There are two ways to make nucleus management. Purebred nucleus management and Zig Zag nucleus management (or crossover as many in DK call it).

By purebred nucleus management is always used the two mother breeds YY =  Yorkshire and LL = Landrace.


Description of purebred nucleus management.

One chooses YY or LL purebred as the mother line.

These two breeds each have their advantages, but the results are the same in the end.

10% of the herd size must be purebred.

Of the 10% there must be served 10% to purebreed littes. 90% must be served to cross litters.

 

Example: Herd of 1000 sows

100 sows must be purebred.

10 sows with the best index and conditions at every time must be served to purebred litters.

90 sows, must be served to cross litters.

YY sow served with YY boar                    YY sow served with LL boar             

YY 10% purebred gilts                              LY 90% crossover gilts

All animals must be registered in Danavl database called data bank (DB). That way they will be part of the great breeding knowledge, which lies in Danavl genes.

When they are included in the databank there can be calculated weekly topical index of all animals in the herd, that way you constantly know what needs to be bred. In addition, there can be made inbreeding analysis on animals before you serve them.

There is used AgroSoft which is a pig-program to link the data with the data bank.

This program is used in everyday life on the stable level to help control lists and analysis of results and the program has the great advantage that it can send data directly to the database and receive data back, which you need in your daily work.

Description of the Zig Zag or crossover nucleus management.

One chooses YL or LY animals as the mother line. YL = Yorkshire father and Landrace mother. LY = Landrace father and Yorkshire mother. The father is always the first letter of the title race.

The entire herd will be production sows where you continuously select the 10% best sows after the index and results / conditions to breed.

Starting for example with:

YL sow served with LL boar                 

               LYL sow served with YY boar                               

                               YLY sow served with LL boar

                                                LYL and so you continue

Immediate advantages and disadvantages of different race and nuclear plans. To this must be mentioned that it is very individual when one is asked about this, in individual herds. We usually say that it's like religion. Someone like this and others like it otherwise. But I will here describe the overall experience I have when I come around.


First you must know that LY or YL has approx. 1.5 piglet more per litter than purebred litters. And YLY and LYL has approx. 0.75 piglet more per litter than purebred litters.


Yorkshire Breed: Good features - is known to be a stronger animal than Landrace. That is why many people choose this to sows, which should go in groups.

Cons - It may be a bit more difficult to work with in relation to the Landrace and in addition, the problem that they often haven´t quite as many tits as Landrace.


 

Landrace: Good features - is known for being easier to work with than Yorkshire and thereby more easy to work with in the everyday.

Cons - it is not so strong if it is to go into group system.


The results are the same if you compare herd performance.


YL and LY is the world's best sow when we're talking productivity. If you are not over 30 weaned piglets per year sow with this race, one is lagging a long way behind. The best are constant at 34-35 weaned piglets per year sow.


YLY or LYL is probably the world's second-best sow. Top herds are at 31-33 weaned piglets per year sow.


What to choose?

Is the herd of 600 sows or more, you should choose purebred. Which race is up to one's own temperament, the results are the same.


Is the herd less than 600 sows, one should choose Zig Zag or crossover nucleus mnagement. The reason is that there will be too few sows to be made in breeding, and when some fail, you haven´t enough animals later. Additionally, the herd quickly becomes narrow on the genetic area. The best is to breed as widely as possible, it recudes the risk of genetic error significantly.