# Presentation: 154713

## Is There a Need forDifferent Genetics inDairy  Grazing Systems?

**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?**

**2006**

**Mid-Atlantic Dairy Grazing Conference, 2006 (****)**

## Grazier breeding

**Objective**
**Cattle with better fertility or other desired characteristics**
**Approaches (occasional use)**
**Bulls from countries that practice grazing**
**Bull breed different from cow breed to capitalize on heterosis**
**Effectiveness in grazing herds?**

## Phenotypic trend in days open

**2**

**3**

**4**

**5**

**Lactation**

## Comparison study

**Daughter performance within herd**
**New Zealand AI Holstein/Friesian bulls**
**Other AI Holstein bulls (predominantly U.S.)**
**Cows included**
**Records in AIPL national database**
**Calved (1****st**** parity) before May 2005**
**Time to express the performance traits**

## Traits examined

**Milk, fat, protein**
**Somatic cell score**
**Days open**
**Conformation traits**

## Yield and SCS data 

**First-lactation daughters ****(159 herds)**
**552 sired by 26 New Zealand bulls**
**6266 sired by 1119 U.S. bulls**
**Second-lactation daughters ****(136 herds)**
**394 sired by 19 New Zealand bulls**
**5212 sired by 1464 U.S. bulls**
**Third-lactation daughters ****(90 herds)**** **
**213 sired by 14 New Zealand bulls**
**3170 sired by 1036 U.S. bulls**

## Yield results

**Milk ****	****U.S. daughter superiority**
**First lactation****	****1060 lb*********
**Second lactation****	****1261 lb*********
**Third lactation****	****1056 lb*********
**Fat****	****New Zealand daughter advantage**
**First lactation****	****2 lb**
**Second lactation ****	****2 lb**
**Third lactation****	****7 lb**
**Protein****	****U.S. daughter superiority/advantage**
**First lactation****	****    11 lb********
**Second lactation****	****       ****15 lb*******  **
**Third lactation****	**** 11 lb   **

## Economic value

**Current U.S. milk prices**
**MFP$ = ****	****0.016****	******** milk****	****+ **
** ****	****	****1.50 ****	******** fat ****	****+**
** ****	****	****1.95 ****	******** protein **
**U.S. daughter MFP$ advantage**
**First lactation****	****	****$35.41**
**Second lactation****	****	****$46.43**
**Third lactation****	****	****$27.85**

## SCS results

**First lactation**
**U.S. daughter superiority of 0.22*****
**Second lactation**
**U.S. daughter advantage of 0.10**
**Third lactation**
**U.S. daughter advantage of 0.06**

## Days open data 

**First-lactation daughters ****(148 herds)**
**513 sired by 25 New Zealand bulls**
**5823 sired by 1078 U.S. bulls**
**Second-lactation daughters ****(122 herds)**
**357 sired by 19 New Zealand bulls**
**4663 sired by 1338 U.S. bulls**
**Third-lactation daughters ****(79 herds)**** **
**183 sired by 14 New Zealand bulls**
**2767 sired by 931 U.S. bulls**

## Days open results

**First lactation**
**New Zealand daughter superiority of 7 days***
**Second lactation**
**New Zealand daughter superiority of 8 days***
**Third lactation**
**New Zealand daughter advantage of 2 days**

## Type data 

**First-lactation daughters**
**79 sired by New Zealand bulls**
**308 sired by U.S. bulls**

## Type results

**Final score**
**U.S. daughters higher by 1.6 points***
**Stature**
**U.S. daughters taller, by 2.3 points***
**Rear udder height**
**U.S. daughter superior by 2.6 points***
**Udder depth**
**U.S. daughter superior by 3.2 points****

## Yield results from spring calvers

**Milk ****	****U.S. daughter superiority**
**First lactation****	****  774 lb*********
**Second lactation****	****1186 lb*********
**Third lactation****	****1642 lb*********
**Fat****	****New Zealand daughter advantage**
**First lactation****	**** 7 lb**
**Second lactation ****	**** 4 lb**
**Third lactation****	****13 lb**
**Protein****	****U.S. daughter superiority/advantage**
**First lactation****	****   9 lb**
**Second lactation****	****    ****18 lb*****  **
**Third lactation****	****     29 lb**   **

## SCS results for spring calvers

**First lactation**
**U.S. daughter superiority of 0.24***
**Second lactation**
**U.S. daughter advantage of 0.16**
**Third lactation**
**U.S. daughter advantage of 0.11**

## Days open for spring calvers

**First lactation**
**New Zealand daughter advantage of 6 days**
**Second lactation**
**New Zealand daughter advantage of 1 days**
**Third lactation**
**New Zealand daughter advantage of 1 days**

## Genetic alternative

**To achieve top fertility, consider direct selection for Daughter pregnancy rate (DPR) from US bulls or those from all sources**

## Definitions

**Days open = days from calving to conception**
**Daughter pregnancy rate (DPR) = percentage of those open (non-pregnant) cows that are between 50 and 250 days in milk that become pregnant within 21 days**

## Days open and DPR by breed

**     ****Breed ****	****Avg. days open      Avg DPR (%)**
**	**
**Ayrshire****	****143                       22.4  **
**Brown Swiss****	****143                       22.4 **
**Guernsey****	****151                       20.5**
**Holstein****	****148                       21.2**
**Jersey****	****127                       26.5**
**Milking Shorthorn****	****135                       24.5**
**DPR = 0.25 (233 – days open)**

## High DPR vs. Active-AI Holsteins

**     ****Traits ****	****High DPR bulls         All Active-AI**
**  **
**Milk (lbs)****	****349                       824 **
**Fat (lbs)****	****14                         32**
**Protein (lbs)****	****19                         26**
**SCS****	****2.84                      2.95**
**Productive Life (mo)****	****4.1                       0.8**
**DPR (%)****	****2.3                      -0.3**
**Net Merit Dollars****	****359                      236**
**     ****# of bulls (DPR****≥****2.0)****	****24                       692****	**

## High DPR vs. All Active-AI Jerseys

**     ****Traits ****	****High DPR bulls      All Active-AI**
**	**
**Milk (lbs)****	****-6                       619  **
**Fat (lbs)****	****46                         40 **
**Protein (lbs)****	****18                         27**
**SCS****	****2.94                      2.95**
**Productive Life (mo)****	****2.3                       1.7**
**DPR (%)****	****1.5                      -0.1**
**Net Merit Dollars****	****302                      269**
**# of bulls (DPR≥1.0)****	****11                        96**

## Higher DPR vs. High Active-AI HO 

**     ****Traits ****	****     Higher DPR bulls         High All Active-AI**
**  **
**Milk (lbs)****	****748                   1142 **
**Fat (lbs)****	****28                       44**
**Protein (lbs)****	****29                       35**
**SCS****	****2.82                    2.90**
**Productive Life (mo)****	****4.8                      1.8**
**DPR (%)****	****2.3                      0.0**
**Net Merit Dollars****	****462                     358**
**     ****# of bulls (DPR****≥****2.0)****	****12                       346****	**

## 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- and second-lactation days open for New Zealand bull daughters**
**Smaller body size for New Zealand bull daughters**
**Better udders for U.S. bull daughters**

## Caution

**Strain differences influenced by individual bulls chosen from each country**
**Found the New Zealand bulls chosen were slightly more selective than the US bulls used**

## 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**

## Thank you!

***Thank you!***

**2006**

**Mid-Atlantic Dairy Grazing Conference, 2006 (****)**