How to get the most return from cull ewes

Press, 19 November 1982, Page 24

How to get the most return from cull ewes

This article was written by DR ALASTAIR NICOL, senior lecturer, Animal Sciences Group, Lincoln College.

Under present economic conditions farm costs are rising more rapidly than farm income and every effort must be made to maximise all sources of farm income.

With the Meat Board selling almost all of the ewe mutton in recent seasons, the opportunity for the producer to possibly enhance his income by risk-taking through pool selling of this product, has essentially been lost. Has the producer selling works ewes any other way of influencing the income from these ewes?

Because lambs take preference over ewes for killing facilities for much of the killing season the opportunity for a producer to influence the return for his ewes by control over the time of kill and the grade of ewes killed is often limited. In many cases, particularly later in the season, it is simply a case of killing as many ewes as killing space allows.

Nonetheless, situations will exist where on-farm decisions can be made which will increase the average returns for cull ewes. Advantage of such situations can only be taken if the factors influencing the price of ewes at the works are clearly understood.

Most producers are aware of the Meat Board’s export grades for ewes. They are reproduced in the accompanying table along with current prices for each grade. There are four levels of fatness namely MM, MX, M and MF which are combined with 1 to 4-separate weight

ranges and given the various grade names indicated in the grid.

MX and MM carcases are very lean but are light in weight with average carcase weights of 15 and 18 kg respectively. Many of these carcases are boned out and although there is little trimming of fat required to meet export requirements, the low carcase weight indicates a relatively poor ratio of meat to bone in the carcase. The lower yield of saleable meat in these light weight carcases tends to lower the exporters’ schedule price. A further contribution to the lower schedule value of the lighter carcases is the relatively higher killing charge. For example the Meat Board annual report for 1981 shows that at March 31, 1981, killing and freezing charges for ewes in the average Canterbury processing plant were $8 per head plus 8c per kg carcase weight. These costs convert to 52c per kg for an 18kg carcase and only 41c per kg for a 24kg carcase. The board is continuously supplied with details of the number of carcases in each grade from all processing plants. The annual total of carcases in each grade is published on a national basis in the annual report and local figures can be obtained from

the board on request. In Canterbury, which is very similar to the national scene, two grades, the MM and MLI, accommodate 50 per cent of all ewe carcases.

Carcases in the MLI, ML2 and MHI- grades are most suitable for export in carcase form and if boned out have satisfactory yields of saleable meat.

These three grades accounted for 47 per cent of the ewes killed in Canterbury in the 1980-81 season. Ewe carcases in the MH2 grade tend to be too fat and are discounted for this excess fatness although not to the extent of very fat MF carcases. ' ,

On average 12 per cent of all ewe carcases are graded MPI and MP2. MPI carcases have received light trimming and MP2 have at least one major portion of the carcass (leg, shoulder, loin) removed from the carcass for reasons of disease or defects.

The prices in the table show very vividly that carcases which fall outside the MLI, ML2 and MHI grades return significantly less to the producer. MM and MX return less due to their low carcase weights and very heavy carcases in the MH2 and MF grades (32 and 31kg respectively) are severely penalised for their association with excess fat.

If farmers and drafters could ensure that ewes were within a liveweight range of 40 to 56kg at slaughter then the majority of the ewe carcases would grade in the optimum grades MLI, ML2 and MHI.

Island was 22.6 kg in October. By January the average had declined to 20.8 kg and by May to 20kg. The decline in weight from October to May was likely to equate to about $3 per carcase. This seasonal decline in ewe carcase weight tends to confirm the opinion that cull ewes have very low priority for feed later in the season and in fact lose live weight. Although dry ewes may contribute to the higher carcase weight earlier in the season they are unlikely to explain the continued decline in weight over the season. The evidence does suggest that the earlier ewes are killed in the season, the greater will be the return for them.

Whether producers can or even wish to try and achieve liveweights of this magnitude in cull ewes depends on a large number of management factors. In many cases using feed to put weight on cull ewes is of very low priority. The requirements of finishing lambs, replacement ewe lambs, two-tooths and the main ewe flock together with conservation of surplus feed as hay most often take precedence over the requirements of cull ewes. The average carcase weight of ewes killed for export is continually monitored and shows a very marked decline as the killing season progresses. For example, in the 1980-81 season, the average carcase weight of ewes killed in the South

The processors (freezing works) are enthusiastic about ewes being submitted for slaughter early in the killing season before lambs come forward in large numbers. There is probably unexploited potential for the early selection, weaning and

shearing of cull ewes to take advantage of the greater opportunity for killing space and possibly increased income from cull ewes earlier in the season.

This year many ewes have been in very light condition for most of the winter and spring. It 'is possible given very good pasture growth following the recent rain that the normal seasonal decline in ewe carcase weight may not be so marked this year. However, the demands on pasture production by other classes of stock and the need to replenish hay reserves may leave little surplus feed for weight gain in cull ewes no matter how good the season is from now on. The carcase value of cull ewes is a function of their carcase weight and grade. The return for works ewes does contribute to farm income and efforts should be made within the constraints of over-all farm management to maximise this return.