Teat and Udder Score EPDs Heather Bradford University

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 – 2. 7 % of cull cows – Especially older cows • Mastitis – Weak suspension – Decreases WW by up to 50 lbs Dueñas et al. , 2001; De. Groot 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 5 8 4 6 7 3 Denton, 2007 2 1

BIF Guidelines, 2010

Research History • American Gelbvieh Association, 2001 – Sapp et al. , 2004 (doi: 10. 2527/2004. 8282277 x) • American Hereford Association, 2012 – Bradford et al. , 2015 (doi: 10. 2527/jas 2014 -8858) • Red Angus Association of America, 2017 – Boldt et al. , in progress

Descriptive Statistics Trait Suspension Teat size Overall score Suspension Teat size Mean SD Hereford 7. 16 1. 42 6. 98 1. 48 7. 23 1. 50 Red Angus 6. 05 1. 68 6. 10 1. 66 N 266, 283 266, 393 303, 112 48, 730 48, 704

Distribution of Scores Overall Score Udder Suspension Teat Size 2 7 20 000 n 15 000 10 000 5 000 0 1 Pendulous suspension Large teats 3 4 5 6 Score 8 9 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 – Additive genetic – Permanent environment • Fixed effects – Contemporary group (herd-year-season) – Age

Repeatability Trait Repeatability Overall Score 0. 49 (0. 004) Udder Suspension 0. 49 (0. 010) Teat Size 0. 47 (0. 005) • L 1 Hereford • Red Angus repeatability = 0. 34 repeatability ~ 0. 30 Mac. Neil and Mott, 2006; Boldt et al. , unpublished

Records per Cow Overall Score Udder Suspension Teat Size 15 000 n 10 000 5 000 0 1 2 3 4 5 Records per cow 6+

Heritability Trait Overall score Suspension Teat size Red Angus • Suspension • Teat size h 2 0. 32 (0. 01) 0. 31 (0. 01) 0. 28 (0. 01) h 2 = 0. 32 h 2 = 0. 28 Boldt et al. , unpublished

Genetic Correlations Suspension Teat size Overall score Suspension 0. 70 (0. 02) 0. 72 (0. 02) 0. 83 (0. 01) Udder suspension and teat size • Gelbvieh r = 0. 95 • Red Angus r = 0. 80 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 Larger EPD Smaller EPD Teat Size

EPDs Udder Suspension Bull (UDDR) A 1. 50 B 0. 50 Avg 1. 16 Teat Size (TEAT) 0. 75 1. 25 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 50000 40000 30000 20000 10000 Year AHA, 2017 16 20 15 20 14 20 13 20 12 20 11 20 10 20 09 20 08 20 07 20 06 0 20 Number of cows 60000 EPD

Genetic Trends 1, 25 1, 2 1, 15 1, 1 1, 05 1 0, 95 0, 9 Birth Year AHA, 2017 14 20 12 20 10 20 08 20 06 20 04 20 02 20 20 Loose suspension Large teats Udder Suspension Teat Size 00 Udder Score Tight suspension Small teats

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