H. Duane Norman Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD Missouri Dairy Summit (1) 2008 Responses to alternative genetic choices in dairy grazing systems

H.D. Norman 2008 Missouri Dairy Summit (2) Phenotypic trend in days open Lactation

H.D. Norman 2008 Missouri Dairy Summit (3) Benefits of improved reproduction Lower semen cost Improved ability to optimize lactation and lifetime yields Reduced culling due to delayed or failed conception More herd replacements

H.D. Norman 2008 Missouri Dairy Summit (4) Bull fertility evaluations Estimated Relative Conception Rate (ERCR)  70-day nonreturn rate (NRR) Source: − DRMS (Raleigh, NC), 1986−2005 − USDA (Beltsville, MD), 2006−present Western Bull Fertility Analysis  75-d veterinary-confirmed conception rate  Source: AgriTech (Visalia, CA), 2003 −present

H.D. Norman 2008 Missouri Dairy Summit (5) ERCR distribution (Aug. 2007)

H.D. Norman 2008 Missouri Dairy Summit (6) New service sire evaluation coming Based on conception rate rather than NRR More accurate  Inseminations from most of the United States  All services (not just first)  Additional model effects included Available in Spring 2008 Documentation at ftp://aipl.arsusda.gov/pub/outgoing/BullFert/

H.D. Norman 2008 Missouri Dairy Summit (7) Pregnancy rate (PR) Percentage of nonpregnant cows between 50 and 250 days in milk that become pregnant during each 21-day period Advantages over days open (DO), the days from calving to conception  Easily defined  Information from nonpregnant cows included more easily  Larger (rather than smaller) values desirable

H.D. Norman 2008 Missouri Dairy Summit (8) PR (continued) PR = [21/(DO − VWP + 11)]100  Voluntary waiting period (VWP) assumed to be 60 days  Factor of +11 adjusts to middle day of 21-day cycle Examples  Herd with average of 133 DO has PR of 25%  Herd with average of 154 DO has PR of 20%

H.D. Norman 2008 Missouri Dairy Summit (9) USDA pregnancy rate Linear approximation PR = 0.25 (233 − DO) 1% higher PR = 4 days fewer open

H.D. Norman 2008 Missouri Dairy Summit (10) Current breed averages BreedPR (%)DO (d) Gestation length (d) Calving interval (d) Ayrshire Brown Swiss Guernsey Holstein Jersey Milking Shorthorn

H.D. Norman 2008 Missouri Dairy Summit (11) Daughter pregnancy rate (DPR) First USDA genetic evaluations in 2003 Same across-breed animal model as for yield traits, productive life (PL), and somatic cell score (SCS) Heritability of 4%

H.D. Norman 2008 Missouri Dairy Summit (12) DPR (continued) Predicted transmitting abilities (PTAs) reported as percentages  Daughters of bull with PTA DPR of 1 expected to be 1% more likely to become pregnant during estrous cycle than if bull had PTA DPR of 0  Each increase of 1% in PTA DPR equals a decrease of 4 days in PTA DO PTA DO approximated by −4 × PTA DPR Example: Bull with PTA DPR of +2.0 would have PTA DO of −8

H.D. Norman 2008 Missouri Dairy Summit (13) Phenotypic trend in days open Lactation

H.D. Norman 2008 Missouri Dairy Summit (14) DPR trend (August 2007 base)

H.D. Norman 2008 Missouri Dairy Summit (15) Bull PTA DPR frequency (Aug. 2007)

H.D. Norman 2008 Missouri Dairy Summit (16) H.D. Norman 2008 Missouri Dairy Summit (16) Application of selection indexes for dairy producers

H.D. Norman 2008 Missouri Dairy Summit (17) Lifetime merit indexes TraitUnits Relative value (%) Net merit Cheese merit Fluid merit ProteinPounds23280 FatPounds MilkPounds0−1224 PLMonths SCSLog−9−7−9 UdderComposite656 Feet/legsComposite333 Body sizeComposite−4−3−4 DPRPercent978 Calving abilityDollars646

