derivation calculation and use of national animal-model information Calculator
Calculate Estimated Breeding Values (EBV) using key genetic and performance data. This tool helps breeders make informed selection decisions based on the principles of derivation calculation and use of national animal-model information.
+7.50 kg
+5.00 kg
+1.75 kg
EBV Component Analysis
Visual comparison of genetic components contributing to the final EBV. This chart illustrates a key aspect of the derivation calculation and use of national animal-model information.
Projected Genetic Gain Over Generations
| Generation | Selection Differential | Cumulative Genetic Gain | Projected Average EBV |
|---|
This table projects potential genetic improvement over time, a primary goal of the derivation calculation and use of national animal-model information.
What is derivation calculation and use of national animal-model information?
The derivation calculation and use of national animal-model information refers to the complex statistical processes used in livestock genetics to estimate an animal’s genetic merit. The core output of this process is the Estimated Breeding Value (EBV). An EBV predicts how an animal’s progeny will perform for specific traits (like growth rate, milk production, or wool quality) compared to the average of the population. This advanced method, often called Best Linear Unbiased Prediction (BLUP), is the gold standard for modern genetic evaluation.
Instead of just looking at an animal’s own performance, the animal model incorporates information from all known relatives, including parents, siblings, and offspring. By analyzing this web of data and accounting for environmental factors, the derivation calculation and use of national animal-model information can more accurately separate an animal’s genetic potential from temporary environmental influences. This leads to more reliable selection decisions and faster genetic progress within a breed or herd.
Who Should Use It?
This methodology is essential for livestock breeders, breed societies, and genetic evaluation companies. Commercial farmers and ranchers also rely on the resulting EBVs to make purchasing decisions for bulls, rams, and other breeding stock. Essentially, anyone involved in improving the genetic quality of livestock for economic or productive purposes will benefit from the derivation calculation and use of national animal-model information. Check out our advanced genetic selection guide for more details.
Common Misconceptions
A common misconception is that an EBV is a guarantee of an animal’s performance. In reality, it is an estimate of genetic potential. The actual performance of an animal and its offspring is still subject to management, nutrition, and other environmental factors. Another myth is that a high EBV for one trait is always desirable. Often, breeders must balance multiple traits to achieve a profitable and sustainable production system, a concept central to the derivation calculation and use of national animal-model information.
derivation calculation and use of national animal-model information Formula and Mathematical Explanation
While the full national animal model involves complex matrix algebra (Mixed Model Equations), we can understand the principles of derivation calculation and use of national animal-model information with a simplified model. The calculator above uses a foundational equation that combines an animal’s parentage with its own performance data.
The step-by-step derivation is as follows:
- Calculate Parent Average (PA): This is the baseline genetic potential inherited from the parents. It’s the average of the sire’s EBV and the dam’s EBV.
Formula: PA = (Sire’s EBV + Dam’s EBV) / 2 - Calculate Phenotypic Deviation: This measures how much better or worse the individual performed compared to its peers who were raised in the same environment.
Formula: Deviation = Individual Performance – Contemporaries’ Average Performance - Calculate Own Performance Contribution: The deviation is then weighted by the heritability of the trait. A higher heritability means more of the deviation is due to genetics.
Formula: Own Performance EBV = Deviation * Heritability - Calculate Final EBV: The final EBV combines the parental baseline with the contribution from the animal’s own performance.
Formula: Final EBV = PA + Own Performance EBV
This process demonstrates the core logic of the derivation calculation and use of national animal-model information: blending pedigree information with individual records to get a more accurate genetic estimate.
Variables Table
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| EBV | Estimated Breeding Value | Trait-specific (kg, cm, etc.) | Varies widely |
| Heritability (h²) | Proportion of trait variation due to genetics | Ratio | 0.05 – 0.60 |
| Individual Performance | The animal’s own measured trait | Trait-specific (kg, cm, etc.) | Varies by herd |
| Contemporaries’ Average | Average performance of the peer group | Trait-specific (kg, cm, etc.) | Varies by herd |
Practical Examples (Real-World Use Cases)
Example 1: Selecting a High-Growth Beef Bull
A cattle rancher wants to increase the weaning weight of their calves. They are considering a young bull for purchase. Using the principles of derivation calculation and use of national animal-model information, they gather the following data:
- Sire’s Weaning Weight EBV: +30 kg
- Dam’s Weaning Weight EBV: +20 kg
- Heritability of Weaning Weight: 0.30 (moderate)
- Bull’s Weaning Weight: 280 kg
- Contemporary Group Average Weight: 250 kg
Calculation:
- Parent Average = (+30 + +20) / 2 = +25 kg
- Phenotypic Deviation = 280 kg – 250 kg = +30 kg
- Own Performance Contribution = +30 kg * 0.30 = +9 kg
- Final Weaning Weight EBV = +25 kg + +9 kg = +34 kg
Interpretation: The bull has a final EBV of +34 kg for weaning weight. This means, on average, his calves are expected to be 34 kg heavier at weaning than calves from a bull with an EBV of 0. This is a powerful insight derived from the derivation calculation and use of national animal-model information. Learn more about interpreting EBV data.
Example 2: Evaluating a Dairy Heifer for Milk Production
A dairy farmer is deciding whether to keep a replacement heifer. The key trait is milk volume.
