Genetic Indexes
By: Colleen Smith
Introduction
Using a genetic index can be a comprehensive way to evaluate your herd and make mating, culling and management decisions based on a group of traits that producers, researchers and industry professionals find important. Indexes take genetic evaluations of specific traits for an individual and weigh them according to the goals of the index. In doing so, animals can be ranked according to their potential according to a group of traits as opposed to just one. Utilizing a genetic index will allow for more rapid genetic gain than phenotypic and parentage decision making in all areas of the index. However, if a producer is only concerned with improving one or two specific traits, more targeted gain can be realized without the use of an index.
Implementation
In order to appropriately use genetic indexes and get the most return on investment for genetic testing, a few important steps must be followed.
- Establish goals for the farm – what do you want to achieve through your genetic program?
- Identify traits of importance that relate to goals – what traits will help you meet these goals?
- Select index that best suits needs – Indexes weigh traits differently, pick the index that best suits your goals and/or milk market
- Genetically test all animals – there is no way to compare animals unless they are all evaluated
- Utilize information to make decisions – rank females and divide into groups for mating decisions, strategically select sires
Links to information comparing indexes
Genetic Index Brochure – A general brochure outlining the different weighting of traits in the following common genetic indexes: lifetime net merit, total performance index(TPI), cheese merit(CM$), fluid merit (FM$) and grazing merit(GM$).
Lifetime Net Merit Handout – A more detailed handout describing Lifetime Net Merit. This handout features the current top LNM bull available in the US as well as answers some general producer questions about the index.
TPI Handout – A more detailed handout describing Total Performance Index. This handout features the current top TPI bull available in the US, answers some general producer questions about the index and shows the formula used to calculate TPI.
CM,FM,GM Handout – This handout highlights the differences between Cheese Merit, Fluid Merit and Grazing Merit. These indexes are designed for producers who target different milk markets. This handout will show how indexes can target traits that will result in the most profitable genetic gain for different producer goals.