H.D. Norman 2008 Missouri Dairy Summit (18) Genetic merit of high-DPR Holstein bulls Trait All active AI bulls Active AI bulls with PTA DPR of ≥2.0 % Top 50% of active AI bulls based on lifetime net merit (>$245) Top 50% of active AI bulls with PTA DPR of ≥2.0% based on PTA DPR (>2.3 %) Bulls (no.)684 PTA milk (lb)838 PTA fat (lb)32 PTA protein (lb)25 PTA SCS2.94 PTA PL (mo)1.1 PTA DPR (%)−0.4 PTA DO (derived)1.6 Net merit ($)242 Semen price ($/unit)24

H.D. Norman 2008 Missouri Dairy Summit (19) Genetic merit of high-DPR Holstein bulls Trait All active AI bulls Active AI bulls with PTA DPR of ≥2.0 % Top 50% of active AI bulls based on lifetime net merit (>$245) Top 50% of active AI bulls with PTA DPR of ≥2.0% based on PTA DPR (>2.3 %) Bulls (no.)68441 PTA milk (lb) PTA fat (lb)3214 PTA protein (lb)2517 PTA SCS PTA PL (mo) PTA DPR (%)− PTA DO (derived)1.6−10.0 Net merit ($) Semen price ($/unit)2425

H.D. Norman 2008 Missouri Dairy Summit (20) Genetic merit of high-DPR Holstein bulls Trait All active AI bulls Active AI bulls with PTA DPR of ≥2.0 % Top 50% of active AI bulls based on lifetime net merit (>$245) Top 50% of active AI bulls with PTA DPR of ≥2.0% based on PTA DPR (>2.3 %) Bulls (no.) PTA milk (lb) ,125 PTA fat (lb) PTA protein (lb) PTA SCS PTA PL (mo) PTA DPR (%)−0.42.5−0.1 PTA DO (derived)1.6− Net merit ($) Semen price ($/unit)2425

H.D. Norman 2008 Missouri Dairy Summit (21) Genetic merit of high-DPR Holstein bulls Trait All active AI bulls Active AI bulls with PTA DPR of ≥2.0 % Top 50% of active AI bulls based on lifetime net merit (>$245) Top 50% of active AI bulls with PTA DPR of ≥2.0% based on PTA DPR (>2.3 %) Bulls (no.) PTA milk (lb) , PTA fat (lb) PTA protein (lb) PTA SCS PTA PL (mo) PTA DPR (%)−0.42.5− PTA DO (derived)1.6− −11.6 Net merit ($) Semen price ($/unit)

H.D. Norman 2008 Missouri Dairy Summit (22) Genetic merit of high-DPR Holstein bulls Trait All active AI bulls Active AI bulls with PTA DPR of ≥2.0 % Top 50% of active AI bulls based on lifetime net merit (>$245) Top 50% of active AI bulls with PTA DPR of ≥2.0% based on lifetime net merit (>$386) Bulls (no.) PTA milk (lb) , PTA fat (lb) PTA protein (lb) PTA SCS PTA PL (mo) PTA DPR (%)−0.42.5− PTA DO (derived)1.6− −10.4 Net merit ($) Semen price ($/unit)

H.D. Norman 2008 Missouri Dairy Summit (23) DPR benefits to herd Decreased units of semen needed per pregnancy Decreased labor and supplies for heat detection, inseminations, and pregnancy checks Additional calves produced Higher yields because more ideal lactation lengths

H.D. Norman 2008 Missouri Dairy Summit (24) Lifetime value Factors in determining economic value to DPR  Loss of about $1.50/DO  2.8 lactations per cow  No breedings for half of cows during final lactation  Correlation of heifer and cow fertility (0.3)  Value of extra calves  Other unmeasured health expenses Total lifetime merit value of $21/PTA DPR unit

H.D. Norman 2008 Missouri Dairy Summit (25) What genetic programs work well for U.S. graziers?

