1. 2001 ADSA Indianapolis 2001 (1) Heterosis and Breed Differences for Yield and Somatic Cell Scores of US Dairy Cattle in the 1990’s. PAUL VANRADEN Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD paul@aipl.arsusda.gov

2. Paul VanRaden 2001 ADSA Indianapolis 2001 (2) From 1939-1954, M.H. Fohrman studied 113 Guernsey, Jersey, Holstein, and Red Danes crosses at Beltsville. Another study of 137 Ayrshire, Brown Swiss and Holstein crosses was conducted from 1959-1968 (McDowell and McDaniel, 1968). USDA Yearbook of Agriculture 1947 Holstein  Guernsey

3. Paul VanRaden 2001 ADSA Indianapolis 2001 (3) 12,904588 Crossbreds averaged 12,904 pounds of milk and 588 pounds of butterfat, outperforming dams by more than sire proof predictions (Fohrman,1947). 13,833 493 In 1945, advanced register Holsteins averaged 13,833 pounds of milk and 493 pounds of fat. USDA Yearbook of Agriculture 1947 Red Dane  Jersey

4. Paul VanRaden 2001 ADSA Indianapolis 2001 (4) Breeds Are Evaluated Separately  Separate data sets reduce bias in evaluations within breeds, but provide:  No evaluations for crossbreds  No method to compare cows across breeds  New Zealand, Australia, and the Netherlands include crossbreds and account for heterosis in evaluations.  USDA-DHIA evaluations exclude crossbred cows unless identified as part of a “grading-up” program.

5. Paul VanRaden 2001 ADSA Indianapolis 2001 (5) Objectives  Document the number and type of crossbred cows in the US.  Estimate heterosis and breed differences using cows of different breed composition competing in the same herd.  Compare the economic merit of crossbred and purebred cows.

6. Paul VanRaden 2001 ADSA Indianapolis 2001 (6) Traits Considered  Milk, fat, and protein yields  Somatic cell score (SCS)  Productive life (PL)  Linear type composites not available  Body size estimates obtained from literature  Udder and leg trait estimates assumed zero  Net merit, cheese merit, fluid merit calculated  Adjusted to Holstein scale  Fertility, mortality, and calving ease not available

7. Paul VanRaden 2001 ADSA Indianapolis 2001 (7) Yield Traits & SCS Data  Data were from the national test-day database available May, 2001.  572 herds each with at least 5 crossbred cows  10,442 crossbred cows born since 1990  140,421 purebred herdmates (80% were Holstein)  Crossbreds defined by sire breed and maternal grandparent breeds.  Sires were purebred, dam breed used for unknown maternal grandparent breed  XX (crossbred) not accepted for maternal grandparents  Holstein and Red & White considered one breed

8. Paul VanRaden 2001 ADSA Indianapolis 2001 (8) Yield Traits & SCS Edits  85% of tests included fat, 82% protein, and 73% SCS  Edits applied:  Lactation length at least 250 days  At least 5 milk tests required before day 305  Sire PTA was obtained to account for possible differences in selection intensity of purebreds vs. crossbreds.

9. Paul VanRaden 2001 ADSA Indianapolis 2001 (9) Yield Traits & SCS Models Yield Traits & SCS Models  The models included effects of:  Herd-year-season  Age  Stage of lactation  Regression on sire PTA  Interaction of sire breed and maternal grand-parent breeds  Individual 3-breed interactions were weighted by number of observations to obtain:  Specific and general heterosis  General recombination effect

10. Paul VanRaden 2001 ADSA Indianapolis 2001 (10) Number of F 1 & Purebred Cows Number of F 1 & Purebred Cows In Mixed Breed Contemporary Groups Sire Breed Dam Breed Ayrshire Brown Swiss GuernseyJersey Milking Shorthorn Holstein Ayrshire 933—1262477 Brown Swiss —25378225242 Guernsey 83117632341228 Jersey 18221165938507 M. Shorthorn —111—1509175 Holstein 145819130163116271,836

