2013-09-18   facebooktwitterrss
Why Purchase Ultrasound Scanned Rams and Bulls?

Tremendous genetic progress has been made in improving growth rates and the sheep and cattle bred today are different to those bred 15-20 years ago.

This has been assisted by our ability to select rams and bulls using Estimated Breeding Values (EBVs), avoiding the need to select the biggest in an attempt to identify those with the best genes for growth.

Ultrasound Scanning

Ultrasound Scanning

It is relatively easy to select animals with superior growth rates, but in doing so frame size increases and as a result breeders need to select animals with superior muscling to ensure carcases are well fleshed and the right conformation. Muscle Depth EBVs (or Muscle Area EBVs for Breedplan recorded beef breeds) provide a fantastic way to assess the genetic potential for muscling across the loin, also improving the overall level of muscling throughout the carcase. Breeders recognise this and strive to breed balanced animals with high growth rates and superior carcase conformation.

The use of ultrasound scanning (and in recent years the measurement of lambs using computed tomography (CT) provide the only repeatable and reliable way to assess muscling in the live animal.

Handling animals will give an indication of fatness and conformation, but it is easy to confuse fat with muscle when handling the loin, particularly in show sheep. Ram buyers also need to remember that the feel of the loin will be influenced by feeding and management. Buyers genuinely interested in the breeding potential of the animal must look at the Muscle Depth EBV. However, be wary of just looking at the muscle depth measurement in isolation, as this measurement will be influenced by the animal’s feeding and age, with older animals tending to have deeper muscles.

Terminal sire sheep breeds have seen dramatic improvements in muscling, partly due to the indirect selection of several major genes. But even when a ram is known to have two copies of a specific muscling gene, it doesn’t mean the rest of his genes are good for muscling and again the EBV provides a better guide to his genetic potential for muscling.

Ram and bull buyers also need to select breeding stock with the optimum fat depth for their particular system, to avoid penalties for overfat animals and achieve the right level of finish. While carcase fatness is heavily influenced by feeding and management, the animal’s genetic potential will also play a role. The Fat Depth EBV indicates whether the animal’s progeny are likely to be genetically fatter or leaner. When the concern is the sale of overfat animals, selecting sires with negative Fat Depth EBVs can help. However, with improvements in growth rates, particularly when keeping purebred terminal sire breeds on grass-based systems, producers may be looking for sires with slightly positive Fat Depth EBVs to ensure the right level of finish.

Sale checklist:

  • Ensure the recorded ram/bull is ultrasound scanned – check the sale chart or use the accuracy values as a guide, alternatively ask the vendor

  • Use EBVs, not raw data, to select animals with superior genetic potential

  • Selecting high EBVs for Muscle Depth will improve muscling throughout the carcase

  • Choose sires with the right Fat Depth EBVs for your system, which may be positive or negative.


Related Links
link Sheep Farmers Urged To Take A 'Buyer Beware' Approach
link Worcester Beltex Sell to 1,700gns
link Quality Lleyns Reap Reward at Ross On Wye
link Sheep Breeders

Stackyard News xml