April 23, 2014

New Zealand agricultural history. No 30. Importing exotic sheep breeds

Comments on composite breeds
Heterosis and hybrid vigour
Facts versus advertising hype
The Finn breed - a mistake
A 4-teated sheep
Triplets and quads - problems

By Dr Clive Dalton

Romney, Finn and Texel composites
When breeders were putting composites together, they didn’t understand some basic genetics about ‘hybrid vigour’, which they pushed as the strong marketing feature of the crosses. The term seemed to carry a lot of magic with it - which was all good news.

True ‘heterosis’ occurs when you mix lines, strains or breeds, and the result can equally be positive or negative. 
 It’s only the 'positive' heterosis which is called ‘hybrid vigour’, which is defined as where the offspring are better than 'the average' of both parents – and not better than both parents, which only happens in plants, where the lines or strains are highly inbred before crossing.

So the point is that positive heterosis or  hybrid vigour only occurs if the genetic differences between the parents are large. And remembering that differences within breeds are always greater than differences between breeds, success depends entirely on the individual parents that are used to make the composite, and not just the breed they represented. Any individual animals representing the breed won't do - it has to be the very top ones.

So  when starting off, unless the composite breeders located individual of each breed for their mixes, that were  genetically vastly better in performance than the average of the breed – then the true hybrid vigour would by a myth.  So any heterosis that occurred would soon run out, and they would be left with average performance of the combined breeds.

The way to keep the crossbred mixes improving, is to select intensively among the population and 'interbreed', mating the best animals as parents to keep the genetic merit going.  Interbreeding with continuous selection was what the Coopworth, Perendale, Corriedale and Borderdale breeders did with great success, along with some of the new meat breed combinations.

Some of the composite breeders have interbred using large flocks of their various initial mixtures, using Sheeplan and now SIL to ensure steady genetic gain.  Robin Hilson's 'one stop ram shop'  calls his 'stableised crossbreds', and not the more general term 'composites' which is a posh name for a crossbred.  In the early days of sheep breeding in New Zealand, a crossbred was considered to be a 'mongrel' and drummed out of town!

So if breeders of so-called composites have not recorded their individual animals on Sheeplan and SIL, then they cannot claim any extra merit over other breeds, and this supports an opinion I was given from a hill country farmer who believed the composite were 'running out of gas' for hard hill country - where all New Zealand sheep are going to be very soon.  

Facts versus advertising hype
In past times when there was a MAF Research Division with stations all over New Zealand, sorting out where the established breeds stand compared with the composites and new stableised crosses in a range of environments, could have been an easy job, so farmers at least had some facts to go on. This information would have been invaluable to see where all these crossbred combinations fitted into our wide range of farming environments. 

Reading sales brochures and breed organisation information seeing general and vague terms like 'good mothers, very productive, well muscled, low lamb mortality and easy care' should make hard pressed farmers really worried.  The major emphasis on meat and  lack of interest in wool makes the composite hype even easier to sell.

Where are the documented facts in peer reviewed literature to compare all the products on the market?  Until there is, there's far too much scope for outrageous statements and down right lies on what various sheep types can do.  But in today's research environment where farmers seem to have been forgotten, there's a better chance of seeing pigs fly!

The Finn – the biggest mistake 
The Finn in my view has been the biggest importation mistake and  financial disaster, as the New Zealand sheep industry didn’t need it. 
 We had identified plenty of ‘big genes’ for fertility in New Zealand, if money had only been put into spreading them around, as we knew where they were and in established breeds. 
But  pictures of  purebred Finn ewes in Finland with litters of from 4 to 6 lambs (see photo on left from Internet) . This had a massive visual impact on farmers who were struggling to get more lambs on the ground with their 90-100% lambing.  What didn't seem to register was that in Finland, these sheep are kept in doors with an army of folk around to nurse these low-birth weight lambs.  

So it was rapidly concluded that the Finn would give a massive boost to litter size at birth in any crossbreds, ignoring the fact that we had gone 'easy-care' shepherding in the 1970s, and the fact that a ewe only had two teats seemed to have been missed.

