high within 60 days of calving; during this ‘early lactation’ stage, death and disease were the most common reasons for culling. Between 46-225 days postpartum, mastitis (inflammation of the udder, primarily caused by a bacterial infection) was the most common reason for culling. During ‘late lactation’ (270+ days postpartum), culling was primarily attributed to reproductive issues (i.e., a failure to conceive).
  - Dam Parity: Culling rates increased significantly for cows with a parity of 4+, suggesting that organic dairy cows that have given birth four or more times in their lifetime may be at a higher risk for reproductive failure, health issues, or reduced milk yields. Notably, primiparous cows (first-time mothers) had higher culling rates than cows with parities of 2 and 3.
  - Milk Production: Culling rates were lower for high-yielding cows than for low-yielding cows, emphasizing the importance of milk yield. Low-yielding cows within a herd may be replaced with higher-yielding cows, and higher-yielding cows may then be provided with preferential care to minimize culling risk.
  - Herd-Level Characteristics: Annual culling rates were higher in large herds than in small herds. This may be due to limited individual attention in larger herds and delayed identification of at-risk cows for timely treatment.
  - Calving Season: Cows that calved during seasons with temperature extremes (summer and winter) were at the highest risk for culling and/or mortality.

Resources

Shrestha, B., Pinedo, P. J., Neupane, R., Valeris-Chacin, R., Piñeiro, J. M., & Paudyal, S. (2026). Dynamics of culling risk of Holstein cows in US organic dairy herds. Journal of Dairy Science, 109(7), 7170–7185.

Collaborators

Bhuwan Shrestha, Texas A&M University
Pablo Pinedo, Colorado State University
Rajesh Neupane, Texas A&M University
Robert Valeris-Chacin, Texas A&M College of Veterinary Medicine & Biomedical Sciences
Juan Piñeiro, Texas A&M University

Region

West/Southwest

Topic

Livestock Well-Being

Year Published

2026