# Presentation: 790615

## Revised estimates of lifetime Net Merit for dairy breeds and breed crosses

**Notes:**
Farmers want to maximize profit, and AIPL has provided indexes for use.  
1971- PD$, predicted difference $
1977 MFP$
1984 CY$  cheese yield
1994 NM$, introduced.  Net Merit has been updated periodically ever few years.
Increasing interest in new “exotic” breeds and crossbreeding.

## Introduction

**Previous estimates used net merit (NM$), cheese merit (CM$), and fluid merit (FM$) formulas from 2000**** **
**Dairy breeds and breed crosses were compared using updated NM$, CM$, and FM$ formulas that include daughter pregnancy rate (DPR), calving ease, and stillbirth**

**Notes:**
My abstract used the 2003 formulas.

## Data and Methods

**National data for milk, fat, protein, productive life, SCS, and DPR were each evaluated using an all-breed animal model**
**New estimates of breed differences were compared to phenotypic breed differences and to previous estimates from studies that only included herds containing crossbred cows**

## Breed Effects and Heterosis

**New estimates of breed differences were generally intermediate between the previous estimates and the phenotypic breed differences; all three estimates were similar**
**Estimates of general heterosis from previous studies were used in the current research and not re-estimated**

**Notes:**
Chose to use phenotypic breed means, should be no difference when new all breed means are used.

## Breed Effects and HeterosisTransmitting ability differences from Holstein

|  | Milk  kg | Fat kg | Pro kg | SCS | PL | DPR |
| --- | --- | --- | --- | --- | --- | --- |
| Jersey | −1698 | −23 | −29 | +0.12 | +2.0 | +2.5 |
| B. Swiss | −927 | −15 | −13 | −0.08 | +0.1 | +0.5 |
| Guernsey | −1996 | −43 | −50 | +0.10 | −0.9 | +0.5 |
| Ayrshire | −1616 | −50 | −43 | −0.07 | +1.0 | +1.1 |
| M. Short. | −1851 | −70 | −51 |   0.00 | +0.8 | +1.7 |
| Heterosis | +318 | +16 | +12 | +0.02 | +0.3 | +1.8 |

- Heterosis and DPR estimates are from previous research

**Notes:**
PTA’s from May 2006 breed averages from cows born in 2000.
All breeds lower for Milk, Fat and Protein than Holstein.
Jersey and Guernsey are at a slight disadvantage for SCS.

## Other Trait Estimates

**Body size composite estimated from mature weight**
**Udder composite, Feet & Leg composite extrapolated from regressions on other traits within Holsteins**
**Size, PL, milk, DPR, SCS**
**Breed means for calving ease and for stillbirth**
**7.3 million HO, 37000 JE, 17000 BS,       2000 GU, 2000 AY, 300 MS**

## Trait Correlations within Holsteins(and Jersey correlations for comparison)

| Breed | Corr with | Size | PL | SCS | DPR | Milk |
| --- | --- | --- | --- | --- | --- | --- |
| HO | Udder | .26 | .30 | −.33 | .03 | −.20 |
| HO | F&L | .22 | .19 | −.02 | −.04 | −.02 |
| JE | Udder | .36 | .41 | −.21 | .13 | −.02 |
| JE | F&L | .53 | .20 | .02 | .21 | −.08 |

**Notes:**
From 2006 proposed Net Merit document.  Generally, good udders correlated with increased size, longer PL, lower SCS, slightly lower milk.
Feet and Leg composites positively associated with larger, longer lived, milk yield, and slight DPR decrease.
Jersey is shown for comparison. More highly correlated with size and PL, Udders were correlated with lower SCS. 
Feet and Leg composite positively correlated with DPR.

## Assumed Effects – Other TraitsTransmitting ability differences from Holstein

|  | Size | Udder | F&L | Calving Difficulty |  | Still-birth |
| --- | --- | --- | --- | --- | --- | --- |
| Jersey | −10.4 | −1.4 | −2.1 | −7.1 | −1.5 |  |
| B. Swiss | 0.0 | 0.7 | 0.3 | −3.2 | −0.7 |  |
| Guernsey | −7.3 | −0.5 | −1.3 | −4.6 | 1.1 |  |
| Ayrshire | −5.8 | −1.6 | −0.9 | −3.5 | −1.2 |  |
| M. Short. | −4.2 | 0.1 | −0.6 | −0.1 | −2.4 |  |
| Heterosis | 0.9 | 0.0 | 0.0 | 0.0 | 0.0 |  |

**Notes:**
Udder and F & L were calculated from regressions using the correlations on the previous slide.
Calving Ease and stillbirths are breed means from June 2006.
Heterosis value for size is from New Zealand. 
Calving Ease heterosis was calculated in a crossbreeding presentation 2 years ago.  Slight positive CE heterosis for 1st lactation , and slight negative for 2nd and later lactations. 
Other heterosis values assumed to be zero.

