Breeding objectives for Holstein dairy cattle in Iran.

Area of Science:

• Animal Science
• Agricultural Economics
• Genetics

Background:

• Dairy farming is crucial for Iran's economy.
• Holstein cattle are a primary dairy breed.
• Optimizing breeding objectives is key for sustainable genetic gain.

Purpose of the Study:

• To derive farm-specific economic weights (EW) for Holstein dairy cattle in Iran.
• To define breeding objectives tailored to Iranian production and economic conditions.
• To compare the proposed Iranian selection index with international indices.

Main Methods:

• Utilized trait-by-trait and multiple-trait bioeconomic modeling.
• Collected production and economic data from 10 Iranian dairy farms (2008-2010).
• Estimated economic weights for milk yield, fat, protein, longevity, weight, health, calving, stillbirth, age at first calving, calving interval, and non-return rate.

Main Results:

• Economic weights varied across farms, with the lowest coefficient of variation for direct calving difficulty and highest for calving interval.
• The Iranian selection index emphasizes production (50%), durability (14%), and health/reproduction (36%).
• International indices show different emphasis: production (41%), durability (37.5%), and health/reproduction (21.5%).

Conclusions:

• Significant differences between Iranian and international selection indices may hinder genetic progress via semen importation.
• The derived economic weights can inform improvements to Iran's national progeny testing and semen importation policies.
• Tailoring breeding objectives to local conditions is essential for sustainable dairy cattle improvement in Iran.