Coopworth breeder Edward Dinger tells me in his view, the Finn should never have been imported and the breed was a disaster for the industry. Edward should know, as he got involved with them and is now actively trying to get rid of their genes and find a gene for twins only. There are plenty of other farmers hoping for this gene to be found some time soon as well as Edward.

Edward even says that 'if there is one thing I regret as ram breeder is using the Finn! A more miserable sheep does not exist'. He goes on to say that their only redeeming feature is their fertility, and you can get that by using other breeds without the hassles that you get by using Finns'.  

Those are very wise words from a top sheep breeder who knows what he's talking about- and has Beef + Lamb Awards to prove it. Who want's to rear  lambs like in the photo below.  It's a very unprofitable form of entertainment.

Former MAF Christchurch Sheep and Beef Officers Lindsay Galloway, backed by former MAF Sheep and Wool farm advisory officer John Dobbie, declares that the Finn was a disaster for the wool industry by introducing ‘cross fibres’ leading to poor drying out, causing yellow pigmentation, severe cotting and subsequent down grading, especially in wet weather conditions.

The New Zealand Halfbred and Borderdale breeders have recently highlighted their concern over the Finn in composites as a threat to their expanding market for quality ‘mid-micron’ wools. Finn wool genes are not wanted in this trade, which has a positive future, and Lindsay Galloway confirms that these breeders are talking sound facts.

And for meat, breeding consultants and sheep farmers like Ian Walsh who purchased Texels from Sheepac stress that the narrow shoulder, swan neck and goat like conformation of the Finn is the last thing the meat trade wants.  The amount of lost carcass weight exports over recent decades due to Finn genetics must have been massive.
A 4-teated sheep
Dr Jock Allison reminded me about a project which he and Dr George Davis was involved in at MAF Invermay Research Centre selecting  ewes with four functional teats.  It got a fair way down the track before someone in the upper layers of the Research Division canned it.   

I was once personally approached by some Coopworth breeders at Raetahi who had got well on the way with a flock of four-teated ewes, and wanted my support to stop them being deported back to  Europe due to problems with their immigration papers. They were kicked out of New Zealand.

Triplets and quads
Now as a result of the Finn genes, many Coopworth breeders who were allowed to incorporate them into their sheep and still call them Coopworths have 40% triplets in their hoggets, which is a disaster. 

Triplets add a great cost to the enterprise to get them off the farm with the added cost of feed, shearing, drenching and dagging, fly protection and labour. 

And with high levels of triplets, the number of quads increases which clearly a total disaster with today’s cost structures, unless you like rearing pet lambs on $100 bags of milk powder, and not charging for labour - which is usually family labour.  There are easier ways to lose money!

On a good  hill country wet night, this Coopworth ewe with no exotic genes in her (pictured) in our flock at Whatawhata Hill Country Research Station in the 1970s, would be lucky to have two lambs alive next morning, due to their low birth weight for a start, and the poor chance of some slipping down the hill. Many shepherds today would bang two lambs on the head and put them out for the slink skin truck to collect, to make a few dollars for the kids' school. 
So the law of unintended consequences has bitten hard with the Finn, but a lot of farmers fail to accept it.  You would have thought that with all the brains in research and the meat and wool trade, that somebody would have done a bit of modeling to test out their negative traits of the Finn for farmers before the first importation.  

 But then, what a reception such a person would have got when the air for these ‘new’ sheep breeds was so full of hype - and the Finn topped the list.

1 comment:

  1. From Dr Leyden Baker
    I like your last few blogs where you question if the importation of the Texel's etc was really worth it. However I also believe you have done the formation of stabilised crossbreds a disservice. Yes there can be as much Phenotypic variation within breeds as between breeds but the between breed genetic variation is 100% heritable !! I agree once you stabilse the crossbred then all further genetic gain must be by within population selection. But the lift in performance in creating the new breed can be dramatic and takes place over just 2-3 generations.