Exercise Posted to lambs (the Lambplan mailing list) on the 10 Nov 2000
Consider the following example of a commercial lamb producer. She produces 2nd cross lambs in a high rainfall area (35" plus).  She has traditionally used British breed rams over 1st cross ewes. Her market has been 20-22 kilogram target market, but really wants to push towards 26 kilograms. She has usually sold in the paddock buts thinks that contract prices over the hooks are more attractive particularly when yield based payments becomes important.  She knows that her suckers are usually very fat "at least and inch and a half on the loin" when her Husband kills them.

Following is a group of rams that have been selected from flock number 000000 TSS (Terminal Sire Solutions owned by Two Drs PTY LTD), all are structurally sound rams.  The client above wants to purchase 4 rams to go over a new group of maiden ewes.  Can you pick which rams are the most suitable and provide an explanation of why these rams are suitable for him? Then can you work out what the value of each of the rams are to that client. The best answer posted back to lambs within two weeks will be placed on the LAMBPLAN web site under the Breeders or commercial clients name and will be sent an exclusive LAMBPLAN Poster Pack (Extremely high value one of a kind collectors edition!)  The judges will be the principals of Two Drs PTY LTD and their decision is final.
The list follows.

Alex Ball

The Solution

The client wants to produce 26kg lambs - export weight. Pasture production is good - high rainfall, so growth rates would be good. Birthweight is an issue with maiden ewes, and because they are crossbred ewes, and given the "fat" history, it  is likely to be a major problem. Conformation (muscle) is important because of the market moving to being yield based (ie payment for lean meat yield), however the crossbred ewes will contribute positively to this. Given the high rainfall it is likely that the target weight will be reached when lambs are 6 - 8 months, so the most applicable ebvs will be the post weaning ones. These are also the most accurate because far more animals are measured at postweaning than yearling. The ideal rams will have a birthweight ebv between 0 and 0.4, less than -1 for fat and positive for eye muscle. The higher the growth (pwwt) ebv the better.    The available rams are :

From the list we can immediately eliminate :
004 - PEMD of -1.172 is too low for yield based payments
005 - YFAT of 0.213 would be too fat, and BWT of -0.16 too low, and likely to cause losses in a high rainfall environment
010 - BWT of 0.729 is too high and would cause dystokia problems
The ram 009 is interesting in that he is very lean  and so will solve any fat problems, but also has very low pemd. I think this, combined with the highish bwt means he can be eliminated too.
So this leaves us with

Rams 001, 002 and 003 are the obvious choices, they have the best growth (pwwt), they are the leanest 3 rams, are all (almost) positive for pemd, and only 003 is slightly high for bwt.
Out of the last 3 I think we can drop 007 because he is fatter and lower growth. Of 006 and 008, while 006 is slightly fatter, 008 is well behind in muscle so the choice is 006.

So, our selected 4 rams are:

How much  extra are these rams worth?

The highest selected  pwwt is 003 at 8.267, while the lowest of all the rams is 009 at 2.316. This is a difference of  almost 6kg liveweight postweaning. As a lamb gets half his genes for growth from the sire, 003's progeny would be 3 kilos heavier postweaning, which equates to an extra 1.4 kg dressed. At $2.00/kg that is an additional $2.80 per lamb.

Most lamb grids have fat penalties in the region of 40c/kg for lambs outside the required range fat score 2 or 3. A ram with a yfat of -1.5 or leaner (001 and 003) could be expected to get almost every lamb into the fat requirement in this situation, while the other 2 rams might only hit specs 60% of the time. Rams as fat as 005 (yfat 0.213) might only hit specs with 10% of their progeny.

A ram which only hits fat specs 10% of the time is costing you 90% of the 40 cent fat discount across all the lambs. This is worth on average a discount of 36 c/kg, or on a 26 kg carcase,  or $9.36 per lamb for using ram 005. A ram which hits fat specs 60% of the time will still be costing you  $4.16 per lamb.

The Pastoral Prime lamb group have been selling in a grid based on carcase conformation (yield based) for several years. It uses the EUROP grading system, where a lamb graded EUR is better conformed (more muscular) and attracts a premium of 20 c/kg, while an O or P has less muscle and attracts a penalty of 20c/kg.

A ram like 002 with a pemd of 3.968 would be expected to get E or U's all the time, so his progeny would get a bonus 20 c/kg. On a 26 kg carcase that equates to an extra $5.20 for each lamb. A ram such as 009 (pemd -1.444) could well only get 20% of his progeny (out of crossbred ewes) into the EUR grade (worth an extra $5.20), so 80% would attract the 20c/kg discount (cost you $5.20). Across all his lambs, a ram like 009 would be costing you 12 c/kg for loss in yield based payment. This is  $3.12 per 26 kg lamb. But to make this worse, you actually have not only lost $3.12, you have missed out on the bonus of $5.20, so the real cost of using the low muscle ram is $8.32 per lamb!.

From the above examples it is easy to see the value in selecting a ram which will help you hit market specifications. With the right ram, the extra growth could be worth almost $3.00 and the increased muscle (in a yield based grid)  worth over $8.00. If you happened to pick the wrong  ram, which left you fatter progeny, this could cost you more than $9 per lamb. With really bad advice you could well end up missing the growth and muscle, and have fat lambs, which in total would see you missing out on $20 per lamb!  If the ram is kept for 4 years, and sires 60 progeny each year, he has cost you $20 on 240 lambs or $4800.00!

Fortunately the ram supplier didn't have any rams this bad.

For the rams in this exercise:

The perfect ram has the best ebvs for each trait, pwwt, yfat and pemd, from the available rams, while the worst possible ram has the worst.

And you think there is no value in Lambplan!

Remember we eliminated ram 010 earlier because of his high birthweight. Dead lambs (and ewes) are worth $0.00. 

Rodney Watt
Felix Poll Dorsets & White Suffolks
rwatt@ix.net.au 
http://www.allstate.net.au/rwatt