Calf mortality in crossbred dairy cattle

Area of Science:

• Animal Science
• Veterinary Medicine
• Dairy Cattle Genetics

Background:

• Crossbreeding dairy calves involves various genetic compositions, influencing their early-life survival.
• Understanding calf mortality is crucial for dairy farm management and economic viability.

Purpose of the Study:

• To investigate calf mortality rates in crossbred dairy populations.
• To identify factors influencing mortality in calves from birth to six months of age.

Main Methods:

• Analysis of mortality data from 1,059 crossbred calves across six genetic groups.
• Categorization of calves based on Holstein, Jersey, and Brown Swiss breed inheritance (50% and 75%).
• Examination of mortality rates in relation to age, genetic composition, season of birth, sex, and birth weight.

Main Results:

• Overall mortality rates were 3.87% (under 1 month), 2.84% (1-3 months), and 1.22% (3-6 months), showing a decline with age.
• Halfbred calves exhibited lower mortality than those with 75% inheritance from temperature-adapted breeds.
• No significant association was found between mortality and season of birth, sex, or birth weight.
• Respiratory diseases were the primary cause of death in calves under one month, shifting to digestive system diseases between three and six months.

Conclusions:

• Calf mortality significantly decreases as calves age.
• Genetic composition, specifically the proportion of heritage dairy breeds, impacts calf survival rates.
• Age-specific disease patterns, such as respiratory issues in neonates and digestive problems in older calves, are critical considerations for management.