May 25, 2015

New Zealand sheep breeding. The search for improved fertility.


By Dr Clive Dalton

Sheep as land developers
Up to the 1960s, New Zealand sheep played a vital tool in converting native bush to productive pasture, so performance levels and especially fertility were not considered major issues.  The national ‘lambing percentage (number of lambs docked/100 ewes to the ram) was around 90%, and if a farmer got 100% then it was pleasing.  One good single lamb weaned per ewe was very satisfactory.

Things changed drastically in the 1970s when pressure came on to increase flock numbers, along with the drive to improve individual sheep performance and especially the national lambing percentage.  There was no shortage of proposals from scientists and farmers alike at the time.

NFRS and Sheeplan
The first was to boost stud flock performance through the National Flock Recording Scheme (NFRS) started in 1967 by MAF and guided by Professor Al Rae and his students at Massey College.  This was updated into Sheeplan in 1972, again by MAF and with plenty of input from stud breeders and breed associations.

As a scientist at the MAF Whatawhata Hill Country Research Station at the time, I acted as Technical Coordinator for Sheeplan to get all interested parties together, and update the scheme which was greatly helped by the arrival of the government’s first big IBM mainframe computer at Trentham in Wellington. The computer was used to process farmers’ data, which was only a small part of the other government requirements for the machine.

Sheeplan’s main feature was the development of Breeding Values and Selection Indexes for farmers sheep which they had never had before, and explaining all the new information was handled by MAF’s Farm Advisory Officers (Animal Husbandry) and Sheep and Beef Officers who serviced the country from each local MAF office.

Whatawhata breed comparison trial
My main role at Whatawhata was to run our breed comparison trial as the Coopworth and Perendale breeds had multiplied rapidly by the 1970s and their enthusiast promoters were making great claims, but there were no data on the breeds’ performance compared with the standard Romney bred on hard hill country. 

We were careful to start off with ‘good’ samples of 200 ewes of each breed approved by each breed organisations, and from then on the flocks were self replacing from their progeny reared at Whatawhata.  This was a vital feature of the trial, which didn’t happen in other breed comparison trials.

Fertility in many flocks
In terms of improving fertility, there was a lot going on at the time but looking back now, some of it didn’t get the publicity is deserved.  Some did but others did not.

The Wallace Ruakura Fertility Flock
Dr Lyn Wallace was a foundation scientist at the Ruakura research station and started selecting and using twin rams for a number of generations in a small flock of Romneys.

Great progress was shown and the overall fertility of the flock was a highlight of Ruakura’s work, which was highlighted at Open Days and conferences.  Neil Clarke carried on the work when Dr Wallace became MAF’s Research Division director, and then it was terminated as other projects claimed higher priority.  But the Wallace flock fertility genes were not offered nationally, and rams only went to a few interested local breeders, so had no real impact on the national flock.

The Raglan Ward flock
This was a flock of Romneys at Ruapuke near Raglan run by the Ward sisters. Like the Ruakura Wallace flock, they had run a closed flock for many sheep generations by only using their own twin rams, and clearly they had isolated a ‘big gene’ for fertility. 

At Whatawhata, the director Dr Doug Lang and scientist Graeme Hight got some rams from the Wards to use in the Whatawhata high fertility flock established in the 1970s from twinning two-tooths identified and purchased from the Lands and Survey Department at Waihora block near Taupo.  Contact with the Wards was not continued although the performance of the sheep was greatly recognised by the Whatawhata scientists.

The Waihora Lands and Survey flock
This was a large exercise started by Whatawhata staff who were allowed to go through the lambing paddocks at the Waihora block and catch and tag two tooths that had produced a good set of twins.  Of those still present at weaning, then 200 were purchased by MAF to start a high fertility line at Whatawhata.

Lands and Survey took up the concept to breed rams for themselves and it grew into a major business as Lands and Survey eventually became the State Owned Enterprise (SOE) of Landcorp. This exercise was one of the largest ‘Group Breeding’ schemes in the country where over 100,000 ewes were screened each season.

Group Breeding Schemes (GBS)
In these schemes a group of breeders (both stud and commercial) identified two tooth ewes under ‘easy care’ shepherding conditions that reared good lambs to weaning.  These were then sent to a central flock where they were mated to the top rams bred in the nucleus, and the next tier of top rams were returned to the contributing flocks at an agreed ratio of usually one ram for four contributed ewes.

These schemes had made spectacular progress in all-round sheep performance for commercial environments, and especially in fertility, and they produced sheep that farmers knew how to manage and which fitted in with market demands.

The Invermay fertility flock
In the 1970s, scientists at the Invermay Research Station near Dunedin led by Dr Jock Allison asked farmers to donate any old ewes that had consistently weaned a minimum of three sets of twins.  Breed didn’t matter and some amazing ewes were found which went on under Dr George Davis at Invermay to eventually isolate some major genes for fertility.  Farmers were delighted to donate their ewes and the project had great potential and at very little cost.  Sadly a business manager cancelled the project and the flock was culled.