## Net Merit Relative Emphasis

| Trait | 2003 | 2006 | Trait | 2003 | 2006 |
| --- | --- | --- | --- | --- | --- |
| Protein | 33 | 23 | Udder | 7 | 6 |
| Fat | 22 | 23 | F&L | 4 | 3 |
| Milk | 0 | 0 | Size | 3 | 4 |
| PL | 11 | 17 | DPR | 7 | 9 |
| SCS | 9 | 9 | CA$ | 4 | 6 |

**DPR**** = daughter pregnancy rate (fertility), ****CA$**** is index of calving ease and stillbirth**

**Notes:**
My abstract reported NM$ and CM$ using 2003 formula.
The results presented today are using the updated 2006 formula.
CA$ values are actually CE values for 2003.
CA$ index is being implemented August 2006.

## NM$, FM$, CM$ - Economic Values

|  | NM$ | FM$ | CM$ |
| --- | --- | --- | --- |
| Milk | 0.00 | 0.11 | −0.07 |
| Fat | 2.70  | 2.70 |   2.70 |
| Protein | 3.55 | 0.00 |   5.73 |

**Other values are same in each index:**
**PL**** 29, ****SCS**** -150, ****Size**** -14, ****Udder**** 28, ****F&L**** 13, ****DPR**** 21, ****CA$**** 1**

**Notes:**
Values are $/PTA unit

## Merit of F1 Holstein Crossbreds

| Second Breed |  | NM$ |  | CM$ |  | FM$ |
| --- | --- | --- | --- | --- | --- | --- |
| Ayrshire |  −304 |  |  −261 |  | −364 |  |
| Brown Swiss |  55 |  |  139 |  | −78 |  |
| Guernsey | −408 |  | −405 |  | −503 |  |
| Jersey |  31 |  | 153 |  | −158 |  |
| M. Shorthorn | −498 |  | −461 |  | −547 |  |

**Compared to 2005 genetic base for Holstein**

**Notes:**
Jersey x Brown Swiss F1 were +76 CM$  better than purebred Holsteins.

## Later Generation Crosses

| Holstein backcross or multi-breed |  | NM$ |  | CM$ |  |     FM$ |
| --- | --- | --- | --- | --- | --- | --- |
| HO x (BS x HO) | +28 |  | +70 |  | −39 |  |
| HO x (JE x HO) | +16 |  | +77 |  | −79 |  |
| BS x (JE x HO) | −32  |  | +109 |  | −251 |  |
| JE x (BS x HO) | −44 |  | +116 |  | −292 |  |
| HO x (BS x JE) | +44 |  | +147 |  | −118 |  |

**Compared to 2005 genetic base for Holstein**

**Notes:**
Three way cross on the bottom line +147 CM$, is similar to F1 JE x HO.

## “Exotic” Breeds

**US has pedigree records for other breeds;  but very little production data**
**For further information:**
**Interbull conversions to Ayrshire base**
**U. Minnesota scientists (Heins et al.) **

**Notes:**
Exotic Breeds - -For example: Normande, Montbelliard, Nordic Red,  Breeds that are not routinely evaluated in the US.
US has pedigree data on these breeds of interest, from Interbull. 
The US has very little domestic production data. 
Currently, Interbull puts all “red” breeds on an Ayrshire basis. 
Proposal is to combine these breeds into a “Red Dairy Cattle” (RDC) breed, however, US would convert these back to an Ayrshire breed.
All-Breed animal model would allow for “all-breeds”, and crossbreds to be evaluated.
2 articles by Brad Heins in the July 2006 Journal of Dairy Science.

## Conclusions

**Breed effects were re-estimated**
**Yield, PL, SCS, DPR by all-breed model**
**Udder, F&L composites from other traits**
**Calving ease and stillbirth breed means**
**New Net Merit formula for August 2006**
**Holsteins still superior for FM$**

**Notes:**
Breed effects for Yield, PL, SCS and DPR using an “all-breed” animal model, very similar to phenotypic breed means.

## Conclusions

**HO x BS and HO x JE higher for NM$ and CM$**
**BS x JE higher than HO for CM$**
**Three breed crosses (HO, BS, JE) are higher than HO backcrosses for CM$, similar for NM$**