Reproductive Performance

Reproductive Performance in sheep can be severely effected by abortions caused by primarily two organisms. Often seeing the actual abortions is difficult any many happen unseen. There may only be a small discharge.

Toxoplasmosis

This can effect a number of animals including people. Up to 30% of a flock may be effected causing a considerable effect on reproductive performance. Usually sheep abort in late pregnancy. Infection can be associated with cats as cats are the only known final host for this coccidia organism. Infected cats excrete vast numbers of oocysts in their faeces over a short time. Intermediate hosts, such as sheep ingest these oocysts to become infected. Once infected, immunity is very strong and seldom will a sheep abort twice from Toxoplasmosis.

Abortion samples are required for a diagnosis. Prevention is best achieved through vaccination (Toxovax). This is given twice to sheep before they go to the ram in the first year of being mated. This vaccination will last for their life.

Please contact us for more information.

Campylobacter Infection.

This is the most common cause of abortion in sheep and an outbreak can reach up to 70% effected. All ages are susceptible, but older sheep previously exposed will be less likely to abort.Usually, abortion is in the last two months of pregnancy, but often they are unseen. Often ewes scanned in July will be very different from lambs born, with a large amount of abortion occurring between scanning and lambing.

Research demonstrates that in flocks not previously vaccinated, a 6% increase in lambing is likely due to vaccination of that flock compared to an unvaccinated flock. This is due to the insidious sub clinical abortion that occurs.

Vaccination is now common throughout New Zealand. Two doses are given to ewe hoggets, the first prior to mating and the second 4 to 6 weeks later. Ewes require an annual vaccination there-after.