Breeding for meat

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Consumers and processors desire tender, nutritious and high yielding lambs. Producers can use genetics to help deliver these qualities.

Rams can be chosen to suit any ewes and the target market for their lambs by using Australian Sheep Breeding Values (ASBVs); either through LAMBPLAN for meat breeds or MERINOSELECT for Merinos.

The currently well-used measurements of live weight, loin eye muscle depth and GR fat depth allow producers to effectively target the right carcase weight with the most appropriate fat score.

Exciting new work being developed between the Sheep CRC Meat Program and MLA has shown that a variety of new traits (still under development) are moderately to highly heritable. These include Lean Meat Yield (LMY), Dressing Percentage (DR%), Intramuscular Fat (IMF) and Shear Force (SF5), also known as tenderness.

Which ASBVs should be used?
When selecting to improve growth rates, use post weaning weight (PWT) ASBV. To select for increased muscle, use the post weaning eye muscle depth (PEMD) ASBV. These traits must be balanced and producers should aim for animals with higher growth, and a PEMD ASBV between 0.0 mm and 3.0 mm.

Fat is also an important component and the level chosen will depend mostly on the combination of breeds being used and the production system that is being targeted. When using a maternal or terminal sire over Merinos, choose a post weaning fat (PFAT) ASBV that is between -0.5 mm and 0.5 mm. Terminal sires used over 1st cross ewes can be selected between -1.0 mm and 0.0 mm.

To avoid lambing difficulties, look for birth weight (BWT) ASBVs that are between 0.1 kg and 0.3 kg. High birth weight is one of the key factors leading to dystocia (lambing difficulties). Very low birth weights should also be avoided as this can lead to light lambs that have little tolerance for cold weather.

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