RSP represents the expected resistance of an animal’s offspring to calfhood respiratory problems in a herd with average management conditions. Larger, positive values are more favorable, indicating greater resistance.
Photo: World Wide Sires
Respiratory Problems (RSP)
Available for Holsteins and Jerseys, RSP predicts the expected resistance of an animal’s offspring to calfhood respiratory problems.
Benefits of Trait
Introduced in August 2026, Respiratory Problems PTA represents the expected resistance of an animal’s offspring to calfhood respiratory problems.
- Raising replacement heifers is among the most costly aspects of dairy production, second only to feed expenses, and these costs are further increased by the occurrence of disease.
- Respiratory disease is one of the two most common causes of dairy heifer mortality.
- Health challenges experienced early in life can have lasting effects on a dairy animal’s productivity, livability, and health later in life.
Resistance to Respiratory Problems Trait
Evaluations are expressed in percentage points of resistance above or below the breed average. Larger, positive values are more favorable, indicating greater resistance.
RSP is currently available for Holsteins and Jerseys. As more data become available, evaluations will be provided for additional breeds.
RSP will not be incorporated into the lifetime merit indexes at its launch. It is expected to be added at the next merit index revision.
RSP heritability is estimated at 2.2% (observed scale), similar to the heritability of cow health traits.
Holsteins: Young genomic bulls are expected to have reliabilities averaging 45%. Progeny-tested bulls are expected to have genomic reliabilities averaging 53%.
Jerseys: Young genomic bulls are expected to have reliabilities averaging 35%. Progeny-tested bulls are expected to have genomic reliabilities averaging 39%.
As additional data are accumulated for both breeds, reliabilities will increase.
The PTA correlation between RSP and DIA was estimated to be 0.34. The correlation of RSP with Heifer Livability was found to be 0.38.
PTA correlations of RSP and DIA with other traits currently under selection were negligible, with the exception of small favorable correlations between both DIA and RSP with Cow Livability.
RSP and DIA calf health evaluations were developed using producer-recorded data available in the National Cooperator Database. Extensive data quality control measures, similar to those used for cow health traits, were developed and implemented to ensure only the most reliable data were included for evaluation. The edited data included over 768,000 RSP records.
Holsteins: The standard deviation (variation) for RSP PTAs in Holstein bulls is 1.8 percentage points. Because one and two standard deviations normally include 68% and 95% of observations, respectively, we assume about 68% of Holstein bulls will have a RSP PTA between -1.8 to +1.8 percentage points, while 95% of Holstein bulls will range from -3.6 to +3.6 percentage points.
In testing of evaluated Holstein bulls born since 2000 with reliabilities of at least 80%, RSP PTAs ranged from -8.0 percentage points to +6.8 percentage points.
Pre-release analysis indicated that active A.I. Holstein sires in December 2025 (697 bulls) ranged from -6.9 percentage points to +3.5 percentage points for RSP, with the average at approximately -0.36.
Jerseys: The standard deviation for RSP PTAs in Jersey bulls is 2.3 percentage points. We assume about 68% of Jersey bulls will have a RSP PTA between -2.3 and +2.3 percentage points, while 95% of Jersey bulls will range from -4.6 to +4.6 percentage points.
In testing of evaluated Jersey bulls born since 2000 with reliabilities of at least 80%, RSP PTAs ranged from -7.4 percentage points to +5.9 percentage points.
Pre-release analysis indicated that active A.I. Jersey sires in December 2025 (123 bulls) ranged from -5.3 to +2.8 percentage points for RSP, with the average at approximately -0.42.
Future Development
Future work will focus on evaluating the potential advantages of a multi-trait approach that jointly analyzes calf health-related traits.
Related Publications
Improving dairy calf health through inclusion of diarrhea and respiratory health data into a US national genetic evaluation. Neupane et al, 2025.
Implementation of a national genetic evaluation for calf health traits in the US. Neupane et al, 2026.
Information last updated April 22, 2026.