By: Avril Helen
This page gives an insight into the different evaluation systems that are available internationally, and explains briefly why a need arose for different evaluation systems. There will also be focus on the evaluation systems of three countries with established dairy industries-namely; Ireland, New Zealand, and the Unites States.
Global dairy production is growing. Since the advent of new reproductive technologies-AI, ET etc it easier than ever to use good genetics and spread desirable traits internationally. But, different countries have different production systems-a bull that performs well in one system may not perform as well in another system in a different country. Therefore, in the 1970’s, it became clear that a way to evaluate bulls internationally was necessary.
Interbull
In 1983, following talks that had begun a decade before, Interbull was set up as a sub organisation of ICAR (International Committee of Animal Recording). The organisation was based in Sweden, and the aim was to create a method of comparing bulls internationally, so that every bull could get an evaluation in each country’s own index. These evaluations currently done through MACE (Multiple Across Country Evaluation). This system accounts for the scale and environment of each country that utilizes it. Six breeds are compared for seven trait groups-milk production, udder health, conformation, longevity, calving, female fertility and workability traits. MACE takes into account all known relatives of the animal internationally-gives a huge volume of pedigree info. Genotype by environment considerations are also accounted for-this explains why certain bulls perform better in different countries due to different production systems.
International Evaluations
Ireland, New Zealand and the USA all have well established dairy industries. The table below shows some facts and figures about each country.
| Ireland | USA | New Zealand | |
| Cow numbers | 1.1 million1 | 9.2 million2 | 4.9 million3 |
| Volume of Production | 4.6 billion litres1 | 91 billion litres2 | 20 billion litres3 |
| % Exports | 85%1 | 15%2 | 95%3 |
| Production System | Grazing | Confined | Grazing |
| Calving Pattern | Seasonal | Year round | Seasonal |
| Selection Index | EBI | NM | BW |
Indexes
Each country’s index- EBI in Ireland, NM in the US, and BW in New Zealand, are all calculated the same way. The trait is given a weighting then multiplied by an economic value. Each country has different priorities, both in terms of traits in the index and the weighting given to each trait. The following table show the traits involved in each index.
| EBI | BW | NM |
| Fertility | Protein | Protein |
| Production | Milk fat | Fat |
| Calving | Milk | Milk |
| Beef | Liveweight | PL |
| Maintenance | Fertility | SCS |
| Management | Somatic Cell | Udder |
| Health | Residual Survival | Feet/Legs |
| Body Size | ||
| DPR | ||
| HCR | ||
| CCR | ||
| CA$ |
These traits are important in each system for that country’s production system. The following table show how 3 different bulls compare in each index
| Bull | Shottle | Sunnyboy | Goldwyn |
| Net Merit $USA | 207 | -79 | 125 |
| NW $NZ | -60 | -100 | -22 |
| EBI €IE | 139 | 65 | 110 |
Sources
- Irish Cattle Breeding Federation (www.icbf.ie)
- Dairy New Zealand (www.dairynz.co.nz)
- United States Dept Of Agriculture (www.usda.gov)
- Interbull (www.interbull.org)
- www.dairybulls.com
- www.crv4all.nl
- www.cdn.ca
- www.ukcows.co.uk