Teat and Udder Score EPDs Heather Bradford University of Georgia

Acknowledgments Kansas State University Shane Bedwell, AHA Ryan Boldt, CSU Larry Keenan, RAAA

Importance for the Cow Longevity Mastitis 2.7 % of cull cows Especially older cows Mastitis Weak suspension Decreases WW by up to 50 lbs Dueñas et al., 2001; DeGroot et al., 2002; Lents et al., 2002; Rupp and Boichard, 2003; USDA, 2010

Importance for the Calf Labor Assisting calves to suckle Pendulous suspension, extreme teat sizes Mortality Later colostrum consumption Long or large diameter teats Growth Smaller teats and udders Wythe, 1970; Edwards, 1982; Frisch, 1982; Ventorp and Michanek, 1992; Goonewardene et al., 2003

Measurement Subjective scores 1 to 9 24 hours after calving Poorest quality quarter Evaluated by same person within a herd Ranking of cows more important than actual score BIF Guidelines, 2010

Measurement at AHA Historically 1 trait recorded (overall score) BIF recommends recording 2 traits in July 2008 Change to 2 traits in August 2008 Udder suspension (UDDR) Teat size (TEAT)

Overall Score 9 8 7 6 5 4 3 2 1 Denton, 2007

BIF Guidelines, 2010

Research History American Gelbvieh Association, 2001 Sapp et al., 2004 (doi: 10.2527/2004.8282277x) American Hereford Association, 2012 Bradford et al., 2015 (doi: 10.2527/jas2014-8858) Red Angus Association of America, 2017 Boldt et al., in progress

Descriptive Statistics Trait Mean SD N Hereford Suspension 7.16 1.42 266,283 Teat size 6.98 1.48 266,393 Overall score 7.23 1.50 303,112 Red Angus 6.05 1.68 48,730 6.10 1.66 48,704

Distribution of Scores Pendulous suspension Large teats Tight suspension Small teats

Model Overall Score Udder Suspension Teat Size Genetic Evaluation Udder Suspension EPDs Teat Size EPDs

Model Multiple-trait animal model Random effects Fixed effects Additive genetic Permanent environment Fixed effects Contemporary group (herd-year-season) Age

MacNeil and Mott, 2006; Boldt et al., unpublished Repeatability L1 Hereford repeatability = 0.34 Red Angus repeatability ~ 0.30 Trait Repeatability Overall Score 0.49 (0.004) Udder Suspension 0.49 (0.010) Teat Size 0.47 (0.005) MacNeil and Mott, 2006; Boldt et al., unpublished

Records per Cow

Boldt et al., unpublished Heritability Red Angus Suspension h2 = 0.32 Teat size h2 = 0.28 Trait h2 Overall score 0.32 (0.01) Suspension 0.31 (0.01) Teat size 0.28 (0.01) Boldt et al., unpublished

Sapp et al., 2004; Boldt et al., unpublished Genetic Correlations Udder suspension and teat size Gelbvieh r = 0.95 Red Angus r = 0.80 Overall score Suspension 0.70 (0.02) Teat size 0.72 (0.02) 0.83 (0.01) Sapp et al., 2004; Boldt et al., unpublished

Implementation 2013 research EPDs on proven bulls Spring 2015 US Fall 2017 US and Canada Coming soon GE-EPDs

EPDs Udder Suspension Teat Size Larger EPD Smaller EPD

Udder Suspension (UDDR) EPDs Bull Udder Suspension (UDDR) Teat Size (TEAT) A 1.50 0.75 B 0.50 1.25 Avg 1.16 1.17 Expect Bull A’s daughters to be 1 score tighter for suspension Expect Bull B’s daughters to be 0.5 score smaller for teat size

Increased Reporting Research EPD AHA, 2017

Genetic Trends Tight suspension Small teats Loose suspension Large teats AHA, 2017

Correlations with Other Traits Udder and Milk moderately negative More milk = more udder problems Udder and WW negative to positive More growth = ? Reproductive and longevity traits? Sapp et al., 2004; MacNeil and Mott, 2006

Challenges Contemporary groups with no variation AHA RAAA ~ 50% (Boldt et al.) Same score for both traits Multiple-trait selection

Conclusions Moderately heritable Selection for intermediate optimum More records per cow, greater accuracy Improved education on scoring system