Rump – Is it Beauty or Utility?

Monday, July 20th, 2015

I have often wondered why the rump in dairy animal conformation evaluation gets undue emphasis compared to the 5 % to 10% weight assigned to it on dairy cow scorecards. After years of listening to the reasons of show judges for cow classes I have determined that udder gets the most mention but coming in second during reasons is rump. Ahead of feet and legs (15% to 28% weight) and frame/capacity/dairy character (combined 20% to 40% weight). So what gives and is this added emphasis given to rump correct?

What’s Considered Ideal?

The 2009 Dairy Cow Unified Scorecard describes the ideal as follows: “Rump (5 points): Should be long and wide throughout. Pin Bones should be slightly lower than hip bones with adequate width between the pins. Thurls should be wide apart. The vulva should be nearly vertical, and the anus should not be recessed. The tail head should set slightly above and neatly between pin bones with freedom from coarseness.”

Holstein Canada’s type classification program describes the ideal as: “Rump (10%) – Ideal qualities: 1) well-sloped, wide and strongly anchored to back/vertebrae; 2) impacts position of reproductive tract to be held high within abdominal cavity; 3)improved fertility; and 4) better calving ease & healthy recovery following calving.

It’s What is Inside that Counts.

As referred to in the Holstein Canada’s type classification program description, it is what cannot be seen below the skin, not the outward appearance of the rump that is important. It is especially important for first calvers as all breeders know so well. In time, the size of the birthing canal of young Holstein females will be critical as age at first calving is reduced to eighteen or less months of age.

So where breeders, show judges and classifiers once thought in terms of what they saw, they need to think in terms of what cannot be seen about the rump that affects reproduction and birthing. The flat, boxcar Holstein rumps of the past no longer cut it. Additionally high or low pins may create problems as they were once thought to.

Why the Over Emphasis on Rump?

When I ask breeders about why they place more than 10% emphasis on rump, they comment that they do it because of tradition, because at eye level at the business end of the cow there is the rump and because there is a limited understanding of what makes for a rump structure that is conducive to problem free calvings.

What would it take for the industry to re-think rumps in the show ring and the barn?

It needs to be recognized that progressive breeders no longer see large calves at birth as a must have. This, therefore, reduces that need for emphasis on rumps. That change has helped both the dams (quicker recovery after calving) and the calves (less stress at birth). Heifer killers need to be eliminated from all breeding programs.

Calving Ease Indexes are a Great Help

Breeders supplying information on all calvings has contributed in a major way in identifying sires and bloodlines that are below average for direct calving ease and maternal calving ease.

In researching for the Bullvine article “She Ain’t Pretty, She Just Milks That Way”, we found that positively rated sires for maternal calving ease are more apt to have daughters that have long careers in herds.

Possible Steps Going Forward

The Bullvine recommends the following:

Breeders continue to eliminate from their breeding programs sires negatively rated for calving ease and maternal calving ease,
Breed associations continue to publish genetic indexes for descriptive traits for rumps but not publish an overall rating for rump as it contributes to the over-emphasis.
More definitive research be done of the best shape and size of birthing canal,
Since most frame traits are moderate to high for heritability, bull dams should be measured and reported for the size/shape of their birthing canal, and
The approved emphasis for rumps must be applied by classifiers and show judges

The Bullvine Bottom Line

In short, the reason rump may be significant because of its role in ‘getting the cows in calf and getting the calf out’. It does not require beauty to do that. It’s about utility when it comes to the rump. Why should breeders emphasize rumps at the expense of other body parts known to have more influence on profit?