Epidemiological, pathological and microbiological investigation of neonatal lamb mortality in the region of Constantine, Algeria.

BACKGROUND

Neonatal lamb mortality affects the sheep flock's productivity. In Algeria, data are very limited, making investigations quite relevant. This study aimed to determine risk factors associated with neonatal lamb mortality, describe gross and histopathological lesions on affected organs, and identify bacterial pathogens involved.

DESIGN

Thirty-five sheep farms located in Constantine participated in this survey between February and December 2022. An epidemiological questionnaire was used to describe monitoring practices and to identify associated risk factors. Twenty-two collected lamb corpses (immediate postmortem changes) underwent detailed postmortem examinations, including anatomopathological, histopathological and microbiological analyses.

RESULTS

The recorded neonatal mortality rate was 5.74%. Statistical analysis revealed significant associations between mortality and factors such as soil and livestock building hygiene, as well as the breeding system used (< 0.05). The lungs, liver, kidneys and heart were the most affected organs. Causes of death included respiratory disorders, omphalitis with septicaemia, stillbirth, trauma and starvation-hypothermia syndrome. From these organs, 218 bacterial strains were isolated, mainly Enterobacteriaceae ( spp., spp.), causing primary infections, alongside non-fermenting Gram-negative bacilli ( spp., spp.), responsible for the associated septicaemic evolution. According to the EUCAST breakpoints, isolates were resistant to commonly used antibiotics: amoxicillin, amoxicillin/clavulanic acid, trimethoprim/sulfamethoxazole and tetracycline. Notably, only spp. strains harboured genes.

CONCLUSION

This study concluded that improved sanitary protocols, early diagnosis and antimicrobial testing are crucial to prevent neonatal mortality. It also recommended larger studies and farmer training programmes to enhance lambing and neonatal care practices.