Schedule may not reward effort put into heavy lambs

Press, 25 October 1985, Page 24

Schedule may not reward effort put into heavy lambs

The current export lamb schedule does not encourage the production of heavy lambs at Ashley Dene, the Lincoln College light land property, according to a recent analysis of drafting patterns on the farm by Dr Alastair Nicol and Mr Phil Beatson.

The lecturers from the Animal Sciences group at the college, compared two drafting methods which produced very different ranges of carcase weights, although the average carcase weight over the whole season was the same for both methods.

More heavy weight carcases were produced by one method, but any advantage these had in value was offset by the lower value of the lighter carcases. “We lost as much on the swings as we gained on the round-abouts, said Dr Nicol and Mr Beatson. A different schedule structure would be needed to encourage the production of more heavy weight carcases.

The drafting pattern (frequency and numbers at each draft) on Ashley Dene is determined by the feed supply or rather the lack of it, so any manipulation of the type of carcases produced must be within the normal drafting pattern. At weaning, 400 lambs were divided into two groups and drafted by two different methods or strategies with the same drafting pattern as the rest of the flock.

One selected the heaviest lambs (“tops”) for slaughter at each draft. The second method aimed at killing Slow growing lambs first.

These are not the only strategies available, said Dr Nichol, nor was either of the two necessarily the most appropriate for Ashley Dene. But the two methods do highlight the differences in results that can be obtained from different drafting strategies. The drafting pattern and the mean carcase weight at each draft are shown in the first tables. '

The first drafting method produced a relatively narrow range in carcase weight (13 to 16 kg) between drafts while the second method gave a large range from 9 to 18.5 kg.

weights later in the season with the second method, drafts of lighter lambs had to be taken early in the season.

As might be expected the two drafting policies resulted in markedly different carcase gradings. Method one yielded 10 per cent Y, 80 per cent P, 9 per cent T, and 1 per cent F with 20 per cent of carcases weighing over 16.5 kg. Carcases produced by method two graded 6 per cent A, 17 per cent Y, 61 per cent P, 11 per cent T and 3 per cent F with 37 per cent of carcases over 16.5 kg and 6 per cent greater than 20.5 kg. One of the penalties of almost doubling the number of carcases over 16.5 kg by the second method was the slightly higher number of T and F grades incurred. If the schedule is to encourage a higher percentage of heavier carcases, then the second method should have returned more for each lamb than the first drafting method. This was not the case.

On the 1984 export schedule (meat price net of

killing charges) the average return was ?21 a lamb for method one and $20.90 for method two or in other words no real difference. On this year’s opening schedule, method two would return only $13.30 a lamb compared with $13.80 for method one.

“This is certainly no incentive to produce a greater proportion of heavy lambs,” said the authors.

What has gone wrong? The schedule is not structured well enough to provide the financial encouragement needed. To explain this the lecturers have illustrated the effects of three different price structures (see graph) on two very simple drafting patterns. One drafting pattern is based on method one, where all carcasses weighed 13 kg, and another where the average is still 13 kg but 25 per cent of the carcasses weigh 12 kg and another 25 per cent 14 kg (more like the method two.) (See table two). The prices represent a value at each carcase weight which is a composite of appropriate fat classes and weight ranges and is called the “weighted price”. With a straight line weighted price (line A on the figure), which is similar to the 1984 schedule, the advantage of the higher schedule for heavier weights ($16.8 for a 15 kg lamb) is almost completely negated by the lower price ($9.6 for a 12 kg lamb) for the lighter weights. Weighted prices B or the mushroom shaped curve, is similar to how this year’s export lamb schedule applies to the Ashley Dene example. The price for A grade is not as high as 1984 and therefore does not “hold-up” the price of lighter drafts. The discount of the T grade over the P is much greater at the higher weights this year which pulls down the weighted price at the top end. Very strict instructions to drafters to avoid lambs likely to grade T would help to keep up the weighted price for heavier lambs but would tend to depress the average carcass weight. Only a banana-shaped weighted price curve (C) would really encourage a greater proportion of heavy weights. All lamb producers can check whether their weighted price gives a straight, mushroom or banana curve in their own particular case. On each killing sheet they would need to divide the average price each lamb by the average carcase weight of the line to give the weighted price or average value for each carcase weight. Then plot on a piece of graph paper each average carcase weight with its corresponding average value in a similar way to the published graph. Be careful that the actual schedule has not varied a lot between drafts. Only if the answer is a banana-shaped curve is it really worth while producing some heavy weight lambs at the expense of some lighter drafts, the lecturers say.

What can be done to convert the straight line or mushroom curve into a banana-shape and make it worth while to increase the proportion of heavy weight lambs produced? ® Obviously a considerably greater premium in

the schedule for heavy lambs over medium weight lambs would need to be offered by the Meat Board and/or the exporters. • Less difference in the value of a P and T grade lamb at heavy weights than at lighter weights would “hold-up” the schedule at higher weights. © The possible selling of lighter lambs on the store market at a net price above their schedule value would also increase the average return.

This discussion has concentrated on the effect of the distribution or range of carcase weights at the same average carcase weight. This is quite different from increasing the average carcase weight over the season.

Further study of the Ashley Dene figures suggests that different drafting strategies, within a fixed drafting pattern can influence the average carcase weight over the whole season by as much as 0.6 kg. It is also possible for lamb producers to markedly alter their lamb production system so patterns of kill allow for increases in average carcase weight (for example, a greater use of lucerne or summer forage crops, a reduced stocking rate, etc). However, any increase in average lamb return will then be due to the

increase in carcase weight itself not because a higher proportion of carcases are in the heavier grades. In conclusion, the lecturers believe that the structure of the current schedule

is not conducive to producing a greater proportion of heavy weight lambs within a fixed drafting pattern but that a suitable schedule could make it worthwhile.

Drafting dates Per Cent Total lambs drafted at each Table One: Drafting Strategies Dec. Dec. Jan. Jan. Feb. Mar. Mar- Mari id 4 31 20 2 13 26 Average 10 21 9 12 10 10 12 16 date First drafting Average carcass 13.8 12.9 13.8 weight (kg) 16.2 16.3 15.2 14.7 15.3 14.6 method Second drafting 9.0 11.8 12.7 14.0 16.8 15.7 18.7 18.6 14.6 method No. of lambs Average Carcass weight Table Two: Schedule Structure Option One Average 400 - 13 13 12 Option TWO 200 100 13 14 Average 13 (kg) Net Value (?) per carcass weighted i«j 13 9.6 13 16.8 13.1 price A io 11.7 11.7 8.4 11.7 11.2 10.7 C 14*3 14.3 12.0 14.3 '19.6 15.0 Examples of weighted price curves 1 For lambs (c/kg carcass weight)