1. 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
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 st- 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