The METR predicted transmitting ability (PTA) represents the expected resistance of an animal’s offspring to metritis in a herd with average management conditions. Larger, positive values are more favorable.
Metritis (METR)
METR measures the resistance to metritis.
Benefits of Trait
Introduced in 2018, 2020, and 2022, genetic and genomic evaluations for resistance to metritis (METR) are provided for Holstein, Jersey, and Brown Swiss males and females. Evaluations are expressed in percentage points of resistance above and below the breed average.
- A case of metritis can increase the risk of fertility problems including ovulatory dysfunction and increased calving to conception interval.
- The direct cost of metritis is approximately $112 per case. This does not include any associated costs such as decreases in production and fertility already accounted for in Net Merit.
- The significant genetic component of this trait indicates that producers can select animals less likely to experience metritis.
Resistance to Metritis (METR)
Percentage points. The average resistance rate is equal to 93.8% in U.S. Holsteins. The resistance rate is equivalent to the incidence rate subtracted from 100.
Daughters of a Holstein bull with a METR PTA of +2.0% are expected to have an average resistance rate to clinical metritis of 96% (assuming the breed average resistance is approximately 94%). Daughters of a Holstein bull with a METR PTA of -2.0% are expected to have an average resistance of 92%. Daughters from the bull with PTA -2.0% are expected to have twice the number of cases of metritis as daughters from the bull with PTA of +2.0%
Health trait evaluations, including for METR, became available for Holsteins on April 3, 2018, for Jerseys on April 7, 2020, and for Brown Swiss on August 9, 2022.
METR is included in selection indexes for Holsteins, Jerseys, and Brown Swiss as part of the Heath $ sub-index.
Estimated heritability is 1.4% for resistance to metritis (observed scale).
Young genomic bulls are expected to have reliabilities averaging 42% for resistance to metritis, and progeny tested bulls are expected to have genomic reliabilities averaging 48%. As additional data is accumulated, reliabilities will increase.
The largest significant (P < 0.05) correlation with PTA for resistance to metritis was with Daughter Pregnancy Rate PTA at 0.46. Additional significant correlations were 0.41 with Cow Conception Rate PTA, 0.32 with Productive Life PTA, 0.26 with Cow Livability PTA, and 0.23 with Heifer Conception Rate PTA.
METR evaluations were developed using producer-recorded data collected through Dairy Herd Information (DHI) affiliates from herds across the U.S. Strict editing was applied to ensure only the most reliable data was included for the development of genetic evaluations. The edited data included a total of 2 million METR records from 1.1 million cows. These health records are used in conjunction with lactation data available in the National Cooperator Database.
The standard deviation (variation) for METR PTA is 0.9%. Because 1 and 2 standard deviations normally include 68% and 95% of observations, respectively, we assume about 68% of bulls will have a MAST PTA between -0.9% and +0.9% while 95% of the bulls will range from -1.8% to +1.8%.
METR PTAs range from 2.3 percentage points below to 2.2 percentage points above average in evaluated Holstein bulls born since 1990 with reliabilities of ≥90% (December 2017).
Pre-release analysis indicates the active A.I. Holstein sires in December 2017 (614 bulls) range from -1.6% to +1.3%, with the average at approximately +0.6 percentage points.
Future Development
In the future, further model improvements and development will be researched and tested. This may include the development of a multi-trait model that incorporates multiple reproductive disorders and/or measures of fertility.
Related Publications
Emanuelson, U., P. A. Oltenacu, and Y. T. Gröhn. 1993. Nonlinear mixed model analyses of five production disorders of dairy cattle. J. Dairy Sci. 76:2765–2772.
Fourichon, C., H. Seegers, and X. Malher. 2000. Effect of disease on reproduction in the dairy cow: A meta-analysis. Theriogenology. 53:1729–1759. doi:10.1016/S0093-691X(00)00311-3.
Donnelly, M. R., A. R. Hazel, B. J. Heins, & L. B. Hansen, 2018. Health treatment cost of Holsteins in 8 high-performance herds. J. Dairy Sci. (in preparation).
Liang, D., L.M. Arnold, C.J. Stowe, R.J. Harmon, & J.M. Bewley, 2017. Estimating US dairy clinical disease costs with a stochastic simulation model. J. Dairy Sci. 100(2): 1472–1486.
Information last updated March 2018.