Update on Structure EPD Development R. L. Weaber, J. Bormann, N Update on Structure EPD Development R.L. Weaber, J. Bormann, N. Bello, B. Jensen, L. Giess, W. Fiske

Overview Introduction of feet and leg structure Materials and Methods Results Conclusion

Introduction Longevity can help offset the cost of replacements Maintaining a mature cow herd which produces a higher percentage of calves balances the cost of replacement heifers (Cundiff, 1992) A cow takes 6 years to repay her capital investment above depreciation value (Brooks, 2015)

Heritability in Dairy cattle Foot angle 0.09 to 0.13 Rear leg side view 0.15 to 0.23 Rear leg rear view 0.06 to 0.11 Composite Score 0.13 to 0.41 (Vollema and Groen 1997, Onyiro and Brotherstone 2008, Laursen et al. 2009, and Wright et al. 2012)

Feet and Legs in the Dairy Industry Moderate genetic relationships with type traits and longevity and functional longevity (Dekkers et al. 1994) Udder conformation Feet and leg structure Longevity tends to be lowly heritable (Vollema and Groen, 1997) 0.09-0.13

Feet and Legs in the Beef Industry Australian Angus Cattle Investigate genetic parameters for feet and leg traits Differences between linear and threshold modeling (Jeyaruban et al., 2012)

Feet and Leg Traits in Beef Cattle Australian Angus Association is currently publishing 5 structural soundness Estimated Breeding Values (EBVs). Front Foot Angle Front Claw Shape Rear Foot Angle Rear Leg Side View Rear Leg Rear View (Australian Angus Association, 2017)

Results Heritability Traits Linear Front Angle 0.32 Front Claw 0.33 Rear Angle 0.29 Rear Claw 0.17 Rear Leg Rear View Rear Leg Side View 0.21 Jeyaruban et al. (2012)

Feet and Leg Traits in Beef Cattle No genetic evaluations on feet and leg traits are currently being published in the United States American Angus Association is asking breeders to collect and submit phenotypes Foot Angle Claw Shape

Feet and leg structure evaluation at K-State Estimate genetic parameters for feet and leg structure in Red Angus (and Simmental) cattle Investigate relationships within feet and leg structure traits and between feet and leg structure and production traits

Traits Measured 1,885 Red Angus cattle were subjectively scored on 14 traits including: Body Condition Score (BCS) Front Hoof Angle (FHA) Front Heel Depth (FHD) Front Claw Shape (FCS) Front Side View (FSV) Front View Knee Orientation (KNEE) Front View Hoof Orientation (FHO) Rear Hoof Angle (RHA) Rear Heel Depth (RHD) Rear Claw Shape (RCS) Size of Hoof (SIZE) Rear Leg Side View (RLSV) Rear Leg Rear View (RV) Composite Score (COMP)

KSU feet and leg scoring system

KSU feet and leg scoring system

KSU feet and leg scoring system

KSU feet and leg scoring system

KSU feet and leg scoring system

KSU feet and leg scoring system

KSU feet and leg scoring system

KSU feet and leg scoring system

KSU feet and leg scoring system

KSU feet and leg scoring system

Material and Methods Every animal must be scored by at least two trained evaluators Scores for each animal were averaged to reduce scorer bias All animals included in the evaluation must have a registration number with Red Angus Association of America

Materials and Methods 1,720 animals included in the evaluation after edits 3 generation pedigree file was acquired from the Red Angus Association of America 13,306 animals 3157 sires, 1282 sires of sires, and 2467 sire of dams 8724 dams, 5913 dam of dams, and 2249 dam of sires

1,217 females 503 males

Mean 56.6 St Dev 4.57 Mean 57.2 St Dev 4.55 Mean 59.69 St Dev 5.73

Distribution of Claw Shape Mean 57.5 St Dev 6.43 Mean 52.76 St Dev 5.76

Results Mean 46.04 St Dev 3.66

Mean 55.78 St Dev 4.95 Mean 53.71 St Dev 2.97

Results Mean 31.37 St Dev 4.04

Linear Animal Model ASREML (Ver 3.0 and 4.0, VSN International, LTD., Hemel Hempstead, UK) (Co) Variance components and correlations 169 bi-variate models Consensus (mean) estimates of additive and residual variances for informative bi-variate models EPDs from Front and Rear Limb models for all animals in pedigree

Variance Components Residual, genetic, and phenotypic variances were averaged between all combinations of 13 traits in bivariate analysis’s Heritability for each trait was calculated from the mean of the variance components 𝒉 𝟐 = 𝝈 𝒂 𝟐 𝝈 𝒑 𝟐

Average Standard Error Trait Average Heritability Average Standard Error Body Condition Score 0.11 0.04 Front Hoof Angle 0.20 0.06 Front Heel Depth 0.17 0.05 Front Claw Shape 0.09 Rear Hoof Angle 0.19 Rear Heel Depth 0.25 Rear Claw Shape Size of Hoof 0.36 Front Side View 0.16 Knee Orientation Front Hoof View Rear Side View 0.30 Rear View 0.14 Composite Score 0.12

