Risk factors that affect reproductive target achievement in fertile dairy cows

Area of Science:

• Reproductive physiology in dairy cattle
• Veterinary internal medicine
• Animal reproduction and fertility

Background:

• Postpartum (pp) reproductive success is crucial for dairy herd productivity.
• Identifying early risk factors can improve reproductive outcomes.
• Previous research highlights metabolic and health challenges affecting pp fertility.

Purpose of the Study:

• Investigate risk factors influencing postpartum reproductive targets in dairy cows.
• Identify key factors affecting pregnancy rates after first artificial insemination (AI).

Main Methods:

• Evaluated 98 Holstein-Friesian cows from wk 1 to 4 postpartum.
• Assessed hematology, biochemistry, reproductive tract health (ultrasonography, mucus scoring), body condition score (BCS), lameness, milk yield, and progesterone levels.
• Correlated various physiological markers and health parameters with reproductive success metrics.

Main Results:

• Reproductive success linked to liver metabolic activity, immune competence, endocrine function, negative energy balance, reproductive tract health, and adequate nutrition.
• Specific indicators included liver enzymes, neutrophil counts, hormone levels (triiodothyronine, IGF-I), metabolite concentrations (NEFA, BHB), BCS loss, uterine health, and mucus discharge.
• Factors increasing first AI pregnancy odds were previous ovulations, BCS >2.5 at AI, and clear vaginal mucus 4 days post-AI.

Conclusions:

• Early postpartum period is critical for identifying risk factors affecting reproductive targets.
• Optimizing metabolic, immune, endocrine, and nutritional status improves fertility.
• Focusing on BCS and reproductive tract health enhances first AI success rates.