H.D. Norman 2008 Missouri Dairy Summit (26) Grazier breeding Objective  Cattle with better fertility or other desired characteristics Approaches (occasional use)  Bulls from countries that practice grazing  Bull breed different from cow breed to capitalize on heterosis  Effectiveness in grazing herds?

H.D. Norman 2008 Missouri Dairy Summit (27) Genetic alternative To achieve top fertility, consider direct selection for daughter fertility  U.S. bulls with high DPR  High fertility bulls from all sources

H.D. Norman 2008 Missouri Dairy Summit (28) Comparison study Daughter performance within U.S. herds  New Zealand AI Holstein/Friesian bulls  Other AI Holstein bulls (predominantly U.S.) Cows included  DHI records in AIPL national database  Calved (1st parity) before December 2006  Time to express the performance traits

H.D. Norman 2008 Missouri Dairy Summit (29) Traits examined Milk, fat, protein Somatic cell score Days open Conformation traits

H.D. Norman 2008 Missouri Dairy Summit (30) Yield and SCS data First-lactation daughters (239 herds)  896 sired by 40 New Zealand bulls  13,251 sired by 1,888 U.S. bulls Second-lactation daughters (211 herds)  680 sired by 34 New Zealand bulls  10,927 sired by 2,283 U.S. bulls Third-lactation daughters (181 herds)  453 sired by 29 New Zealand bulls  7,403 sired by 1,784 U.S. bulls

H.D. Norman 2008 Missouri Dairy Summit (31) Yield results Milk U.S. daughter superiority  First lactation 983 lb***  Second lactation1,115 lb***  Third lactation 772 lb*** FatNew Zealand daughter superiority/advantage  First lactation 10 lb**  Second lactation 4 lb  Third lactation11 lb ProteinU.S. daughter superiority/advantage  First lactation 10 lb***  Second lactation 12 lb***  Third lactation 5 lb

H.D. Norman 2008 Missouri Dairy Summit (32) Economic value Current U.S. milk prices MFP$ =  milk  fat  protein U.S. daughter MFP$ superiority  First lactation$20.76  Second lactation$34.80  Third lactation $6.21

H.D. Norman 2008 Missouri Dairy Summit (33) SCS results First lactation  U.S. daughter superiority of 0.15*** Second lactation  U.S. daughter advantage of 0.09 Third lactation  New Zealand daughter advantage of 0.05

H.D. Norman 2008 Missouri Dairy Summit (34) DO data First-lactation daughters (219 herds)  816 sired by 38 New Zealand bulls  9,747 sired by 2,113 U.S. bulls Second-lactation daughters (189 herds)  614 sired by 33 New Zealand bulls  9,747 sired by 2,113 U.S. bulls Third-lactation daughters (161 herds)  392 sired by 28 New Zealand bulls  6,561 sired by 1,637 U.S. bulls

H.D. Norman 2008 Missouri Dairy Summit (35) DO results First lactation  New Zealand daughter superiority of 8 days** Second lactation  New Zealand daughter superiority of 7 days** Third lactation  New Zealand daughter advantage of 2 days

H.D. Norman 2008 Missouri Dairy Summit (36) Type data First-lactation daughters  100 sired by 14 New Zealand bulls  376 sired by 225 U.S. bulls

H.D. Norman 2008 Missouri Dairy Summit (37) Type results Final score  U.S. daughter superiority of 1.5 points* Strength  N.Z. daughter scored higher by 1.9 points* Rear legs  U.S. daughter scored higher by 2.4 points* Foot angle  N.Z. daughter scored higher by 1.7 points*

H.D. Norman 2008 Missouri Dairy Summit (38) Type results (continued) Body condition  N.Z. daughter scored higher by 2.3 points* Rear udder height  U.S. daughter superiority of 1.8 points* Udder depth  U.S. daughter scored higher by 3.3 points*** Teat placement  U.S. daughter scored higher by 2.3 points*

H.D. Norman 2008 Missouri Dairy Summit (39) Spring-calver subset In addition to studying all herds using New Zealand bulls, a “grazing” subset was defined by seasonal calving  Number of March–May calvings more than 3 times number of September– November calvings for at least 3 of 5 years during 2002–06  At least 25 reported calvings per year