11. Paul VanRaden 2001 ADSA Indianapolis 2001 (11) Number of F 1 & Backcross Cows Number of F 1 & Backcross Cows With Holstein Sire or Grandparent Holstein Genes Second Breed 25% 25% 50% 50% 75% 75% Ayrshire 17 17 622 622124 Brown Swiss 1241061196 Guernsey 32 321358367 Jersey 1712138321 M. Shorthorn 14 14 337 337 48 48

12. Paul VanRaden 2001 ADSA Indianapolis 2001 (12) Productive Life Data  Data from the national database available July, 1994  41,131 crossbred cows born from 1960 through 1991  726,344 purebred cows in the same herd-years  Breed composition from five generation pedigrees  Percent genes from each breed  Progeny breed = mean of parents’ breeds  Unknown parent breed = progeny breed  Breed ‘XX’ progeny with unknown parents excluded  Holstein and Red & White considered one breed

13. Paul VanRaden 2001 ADSA Indianapolis 2001 (13) Productive Life Models  Model 1 included effects of:  Herd-year-season  Regressions on breed composition  Regression on coefficient of heterosis  Incomplete records weighted by age  Model 2 also included:  Interaction of birth year with breed composition  Interaction of birth year with heterosis

14. Paul VanRaden 2001 ADSA Indianapolis 2001 (14) Results  Estimated breed means  Estimates of heterosis  Economic comparisons  Rank other breeds on Holstein base  Some new crossbreeding theory

15. Paul VanRaden 2001 ADSA Indianapolis 2001 (15) Breed Effects for Yield Traits Calculated from Holstein Means BreedMilk(kg/d)Fat(kg/d)Protein(kg/d) Ayrshire 26.30.990.81 Brown Swiss 26.81.040.87 Guernsey 24.11.010.77 Jersey 23.91.040.81 M. Shorthorn 25.60.920.73 Holstein 31.51.120.93

16. Paul VanRaden 2001 ADSA Indianapolis 2001 (16) USDA Yearbook of Agriculture 1947 Holstein  Jersey Cow #Pounds of Milk% Butterfat Pounds of Butterfat X-513,0324.62602 X-1112,5844.82606 X-2012,3835.13636 X-3011,8675.60664 X-3811,9295.09607 X-4013,6904.74649 X-5113,8004.44613 All cows sired by Beltsville Holstein No. 966

17. Paul VanRaden 2001 ADSA Indianapolis 2001 (17) USDA Yearbook of Agriculture 1947 Jersey  Holstein Cow #Pounds of Milk% Butterfat Pounds of Butterfat X-1 9,7844.85475 X-313,0654.71615 X-1713,8373.85533 X-3213,7283.94540 X-4112,4534.63576 X-42 9,4174.90461 X-4712,1895.13625 X-1 and X-47 were sired by an unidentified Jersey sire. All others sired by Beltsville Jersey No. 1114

18. Paul VanRaden 2001 ADSA Indianapolis 2001 (18) Heterosis for Yield Traits Heterosis for Yield Traits Percent of Parent Breed Average MilkFatProtein Breed Holstein Sire Holstein Dam Holstein Sire Holstein Dam Holstein Sire Holstein Dam Ayrshire  2.4-2.02.7-1.82.9-2.4 Brown Swiss  5.6 3.2 3.24.8 4.5 4.54.7 3.8 3.8 Guernsey  5.2 2.4 2.47.1 4.4 4.45.5 4.0 4.0 Jersey  7.5 1.6 1.66.6 4.5 4.57.2 4.1 4.1 M. Shorthorn  2.8 0.3 0.33.2 1.3 1.33.6 1.2 1.2 Heterosis 3.4 (SE=0.3) 4.4 (SE=0.4) 4.1 (SE=0.4)

19. Paul VanRaden 2001 ADSA Indianapolis 2001 (19) Breed Effects & Heterosis for SCS Breed Mean SCS % Heterosis for Holstein  Ayrshire 2.72 2.72 3.98 3.98 Brown Swiss 2.82 2.82-0.20 Guernsey 2.86 2.86-0.57 Jersey 2.99 2.99 2.09 2.09 M. Shorthorn 2.84 2.84-1.52 Holstein 2.95 2.95— Heterosis 0.72 % (unfavorable) (SE=0.9)

