# Presentation: 857627

## Status of Dairy Cattle Breeding in the United States

**Dr. H. Duane Norman**
**Animal Improvement Programs Laboratory**
**Agricultural Research Service, USDA**
**Beltsville, MD 20705-2350, USA**
**dnorman@aipl.arsusda.gov**** ******** 301-504-8334**

## U.S. dairy statistics (2004)

**9.0 million cows**
**67,000 herds**
**135 cows/herd**
**19,000 lb (8600 kg)/cow**
**~93% Holsteins, ~5% Jerseys**
**~75% bred AI**
**46% milk recorded through Dairy Herd Improvement (DHI)**

## U.S. dairy population and yield

## DHI statistics (2004)

**4.1 million cows**
**97% fat recorded**
**93% protein recorded**
**93% SCC recorded**
**25,000 herds**
**164 cows/herd**
**21,250 lb (9640 kg)/cow**
**3.69% fat**
**3.09% (true) protein **

## U.S. progeny-test bulls (2000)

**Major and marketing-only AI organizations plus breeder proven**
**Breeds**
**Ayrshire****	****	****	****    ****10 bulls**
**Brown Swiss****	****	****    ****53 bulls**
**Guernsey****	****	****	****    ****15 bulls**
**Holstein****	****	****	****1436 bulls**
**Jersey****	****	****	****  ****116 bulls**
**Milking Shorthorn****	****      ****1 bull**

## National Dairy Genetic Evaluation Program

**AIPL**

**CDCB**

**NAAB**

**PDCA**

**DHI**

**Universities**

**AIPL**** ****	****Animal Improvement Programs Lab., USDA**
**CDCB****	****Council on Dairy Cattle Breeding**
**DHI****	****Dairy Herd Improvement (milk recording organizations)**
**NAAB****	****National Association of Animal Breeders (AI)**
**PDCA****	****Purebred Dairy Cattle Association (breed registries)**

## AIPL mission

**Conduct research to discover, test, and implement improved genetic evaluation techniques for economically important traits of dairy cattle and goats**
**Genetically improve efficiency of dairy animals for yield (milk, fat, protein) and fitness (longevity, mastitis resistance, reproduction, conformation)**

## AIPL research objectives

**Maintain a ****national database**** with animal identification, production (yield, milk composition), fitness (conformation, longevity), reproduction (dystocia, fertility), and health (mastitis, disease resistance) traits to support research on dairy genetics and management; provide data to others researchers submitting proposals compatible with industry wishes**

## AIPL research objectives (cont.)

**Increase ****accuracy of genetic evaluations**** for traits through improved methodology and through inclusion and appropriate weighting of deviant data**
**Develop ****bioinformatic tools**** to automate data processing in support of ****quantitative trait locus**** ****detection****, marker testing, and mapping methods**

## AIPL research objectives (cont.)

**Improve genetic rankings for ****overall economic merit**** by evaluating appropriate traits and by determining economic values of those traits in the index; improved profit functions are derived from reviewing incomes and expenses associated with each trait available for selection**

## AIPL research objectives (cont.)

**Characterize ****dairy industry practices**** in milk recording, breed registry, and artificial-insemination to ****document status and changes**** in data collection and use and in observed and genetic trends in the population**

## Traits evaluated

**Yield (milk, fat, protein volume; component percentages)**
**Type/conformation**
**Productive life/longevity**
**Somatic cell score/mastitis resistance**
**Fertility**
**Daughter pregnancy rate (cow)**
**Estimated relative conception rate (bull)**
**Calving ease/dystocia (service sire, daughter)**

**2004**

## Evaluation methods

**Animal model ****(linear)**
**Yield (milk, fat, protein)**
**Type**
**	****(Ayrshire, Brown Swiss, Guernsey, Jersey)**
**Productive life**
**SCS**
**Daughter pregnancy rate**
**Sire**** ****–**** ****maternal grandsire model ****(threshold)**
**Service sire calving ease**
**Daughter calving ease**

**2004**

**Heritability**
**25**** ****–**** ****40%**
**7**** ****–**** ****54%**
**	**
**8.5%**
**12%**
**4%**
**8.6%**
**3.6%**

## Genetic trend – Milk

**2004**

**Phenotypic base = 11,638 kg**

**sires**

## Genetic trend – Fat

**2004**

**Phenotypic base = 424 kg**

## Genetic trend – Protein

**2004**

**Phenotypic base = 350 kg**

## Genetic trend – Productive life (mo)

**2004**

**Phenotypic base = 24.6 months**

## Genetic trend – Somatic cell score

**2004**

**Phenotypic base = 3.08 (log base 2)**

## Genetic trend – Daughter pregnancy rate (%)

**Phenotypic base = 21.53%**

## Genetic trend – calving ease

**2004**

**Phenotypic base = 8.47% DBH**

**Phenotypic base = 7.99% DBH**

## Genetic-economic indexes

**2004**

| Trait | Relative value (%) |  |  |
| --- | --- | --- | --- |
|  | Cheese
merit | Net merit | Fluid merit |
| Protein (lb) | 36 | 33 | 9 |
| Fat (lb) | 18 | 22 | 22 |
| Milk (lb) | –10 | 0 | 24 |
| Productive life (mo) | 9 | 11 | 11 |
| Somatic cell score (log base 2) | –7 | –9 | –9 |
| Udder composite | 6 | 7 | 7 |
| Feet/legs composite | 3 | 4 | 4 |
| Body size composite | –2 | –3 | –3 |
| Daughter pregnancy rate (%) | 5 | 7 | 7 |
| Service sire calving difficulty (%) | –2 | –2 | –2 |
| Daughter calving difficulty (%) | –2 | –2 | –2 |

## Index changes

**2004**

| PTA traits included | Relative emphasis on traits in index (%) |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- |
|  | PD$
(1971) | MFP$
(1976) | CY$
(1984) | NM$
(1994) | NM$
(2000) | NM$
(2003) |
| Milk | 52 | 27 | –2 | 6 | 5 | 0 |
| Fat | 48 | 46 | 45 | 25 | 21 | 22 |
| Protein | ... | 27 | 53 | 43 | 36 | 33 |
| Productive life | ... | ... | ... | 20 | 14 | 11 |
| Somatic cell score | ... | ... | ... | –6 | –9 | –9 |
| Udder composite | ... | ... | ... | ... | 7 | 7 |
| Feet/legs composite | ... | ... | ... | ... | 4 | 4 |
| Body size composite | ... | ... | ... | ... | –4 | –3 |
| Daughter pregnancy rate | ... | ... | ... | ... | ... | 7 |
| Service sire calving difficulty | ... | ... | ... | ... | ... | –2 |
| Daughter calving difficulty | ... | ... | ... | ... | ... | –2 |