# Presentation: 164067

## Selection for Fertility in Dairy Cattle

## Factors Affecting Fertility

**Environment and management**
**Season, region, herd, age, milk yield**
**Calving difficulty, twins, mastitis, health **
**Estrus detection and / or synchronization**
**Voluntary waiting period**
**Genes of cow ****(Daughter Pregnancy Rate)**
**Fertility of bull ****(ERCR)**
**Interaction of bull’s and cow’s genes**

## Genetic Interactions

**Lethal recessive genes**
**CVM**** aborts pregnancy 30-280 days**
**DUMPS**** aborts embryo at ~45 days**
**New defect causes loss at ~5 days**
**Inbreeding reduces fertility**
**Crossbreeding improves fertility**
**1.8% increase in pregnancy rate**

## USA Bull Fertility Evaluation

**Measure of current semen fertility**
**Based on 1.6 million inseminations in last 3 years **
**Estimated Relative Conception Rate (ERCR) ranges +5% to –6%**

## Bull Fertility ResearchKuhn, 2006

**Moved evaluation to USDA from DRMS in Raleigh, NC in 2006**
**Data from eastern half of United States**
**Planning to use all services and pregnancy exams**
**Bull fertility is not correlated to daughter fertility (heifers or cows)**

## Why Does Fertility Differ?

**Male fertility includes**
**Ability of sperm to fertilize egg**
**Bull’s environmental conditions**
**Female fertility includes**
**Ability to cycle and show estrus**
**Ability of egg to conceive**
**Maternal support of embryo**
**Milk production stress (cows only)**

## Heifer Fertility ResearchKuhn et al, 2006 J Dairy Sci 89:4907

**Insemination records for 537,938 heifers in years 2003-2005**
**Average conception rate = 57%**
**Heritability = .5% (linear model), 1% (logistic model)**
**Genetic correlation = .39 with cow conception rate, -.19 with milk yield**

## Heifer Fertility is Good

- Paul VanRaden,
- 1995

## Problem: Cows Conceive LaterUSA Holsteins 1965-2000

**5****th**

**4****th**

**3****rd**

**2****nd**

**1****st**

**Lactation**

## 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 to ConceiveHolstein Calvings 1990 - 2001

**≤**** ****50**

**≥**** ****250**

**Distribution of Days to Conceive****Holstein Calvings 1990 - 2001**

**Cows culled for reproductive reasons**

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

## USA Cow 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 in ****2003**
**Use same programs as other USDA traits**
**Compare cows within herd, season, and age**
**Convert to pregnancy rate (4 more days to conceive = 1% lower pregnancy rate)**
**Fertility 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 reliability of DPR for new bulls**
**Fertility used to predict longevity**
**4%**** gain in REL of PL for recent bulls**

## All-Breed Animal Model

**Combined analysis of all breeds**
**Data from crossbreds included**
**Genetic differences among breeds are estimated**
**Planning to implement in May 2007**

## Genetic Trends for Each Breed Daughter Pregnancy Rate, 1960-2000

**+1.8% Heterosis**

## Correlation of Yield and Fertility r = - .35

## 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 |

## 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**
**9% ****in Lifetime Net Merit**
**5% ****in TPI, also**
**-2% ****for dairy form in TPI**

## Cow Fertility Trait Heritabilities and Genetic Correlations

| Trait | Days Conc. | Days 1st | Cow CR | Heifer CR |
| --- | --- | --- | --- | --- |
| Days to Conceive | .04 | .85 | -.21 |  |
| Days to 1st Service |  | .07 | .24 |  |
| Cow Conc. Rate |  |  | .01 | .39 |
| Heifer Conc. Rate |  |  |  | .005 |

**Heritabilities on diagonal**

## Interbull

**Provides international evaluations using data from 26 countries**
**Europe, North America, Australia, New Zealand, S. Africa, Israel, Japan**
**No South American countries yet**
**Office located in Sweden**
**Many traits are evaluated**

## Countries with Most Holsteinsand Interbull abbreviations

| Country | Name |
| --- | --- |
| USA | United States |
| DEU | Germany |
| FRA | France |
| NZL | New Zealand |
| NLD | Netherlands |
| CAN | Canada |
| GBR | Great Britain (U. Kingdom) |

## Fertility Traits and Emphasis In Largest Holstein Populations

| Trait    Country | USA | DEU | FRA | NZL | NLD | CAN | GBR |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Emphasis (%) | 9 | 1 | 13 | 7 | 10 | 5 | 7 |
| Days to Conceive | Yes |  |  | Yes | Yes |  | Yes |
| Days to first AI |  |  |  | Yes | Yes | Yes | Yes |
| Conception rate  |  | Yes | Yes |  | Yes | Yes | Yes |
| Heifer conception |  |  | Yes |  |  | Yes |  |

## Fertility Trait Indexes% of fertility emphasis

| Trait | NLD | ITA | ESP | CAN | DNK1 | USA2 |
| --- | --- | --- | --- | --- | --- | --- |
| Days to 1st  service | 54 | 56 | 52 | 25 | 15 | 69 |
| Conception Rate | 46 | 44 | 48 | 65 | 70 | 31 |
| Heifer fertility |  |  |  | 10 | 15 |  |

**1****Time from first to last insemination replaces non−return rate**
**2****Countries that evaluate days to conception or calving interval**

## Countries with Days to Conceptionand Interbull abbreviations

| Country | Name |
| --- | --- |
| BEL | Belgium |
| DFS | Denmark-Finland-Sweden |
| ESP | Spain |
| GBR | Great Britain (U. Kingdom) |
| IRL | Ireland |
| ITA | Italy |
| NLD | Netherlands |
| USA | United States |

