# Presentation: 665284

## Genetic selection for reproduction:

**	****Current reproductive status****	****of the national herd;**

**	****Application of selection indexes****	****for dairy producers**

## Current reproductive statusof the national herd

**H.D. Norman**

**Dairy Cattle Reproductive Council Convention (****)**

**Current reproductive status****of the national herd**

## Bull fertility

**Estimated Relative Conception Rate (ERCR)**
**70-day nonreturn rate (NRR)**
**Phenotypic evaluation**
**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**

## ERCR distribution (Aug. 2007)

## Survey of AI organizations

**Does your organization rate bulls on fertility from field data?**
**Where do you obtain the data you use to evaluate them?**
**How long a time period is included in your evaluation? **
**What do you publish? **
**How many nonreturn days are in your calculation?**
**Is your evaluation derived from first or all services? **
**Do you eliminate cows sold before a specific number of days after insemination?**
**Do you eliminate cows in herds that go off test before a specific number of days after insemination? **
**Is information on services from natural service bulls that follow AI breedings available to you to document failures of those AI breedings? **

## Survey results

**All had programs to monitor bull fertility, but few relied completely on in-house information**
**Most received some information from technician breedings**
**One purchased breeding records from a dairy records processing center**
**Another obtained breeding records directly from cooperating herds**
**Most common fertility measure was NRR**
**Varied from 59 to 90 days for first breeding**
**Some organizations used a range of days**

## Survey results (cont.)

**Conception rate (CR) used by one because of availability of pregnancy-check records**
**Time period for data included in a bull’s fertility evaluation varied from 1 year to no limit**
**Equal number included only first services compared with all services**
**Data from technician breedings**
**Not adjusted for cow departures because of culling or when a herd discontinued production testing**
**No access to data that showed when natural service followed an AI mating**

## New USDA service sire evaluation

**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 early 2008 **
**Documentation at ****ftp://aipl.arsusda.gov/pub/outgoing/BullFert/**

## Cow fertility trends

| Year bred | Calving to 1st
breeding (d) |  |  | 70-d NRR for
1st service (%) |  |  | 1st service
CR (%) |  |  | Services per
lactation (no.) |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |
| 1996 | 89 | 82 |  |  |  |  |  |  |  |  |  |
| 1997 | 91 | 84 |  |  |  |  |  |  |  |  |  |
| 1998 | 91 | 85 |  |  |  |  |  |  |  |  |  |
| 1999 | 92 | 85 |  |  |  |  |  |  |  |  |  |
| 2000 | 90 | 84 |  |  |  |  |  |  |  |  |  |
| 2001 | 92 | 85 |  |  |  |  |  |  |  |  |  |
| 2002 | 88 | 81 |  |  |  |  |  |  |  |  |  |
| 2003 | 88 | 83 |  |  |  |  |  |  |  |  |  |
| 2004 | 86 | 84 |  |  |  |  |  |  |  |  |  |
| 2005 | 86 | 84 |  |  |  |  |  |  |  |  |  |
| 2006 | 85 | 83 |  |  |  |  |  |  |  |  |  |

## Cow fertility trends

| Year bred | Calving to 1st
breeding (d) |  |  | 70-d NRR for
1st service (%) |  |  | 1st service
CR (%) |  |  | Services per
lactation (no.) |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |
| 1996 | 89 | 82 |  | 54 | 57 |  |  |  |  |  |  |
| 1997 | 91 | 84 |  | 55 | 57 |  |  |  |  |  |  |
| 1998 | 91 | 85 |  | 54 | 56 |  |  |  |  |  |  |
| 1999 | 92 | 85 |  | 53 | 55 |  |  |  |  |  |  |
| 2000 | 90 | 84 |  | 53 | 55 |  |  |  |  |  |  |
| 2001 | 92 | 85 |  | 52 | 56 |  |  |  |  |  |  |
| 2002 | 88 | 81 |  | 50 | 53 |  |  |  |  |  |  |
| 2003 | 88 | 83 |  | 48 | 53 |  |  |  |  |  |  |
| 2004 | 86 | 84 |  | 48 | 53 |  |  |  |  |  |  |
| 2005 | 86 | 84 |  | 46 | 52 |  |  |  |  |  |  |
| 2006 | 85 | 83 |  | ... | ... |  |  |  |  |  |  |