20. Paul VanRaden 2001 ADSA Indianapolis 2001 (20) Breed Effects & Heterosis for PL Breed PL (mo) 1990 births 1995 Base Change (mo) PL (mo) 1995 births Ayrshire22.7.523.2 Brown Swiss 23.5.323.8 Guernsey17.7.518.2 Jersey24.9.925.8 M. Shorthorn 18.9.619.5 Holstein23.8.524.3 Heterosis 1.2% (SE=0.1)

21. Paul VanRaden 2001 ADSA Indianapolis 2001 (21) Breed Effects & Heterosis for Body Size & Size Composite Breed Mature Size (kg) Size Composite (BV) Ayrshire550-12 Brown Swiss 680 -4 -4 Guernsey520-12 Jersey450-21 M. Shorthorn 590 -8 -8 Holstein 680 0 Heterosis 3.0 % (Lopez-Villalobos, 1998)

22. Paul VanRaden 2001 ADSA Indianapolis 2001 (22) Breed Differences & Heterosis for Economic Merit Breed Net Merit ($) Cheese Merit ($) Fluid Merit ($) Ayrshire-510-469 -728 -728 Brown Swiss -355-256 -808 -808 Guernsey-761-692-1117 Jersey-305-186 -865 -865 M. Shorthorn -892-862-1073 Holstein——— Heterosis$197$207$163

23. Paul VanRaden 2001 ADSA Indianapolis 2001 (23) Merit of F 1 Holstein Crossbreds Second Breed Net Merit ($) Cheese Fluid Ayrshire -58 -58 -27 -27-201 Brown Swiss 18 18 79 79-241 Guernsey-184-138-395 Jersey 44 44 113 113-269 M. Shorthorn -249-223-373 Compared to 2000 genetic base for Holstein

24. Paul VanRaden 2001 ADSA Indianapolis 2001 (24) Mates for Holstein Cows Brown Swiss Jersey Top US Sire Ransom Fan Club NM$ (breed scale) $519 $519 $467 $467 Breed Difference (from HOL) - $178 - $153 Heterosis (NM$) + $197 + $197 + $197 Adjusted NM$ (HOL scale) $538 $538 $511 $511 NM$ Rank (HOL scale) 28 28 40 40 CM$ Rank (HOL scale) 13 13 12 12

25. Paul VanRaden 2001 ADSA Indianapolis 2001 (25) 0255075100 0.88 0.90 0.92 0.940.96 Protein kg/d % Holstein genes 0.86 — Holstein mean Crossbreeding Theory Holstein  Brown Swiss Protein Yield —A+Dominance (D) max heterosis (H) max heterosis (H) — A+D min H — A+D+A  A max H — A+D+A  A min H — Additive (A) only

26. Paul VanRaden 2001 ADSA Indianapolis 2001 (26) Heterosis and Inbreeding  Animals become more related within but not across breeds.  Inbreeding rises by 2 to 3% per decade.  Crossbreeding removes accumulated inbreeding depression.  Heterosis for yield should increase by 0.6 to 0.9% per decade.

27. Paul VanRaden 2001 ADSA Indianapolis 2001 (27) Conclusions

28. Paul VanRaden 2001 ADSA Indianapolis 2001 (28) Conclusions  Currently < 0.5% of DHI cows are crossbred.  Heterosis was about 4% for yield traits, < 1% (unfavorable) for SCS, and 1% for PL.  Profit from Jersey  Holstein and Brown Swiss  Holstein crosses is higher than from Holsteins.  Fewer extreme bulls are found in minor breeds.  Backcross yields were higher than expected.

29. Paul VanRaden 2001 ADSA Indianapolis 2001 (29) Butterfat yield of three breed crosses was greater than from their F 1 crossbred dams. 14,927 641 Three breed crosses averaged 14,927 pounds of milk and 641 pounds of butterfat as 2-year-olds in 1947. USDA Yearbook of Agriculture 1947 Three-Breed Crosses