## Fertility Genetic Correlations Interbull test run, Sept. 2006

|  | BEL | DFS | ESP | GBR |  | IRL | ITA | NLD | USA |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| BEL |  | .85 | .94 |  | .89 | .86 | .78 | .86 | .88 |
| DFS | .85 |  | .84 |  | .89 | .73 | .86 | .91 | .85 |
| ESP | .94 | .84 |  |  | .88 | .81 | .87 | .86 | .93 |
| GBR | .89 | .89 | .88 |  |  | .82 | .85 | .86 | .82 |
| IRL | .86 | .73 | .81 |  | .82 |  | .76 | .75 | .72 |
| ITA | .78 | .86 | .87 |  | .85 | .76 |  | .84 | .86 |
| NLD | .86 | .91 | .86 |  | .86 | .75 | .84 |  | .83 |
| USA | .88 | .85 | .93 |  | .82 | .72 | .86 | .83 |  |

## Correlation of NLD and USA Fertility r = .91

## Genetic Correlations of Traits Mark, 2003 EAAP meeting

| Trait |  Coun-tries | Average corr. |
| --- | --- | --- |
| Protein | 27 | .87 |
| Stature | 21 | .89 |
| Fore Udder | 21 | .75 |
| Somatic Cell Score | 20 | .85 |
| Longevity | 14 | .59 |
| Direct Calving Ease | 10 | .83 |
| Maternal Calving Ease | 10 | .58 |

## Reporting of Daughter FertilityNational evaluation scales

| Scale | Mean | SD | Scale | Mean | SD |
| --- | --- | --- | --- | --- | --- |
| BEL | 0 | 4 | GBR | 0 | 3 |
| CAN | 66 | 3 | ISR | 0 | 2.5 |
| CZE | 0 | 3 | IRL | 0 | 2.5 |
| DEU | 100 | 12 | ITA | 100 | 5 |
| DFS | 100 | 10 | NLD | 100 | 4 |
| ESP | 100 | 10 | NZL | -8 | 4 |
| FRA | 0 | 1 | USA | 0 | 1.4 |

## Days to ConceptionCorrelations with other traits

|  | Milk | Dairy Form | SCS | Long-evity |
| --- | --- | --- | --- | --- |
| DNK | .31 |  | .18 | -.34 |
| ESP | .38 | .36 | .16 | -.38 |
| GBR | .36 | .40 | .13 | -.30 |
| IRL | .40 |  |  | -.49 |
| NLD | .52 | .43 | .13 | -.06 |
| USA | .21 | .31 | .12 | -.48 |

## Skewness

## Skewness of Fertility Evaluationswithin each country

**Heifer conception rate**
**Range -.23 to .11**
**Days to first insemination**
**Range .09 to .33 **
**Cow conception rate**
**Range -.20 to .10**
**Calving interval, days open, or DPR**
**Range .04 to .35, skewness in USA = .04**

## Skewness of Fertility

**Fertility trait data often have unusual distributions**
**Genetic evaluations are close to normally distributed**
**Standard linear models work well for large data sets**

## Effects of Synchronization

**Days to first insemination has less variation if herds synchronize heat**
**Sire rank for days to conception is similar in herds with heat detection or synchronization (Goodling et al, 2005 JDS) **
**DPR is adjusted for differences in herd variation**

## Are Fertility Proofs Stable?

**Bulls have about 100 daughters in first crop**
**Bulls later have thousands of daughters in second crop**
**How accurate are predictions?**
**Examined Select Sires bulls**

## Top DPR Proof StabilitySelect Sires bulls born 1995-96, high reliability in 2006

| Bull | 2003 | 2004 | 2006 |
| --- | --- | --- | --- |
| Mozer | +.5 | +.8 | +.6 |
| Geno | +.3 | +.6 | +.5 |
| Beach | +.2 | +1.6 | +1.4 |
| Brass | +.2 | -.3 | -.9 |
| Alloy | +.0 | -.1 | +1.2 |
| 
Reliability | 67% | 82% | 96% |

**DPR adjusted to 2005 base**

## Bottom DPR Proof StabilitySelect Sires bulls born 1995-96, high reliability in 2006

| Bull | 2003 | 2004 | 2006 |
| --- | --- | --- | --- |
| Hi Metro | -3.4 | -3.0 | -2.8 |
| Hillcrest | -2.6 | -2.1 | -3.1 |
| Louie | -2.4 | -1.9 | -1.6 |
| Calvin | -2.2 | -1.9 | -1.8 |
| Sovereign-Red | -2.0 | -1.6 | -1.6 |
| 
Reliability | 67% | 82% | 96% |

**DPR adjusted to 2005 base**

## Daughter Fertility of Active Bulls

**+1.8% DPR average for top 10%**
**–****2.1% DPR average, bottom 10% **
**Difference = 16 days to conception**
**Reliability for bulls averages 63%**

## Daughter Fertility of Famous BullsNovember 2006 USA scale

|  | Coun-tries | Daughters |  | DPR |  |
| --- | --- | --- | --- | --- | --- |
|  |  | Total | USA | REL | PTA |
| Die-Hard | 11 | 25,256 | 15,160 | 99% | 2.7 |
| Duster | 8 | 32,399 | 27,602 | 99% | 2.2 |
| Manfred | 15 | 19,292 | 8,011 | 99% | 2.0 |
| Morty | 13 | 20,481 | 4,177 | 97% | -2.5 |
| Demand | 14 | 38,388 | 17,972 | 99% | -2.2 |
| Emerson | 18 | 50,811 | 31,245 | 99% | -2.2 |

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

## Conclusions

**Bulls with good fertility and daughter fertility are available **
**Cow fertility traits receive 1% to 13% of total selection in many countries**
**Select for fertility using an index**
**Fertility traits have lower heritability but more variation than yield and type**
**Management and genetics affect fertility**

## Questions?