H.D. Norman 2008 Missouri Dairy Summit (40) Spring-calver data First-lactation daughters (18 herds)  222 sired by 18 New Zealand bulls  2,536 sired by 203 U.S. bulls Second-lactation daughters (23 herds)  153 sired by 16 New Zealand bulls  1,845 sired by 243 U.S. bulls Third-lactation daughters (14 herds)  97 sired by 13 New Zealand bulls  1,043 sired by 13 U.S. bulls

H.D. Norman 2008 Missouri Dairy Summit (41) Spring-calver yield results Milk U.S. daughter superiority  First lactation 762 lb***  Second lactation1,102 lb***  Third lactation1,064 lb*** FatNew Zealand daughter advantage  First lactation 11 lb  Second lactation 5 lb  Third lactation 5 lb ProteinU.S. daughter superiority/advantage  First lactation 11 lb*  Second lactation 16 lb*  Third lactation12 lb

H.D. Norman 2008 Missouri Dairy Summit (42) Spring-calver SCS results First lactation  U.S. daughter superiority of 0.24** Second lactation  U.S. daughter advantage of 0.12 Third lactation  U.S. daughter advantage of 0.17

H.D. Norman 2008 Missouri Dairy Summit (43) Spring-calver DO results First lactation  U.S. daughter advantage of 4 days Second lactation  New Zealand daughter advantage of 3 days Third lactation  Days open averaged the same for both

H.D. Norman 2008 Missouri Dairy Summit (44) H.D. Norman 2008 Missouri Dairy Summit (44) Conclusions

H.D. Norman 2008 Missouri Dairy Summit (45) Conclusions Strain differences between U.S. Holsteins and New Zealand Friesians for several traits Higher milk and protein yields for U.S. bull daughters; higher fat yield in 1st lactation for New Zealand bull daughters Superior 1st-lactation SCS for U.S. bull daughters

H.D. Norman 2008 Missouri Dairy Summit (46) Conclusions (continued) Fewer 1st- and 2nd-lactation DO for New Zealand bull daughters Higher strength and body condition score for New Zealand bull daughters Better rear udder height, udder depth, and teat placement for U.S. bull daughters

H.D. Norman 2008 Missouri Dairy Summit (47) Caution Strain differences observed influenced by individual bulls chosen from each country Slightly greater selection intensity for New Zealand bulls than for U.S. bulls

H.D. Norman 2008 Missouri Dairy Summit (48) Recommendations to breeders Usual Recommendation: Don’t select bulls solely on one trait because many traits have economic value Consider economic value of all performance traits in your own market when making genetic choices Dairies with seasonal calving should find an index that puts more weight on daughter fertility than those recommended for the general industry

H.D. Norman 2008 Missouri Dairy Summit (49) Selection for bull fertility Breeding to bulls with higher conception rates returns a profit fairly quickly  Premium of $2 could be paid for semen per 1% improvement in fertility  Thus, a unit of semen from bull with ERCR of +2 is worth $8 more than a unit from bull with ERCR of −2 Use bull fertility as a secondary selection trait after picking bulls on their economic indexes

H.D. Norman 2008 Missouri Dairy Summit (50) Selection for cow fertility Selection for improved fertility will pay off, even though the benefit is delayed for 2 years Choose your sires based on lifetime economic merit that includes daughter fertility, rather than for daughter fertility alone However, producers with herd fertility problems could emphasize DPR extensively with little loss in overall net merit

H.D. Norman 2008 Missouri Dairy Summit (51) Fertility emphasis Service-sire fertility and DPR especially important for grazing herds with seasonal calving Use of a few bulls that average 3.0% for PTA DPR (equivalent to a decrease of 12 DO) could neutralize r much of genetic decline in fertility from use of high-yield bulls for 40 years Select for overall merit based on genetic-economic index appropriate for your situation and milk market

H.D. Norman 2008 Missouri Dairy Summit (52) Thank you!