## Cow fertility trends

| Year bred | Calving to 1st
breeding (d) |  |  | 70-d NRR for
1st service (%) |  |  | 1st service
CR (%) |  |  | Services per
lactation (no.) |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |
| 1996 | 89 | 82 |  | 54 | 57 |  | 36 | 39 |  |  |  |
| 1997 | 91 | 84 |  | 55 | 57 |  | 34 | 37 |  |  |  |
| 1998 | 91 | 85 |  | 54 | 56 |  | 32 | 36 |  |  |  |
| 1999 | 92 | 85 |  | 53 | 55 |  | 31 | 35 |  |  |  |
| 2000 | 90 | 84 |  | 53 | 55 |  | 31 | 35 |  |  |  |
| 2001 | 92 | 85 |  | 52 | 56 |  | 31 | 36 |  |  |  |
| 2002 | 88 | 81 |  | 50 | 53 |  | 29 | 35 |  |  |  |
| 2003 | 88 | 83 |  | 48 | 53 |  | 30 | 36 |  |  |  |
| 2004 | 86 | 84 |  | 48 | 53 |  | 31 | 36 |  |  |  |
| 2005 | 86 | 84 |  | 46 | 52 |  | 30 | 35 |  |  |  |
| 2006 | 85 | 83 |  | ... | ... |  | ... | ... |  |  |  |

## Cow fertility trends

| Year bred | Calving to 1st
breeding (d) |  |  | 70-d NRR for
1st service (%) |  |  | 1st service
CR (%) |  |  | Services per
lactation (no.) |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |
| 1996 | 89 | 82 |  | 54 | 57 |  | 36 | 39 |  | 2.1 | 2.0 |
| 1997 | 91 | 84 |  | 55 | 57 |  | 34 | 37 |  | 2.1 | 2.1 |
| 1998 | 91 | 85 |  | 54 | 56 |  | 32 | 36 |  | 2.2 | 2.1 |
| 1999 | 92 | 85 |  | 53 | 55 |  | 31 | 35 |  | 2.3 | 2.1 |
| 2000 | 90 | 84 |  | 53 | 55 |  | 31 | 35 |  | 2.3 | 2.1 |
| 2001 | 92 | 85 |  | 52 | 56 |  | 31 | 36 |  | 2.3 | 2.1 |
| 2002 | 88 | 81 |  | 50 | 53 |  | 29 | 35 |  | 2.5 | 2.2 |
| 2003 | 88 | 83 |  | 48 | 53 |  | 30 | 36 |  | 2.5 | 2.3 |
| 2004 | 86 | 84 |  | 48 | 53 |  | 31 | 36 |  | 2.5 | 2.3 |
| 2005 | 86 | 84 |  | 46 | 52 |  | 30 | 35 |  | 2.6 | 2.4 |
| 2006 | 85 | 83 |  | ... | ... |  | ... | ... |  | ... | ... |

## Parity averages (2005 breedings)

| Parity | Calving to 1st
breeding (d) |  |  | 70-day NRR for 1st service (%) |  |  | 1st-service
CR (%) |  |  | Services per
lactation (no.) |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |
| 1 | 85 | 85 |  |  |  |  |  |  |  |  |  |
| 2 | 85 | 83 |  |  |  |  |  |  |  |  |  |
| 3 | 87 | 82 |  |  |  |  |  |  |  |  |  |
| 4 | 88 | 84 |  |  |  |  |  |  |  |  |  |
| 5 | 90 | 85 |  |  |  |  |  |  |  |  |  |
| >5 | 92 | 88 |  |  |  |  |  |  |  |  |  |