Genetic (red; above diagonal) Phenotypic (purple; below diagonal) Correlations Trait BCS FHA FHD FCS RHA RHD RCS Size FSV Knee FHO RSV RV Comp   0.27 0.25 0.20 0.26 0.51 0.28 0.08 -0.04 0.24 0.19 0.40 0.38 -0.68 -0.70 -0.27 0.22 -0.26 0.07 0.29 -0.03 0.026 0.89 0.06 -0.21 0.88 0.85 0.09 -0.17 0.11 0.18 0.46 -0.05 0.23 -0.25 0.63 0.15 0.36 -0.33 -0.02 0.025 0.82 0.01 -0.31 0.10 0.94 -0.12 -0.06 0.45 0.05 -0.20 0.17 -0.36 0.03 0.13 0.75 0.12 -0.01 -0.13 0.31 0.02 0.47 0.14 0.86 -0.09 0.004 0.21 -0.24 0.72 -0.44 0.52 0.83 -0.23 0.16 0.56 -0.57 -0.11 0.41 -0.003 0.04 0.32 -0.59 -0.75 -0.07 -0.10 0.87 0.95 -0.38 -0.14 0.73 -0.46 0.002 -0.40 -0.64 -0.15 -0.30 -0.28 -0.32 1 2 3 4

Genetic and Phenotypic Correlations Trait BCS FHA FHD FCS RHA RHD RCS Body Condition Score   0.27 0.25 0.20 0.26 0.51 0.28 0.08 -0.04 0.24 0.19 Front Hoof Angle -0.03 0.026 0.89* 0.06 -0.21 0.88* 0.85* 0.09 -0.17 0.22 Front Heel Depth -0.02 0.025 0.82* 0.01 -0.31 0.10 0.94* -0.12 Front Claw Shape 0.05 0.10* 0.03 0.13 -0.05 0.75* 0.17 Rear Hoof Angle -0.01 0.51* 0.02 0.47* 0.14* 0.86* -0.09 0.23 Rear Heel Depth 0.46* 0.52* 0.12* 0.83* 0.11 0.21 Rear Claw Shape 0.38* 0.18* FHA and FHD Strong correlations FHA, FHD strong genetic corr with RHA and RHD FCS and RCS low phenotypic corr; strong genetic corr.

Genetic and Phenotypic Correlations Trait Size of Hoof Front Side View Knee Orientation Front Hoof Orientation Rear Side View Rear View Composite Score Body Condition Score 0.40* 0.19 0.38 0.25 -0.68* 0.26 -0.70* 0.24 -0.27 0.22 -0.26 0.07 0.29 Front Hoof Angle 0.11 0.18 0.46* -0.05 0.23 -0.25 0.63* 0.15 0.36* -0.33 Front Heel Depth -0.06 0.45* 0.05 -0.20 0.51* 0.17 -0.36 Front Claw Shape 0.20 0.08 0.28 0.12 -0.01 -0.13 0.31 Rear Hoof Angle 0.004 0.21 -0.04 -0.24 0.72* -0.44* Rear Heel Depth -0.23 0.16 0.01 0.56* -0.57* Rear Claw Shape -0.11 0.03 0.41* -0.36* 0.14 Front limb angles modest correlation with FHA and FHD Rear limb angles modest genetic corr with RHA and RHD Limb angles good indicator traits for hoof attributes

Genetic and Phenotypic Correlations Trait Body Condition Score Front Hoof Angle Front Heel Depth Front Claw Shape Rear Hoof Angle Rear Heel Depth Rear Claw Shape Size of Hoof 0.23* 0.025 -0.003 0.03 -0.05 0.04 0.01 -0.03 0.02 Front Side View 0.13* 0.07* 0.05 0.08* -0.02 Knee Orientation -0.11* 0.11* Front Hoof Orientation -0.14* 0.12* Rear Side View -0.12* 0.026 0.16* 0.06 0.15* 0.002 0.24* Rear View 0.10* 0.19* 0.21* Composite Score -0.15* -0.20* -0.30* -0.21* -0.23* -0.28* RHA and RHD low phenotypic correlations with limb angles

Genetic and Phenotypic Correlations Trait SIZE FSV KNEE FHO RSV RV COMP Size of Hoof   0.11 0.18 0.06 0.19 0.17 0.03 0.16 -0.17 0.32 Front Side View 0.02 -0.59* 0.21 -0.75* -0.07 0.20 -0.10 0.24 0.87* Knee Orientation -0.11* -0.13* 0.95* 0.07 -0.38* 0.23 0.26 Front Hoof Orientation -0.24* 0.73* 0.01 -0.46* -0.25 0.27 Rear Side View -0.01 0.09* 0.10* 0.08* 0.31 -0.40 Rear View -0.10* 0.21* 0.23* 0.32* -0.64* Composite Score 0.25* 0.38* -0.07* -0.09* -0.06* -0.32* KNEE, FHO and FSV modest to strong genetic correlations Low (and some negative) genetic correlations between front and rear limb angles

Conclusion Feet and leg traits have low to moderate heritability; Useful indicator trait data obtainable from limb information via genetic correlations If selection pressure is place on these traits genetic change can be realized

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