# Presentation: 514530

## Selection for Fertility in Dairy Cattle

## Factors Affecting Fertility

**Environment and management**
**Season, region, herd, age, milk yield**
**Estrus detection and / or synchronization**
**Voluntary waiting period**
**Fertility of bull ****(ERCR in USA)**
**Genes of cow ****(Dau. Pregnancy Rate)**
**Interaction of bull’s and cow’s genes**
**Inbreeding, recessives ****(CVM, DUMPS)**

## Fertility Does Not Show

- Paul VanRaden,
-  1974

## For Fertility, You Need Data

- Paul VanRaden,
- 1995

## Problem: Cows Are Less FertileUSA Holsteins 1965-2000

**5****th**

**4****th**

**3****rd**

**2****nd**

**1****st**

**Lactation**

## Coefficients of Variation (CV)Standard deviation divided by mean

| Trait | Herit-ability | CV (%) |  |
| --- | --- | --- | --- |
|  |  | Pheno- typic | Genetic |
| Stature  | .42 |   3 |   2 |
| Protein yield | .30 | 13 | 	7 |
| Longevity | .08 | 54 | 	16 |
| Fertility | .04 | 65 | 	13 |

## Pregnancy Rate

**The percentage of nonpregnant cows that become pregnant during each 21-day time period**
**Pregnancy rate < conception rate**
**Cows that are not cycling **
**Estrus not expressed or detected**
**Typical pregnancy rates**
**20%**** if calving interval is ****14.3**** months**
**25%**** if calving interval is ****13.6**** months**

## Pregnancy Rate and Days Open

**Pregnancy Rate and Days Open**

**0**

**10**

**20**

**30**

**40**

**50**

**60**

**70**

**80**

**90**

**100**

**60**

**81**

**102**

**123**

**144**

**165**

**186**

**207**

**228**

**249**

**Number of Chances**

**Pregnancy Rate**

**9**

**8**

**7**

**6**

**5**

**4**

**3**

**2**

**1**

**Days Open**

## Sources of Fertility Data Percentages from 1998-1999 records

| Breeding date: | BSW | HOL |
| --- | --- | --- |
| Verified by next calving date | 54 | 57 |
| Disagrees with calving date |  8 |  5 |
| Breeding date but no next calf | 15 | 19 |
| No breeding reported, only next calf |  9 |  6 |
| Cow sold for infertility |  5 |  5 |
| No information for fertility |  9 |  8 |

**Sources of Fertility Data ****Percentages from 1998-1999 records**

## Distribution of Days OpenHolstein Calvings 1990 - 2001

**≤**** ****50**

**≥**** ****250**

**Distribution of Days Open****Holstein Calvings 1990 - 2001**

**Cows culled for reproductive reasons**

## Seasonal Effects on FertilityHolsteins calving since 1997 in each USA region

## USA Fertility Evaluation

**Holstein**** data in evaluation**
**44 million**** lactation records since 1960**
**17 million**** cows**
**Lactations ****1-5**** are included**
**Reliability for recently proven bulls **
**59%**** REL for Daughter Pregnancy Rate**
**61%**** REL for Productive Life**
**69%**** REL for Somatic Cell Score**
**85%**** REL for Milk Yield**

## USA Evaluation Methods

**Animal model, introduced ****Feb 2003**
**Same programs as yield, PL, SCS**
**Compare cows within herd, season, and age**
**Convert days open to pregnancy rate = (233 – DO) / 4**
**Parameter estimates used:**
**Heritability = ****4%**
**Repeatability = ****11%**
**Sire-by-herd interaction = ****4%**

## Recent USA ChangesNovember 2003 and November 2004

**Earlier evaluation of cow fertility**
**Records in progress used at ****130**** instead of ****250**** days in milk**
**Pregnancy exams used in prediction**
**6%**** gain in REL of DPR for new bulls**
**Fertility used to predict longevity**
**4%**** gain in REL of PL for recent bulls**

## Selection for Longevity

**Productive Life introduced in USA in ****1994**** to select for longevity**
**Genetic correlations with other traits:**
**Daughter pregnancy rate = ****.59**
**Somatic cell score = ****-.35**
**Udder composite = ****.30**
**Daughter calving ease = ****-.24**

## Holstein Pregnancy Rate - Phenotypic and Genetic Trend 1965-2000

## Value of Cow Fertility

**Fertility expenses per day open**
**Heat detection ($20 / lact ******** .005)****	****	****= ****$.10**
**Semen ($15 / unit + $5 labor) *.025****	****= ****$.50**
**Pregnancy exam ($10 / exam)*.012****	****= ****$.12**
**Lactations too long or short****	****	****= ****$.75**
**Value of DPR as % of total economic value**
**7% ****in Net Merit since August 2003**
**5% ****in TPI since February 2005, also**
**-2% ****for dairy form in TPI since February 2005**

