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Purchasing Rams

Performance recording is a useful tool for assessing the true performance potential of a ram. The Sheep Ireland €uro – Star breeding indexes predicts how much profit (€) a farmer can expect to achieve from selecting a particular ram.

The Sheep Value breeding indexes are split into two indexes:

  1. Terminal index - ranks animals based on their ability to produce live, fast growing terminal progeny with little lambing difficulty. This takes into account the progeny’s growth rate, carcass characteristics, days to slaughter and also lamb survival and lambing difficulty.
  2. Replacement index - ranks animals on the expected maternal performance such as milk yield, lamb survival and the ease of lambing, however it also includes some terminal traits to account for the efficiency at which animal’s progeny are finished.

The €uro - star ratings indicates where the animal is for a particular trait relative to the breed average. A five star rating indicates the animal is in the top 20%, four star in the top 40%, three star average, two star in the bottom 40% and one star in the bottom 20%.

When selecting terminal sires focus on selecting Four or Five Star Production Index rams with above average Lambing and Overall Indices. For maternal sires select from rams with Four/Five star Maternal and Lambing and above average Overall Sheep Value Indices.


Printed next to the €uro-star value for each animal is an accuracy %. This value refers to the “confidence” in the published genetic merit (e.g., Replacement or Terminal Index) of an animal as a reflection of the true genetic merit of an animal. The accuracy value is just as important as the index of the animal. Accuracy values are expressed as a % ranging from 0 (lowest confidence) to 100 (total confidence) and are an important indicator of the quantity and quality of records used to produce the index of the ram. Progeny from sires with low levels of accuracy (e.g. 10%) can have large fluctuations in their performance compared to the index or star rating. However will higher levels of accuracy (>40%) the difference between the expected progeny performance and the actual performance should be reduced considerably.