Frame score revisited

Frame score revisited

BENDING THE GROWTH CURVES: Due to selection pressures, cattle weight to height ratios are increasing. Angus cattle (as well as other breeds) are getting deeper and wider.

BENDING THE GROWTH CURVES: Due to selection pressures, cattle weight to height ratios are increasing. Angus cattle (as well as other breeds) are getting deeper and wider.


A US beef extension specialist argues that it is time to update and gain improved usefulness from frame scores.


IN a recent published article, associate professor and beef extension specialist at Michigan State University Dan Buskirk argues it is time to update and gain improved usefulness from a management tool that dates back to the 1970s, frame score.

Because beef cattle stature was recognised as one of the most heritable traits under the control of a cattle producer, it was considered beneficial to be able to estimate the growth curve and resulting mature skeletal size of beef cattle.

The resultant tool was measurement of hip height at a given age converted to a 1-10 frame score.

Although height increases with age, it was recognised that most animals maintain a constant frame score during their lifetime and therein lay its usefulness in predicting how large a replacement heifer would become as a mature cow or the projected harvest weight of feeder steers and heifers.

But Professor Buskirk maintains that the cattle of today are distant relatives of the 1970s cattle that were used to develop frame-score standards.

He argues that seedstock and commercial operators should quite rightly be focused on weight because payday is based on weaning or carcase weight and herd maintenance cost is directly related to mature cow weight.

Within its original construct, frame score was able to be used as a predictor of future weights but it is his observation that cattle height to weight ratio is changing rapidly.

Cattle breeders have purposefully selected breeding stock with relatively light birth weights to facilitate calving ease while at the same time looking for heavy weaning and yearling weights to produce growthy cattle capable of quickly achieving their finished endpoint.

In so doing, cattle breeders have succeeded in bending the growth curves. That is, they have sought animals that uncouple the normally strong positive correlations of birth, weaning, yearling and mature weights.

Herd improvement records from the American Angus Association since 1972 illustrate this change in weight to height relationship.

During the 1970s and 1980s, Angus bulls were being selected for increased stature.

Frame scores rose sharply from a low of 2.5 to around 5.5. At the same time yearling weight increased in parallel.

Then in the 1990s, frame scores levelled out and in the 20 years since have gone into steady decline.

But as the frame-score curve trended down, it intersected with the weight curve which continued its upward trajectory.

In other words due to selection pressures, cattle weight to height ratios are increasing. Angus cattle (as well as other breeds) are getting deeper and wider.

The 5.5 frame score yearling Angus bull of today is 150lbs (68kg) heavier than the same frame size bull of the mid-1980s.

Similarly because weight is highly heritable, Professor Buskirk notes that daughter mature weight is also creeping upward with Angus cow mature weights up by more than 100lbs (45kg) since the mid-1980s.

This upward weight trend carries a risk if producers continue to base their selections from the upper end of the frame-score scale.

Average dressed steer weights are approaching 900lbs (409kg) and with packers imposing heavy discounts at the 1000lb (454kg) mark, the prospect of discounted carcases and cows that have a higher annual maintenance cost is real.

This has prompted a warning in Beef Improvement Federation guidelines that predictions of expected carcase weights or mature cow weights based on frame scores that appear in many publications are likely incorrect.

But rather than dump frame score as no longer relevant in today's environment, Professor Buskirk advocates some remedial action.

The length of the yardstick hasn't changed he argues, but the way we use it must be updated to more accurately reflect current genetics.

Argentina resumes beef exports to China

ACCORDING to the Buenos Aires Times, Argentina's Agriculture, Livestock and Fisheries Minister, Julian Dominguez, announced last week that the country will resume beef exports to China starting Monday this week.

The move follows a suspension of beef exports in May subsequently adjusted to a cap of 50 per cent of normal volume in an attempt to tackle rising domestic beef prices.

Some export restrictions will remain, however, on seven cuts that are considered essential for maintaining domestic supply.

The minister added that the issue will be reassessed every 60 days and that further normalisation can be expected in 2022.

Agricultural groups and cattle producers reacted strongly to the control measures, temporarily halting cattle and grain trading and threatening strike action.

The move came after the government was badly beaten in the Sunday, September 12 congressional primary vote which is seen as a reliable indicator of the mid-term election due November 4.

Short weeks ahead as supply tightens

THERE has been little or no change in slaughter-cattle rates this week in the wake of some very good rainfall registrations principally in NSW and Victoria and to a lesser extent in south east Queensland.

Southern Qld grids remain on 760c/kg for 4-tooth ox and 710-730c for heavy cow.

While major processors in Qld have generally held kills at five days (except public holidays), it is now getting tighter despite the amount of money being offered.

October has not filled yet and contacts say that the latter weeks may need to drop back to four days.

They report very few slaughter cattle coming out of central NSW and are not optimistic about what there is to come out of central Qld in the run down to the end of the year.

Meanwhile overseas, Ireland is getting anxious over the still unresolved issue of Brazilian beef exports to China.

Ireland lost access to China in May 2020 over a similar atypical BSE case and has been excluded from that market since but more concerning to them is the build-up of beef stocks in Brazil.

Europe has not excluded Brazilian beef and Ireland is concerned that if the stocks cannot be released to China they will end up in Europe and other world destinations with adverse market consequences.

The story Frame score revisited first appeared on Farm Online.


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