What to trust: Your eyes or the figures, or both?

Gordon Levet enters the debate on sheep selection – should it be on breed values or structural soundness, or both?

Gordon Levet collects blood samples from his ram hoggets to determine resistance to foot diseases.

Gordon Levet collects blood samples from his ram hoggets to determine resistance to foot diseases.

At the  Beef + Lamb NZ Ram Breeders' Forum held in Dunedin last spring, those present at one of the sessions were asked to identify what they considered the most important factor in selecting their sire and ewe replacements.  

From recollection, there were four or five productive traits along with structural soundness to choose from.  Those choosing structural soundness totaled 57 per cent.  This left 43 per cent choosing various production traits ahead of soundness. 

About 100 breeders attended this forum representing most breed and composites, including new breeders and old hands like myself.

This topic of structural soundness versus production figures has been hotly debated since the introduction of performance recording which, in the case of sheep, was the advent of the National Recording Scheme in 1967. 

Before 1967 virtually all selection was based on eye appraisal.  In the case of wool, both eyes and hands were used; hands to feel for wool density and softness, and eyes to assess wool staple length, whiteness, staple structure, freedom from hair, black fibre, canary yellowing and the water shedding qualities of the fleece.

In the early years of performance recording, most ram breeders stuck with the traditional method of eye appraisal.  A few selected solely by the figures provided by performance recording. 

Some breeders like myself, selected for both structural soundness and performance.

Over the years, performance recording has become accepted by virtually all breeders as a valuable tool for selecting the most productive animals.  Today, as indicated by the Dunedin vote, it is more a matter of where breeders place most emphasis.

When performance figures first became available, there were two schools of thought, or two camps.  In one camp were scientists, other academics and ram breeders seeking change in traditional methods.

These people were trained, and became skilled in analysing figures relating to productive traits, and seeing their relevance in the bigger picture of breeding productive animals. 

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However, generally they were not practical stockmen, and therefore were unable to observe the physical strengths and weaknesses of animals. 

In the other camp were the practical ram breeders, who had great stockmanship skills, and could recognise physical faults and see how these faults could result in premature failure.

There was considerable animosity between the two camps and, sadly, no recognition that there was merit on both sides of the argument.

The academic camp based their breeding philosophy on the theory that, "If an animal had physical faults, it would show up in the figures and be culled".  Therefore, the performance figures should be the only factors in selection. 

A fine theory, but in practice it does not work.  Why?  There are several reasons. 

First, an animal can have excellent figures with a high index and also have moderate or serious physical faults (the same applies to wool faults like black fibre and hair etc).  Using such a sire will ensure that his progeny will inherit his faults which may not show up but will carry the genes. 

If these practices are continued, then these faults will become endemic in the flock within three to four generations. 

Once such faults, which I believe are highly heritable, become entrenched in a flock, it would take at least five generations to correct, and a further period of careful observation.

Secondly, if figures are the only basis for selection, constitution and longevity will be lost.  It happened in the dairy industry where the average age of cows in the herd became very low.

It is my contention that if traits are not positively selected for, they gradually recede. 

We all understand this for productive traits and select to maintain and improve productive factors.  The same applies to physical correctness, longevity, disease resistance and last, but not least, the immune system, which ensures health and protection from disease.  If these other traits are not positively selected for, they will gradually become recessive.

I recently visited an old acquaintance, Holmes Warren, and spent an enjoyable two hours with him discussing breeding philosophy, developments in stud breeding over the past 60 years and other topics of mutual interest.

 Holmes has a great knowledge of the history of sheep breeding and is rightly acknowledged for his contribution to the whole sheep industry. 

I asked him what significance he placed on structural soundness.  He stated that "he has always said that structural soundness was as important as the foundation of any building". 

Another observation is worth noting.  He said that when he observes his top-producing ewes they had one thing in common.  Invariably, they had great rib and gut capacity.

Lincoln animal breeding and genetics Professor Jon Hickford told me he tells his students about the need for "balance" between breeding, genetics and market demand. 

"In this respect we have bred sheep for thousands of years, selecting against the things we didn't like and for the things we did like," Jon says. 

"Genetics is the relative newcomer to our approach and it most certainly adds value, but this value needs to be in the context of what is good for farmers and what actually sells. 

"There is, for example, little value in having highly productive livestock if no market exists and thus farmers are getting no income." 

He says this "balance" is tested by the commercialisation of sheep breeding and the inevitable marketing of apparently "superior rams". 

"Every second breeder now employs an advertising person to sell the virtues of their livestock.  Claims are made, but the ability of the ram buyer to prove their validity is very limited. 

"Do you trust the person, the figures, your eyes, past performance, and so on? 

"When the figures derived from genetic analysis are well calculated, then they provide immense benefit."
 He agrees that performance is only guaranteed if the animal is sound physically and meets other performance criteria too.  For example, there is little point in having a precise EBV for fleece weight, if that wool is medulated, or full of black fibre; and quite simply because the market perceives these as major wool faults.

 "As I teach my students," he says, "there is as little point in putting a Formula 1 racing V8 in a Mini Minor, as there is in putting a Mini engine in a Formula 1 car.    The A+ students now point out that Formula 1 cars have 1.6-litre, six-cylinder engines, which illustrates how the market is always changing!"

I strongly believe that there needs to be balance between breed characteristics, structural soundness and productive traits. 

Furthermore, I contend that performance levels should be governed by the geology, fertility and terrain of a property.  It is also my belief that animals will not reach their genetic potential for productivity unless they are structurally sound.


Godon Levet has had a wide experience in the stud breeding industry, having bred romney sheep his whole life.

He has also had a close relationship with scientists, especially over the past 30 years.

He is also known to be controversial at times. He says, "I enjoy throwing spanners in the works of conventional thinking, be that the thinking of fellow breeders or scientists".

He was the first stud breeder to be involved in the embryo transfer technique at Ruakura in 1972 and continued on in the local vet club over the following several years.

In 1987, believing there was a genetic factor in either resistance or susceptibility to worms, Levet visited Ruakura and asked scientists to set up protocols to breed for resistance.

He was seen by other breeders as somewhat of a crank in these early days, but this is now accepted by many farmers as a desirable trait.

He has also been deeply involved in stud breeding politics, having served 23 years on the Rommey Council including two years as president.

Over the years, Levet has been recognised for his contributions. In 1993, he received the Alan Leslie medallion for services to the veterinary club movement and his services in the wider animal health areas (he was the founding chairman of the Wellsford Vet Club in the 1960s).

In 2001, Levet was the only New Zealand sheep farmer asked to speak at the World Sheep Congress in Christchurch.

In 2008, he received the Royal Agricultural Award. This annual award is given to those making an outstanding contribution either scientifically or in other aspects of animal welfare and production.

In 2012, he received a Certificate of Achievement award in the senior section of the New Zealander of the Year.

 - Stuff

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