# Presentation: 254918

## 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

- 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

- RESULTS
- DFS
- Breeding year means  	   Parity means (2005)
- 70-d NRR for 1st service
- Breeding year means  	   Parity means (2005)
- CR for 1st service
- Breeding year means  	   Parity means (2005)
- Services per lactation
- Breeding year means  	   Parity means (2005)

- RESULTS *(continued)*
- 70-d NRR by parity and service
- Holstein means (2005)	   Jersey means (2005)
- CR by parity and service
- Holstein means (2005)    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

- http://aipl.arsusda.gov/

- 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

| 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 |

| 
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 | 2.9 |
| Synchronized | 72 | 35 | 26 | 3.1 |

- 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

- 2008