The Booroola Merino
We included a flock of merino ewes in our breed comparison trial at Whatawhata but they were a spectacular failure because of the wet conditions.  My director Dr Doug Lang managed to get two Booroola rams from Dr Helen Newton-Turner at CSIRO in Australia but by the time they arrived, our Merinos were on the way out.  Two farmer brothers on the Booroola property in Australia had selected twins for generations and had clearly isolated a major gene for fertility.

So we gave the rams to Dr Jock Allison at Invermay research station to be used on their high country merinos at Tara Hills, and from there they got on to local farms such as Haldon Station in the McKenzie country where they made a major contribution to improving fertility.

Conclusion from these flocks
The conclusion was very clear.  There was plenty fertility genes in New Zealand in the 1970s to drive the revolution needed in the national flock, and the strong point was that these were in breeds that New Zealand farmers knew how to manage, and that produced wool the market accepted. 

But this conclusion seemed to have no major impact on the scientists who then urged MAF bureaucrats and politicians to consider importing sheep from UK and Europe.  The main argument put forward for importing new breeds was that the exercise would produce faster results.

Importations


Purebred Finnish Landrace

By the 1970s sheep researchers around the world had discovered the Finnish Landrace sheep, which produced ‘litters’ of lambs with many individuals producing in excess of quads.  These genes were seen as a guaranteed and rapid way to improve the national lambing percentage through crossbreeding.

In New Zealand, scientists at the Ruakura Research Centre’s Genetics Section led by Dr Alan Carter were most enthusiastic for an importation of new breeds, and especially the Finn. So they lobbied government over a long period, backed by their MAF Research Division colleagues. 
But Carter’s proposal was not supported by the then Director of Animal Health, Scotsman Dr George Adlam due to his concern over the risk of importing the slow virus disease called Scrapie with the sheep. His concerns were also strongly supported by Professor Neil Bruere of Massey University’s vet school.

But Carter never gave up and when Adlam retired, along with other bureaucrat changes in MAF, an importation of live sheep from UK (Finnish Landrace, East Friesian, Oxford Down and German White Headed Mutton or Oldenburg) was organised to arrive in 1972, and it certainly created both interest and concern from the different interested parties. All the scientists involved were certainly excited about the scientific papers that this work would produce, and farmer interest and benefits from it.

Quarantine
The sheep arrived into maximum quarantine on Soames Island in Wellington harbour, and then as they multiplied moved to Mana Island near Wellington, with their progeny then moving to Lands and Survey block at Crater near Rotorua.  Sadly a Finn ewe developed scrapie on Mana so the all the sheep were slaughtered and the land (Mana and Crater) banned from running sheep ever again.

A second importation of Finns along with Oxford Downs and Texels was imported as frozen embryos and semen in 1990 and successfully completed quarantine via Somes island and Hopuhopu farm near Huntly and were released to farmers though a joint MAF and farmer investor company called Sheepac.

Fertility of the Finn F1

Purebred Finnish Landrace
There’s no doubt that the Finn caused a spectacular increase in the national lambing percentage, especially in the first cross, which was attributed to hybrid vigour. The F1 was just the average of both parents so if you mated a Finn with 300% lambing to the 90% Romney – the average of 195% lambs born looked like hybrid vigour (positive heterosis) which it was not.

Unintended consequences
Looking back now at the contribution of the Finn, there were some clear unintended consequences which the enthusiasts at the time seem slow to admit now.

1.     As litter size increased, lamb birth weight decreased which led to higher lamb mortality, especially under the NZ traditional system of ‘easy care’ management.
2.     Rearing extra lambs (triplets and quads) removed from the ewe was never economic because of the price of milk replacer and the labour involved. 
3.     These smaller lambs from large litters were slow to grow and hence were on the farm for longer adding extra cost in animal health, crutching, shearing, fly control and dipping.
4.     The wool of the Finn added no great advantage to the national wool clip. Some enthusiasts claimed the extra lustre was of value and the wool trade didn’t agree.
5.     The carcass characteristics of the Finn added nothing of merit to the export meat market.

One noted Cambridge Coopworth breeder (Edward Dinger) who purchased Finns from Sheepac to incorporate into his flock, as the Coopworth Society officially allowed adding up to a quarter of Finn genes, now says that it was the worst decision he ever made, due to most of the points made above.

Where is the Finn now?
Finn genes can now only be found in composite breeds with a quarter Finn being the most you will find.  The wool trade never welcomed them, although enthusiasts at the start claimed that the extra lustre could be a good feature for some markets. It didn’t turn out that way.

Cost/benefits
It’s impossible to work out the overall cost-benefit of importing the Finn, as no account has been taken of the cost of both the 1970 and 1990 exotic sheep importations with the Finn being a major driver for both. 

Sheepac directors are adamant that they as a company made money, but this again is invalid, as they didn’t have to pay the importation costs.  The taxpayer paid!  Sheepac only bought the sheep off MAF and sold them, and MAF would have had no idea about the cost.

As one of my former colleagues said – nobody worried then or subsequently about the cost of the importations’, as ‘it wasn’t real money’!  It was taxpayers’ money!

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