Farm Tech

In The Paddock
Seasonal sheep flock management tips November 2002

Ram buying tips – Rams have a definite purpose

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Key points

• Select rams which will produce profitable lambs
• Performance recording is the only way to accurately identify genetic merit
• Breeding values describe individual traits
• Indexes describe the total genetic package
• Genetic trend graphs indicate whether your ram breeder has adopted good selection practices
• Select rams on index first, then on structure and appearance

Take time when making ram buying decisions — the results could affect your bottom line for the rest of your farming life!

The main purpose of a ram is to produce progeny that are more profitable than those bred the previous year. He's an investment from which you need to maximise the return.

Like all investments, there are risks. But you can minimise those risks by remembering that the ultimate proof of a ram's breeding ability is the performance of his progeny.

When stud breeders record animal performance they create data that can be used to provide best-bet estimates of how an animal will breed. But first the data must be corrected for ‘environmental’ factors which may have affected the performance of individual animals.

For example, at weaning, Ram A weighs 38 kg, Ram B 35 kg. At first glance, Ram A appears to be the better bet.

But when we check their age, Ram A turns out to be 110 days old and Ram B 95 days old. This means Ram B actually grew at a faster rate (316 g/day versus 300 g/day)!

Of course, growth rate is only one of several traits of importance to sheep farmers (such as fecundity, lamb survival, wool weight and disease resistance). Also, there are many more environmental factors to consider (such as age of mother, climate and whether the lamb is a twin or single).

Handling all this information and many thousands of animals is where SIL comes in.

SIL

SIL is the national sheep genetics database. It has one aim — to increase the rate of genetic gain in sheep, and therefore sheep farm profitability.

The SIL database ‘crunches’ the numbers, allowing for environmental differences and the degree to which traits are inherited. Its predictions of how a ram's progeny will perform — often based on records from thousands of relatives — are as accurate as it is possible to be.

But at the end of the day, SIL is only a tool. It doesn't tell breeders what to breed for, and it doesn't breed rams itself.

Also, it doesn't score every trait. Farmers still need to select and cull for other traits they consider important, such as black spots.

The breeder

The ideal ram breeder will be committed to improving the traits which are important to their farmer clients.

They will be performance recording and for most, this means with an SIL bureau. Breeders who aren't recording with SIL may have good genetics, but it is much harder to tell.

Ask yourself, what is the greater risk to your farm business — unknowingly turning down a good ram or buying and using a poor one?

When buying rams, ask the breeder:

• What traits is he/she targeting? Ask to see the make-up of their SIL overall index.
• How is the flock managed? (Intensively shepherded or easy-care? Low or high chemical input?)
• Is their flock large or part of a sire referencing/group breeding scheme? The more animals they have in their genetic pool, the faster the potential rate of genetic gain.
• What genetic progress are they making and from what base? Ask to see their ‘Genetic Trend Graphs’ (check the scale).
• The names of satisfied customers. Find out how their rams are performing in other buyers' flocks.

SIL reports

SIL produces a number of reports that estimate the genetic merit of animals. Ask your ram breeder to show you the reports they have for the rams you are buying and to explain what they mean.

1. Breeding values (BVs)

These are estimates of genetic merit for traits of economic importance, such as Number of Lambs Born (NLB), Weaning Weight (WWT), 8 month liveweight (LW8), 12 month fleece weight (FW12), Mean Fibre Diameter (FDIAM) or Ewe Liveweight (EWT).

2. Goal trait groups

These are sub-indexes for one or more economically important production objectives. Each index is expressed in cents per ewe lambing to give you a better idea of its relative impact on financial returns.

3. Overall indexes

The overall index (for dual purpose, terminal sire or fine wool sheep) combines all the factors that influence productivity and returns, by adding together the goal trait groups. Again, units are in cents per ewe lambing.

4. Genetic trend graphs

These show you changes in the average genetic merit of the flock over time. They let you know whether a breeder is improving the traits you are interested in.

Once you have identified the best breeder for you, selecting the rams is relatively simple.

Select on index first. Ask the breeder to only show you the highest index rams in your price range, then sort through them by eye for traits you think are important.

When rejecting animals, the only criteria you should use are those that affect your financial returns.

More information

Available from MWI:

SIL Ram Buyers Guide, Sheep Improvement Limited.

A Guide to Genetic Improvement in Sheep, K G Geenty.

Your local farm consultant or veterinarian can provide useful advice about buying rams. Alternatively, contact your local Meat & Wool Innovation extension specialist: