Reproductive trends of dairy herds in the United States H. D. Norman, J. R. Wright, S. M. Hubbard,* M. T. Kuhn, and R. H. Miller Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350 Abstr. T18 2008 INTRODUCTION Many producers have expressed concern about the fertility of today's milking herds Research studies since 2000 have confirmed the validity of that concern Objective was to document national trends in cow reproductive traits to provide information that can be used for improving reproductive efficiency INTRODUCTION Many producers have expressed concern about the fertility of today's milking herds Research studies since 2000 have confirmed the validity of that concern Objective was to document national trends in cow reproductive traits to provide information that can be used for improving reproductive efficiency RESULTS DFS Breeding year means w Parity means (2005) 70-d NRR for 1st service CR for 1st service Services per lactation RESULTS (continued) 70-d NRR by parity and service Holstein means (2005) w Jersey means (2005) CR by parity and service Holstein means (2005) w Jersey means (2005) Regional Holstein means (2005) Southwest had fewest DFS (73 d) and lowest 1st- service 70-d NRR (36%) Mountain-Prairie had greatest DFS (93 d) and highest 70-d NRR (48%) Southeast had lowest 1st-service CR (23%) and most services per lactation (3.0) Northeast had highest CR (31%) and fewest services per lactation (2.6) Holstein means (2005) by herd status for synchronized breeding CONCLUSIONS Holstein DFS increased by 2 d from 1996 through 2001 and then declined by 6 d through 2005; no trend was observed for Jersey DFS Days to last service (not shown) increased by 16 d for both Holsteins and Jerseys First-service 70-d NRR declined by around 10% for Holsteins and 5% for Jerseys First-service CR declined by around 5% for both breeds Services per lactation increased by around 0.5 for both breeds Days open (not shown) increased during early years but have stabilized for both breeds Gestation length (not shown) showed no change across time for either breed Later parities in 2005 were associated with longer DFS, lower 1st-service 70-d NRR, and decreased 1st- service CR compared with early parities for both breeds Services per lactation across parities in 2005 remained fairly constant for Holsteins and increased slightly for Jerseys First- and 2nd-service 70-d NRR in 2005 declined as parity increased for both breeds Second-service CR in 2005 was highest within parity for both breeds CR for specific services in 2005 generally declined as parity increased for both breeds Trends likely were impacted by geographic region, producer preferences, and increased use of synchronized breeding DATA Data from USDA national dairy database for breedings in US herds since January 1, 1996 Traits Days from calving to first service (DFS) Days from calving to last service 70-d nonreturn rates (NRR) for services 1 through 5 Conception rates (CR) for services 1 through 5 Services per lactation Days open Gestation length Breed Breedings Lactations Cows Herds Holstein 15,851,120 7,107,057 3,645,987 20,746 Jersey 776,364 387,441 184,398 1,963 ANALYSIS Means of reproductive traits within breed by breeding year Means for same traits for 2005 breedings By parity within breed By geographic region for Holsteins By herd status for synchronized breeding (estrous synchronization and timed AI) for Holsteins Synchronized breeding status DFS, d 70-d NRR for 1st service, % CR for 1st service, Services per lactation, n None 90 47 30 2.6 Possible 78 40 28 2.9 Probable 74 38 27 72 35 26 3.1 http://aipl.arsusda.gov/