## Parity averages (2005 breedings)

| Parity | Calving to 1st
breeding (d) |  |  | 70-day NRR for 1st service (%) |  |  | 1st-service
CR (%) |  |  | Services per
lactation (no.) |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |
| 1 | 85 | 85 |  | 48 | 54 |  |  |  |  |  |  |
| 2 | 85 | 83 |  | 45 | 52 |  |  |  |  |  |  |
| 3 | 87 | 82 |  | 45 | 52 |  |  |  |  |  |  |
| 4 | 88 | 84 |  | 45 | 50 |  |  |  |  |  |  |
| 5 | 90 | 85 |  | 45 | 51 |  |  |  |  |  |  |
| >5 | 92 | 88 |  | 45 | 49 |  |  |  |  |  |  |

## Parity averages (2005 breedings)

| Parity | Calving to 1st
breeding (d) |  |  | 70-day NRR for 1st service (%) |  |  | 1st-service
CR (%) |  |  | Services per
lactation (no.) |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |
| 1 | 85 | 85 |  | 48 | 54 |  | 32 | 37 |  |  |  |
| 2 | 85 | 83 |  | 45 | 52 |  | 29 | 36 |  |  |  |
| 3 | 87 | 82 |  | 45 | 52 |  | 29 | 35 |  |  |  |
| 4 | 88 | 84 |  | 45 | 50 |  | 28 | 34 |  |  |  |
| 5 | 90 | 85 |  | 45 | 51 |  | 27 | 32 |  |  |  |
| >5 | 92 | 88 |  | 45 | 49 |  | 25 | 30 |  |  |  |

## Parity averages (2005 breedings)

| Parity | Calving to 1st
breeding (d) |  |  | 70-day NRR for 1st service (%) |  |  | 1st-service
CR (%) |  |  | Services per
lactation (no.) |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |  | Holstein | Jersey |
| 1 | 85 | 85 |  | 48 | 54 |  | 32 | 37 |  | 2.6 | 2.3 |
| 2 | 85 | 83 |  | 45 | 52 |  | 29 | 36 |  | 2.7 | 2.3 |
| 3 | 87 | 82 |  | 45 | 52 |  | 29 | 35 |  | 2.6 | 2.4 |
| 4 | 88 | 84 |  | 45 | 50 |  | 28 | 34 |  | 2.6 | 2.4 |
| 5 | 90 | 85 |  | 45 | 51 |  | 27 | 32 |  | 2.6 | 2.4 |
| >5 | 92 | 88 |  | 45 | 49 |  | 25 | 30 |  | 2.7 | 2.5 |

## Holstein NRR (2005 breedings)

| Parity | 70-day NRR (%) |  |  |  |  |
| --- | --- | --- | --- | --- | --- |
|  | 1st service | 2nd
service | 3rd service | 4th
service | 5th service |
| 1 | 48 | 46 | 43 | 41 | 39 |
| 2 | 45 | 43 | 41 | 40 | 38 |
| 3 | 45 | 44 | 42 | 41 | 39 |
| 4 | 45 | 44 | 43 | 41 | 39 |
| 5 | 45 | 43 | 42 | 41 | 40 |
| >5 | 45 | 43 | 43 | 41 | 39 |

## Holstein CR (2005 breedings)

| Parity | CR (%) |  |  |  |  |
| --- | --- | --- | --- | --- | --- |
|  | 1st service | 2nd
service | 3rd service | 4th
service | 5th service |
| 1 | 32 | 33 | 31 | 29 | 26 |
| 2 | 29 | 30 | 29 | 28 | 26 |
| 3 | 29 | 30 | 30 | 28 | 26 |
| 4 | 28 | 30 | 29 | 27 | 26 |
| 5 | 27 | 28 | 28 | 26 | 25 |
| >5 | 25 | 26 | 26 | 25 | 25 |

