From January 1st 2001 Sheep Improvement Ltd will issue the Breeding Values of the new 2th selection lists which will be calculated by a new genetic engine and whereby the Breeding Values will be "BLUPbed"
BLUP is the acronym for Best Linear Unbiased Prediction.
It gives the Breeding Values a rating or breeding quality number and is a prediction of the breeding potential of the individual animal and how likely it is that that animal will improve (or not improve) its offspring.

BLUP calculations are used to predict everything from sow birth rates to volcanic activity. It has been used in the horse breeding industry for over 40 years.
With BLUP it is possible to track and predict the different inherited traits through complicated objectively mathematical and statistical calculations. Its requires a very powerful computer to crunch the numbers.

A BLUP rating is linear because of the constant updating of the numbers and unbiased because there is little room for subjective opinion. The resulting numbers allow ram breeders to make informed predictions when choosing breeding stock.
BLUP is expected to be used as a supplement to other evaluations and insight, but not to rely on alone. It can help to check to see how good the animals are likely to become, but it is a only hint, not a final truth; it is still a prediction and not a cast iron sure thing.

In the previous system that Animal Plan and Floc Linc were using, only the Breeding Values of the dam for fertility and milking ability (weaning weight) and the Breeding Values from the hogget (ewe or ram) for growth rate and fleece weight, compensated for rearing rank (single, twin or triplet). These were put together to form the index, taking into account the relative economic value for each trait.
In the new "BLUPbed" production index, not only dam and off spring BVs are taken into account, but also the BV's from its nearest family, sire, siblings and grandparents.

The BLUP is normally-distributed with an average at 100, e.g. the average animal being evaluated has a BLUP value of 100. The higher the BLUP is over a 100, the more likely that the offspring will be above average. The reverse will be true with BLUP values below 100.

The BLUP is calculated for all the characters that are evaluated.
If a particular ram gets a 100 in BLUP for lets say fleece weight, it means that if you breed from that ram, it is not likely to influence fleece weight in a positive or negative way. Its breeding potential is simply average for that character.
If the information about a ram regarding fleece weight is above average then its BLUP will show an above average for fleece weight.
When the BLUP for say ram No.321 is calculated, all available individual evaluations scores that are connected to ram 321 are used for the calculations, both the score of the ram itself, its offspring, parents and grandparents. Virtually all evaluation scores of all known relatives are used. Through this, the reliability of the production index has increased from about 60% to 90%, maybe even more in some cases.

Individual animals can be evaluated many times and when new information becomes available. BLUP's of individual ewes and rams can be taken again after each lambing and weaning and when growth rates and fleece weights of their offspring is recorded during their lifetime. Because the BLUP is also based on the relatives of the individual, the more relatives there are the more reliable the BLUP becomes.
BLUP is expected to be used as a supplement and reinforcement to the BVs and enhancing the reliability of the BVs.

For the commercial breeder it will mean that when choosing a ram he can have more certainty that if he wants to emphasise a particular trait, say fleece weight, that a ram, if it has a high positive BV for fleece weight, will indeed pass this trait on. The BLUP on that ram has indicated that not only the ram itself (as was the case before BLUP), but his whole family has on average a high BV for fleece weight.

The BLUP of an animal can improve when his/her offspring has shown to be better than average. If, for example, two rams who start with equal BVs for fleece weight, but one gets off spring with higher fleece weights than could be expected (from the average of the parents), then the BLUP of that ram will increase its BV for fleece weight.
So over a lifetime of an animal its BLUP could change the original BVs up or down depending on how good a breeder that particular animal has proven to be for a trait or several traits.
Consequently a very good or bad performance from a near relative could change the BVs of a particular animal through the BLUP.

Another way to use the value of BLUP is when choosing young rams. It can help to look at several hoggets from one sire and check the BVs to see how good they are likely to become. This is only an indication, not the final truth and only important with a breeder who has just started with unevaluated stock. A breeder with a long history of recording and thus many close relatives in the flock will have stable evaluations and thus a reliable BLUP.

Abbreviated and adjusted from "What is BLUP" from http://

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