# Presentation: 909996

## Genetic Alternatives for Dairy Producers who Practise Grazing

**H. D. Norman, J. R. Wright, R. L. Powell**
**Animal Improvement Programs Laboratory**
**Agricultural Research Service, USDA**
**Beltsville, MD 20705-2350**
**dnorman@aipl.arsusda.gov**** ******** 301-504-8334**

## What genetic programs work well for U.S. graziers?

**What genetic programs work well for U.S. graziers?**

**XX International Grassland Conference 2005 (****)**

## Grazier breeding

**Objective**
**Cattle with better fertility or other desired characteristics**
**Approaches (occasional use)**
**Bulls from countries that practise grazing**
**Bull breed different from cow breed**
**Effectiveness?**

## Phenotypic trend in days open

**2**

**3**

**4**

**5**

**Lactation**

## Comparison

**Daughter performance within herd**
**New Zealand AI Holstein or Friesian bulls**
**Other AI Holstein bulls (predominantly U.S.)**
**Cows included**
**Records in AIPL national database**
**Calved before March 2004**
**Time to express the performance traits**

## Yield and SCS data 

**First-lactation daughters ****(149 herds)**
**489 sired by New Zealand bulls**
**5419 sired by U.S. bulls**
**Second-lactation daughters ****(126 herds)**
**345 sired by New Zealand bulls**
**5057 sired by U.S. bulls**
**Third-lactation daughters ****(78 herds)**** **
**174 sired by New Zealand bulls**
**2840 sired by U.S. bulls**

## Yield results

**Milk ****	****U.S. daughter superiority**
**First lactation****	****501 kg*********
**Second lactation****	****467 kg*********
**Third lactation****	****448 kg*********
**Fat****	****New Zealand daughter advantage**
**First lactation****	****2 kg**
**Second lactation ****	****2 kg**
**Third lactation****	****2 kg**
**Protein****	****U.S. daughter superiority/advantage**
**First lactation****	****    5 kg********
**Second lactation****	****   ****5 kg*****  **
**Third lactation****	**** 4 kg   **

## Economic value

**Current U.S. milk prices**
**MFP$ = ****	****0.012****	******** milk****	****+ **
** ****	****	****1.30 ****	******** fat ****	****+**
** ****	****	****2.30 ****	******** protein **
**U.S. daughter MFP$ advantage**
**First lactation****	****	****$35.09**
**Second lactation****	****	****$30.83**
**Third lactation****	****	****$28.39**

## SCS results

**First lactation**
**U.S. daughter advantage of 0.1**
**Second lactation**
**U.S. daughter superiority of 0.2*****
**Third lactation**
**U.S. daughter advantage of 0.2**

## Days open data 

**First-lactation daughters ****(138 herds)**
**450 sired by New Zealand bulls**
**5036 sired by U.S. bulls**
**Second-lactation daughters ****(112 herds)**
**311 sired by New Zealand bulls**
**4781 sired by U.S. bulls**
**Third-lactation daughters ****(68 herds)**** **
**146 sired by New Zealand bulls**
**1939 sired by U.S. bulls**

## Days open results

**First lactation**
**New Zealand daughter superiority of 7 days***
**Second lactation**
**U.S. daughter advantage of 2 days**
**Third lactation**
**U.S. daughter advantage of 3 days**

## Type data 

**First-lactation daughters ****(42 herds)**
**76 sired by New Zealand bulls**
**376 sired by U.S. bulls**

## Type results

**Size composite**
**New Zealand daughters smaller by 0.91 points*****
**Udder composite**
**U.S. daughter advantage of 0.79 points**
**Foot composite**
**U.S. daughter superiority of 0.68 points****

## Conclusions

**Strain differences between U.S. Holsteins and New Zealand Friesians for several traits**
**Higher milk and protein yields for U.S. bull daughters**
**Lower first-lactation SCS for U.S. bull daughters**

## Conclusions (continued)

**Fewer first-lactation days open for New Zealand bull daughters**
**Smaller body size for New Zealand bull daughters**
**Better feet for U.S. bull daughters**

## Caution

**All strain differences influenced by individual bulls chosen from each country**

## Recommendations to breeders 

**Don’t select bulls solely on one trait because many traits have economic value **
**Consider economic value of all performance traits in your own market when making genetic choices**
**For seasonal calving, use an index that puts more weight on daughter fertility than those recommended for the general industry**

## Alternative approaches

**Comparisons needed**
**Productive life**
**Crossbreds**
**Advantages of either alternative**

## Crossbreeding

**Heterosis**
**Milk****	**** ****3.4%**
**Fat****	**** ****4.4%**
**Protein****	**** ****4.1%**
**SCS****	********0.7%**
**Days open****	**** ****1.8%**** **

## Thank you!

**XX International Grassland Conference 2005 (****)**

***Thank you!***