## Holstein regional averages (2005 breedings)

| Region | Calving
to 1st breeding
(d) | 70-day
NRR for
1st service
(%) | CR
(%) | Services
per
lactation
(no.) | Preg-nancy rate
(%) |
| --- | --- | --- | --- | --- | --- |
| Mideast | 92 |  |  |  |  |
| Midwest | 86 |  |  |  |  |
| Mountain | 93 |  |  |  |  |
| Northeast | 85 |  |  |  |  |
| Northwest | 76 |  |  |  |  |
| Southeast | 89 |  |  |  |  |
| Southwest | 73 |  |  |  |  |

## Holstein regional averages (2005 breedings)

| Region | Calving
to 1st breeding
(d) | 70-day
NRR for
1st service
(%) | CR
(%) | Services
per
lactation
(no.) | Preg-nancy rate
(%) |
| --- | --- | --- | --- | --- | --- |
| Mideast | 92 | 47 |  |  |  |
| Midwest | 86 | 46 |  |  |  |
| Mountain | 93 | 48 |  |  |  |
| Northeast | 85 | 46 |  |  |  |
| Northwest | 76 | 42 |  |  |  |
| Southeast | 89 | 44 |  |  |  |
| Southwest | 73 | 36 |  |  |  |

## Holstein regional averages (2005 breedings)

| Region | Calving
to 1st breeding
(d) | 70-day
NRR for
1st service
(%) | CR
(%) | Services
per
lactation
(no.) | Preg-nancy rate
(%) |
| --- | --- | --- | --- | --- | --- |
| Mideast | 92 | 47 | 29 |  |  |
| Midwest | 86 | 46 | 30 |  |  |
| Mountain | 93 | 48 | 27 |  |  |
| Northeast | 85 | 46 | 31 |  |  |
| Northwest | 76 | 42 | 29 |  |  |
| Southeast | 89 | 44 | 23 |  |  |
| Southwest | 73 | 36 | 27 |  |  |

## Holstein regional averages (2005 breedings)

| Region | Calving
to 1st breeding
(d) | 70-day
NRR for
1st service
(%) | CR
(%) | Services
per
lactation
(no.) | Preg-nancy rate
(%) |
| --- | --- | --- | --- | --- | --- |
| Mideast | 92 | 47 | 29 | 2.7 |  |
| Midwest | 86 | 46 | 30 | 2.7 |  |
| Mountain | 93 | 48 | 27 | 2.8 |  |
| Northeast | 85 | 46 | 31 | 2.6 |  |
| Northwest | 76 | 42 | 29 | 2.8 |  |
| Southeast | 89 | 44 | 23 | 3.0 |  |
| Southwest | 73 | 36 | 27 | 2.8 |  |

## Pregnancy rate (PR)

**Percentage of nonpregnant cows that become pregnant during each 21-day period**
**Advantages over days open (DO)**
**Easily defined**
**Information from nonpregnant cows included more easily**
**Larger (rather than smaller) values desirable**
**PR = [21/(DO − voluntary waiting period + 11)]100**
**Voluntary waiting period 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%**

## Holstein regional averages (2005 breedings)

| Region | Calving
to 1st breeding
(d) | 70-day
NRR for
1st service
(%) | CR
(%) | Services
per
lactation
(no.) | Preg-nancy rate
(%) |
| --- | --- | --- | --- | --- | --- |
| Mideast | 92 | 47 | 29 | 2.7 | 19.0 |
| Midwest | 86 | 46 | 30 | 2.7 | 21.5 |
| Mountain | 93 | 48 | 27 | 2.8 | 19.6 |
| Northeast | 85 | 46 | 31 | 2.6 | 22.4 |
| Northwest | 76 | 42 | 29 | 2.8 | 23.4 |
| Southeast | 89 | 44 | 23 | 3.0 | 17.3 |
| Southwest | 73 | 36 | 27 | 2.8 | 23.7 |

## Herds with synchronized breeding

| Synchroni-zation
status | Calving
to 1st breeding
(d) | 70-day
NRR for
1st service
(%) | CR
(%) | Services
per
lactation
(no.) | Preg-nancy rate
(%) |
| --- | --- | --- | --- | --- | --- |
| None | 90 | 46 | 30 | 2.6 | 20.2 |
| Possible | 78 | 40 | 27 | 2.9 | 21.8 |
| Probable | 74 | 38 | 27 | 2.9 | 22.4 |
| Synchronized | 72 | 35 | 25 | 3.1 | 21.7 |

