The recent study of neonatal deaths in lambs involved doing post-mortem examinations on 163 lambs that died before six days of age. Most of the lambs, which came from 17 separate mobs, were Norwegian White breed. The lambing occurred indoors and details on each lambing experience were collected. Only lambs with partly or fully inflated lungs were included in the study.
Holmoy said traumas experienced during birth was the factor for a large percentage of the lamb deaths. Results showed that 80% of the lambs died in the first two days, with half of them dying on the day they were born. Of those lambs that died on the day of birth, 40% had experienced birth difficulties. In the post-mortem examinations those lambs suffered rib fractures, rupture of the liver, etcetera.
A major factor in suffering an early (0-1 day) neonatal death was assisted birth, with 75% of lambs that died after day one experiencing a normal birth.
Infection was another significant factor, causing 33% of the neonatal deaths. Of those lambs 53% died from sepsis, 19% died from pneumonia, and 17% from gastrointestinal infections.
Birth traumas were the cause of death in 12% of the lambs, starvation in 10%, congenital malformations in 9% and post-parturient traumas in 8%.
Of the 163 lambs, 10% died from various causes and in the remaining 18% no diagnosis was made.
Holmoy said there were many variations in neonatal loss from flock to flock. Neonatal deaths changed from year to year and this information might not be valid to other sheep-producing countries.
The study was done with small flocks kept inside and supervised, so starvation and exposure, which cause a high number of deaths in New Zealand, were not as prevalent.