# Presentation: 710535

## Rear Legs (Rear View) for Brown Swiss and Guernsey Breeds

**Notes:**
Traits were introduced as response to producer concern about mobility issues in these two breeds
Evaluation release in May 2006

## Why Rear Legs (Rear View)?

**Mobility is major producer concern**
**Lameness is third most likely cause for culling**
**Not considering production**
**Selection could improve mobility and productive life**

**Notes:**
Identify bulls siring daughters with poor mobility

## International participation

**Holstein RLRV is reported from all participants but CZE and NZL**
**Ayrshire RLRV is reported from AUS, CAN, DEU, DFS, and NOR**
**Jersey RLRV is reported from AUS, CAN, DNK, ITA, NLD, ZAF**
**Guernsey RLRV is only reported from AUS, CAN**
**Brown Swiss RLRV is not included as an INTERBULL trait**

## Scoring

**Brown Swiss scored on scale of 1 (low) to 9 (high)**
**Guernsey scored 1 to 50**
**Higher scores generally preferred, but extremes are not desired**

**Notes:**
Different BS recording because of contractor for appraisals
No set score is optimum, dependent somewhat on breed

## Score Frequency

**1****Brown Swiss scores multiplied by five**

**2****Guernsey scores grouped by fives**

**0**

**500**

**1000**

**1500**

**2000**

**2500**

**3000**

**0**

**5**

**10**

**15**

**20**

**25**

**30**

**35**

**40**

**45**

**50**

**Score for Rear Legs (Rear View)**

**1,2**

**Animals**

**Guernsey**

**Brown Swiss**

**Notes:**
Because BS scored 1-9, no scores show in tales
Both breeds not strict normal distribution, but BS has higher optimum than GU

## Scoring cont.Trait Description

**Appearance of rear legs**

**Score**

**Perpendicular to ground, may hock out, toe in**

**High**

**Straight track, no hock in or out, no toe in or out**

**Optimum**

**Hock in, slight toe out**

**Moderate**

**Severely hock in, toe out**

**Low**

## Scoring cont.

**Hock in, toe out**

**Correct**
**conformation**

**Picture credit: http://www.ansci.umn.edu/dairy/documents/judging_dairy_cattle.pdf**

## Data

**9**

**9**

**Unknown parent groups****1**

**213**

**228**

**Sires with ≥5 daus**

**17,827**

**23,353**

**Pedigrees including ancestors**

**229**

**417**

**Herds**

**4,749**

**7,676**

**Cows**

**5,437**

**8,503**

**Records**

**Guernsey**

**Brown Swiss**

**1****2 birth years/group**

## Rear Legs (Rear View) Parameters

**5.8**

**0.102**

**Brown Swiss**

**7.4**

**8.8**

**Standard deviation**

**0.078**

**0.11**

**Heritability**

**Guernsey**

**Holstein**

**Notes:**
Heritability similar to HO
SD not significantly different

## Genetic Correlation of Rear Legs (Rear View) with Linear Type Traits

**0.34**

**0.44**

**−****0.03**

**Dairy form**

**0.22**

**0.31**

**0.15**

**Rear udder height**

**−****0.11**

**0.01**

**0.10**

**Udder depth**

**0.43**

**0.71**

**0.20**

**Rear udder width**

**0.17**

**−****0.14**

**−****0.42**

**0.23**

**0.32**

**Holstein**

**0.06**

**0.24**

**Fore udder attachment**

**−****0.08**

**−****0.19**

**Rump angle**

**−****0.46**

**−****0.11**

**Rear legs (side view)**

**0.16**

**0.47**

**Thurl width**

**0.30**

**0.49**

**Strength**

**Guernsey**

**Brown Swiss**

**Trait**

**Notes:**
Traits selected on basis of greatest absolute difference between correlations between breeds
Differences may be due to lack of data where short collection occurs

## Calculation of Evaluations

**First:**** Evaluate final score & 15 linear traits with current system**
**Second:**** Evaluate rear legs (rear view)**
**Use only records with rear legs (rear view) in 17-trait system**
**Allows use of correlated trait information**
**No heterogeneous variance adjustments**
**Only rear legs (rear view) evaluations retained**

**Notes:**
Normal evaluation run
Select only records with RLRV appraisals, run without HV adjustment, evaluations estimated for all animals evaluated (in first step), then only RLRV evaluations kept from second step.

## Cow evaluations

|  | Brown Swiss | Guernsey |
| --- | --- | --- |
| Records | 5,709 | 4,749 |
| Reliability, % | 32.9 | 29.9 |
| Mean, PTA | 0.01 | 0.08 |
| Minimum, PTA | −1.50 | −2.70 |
| Maximum, PTA | 1.30 | 2.60 |
| Standard deviation | 0.39 | 0.52 |

## Bulls with ≥5 daughters

|  | Brown Swiss | Guernsey |
| --- | --- | --- |
| Bulls | 228 | 213 |
| Daughters | 20.9 | 19.0 |
| Herds | 12.8 | 10.4 |
| Reliability, % | 49.6 | 44.7 |
| Mean, PTA | 0.02 | 0.07 |
| Minimum, PTA | −1.20 | −1.70 |
| Maximum, PTA | 1.30 | 2.20 |
| Standard deviation | 0.43 | 0.61 |

## Further Research

**Introduced in May 2006**
**Investigate trait inclusion in Feet & Legs Composite**
**Check impact on Net Merit**
**Second evaluation step may be unnecessary after more years of data accumulate**