## Current breed averages

| Breed | PR (%) | DO (d) | Gestation length (d) | Calving interval (d) |
| --- | --- | --- | --- | --- |
| Ayrshire | 23.2 | 140 | 281.7 | 422 |
| Brown Swiss | 20.3 | 152 | 287.5 | 440 |
| Guernsey | 19.1 | 157 | 285.8 | 443 |
| Holstein | 22.0 | 145 | 279.5 | 425 |
| Jersey | 26.4 | 127 | 280.0 | 407 |
| Milking
   Shorthorn | 24.8 | 134 | 281.3 | 415 |

## USDA pregnancy rate

**Linear approximation**
**PR = 0.25 (233 − DO)**
**1% higher PR = 4 days fewer open**

## 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%**
**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 equivalent to 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**

## DPR trend (August 2007 base)

## Bull PTA DPR frequency (Aug. 2007)

## Application of selection indexesfor dairy producers

**H.D. Norman**

**Dairy Cattle Reproductive Council Convention (****)**

**Application of ****selection indexes****for dairy producers**

## Lifetime merit indexes

| Trait | Units | Relative value (%) |  |  |
| --- | --- | --- | --- | --- |
|  |  | Net
merit | Cheese 
merit | Fluid
merit |
| Protein | Pounds | 23 | 28 | 0 |
| Fat  | Pounds | 23 | 18 | 23 |
| Milk | Pounds | 0 | −12 | 24 |
| PL | Months | 17 | 13 | 17 |
| SCS | Log | −9 | −7 | −9 |
| Udder | Composite | 6 | 5 | 6 |
| Feet/legs | Composite | 3 | 3 | 3 |
| Body size | Composite | −4 | −3 | −4 |
| DPR | Percent | 9 | 7 | 8 |
| Calving ability | Dollars | 6 | 4 | 6 |

## 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
(>$245) | Top 50% of active AI bulls
with PTA DPR of ≥2.0% based on
PTA DPR
(>2.3 %) |
| --- | --- | --- | --- | --- |
| Bulls (no.) | 684 |  |  |  |
| PTA milk (lb) | 838 |  |  |  |
| PTA fat (lb) | 32 |  |  |  |
| PTA protein (lb) | 25 |  |  |  |
| PTA SCS | 2.94 |  |  |  |
| PTA PL (mo) | 1.1 |  |  |  |
| PTA DPR (%) | −0.4 |  |  |  |
| PTA DO (derived) | 1.6 |  |  |  |
| Net merit ($) | 242 |  |  |  |
| Semen price ($/unit) | 24 |  |  |  |

## 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
(>$245) | Top 50% of active AI bulls
with PTA DPR of ≥2.0% based on
PTA DPR
(>2.3 %) |
| --- | --- | --- | --- | --- |
| Bulls (no.) | 684 | 41 |  |  |
| PTA milk (lb) | 838 | 287 |  |  |
| PTA fat (lb) | 32 | 14 |  |  |
| PTA protein (lb) | 25 | 17 |  |  |
| PTA SCS | 2.94 | 2.86 |  |  |
| PTA PL (mo) | 1.1 | 4.2 |  |  |
| PTA DPR (%) | −0.4 | 2.5 |  |  |
| PTA DO (derived) | 1.6 | −10.0 |  |  |
| Net merit ($) | 242 | 346 |  |  |
| Semen price ($/unit) | 24 | 25 |  |  |

