Culling hoggets on wool weight

Press, 3 December 1982, Page 19

Culling hoggets on wool weight

Firmers are wasting their time weighing hogget fleeces unless they select most of their culls on the basis of wool weights. A Ministry of Agriculture and Fisheries sheep and beef officer, Mr Mike Desmond, says real genetic and economic gains can be achieved by selecting replacement ewe hoggets on fleece weights. “Farmers should be prepared to cull up to 30 to 40 per cent of the hogget flock on this basis,” he says. “Wool accounts for about half of the gross income for a sheep breeding unit. It is logical, therefore, to retain those two-tooth ewes which will produce the most wool during their lifetime.” Mr Desmond adds that sheep can exhibit serious faults such as over or undershot jaws or bad feet. Culling for these faults still remains of utmost importance and will ’take precedence over culling for other factors such as wool weights. In general, however, the number of animals culled for these faults will be small (5 to 10 per cent). “Research has clearly shown that hogget fleece weight is one of the most highly inherited characteristics a farmer can cull for to improve his flock.

“The trouble is many farmers decide to cull for fleece weight, as well as other less productive traits such as conformation, type or other wool characteristics.” ;. Mr Desmond says these other characteristics must be secondary considerations until total flock wool production is increasing. Culling 10 to 20 per cent of hoggets for fleece weight, and then perhaps another 10 to 15 per cent by eye will give too small a wool production gain to warrant the work of weighing all fleeces. Around 30 or 40 per cent is more realistic, he says. Degree of accuracy is also important. A difference of, say, 100 grams is meaningless when the variability in shearing, dirt and grease in the fleece is considered. To achieve a useful culling percentage for wool, Mr Desmond says farmers should use a culling fleece weight range technique. For example, where a farmer wants to cull 35 per cent of his ewe hoggets he will determine the culling fleece weight by taking a sample from the flock. He may find that to cull the 35 per cent he will need to remove all those with a fleece weight of less than 2.7 kg. He should definitely cull the hoggets with fleeces weighing 2.5 kg and below, and retain those with fleece weights of 2.Bkg and above. All the hoggets in the “borderline” 2.6 to 2.Bkg range should be marked and then selected on size.