# Presentation: 738874

##  Genetic Base and Trait Definition Update

## Previous USA Base Changes

| 1965 | Predicted Difference (subtract mean yield) |
| --- | --- |
| 1974 | Modified Contemporary Comparison |
| 1984 | Red & White and Holstein bases separated |
| 1989 | Red & White and Holstein bases merged, Animal Model |
| 1995 | Age-Parity adjustments (changed trend) |
| 2000 | Lifetime Net Merit, true protein (SD change)  |

## 2005 Trait and Model Changes

**Adjust for past inbreeding and expected future inbreeding (EFI)**
**Adjust for differing parity SD**
**Yield PTA expressed to average age instead of mature equivalent**
**Use cow instead of bull base for DPR**
**Convert PTA SCS to Udder Health?**

## Genetic Gain 1995-2000(birth year)

| BV | HO | JE | BS  | GU | AY | MS |
| --- | --- | --- | --- | --- | --- | --- |
| Prot (kgs) | 17 | 15 | 15 | 11 | 7 | 5 |
| Fat (kgs) | 16 | 15 | 18 | 15 | 8 | 8 |
| Milk (kgs) | 535 | 407 | 436 | 387 | 235 | 212 |
| Prod Life | .5 | .7 | .7 | .5 | .5 | 1.1 |
| SCS | .02 | .01 | -.08 | .03 | -.01 | .03 |
| DPR (%) | -.1 | -.2 | -.4 | -.4 | .0 | .1 |

## Daughter Pregnancy Rate Bases

| PTA DPR | HO | JE | BS | GU | AY | MS |
| --- | --- | --- | --- | --- | --- | --- |
| 1995 cow mean  | .4 | .2 | .6 | -.3 | -.1 | .5 |
| progress | -.1 | -.1 | -.2 | -.2 | .0 | .0 |
| Base change | -.3 | -.1 | -.4 | +.5 | +.1 | -.5 |

## Inbreeding AdjustmentsVanRaden and Smith 1999 JDS 82:2771

**Past inbreeding (F) and future (EFI)**
**Regression on F in animal model (PTA****0****)**
**PTA****EFI**** = PTA****0**** + EFI * b****yield.F**** **
**Publish PTA****EFI**** , use PTA****0**** in mating program**
**Helps pass Interbull trend tests 2 and 3**
**Corr (current PTA, PTA****EFI****) = .9976**
**PTA****EFI**** trend 6% lower, PTA****0**** trend 3% higher**
**Corr (USA, other countries) decline by .01**

## Parity SD Adjustments

**Multiplicative age factors**
**Means are adjusted to mature yield**
**Variances are not quite equal**
**Deviations will be multiplied by**
**[1.07 1.00 .95 .90 .85] (parities 1-5)**
**Helps pass Interbull trend test 1**
**Corr (official, adjusted PTA) = .9998 for Holstein bulls born since 1995**

## Adjust Yield PTA to Average Age

**Average age vs. mature offsets base SD**
**Base SD has not been updated since 1995**
**Change would multiply PTA by 1.11 (Hol)**
**Reduced age (36 mo) divides by 1.10**
**PTA lb / EBV kg = 2.2 / 2 = 1.10**
**Proposed by USDA (M. Schutz) in 1994**
**Recommended by Holstein GAC, Oct 1994**
**Vetoed by Council “to allow the industry time to consider the nature and effect of such a change.”**

## Somatic Cell Count

**Measured with same standard metric unit (cells / ml) in every country**
**Transformed by log 2, log 10, or log e**
**Reversed scales in 9 of 19 countries**
**Added means of 100, 3, 4, etc.**
**Changed SD to report EBV, PTA, or STA**

***Different choice in almost every country!***

## International Udder Health Scales

| Ctry | Unit | Mean | SD | Dir | Ctry | Unit | Mean | SD | Dir |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| USA | PTA | 3.1 | .22 | - | NLD | RBV | 100 | 4 | + |
| CAN | PTA | 3.0 | .25 | - | DNK | RBV | 100 | 5 | + |
| BEL | EBV | 3.0 | .47 | - | SWE | RBV | 100 | 7 | + |
| JPN | EBV | 2.4 | .42 | - | DEU | RBV | 100 | 12 | + |
| AUS | EBV | 0 | .11 | - | ITA | STA | 4 | 1 | + |
| GBR | PTA | 0 | 13 | - | FRA | STA | 0 | 1 | + |
| HUN | STA | 0 | 1 | - | ESP | STA | 0 | 1 | + |

## SCS vs. Udder Health

**PTA UH = -5 (PTA SCS – breed avg.)**
**Reversed scale with mean 0, SD 1**
**Interpreted like linear trait STAs**
**Positive numbers would be favorable**
**Range would be similar to DPR, PL**
**+1 PTA UH would equal a reduction in SCC of 13%**
**Udder Health is an Interbull term **

## SCS  Breed Means

| SCS | HO | JE | BS | GU | AY | MS |
| --- | --- | --- | --- | --- | --- | --- |
| 1995  | 3.10 | 3.31 | 3.09 | 3.21 | 2.93 | 3.03 |
| 2000 | 3.09 | 3.34 | 2.94 | 3.31 | 2.97 | 3.07 |
| Difference | -0.01 | 0.03 | -0.15 | 0.10 | 0.04 | 0.04 |
| Instead use: | 3.00 | 3.00 | 3.00 | 3.00 | 3.00 | 3.00 |

## Summary

**Genetic progress in most recent 5 years similar to previous 5 years**
**Adjustments for inbreeding and for differing parity SD will be introduced **
**PTA SCS will not change to udder health**
**February 2005 changes must be sent to Interbull by September 1, 2004**