## 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
(>$245) | Top 50% of active AI bulls
with PTA DPR of ≥2.0% based on
PTA DPR
(>2.3 %) |
| --- | --- | --- | --- | --- |
| Bulls (no.) | 684 | 41 | 342 |  |
| PTA milk (lb) | 838 | 287 | 1,125 |  |
| PTA fat (lb) | 32 | 14 | 43 |  |
| PTA protein (lb) | 25 | 17 | 34 |  |
| PTA SCS | 2.94 | 2.86 | 2.88 |  |
| PTA PL (mo) | 1.1 | 4.2 | 2.1 |  |
| PTA DPR (%) | −0.4 | 2.5 | −0.1 |  |
| PTA DO (derived) | 1.6 | −10.0 | 0.4 |  |
| Net merit ($) | 242 | 346 | 357 |  |
| Semen price ($/unit) | 24 | 25 | 25 |  |

## 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
(>$245) | Top 50% of active AI bulls
with PTA DPR of ≥2.0% based on
PTA DPR
(>2.3 %) |
| --- | --- | --- | --- | --- |
| Bulls (no.) | 684 | 41 | 342 | 20 |
| PTA milk (lb) | 838 | 287 | 1,125 | 179 |
| PTA fat (lb) | 32 | 14 | 43 | 13 |
| PTA protein (lb) | 25 | 17 | 34 | 16 |
| PTA SCS | 2.94 | 2.86 | 2.88 | 2.84 |
| PTA PL (mo) | 1.1 | 4.2 | 2.1 | 4.4 |
| PTA DPR (%) | −0.4 | 2.5 | −0.1 | 2.9 |
| PTA DO (derived) | 1.6 | −10.0 | 0.4 | −11.6 |
| Net merit ($) | 242 | 346 | 357 | 350 |
| Semen price ($/unit) | 24 | 25 | 25 | 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
lifetime net merit (>$386) |
| --- | --- | --- | --- | --- |
| Bulls (no.) | 684 | 41 | 342 | 20 |
| PTA milk (lb) | 838 | 287 | 1,125 | 735 |
| PTA fat (lb) | 32 | 14 | 43 | 31 |
| PTA protein (lb) | 25 | 17 | 34 | 30 |
| PTA SCS | 2.94 | 2.86 | 2.88 | 2.84 |
| PTA PL (mo) | 1.1 | 4.2 | 2.1 | 5.1 |
| PTA DPR (%) | −0.4 | 2.5 | −0.1 | 2.6 |
| PTA DO (derived) | 1.6 | −10.0 | 0.4 | −10.4 |
| Net merit ($) | 242 | 346 | 357 | 476 |
| Semen price ($/unit) | 24 | 25 | 25 | 26 |

## DPR benefits over productive life

**Additional calves produced**
**Decreased units of semen needed per pregnancy**
**Decreased labor and supplies for heat detection, inseminations, and pregnancy checks**
**Higher yields because more ideal lactation lengths**

## Lifetime value

**Factors in determining economic value**
**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**

## Total Performance Index (TPI)

**Calculated by Holstein Association USA (Brattleboro, VT)**
**Emphasis of 19% on early breeding**
**10% on PL**
**8% on DPR**
**−****1% on dairy form**
**95% correlation between USDA lifetime net merit and Holstein TPI**

## Conclusions

**H.D. Norman**

**Dairy Cattle Reproductive Council Convention (****)**

**Conclusions**

## Service sires

**Using bulls with higher conception rates returns profit fairly quickly**
**Premium of $2 could be paid for semen per 1% improvement in fertility**
**Unit of semen from bull with ERCR of +2 worth $8 more than unit from bull with ERCR of −2**
**Little genetic improvement in male fertility expected over time**
**Use bull fertility as a secondary selection trait after production and economic indexes**

## Selection for cow fertility

**Selection for improved fertility possible and recommended**
**Most benefits delayed for 2 years or more**
**Select service sires for overall lifetime merit that includes daughter fertility rather than for daughter fertility alone**
**Producers with herd fertility problems may choose to emphasize DPR extensively, which can be done with little loss in overall net merit**

## 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**

## Fertility emphasis

**Service-sire fertility and DPR important for all management systems, but most 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 recover much of genetic decline in fertility from use of high-yield bulls for 40 years**
**General recommendation still is to select for overall merit based on genetic-economic index appropriate for current milk market **