## Response to NM$ SelectionPercent of single trait response

| 
Trait | NM$ 2000 | NM$ 2003 | 
Trait | NM$ 2000 | NM$ 2003 |
| --- | --- | --- | --- | --- | --- |
| Protein | 81 | 74 | Udder | 19 | 22 |
| Fat | 68 | 67 | Feet / leg | 17 | 16 |
| Milk | 68 | 58 | Size | -10 | -10 |
| Longevity | 51 | 58 | Calving Ease | 13 | 23 |
| SCS | 35 | 38 | Dau. C.Ease | 11 | 21 |
| Fertility | 0 | 15 |  |  |  |

## Heritability and Correlations Among Cow Fertility Traits

| Trait | DO | D1st | NR70 | NS |
| --- | --- | --- | --- | --- |
| Days Open | .04 | .85 | -.21 | .61 |
| Days 1st service |  | .07 | .24 | .15 |
| Non-return rate |  |  | .01 | -.88 |
| Number of Services |  |  |  | .02 |

**Heritability on diagonal, USA data**

## Cow Fertility Traits Evaluated in Largest Holstein Populations

| Trait         Country | USA | DEU | FRA | NZL | NLD | CAN | GBR |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Ability to cycle |  |  |  | Yes | Yes | Yes | Yes |
| Ability to conceive  |  | Yes | Yes |  | Yes | Yes | Yes |
| Combined trait | Yes |  |  | Yes | Yes | Yes | Yes |
| Emphasis | 7% | 2% | 13% | 10% | 10% | 5% |  |

## Genetic Correlations of Traits Mark, 2003 EAAP meeting

| Trait |  Coun-tries | Average corr. | Corr(ITA, USA) |
| --- | --- | --- | --- |
| Protein | 27 | .87 | .92 |
| Stature | 21 | .89 | .95 |
| Fore Udder | 21 | .75 | .95 |
| Somatic Cell | 20 | .85 | .92 |
| Longevity | 14 | .59 | .73 |
| Direct Calving | 10 | .83 | .65 |
| Maternal Calving | 10 | .58 | .80 |

## Days Open Genetic Correlations Jorjani, 2005 Interbull Bulletin

|  | DFS | ESP | GBR | IRL | NLD | NZL | USA |
| --- | --- | --- | --- | --- | --- | --- | --- |
| DFS |  | .91 | .91 | .75 | .93 | .76 | .91 |
| ESP | .91 |  | .89 | .82 | .90 | .83 | .93 |
| GBR | .91 | .89 |  | .84 | .96 | .84 | .85 |
| IRL | .75 | .82 | .84 |  | .80 | .70 | .80 |
| NLD | .93 | .90 | .96 | .80 |  | .83 | .88 |
| NZL | .76 | .83 | .84 | .85 | .83 |  | .73 |
| USA | .91 | .93 | .85 | .80 | .88 | .73 |  |

**DFS**** = Denmark-Finland-Sweden**

## Conception Rate Genetic CorrelationsJorjani, 2005 Interbull Bulletin

|  | CAN | DEU | DFS | FRA | ISR | NLD |
| --- | --- | --- | --- | --- | --- | --- |
| CAN |  | .90 | .80 | .78 | .72 | .70 |
| DEU | .90 |  | .72 | .92 | .65 | .47 |
| DFS | .80 | .72 |  | .75 | .96 | .62 |
| FRA | .78 | .92 | .75 |  | .70 | .42 |
| ISR | .72 | .65 | .96 | .70 |  | .64 |
| NLD | .70 | .47 | .62 | .42 | .64 |  |

**DFS**** = Denmark-Finland-Sweden**

## Cow Fertility of Famous BullsAugust 2005 USA data

|  | Daughters |  | PTA |  |
| --- | --- | --- | --- | --- |
|  | ITA | USA | PL | DPR |
| Mtoto | 33813 | 1407 | 1.9 | 1.0 |
| Tugolo | 30727 | 389 | 2.0 | 1.2 |
| Raven | 25132 | 234 | -1.3 | .2 |
| Juror | 22010 | 18721 | .7 | -1.0 |
| Rudolph | 18031 | 11930 | 2.8 | 2.2 |
| Goodtime | 14007 | 160 | .0 | -1.0 |

**Notes:**
DO = Days Open
DPR = Daughter Pregnancy Rate

## Conclusions

**Fertility traits are less heritable but more variable than yield and type**
**Selection for high yield reduces fertility**
**Selection for longevity increases fertility**
**Cow fertility traits receive 2% to 13% of total selection in many countries**
**Bulls that sire good fertility are available**