Picking bulls which complement your herd

During a recent breeding information event, Seamus Hughes – a Progressive Genetics dairy breeding adviser – outlined what the essential sub-indexes to look at are, when picking a team of bulls for your herd.

Explaining his approach to picking bulls, he said: “I really only focus on two numbers, which is the fertility sub-index and the production sub-index.”

He also emphasised the importance of recognising that the “milk sub-index or the production sub-index has nothing to do with kilos of milk and it is very important to remember that”.

“We need to pick bulls for production based on how they preform on the A plus B minus C system; if we pick bulls for just kilos of milk you are picking them for the minus C component, water.

We must pick bulls particularly for protein and obviously for fat as well, but we need them in the right ratio.

Along with the production sub-index, he highlighted why you should additionally keep in mind the fertility sub-index when picking bulls.

He said: “Our cows on average are around 2.9 lactations in the country. If we can increase this figure to five lactations, we will increase production by 50%.

“If you want to maximise production per hectare you must have cows that are going to last longer in the herd and if they don’t have good fertility they won’t last.”

He then went on to mention what the other sub-indexes which make up the EBI mean.

Other sub-indexes:
  • Calving sub-index is about whether the bull is easy calving or not;
  • Beef sub-index is about cull cow value;
  • A plus for maintenance means a smaller cow or a more easily managed cow;
  • Management sub-index is milking time – are they slow milkers and temperament;
  • Health sub-index is about SCC, mastitis and lameness.

“A lot more people are beginning to put more emphasis on the health sub-index, but it is not something I am big into yet.

“It is not overly reliable and if we want healthy cows to survive from one lactation to the next, that is already included in fertility sub-index,” concluded Seamus.