The Saved feed index consists of two parts: Maintenance efficiency and Metabolic efficiency. Maintenance measures how much energy a cow uses due to her body size. It is well known that heavier cows use more energy than less heavy cows at the same production level. Metabolic efficiency measures how efficient the cow is in converting feed energy in her body. This is energy used, for instance, to support milk production.
This new index has until now only consisted of the maintenance efficiency aspect. The breeding value for maintenance efficiency is based on different measures of live weight with the conformation traits like stature, body depth and chest width used as indicator traits.
The researchers continue to collect data on the live weight of cows in herds that are included in the research. Besides, the Natural Resources Institute Finland (Luke) is also investigating whether the slaughter weights can be used as a measure of the size of the cows in the calculations.
The size of the cow matters
By adding the Saved Feed Index to the NTM the idea is also to have a better control of two aspects that are of high relevance for daily dairy farming:
- Set a limit to the size of the cows.
- Improve cows´ feed conversion ability.
The fact that cows are getting bigger is unprofitable because it leads to higher feed costs and poorer durability. There is a negative genetic link between the cow´s growing size and its longevity.