- Sire’s Milk EBV: +800 liters
- Dam’s Milk EBV: +400 liters
- Heritability of Milk Volume: 0.25 (low-moderate)
- Heifer’s Dam’s First Lactation Yield: 9,500 liters (Note: We use the dam’s record as a proxy for the uncalved heifer)
- Contemporary Group Average First Lactation Yield: 9,000 liters
Calculation:
- Parent Average = (+800 + +400) / 2 = +600 liters
- Phenotypic Deviation = 9,500 – 9,000 = +500 liters
- Own Performance Contribution = +500 * 0.25 = +125 liters
- Final Milk EBV = +600 + +125 = +725 liters
Interpretation: The heifer has a strong EBV for milk production, suggesting she has high genetic potential and is a good candidate to keep in the herd. This decision is strengthened by the robust framework of the derivation calculation and use of national animal-model information.
How to Use This derivation calculation and use of national animal-model information Calculator
This calculator provides a simplified yet powerful demonstration of the derivation calculation and use of national animal-model information. Follow these steps to get a meaningful result:
- Enter Parental EBVs: Input the Estimated Breeding Values for the sire (father) and dam (mother) for the trait you are analyzing. Use positive or negative numbers as provided by the breed society.
- Set Trait Heritability: Enter the heritability estimate for the specific trait. This value, between 0 and 1, is crucial for weighting the animal’s own performance. You can often find this in technical documents from your breed association.
- Input Performance Data: Provide the individual animal’s own performance record (e.g., its weight, height, or yield) and the average performance of its contemporary group. A contemporary group consists of animals of the same sex and age, raised under the same management and environmental conditions.
- Read the Results: The calculator instantly updates. The primary result is the “Final Estimated Breeding Value (EBV)”. This is the most important number for selection. The intermediate values show how the Parent Average and the animal’s own performance contributed to this final figure.
- Analyze the Chart and Table: Use the dynamic chart to visualize the impact of each component. The projection table shows the potential for long-term genetic improvement, which is the ultimate goal of the derivation calculation and use of national animal-model information. For further reading, see our article on long-term genetic strategies.
Key Factors That Affect derivation calculation and use of national animal-model information Results
The accuracy and outcome of the derivation calculation and use of national animal-model information depend on several critical factors:
- Data Accuracy: Garbage in, garbage out. Accurate pedigree records, performance measurements, and contemporary group assignments are paramount. Errors in data lead to biased EBVs.
- Heritability (h²): The heritability of a trait determines how much weight is given to an animal’s own performance versus its pedigree. Lowly heritable traits (like fertility) rely more on relative data, while highly heritable traits (like carcass traits) are more influenced by the individual’s record.
- Genetic Correlations: Traits are often genetically linked. For example, selecting for extreme growth might negatively impact calving ease. A full animal model accounts for these correlations, which is a key strength of the derivation calculation and use of national animal-model information. Explore our guide on correlated traits.
- Size of Contemporary Group: Comparing an animal to a large, well-managed contemporary group provides a much more reliable measure of its environmental deviation than comparing it to a small group. This improves the accuracy of the final EBV.
- Genomic Data (gEBV): The inclusion of DNA marker information can significantly increase the accuracy of EBVs, especially for young animals without progeny. This is the latest evolution in the derivation calculation and use of national animal-model information.
- The Animal Model Itself: Different models can be used (e.g., single-trait vs. multi-trait). The specific statistical model chosen by the national evaluation program affects how different sources of information are weighted and combined.
Frequently Asked Questions (FAQ)
Estimated Breeding Value (EBV) and Expected Progeny Difference (EPD) are closely related. An EPD is simply half of the EBV (EPD = EBV / 2). The EPD predicts the performance of an animal’s future offspring, while the EBV predicts the animal’s own total genetic merit. Both are outputs of the derivation calculation and use of national animal-model information.
A negative EBV is not necessarily bad. It simply means the animal’s genetic merit for that trait is below the current breed baseline or average (which is set to zero). For some traits, like Birth Weight or Calving Ease, a negative EBV can be highly desirable.
Breed associations periodically set a “base year” where the average EBV of animals born in that year is set to zero. All subsequent EBVs are then expressed as a deviation from that base. This is an important detail in the derivation calculation and use of national animal-model information.
No, not directly. Each breed runs its own genetic evaluation. The baseline, heritability estimates, and data pools are different. Comparing a +50 kg EBV from Breed A to a +50 kg EBV from Breed B is not a valid comparison.
Accuracy is a value between 0 and 1 that indicates the reliability of the EBV. An accuracy value closer to 1 means the EBV is a more precise estimate of the animal’s true genetic merit and is less likely to change as more data (e.g., from progeny) becomes available. Young animals have lower accuracy EBVs than older, proven sires.
EBVs are not static. They are recalculated regularly (often weekly or monthly) as new data from relatives and progeny flows into the national database. A change in an EBV reflects an update in its estimated genetic merit based on this new information, which is a dynamic feature of the derivation calculation and use of national animal-model information.
Selection indexes combine multiple EBVs for different traits into a single value, weighted by their economic importance. For example, a “Terminal Sire Index” might combine EBVs for growth, carcass weight, and fat depth. These indexes simplify selection for a specific breeding objective. You can learn to build your own with our index construction tool.
No. The derivation calculation and use of national animal-model information is applied to many species, including sheep, pigs, goats, and even in aquaculture for fish breeding programs. The principles are universal.