Add Support for Meat, Reproduction and Maternal Traits (ICAR Guidelines Section 21)

[maximeleduc]

Description

ICAR Guidelines Section 21 "Meat, Reproduction and Maternal Traits in Sheep and Goats" defines standardized approaches for recording growth, carcass, and reproductive performance traits. Most of these specialized traits cannot currently be exchanged using the ADE standard.

Context

These traits are essential for:

• Meat-focused breeding programs (carcass composition, growth efficiency)
• Balanced breeding objectives (avoiding antagonistic selection responses)
• International genetic evaluations for dual-purpose breeds
• Optimizing farm efficiency and profitability

Proposed New Resources

Growth & Carcass Traits

1. icarUltrasoundScanEventResource - In vivo ultrasound measurements: fat depth (mm), eye muscle depth/width/area, gigot muscularity, operator ID, live weight at scan

2. icarCTScanEventResource - Computer tomography: total/regional fat/lean/bone (kg, %), intramuscular fat (IMF), spine measurements, scan protocol details

3. icarLinearConformationScoreEventResource - Visual linear scores (1-10): shoulder width, rump width/depth, back-loins, gigot muscularity, trained operator ID

4. icarCarcassTraitsEventResource - Post-slaughter measurements: hot/cold carcass weight, killing out % (KO%), fat depth at GR/C sites, eye muscle dimensions, regional cut weights

5. icarMeatQualityEventResource - NIR measurements: intramuscular fat %, marbling score, pH, color, sensory traits (juiciness, tenderness, flavor), nutrient content

Reproduction & Maternal Traits

6. icarReproductionPerformanceResource - Calculated metrics: number born alive/dead, number reared (at defined age), lambing interval, age at first lambing, flock efficiency indicators

7. icarLambKidSurvivalEventResource - Survival as dam trait (number alive at age) or direct lamb trait (0/1), difference between scanned and reared, maternal genetic variance

8. icarMaternalAbilityEventResource - Maternal milking ability (standardized offspring weight at 30 days), lambing ease score, lamb vigor/activity at birth

9. icarScrotumMeasurementEventResource - Male fertility: scrotal circumference (cm), age and weight at measurement

10. icarMajorGeneStatusResource - Major gene genotypes:

    • Meat genes: Callipyge, Carwell, GDF8 (myostatin), BCO2 (yellow fat)
    • Prolificacy genes: BMPR1B (Booroola), BMP15, GDF9 (Galway), FecL, Thoka
    • Genotype status (homozygous/heterozygous/absent), management recommendations

11. icarGeneticConnectednessMetricsResource - Inter-flock evaluation metrics: connectedness index, prediction error variance, connectedness rating, minimum progeny links (typically 20 progeny per sire across groups)

Enhancements to Existing Resources

icarReproPregnancyCheckEventResource - Add:

• Number of foetuses detected (0,1,2,3,4+)
• Gestational age at scan (days, ideally 40-70d)
• Expected lambing timing (early/late)
• Operator/technician ID

icarWeightEventResource - Add standardized ages:

• Birth (<24h, pre-suckling), 30d, 6 weeks, 100d, 150d, adult (repeated annually)
• Growth rates (birth-weaning, post-weaning)
• Days to slaughter, pre-slaughter weight
• Measurement conditions (fasting period, time of day, scale calibration)

icarReproInseminationEventResource - Add:

• Reproduction method (AI, natural, ET)
• Oestrus type (induced/synchronized vs natural - different genetic traits, rg≈0.75)
• Hormonal treatments used
• Teaser male exposure

All Event Resources - Add:

• Management mob groups (grazing groups)
• Contemporary group details (flock×year×season×location)

Questions

1. Should ultrasound and CT scans be separate resources or combined?
2. How to handle major gene information - separate resource or extension of animal core?
3. Priority for implementation: carcass traits vs reproductive traits?
4. Target ADE version (1.5, 2.0)?

Benefits

• Enable complete meat breeding program data exchange
• Support balanced selection (growth + reproduction + maternal)
• Standardize in vivo carcass prediction methods (ultrasound, CT)
• Facilitate international genetic evaluations for dual-purpose breeds
• Manage major gene effects systematically

Reference

ICAR Guidelines Section 21 - Meat, Reproduction and Maternal Traits

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Labels: enhancement, sheep, goats, meat, reproduction, maternal

Feedback welcome from: sheep/goat meat breeding organizations, ultrasound/CT scanning services, ICAR Working Group members