Various What Are Genetic Trait Indexes for Dairy Cattle?
By Various
Last reviewed: December 2025
Genetic trait indexes are numerical values that predict an animal's genetic merit for specific traits like milk production, fertility, health, or...
Genetic trait indexes are the numerical language of dairy breeding. These values predict the genetic merit an animal will transmit to offspring, enabling selection decisions based on inherited potential rather than environmental factors.
The foundation is Predicted Transmitting Ability (PTA). A bull's PTA Milk of +1,500 pounds means his daughters are expected to produce 1,500 pounds more milk than daughters of an average (zero PTA) bull when milking in similar environments. The "transmitting" aspect is key—we're predicting what the animal passes to offspring.
Single-trait PTAs exist for dozens of characteristics: production (milk, fat, protein), type (stature, udder, feet/legs), health (somatic cell score, disease resistance), fertility (daughter pregnancy rate), and longevity (productive life). Each trait's PTA is estimated from a combination of the animal's own performance, relative performance, and progeny performance.
Selection indexes combine multiple traits into single values weighted by economic importance. Net Merit (NM$) is the primary U.S. index, combining production, health, longevity, fertility, and type traits weighted by their economic impact. Other indexes emphasize different priorities: Cheese Merit (CM$) values cheese yield; Fluid Merit (FM$) values fluid milk production; Grazing Merit (GM$) suits pasture operations.
Genomic testing has revolutionized indexes by enabling genetic predictions at birth based on DNA rather than waiting for progeny performance. Young genomic bulls have reliability of 70%+, compared to 99%+ for proven bulls with thousands of daughters, but early predictions enable faster genetic progress.
Key Features
- Predicted Transmitting Ability (PTA): Predicts genetic merit transmitted to offspring for individual traits
- Selection Indexes: Combined values weighting multiple traits by economic importance
- Reliability Values: Indicates confidence level based on information sources
- Breed Comparisons: Base adjustments enable comparison across breeds
- Regular Updates: Evaluations updated as new data becomes available
Advanced Features
- Genomic Predictions: DNA-based estimates available at birth
- Inbreeding Coefficients: Expected inbreeding level when mated to specific animals
- Haplotype Information: Identifies genetic recessives and beneficial variants
- Custom Indexes: Some services create farm-specific indexes matching operation goals
Ideal For
Farm Types: All dairy operations making breeding decisions
Competitive Advantages
What sets What Are Genetic Trait Indexes for Dairy Cattle? apart from alternatives:
- Enables permanent genetic improvement that compounds over generations
- Objective comparison of breeding animals for specific goals
- Balances multiple traits weighted by economic value
- Early predictions through genomics accelerate genetic progress
- Reduces reliance on subjective visual evaluation
Pricing Information
Here is the pricing information for What Are Genetic Trait Indexes for Dairy Cattle?:
CDCB evaluations: free to access; female genomic testing: $30-$50 per animal; mating programs: $5-$15 per breeding
Pricing Model: Genetic evaluations generally accessible at no direct cost; genomic testing fee per animal
Genomic testing costs have decreased dramatically, improving ROI
ROI & Value Proposition
Understanding the return on investment for What Are Genetic Trait Indexes for Dairy Cattle?:
Key Benefits:
- Genetic gain acceleration increasing lifetime milk production by 1,200-1,800 pounds per lactation
- Reduced veterinary costs averaging $125-200 per cow annually through improved health trait selection
- Enhanced reproductive efficiency reducing days open by 8-12 days per cow
- Improved feed conversion efficiency saving $180-250 per cow per year in feed costs
- Extended productive cow lifespan reducing replacement costs by $240-320 per cow
- Better udder health reducing somatic cell count by 15,000-25,000 cells/mL
- Increased conception rates improving first service conception by 4-7 percentage points
- Enhanced milk component quality increasing protein and fat premiums by $65-95 per cow annually
Implementation & Setup
How to implement What Are Genetic Trait Indexes for Dairy Cattle? on your dairy operation:
Implementation Timeline: Immediate application to breeding decisions; genetic improvement visible across generations
Training & Support
Training and support options available for What Are Genetic Trait Indexes for Dairy Cattle?:
Support Channels:
Buying Considerations
Important factors to consider when evaluating What Are Genetic Trait Indexes for Dairy Cattle?:
- Index Comprehensiveness: Evaluate whether indexes include production, health, fertility, longevity, and efficiency traits relevant to your operation's goals and economic conditions
- Genomic Accuracy Reliability: Look for indexes with genomic reliability scores above 70% for young animals, ensuring breeding decisions are based on dependable genetic predictions
- Economic Weighting Relevance: Choose indexes with economic weightings matching your milk pricing system, feed costs, and operational priorities to maximize profit potential
- Population Base Size: Select indexes from organizations with large reference populations (50,000+ animals) to ensure accurate genetic predictions across diverse bloodlines
- Update Frequency: Prioritize indexes updated multiple times annually with current genomic information to maintain breeding program competitiveness and accuracy
Evaluation Questions
Key questions to consider when evaluating What Are Genetic Trait Indexes for Dairy Cattle?:
- What traits are most economically important for our operation?
- Which selection index best matches our production goals and market?
- Should we genomically test heifers to identify genetic leaders?
- How do we balance genetic progress with inbreeding control?
- What mating program optimizes our index while managing defects?
Common Mistakes to Avoid
Avoid these common mistakes when implementing What Are Genetic Trait Indexes for Dairy Cattle?:
- Overemphasizing single traits like milk production while ignoring health and fertility indexes
- Selecting sires based on genomic evaluations with reliability scores below 50%
- Ignoring breed-specific genetic indexes when using crossbreeding programs
- Failing to update breeding goals as market conditions and farm priorities change
Market Overview
Market Size: $1.8 billion globally in 2024 for dairy genetics and breeding services
Industry Trends: Integration of genomic testing reducing genetic index accuracy timeframes from 5 years to 12 months,Focus on feed efficiency and methane emission traits in response to sustainability pressures,Adoption of multi-trait selection indexes balancing production, health, and fertility,Increased use of female fertility and daughter pregnancy rate indexes following industry fertility declines,Implementation of breed-specific indexes for Jersey, Holstein, and crossbred populations,Rising demand for polled genetics driving development of horn status genetic markers