Congenital respiratory tract defects in lambs

Area of Science:

• Veterinary Pathology
• Congenital Malformations
• Sheep Reproduction

Background:

• Perinatal lamb mortality is a significant concern in sheep farming.
• Congenital defects contribute to lamb mortality, with respiratory issues being a focus.
• Understanding the prevalence and nature of congenital respiratory defects is crucial for flock management.

Purpose of the Study:

• To investigate the causes of perinatal lamb mortality by examining congenital respiratory tract defects.
• To determine the incidence and types of respiratory malformations in newborn lambs.
• To identify the most common respiratory defects and their relationship to other congenital abnormalities.

Main Methods:

• Examination of 147 newborn lambs with congenital defects over a 3-year period.
• Analysis of necropsy findings for respiratory tract malformations in a cohort of 4,417 lambs.
• Categorization of defects based on location (upper vs. lower respiratory tract) and association with other malformations.

Main Results:

• Respiratory defects occurred in 3.3% of all lambs and 36.6% of congenitally malformed lambs.
• All identified respiratory defects were secondary to more extensive congenital malformations.
• Upper respiratory tract defects (e.g., choanal atresia, harelip) were more frequent than lower tract defects (e.g., pulmonary hypoplasia).
• Choanal atresia and secondary pulmonary hypoplasia were the most prevalent defects.

Conclusions:

• Primary congenital defects of the ovine respiratory tract are uncommon.
• Secondary respiratory tract malformations are relatively common, often linked to other significant congenital abnormalities.
• These findings highlight the importance of considering systemic congenital issues when diagnosing respiratory problems in lambs.