Changes

Abortion is the '''expulsion before full term of a foetus''' which is incapable of independent life. Gestation length in ewes is usually 147 days but breed differences mean that it can vary from 140 to 150 days.

Abortion is the '''expulsion before full term of a foetus''' which is incapable of independent life. Gestation length in ewes is usually 147 days but breed differences mean that it can vary from 140 to 150 days.

During any abortion episode, some foetuses may be infected yet still carried to term and some may be carried to term and fully viable. There are many causes of ovine abortion and sometimes the episodes can be '''multifactorial''', with infectious agents, nutritional and management factors involved.

During any abortion episode, some fetuses may be infected yet still carried to term and some may be carried to term and fully viable. There are many causes of ovine abortion and sometimes the episodes can be '''multifactorial''', with infectious agents, nutritional and management factors involved.

The national annual incidence of abortion in the UK is estimated at 2-3%, and additionally, some flocks may experience '''abortion storms''' involving large numbers of ewes, especially after the first exposure of a totally naive flock to a new infectious agent.

The national annual incidence of abortion in the UK is estimated at 2-3%, and additionally, some flocks may experience '''abortion storms''' involving large numbers of ewes, especially after the first exposure of a totally naive flock to a new infectious agent.

The stage during gestation at which abortion takes place does not usually guide to a specific cause, but can sometimes guide to the timing of infection and nutritional stress.

The stage during gestation at which abortion takes place does not usually guide to a specific cause, but can sometimes guide to the timing of infection and nutritional stress.

Gross pathology is often unhelpful except in cases of Enzootic Abortion of Ewes and Toxoplasmosis.

Gross pathology is often unhelpful except in cases of [[Enzootic Abortion - Sheep|enzootic abortion of ewes]] and [[Toxoplasmosis - Sheep|toxoplasmosis]].

==Causes of abortion==

==Causes of Abortion==

===Non-infectious causes===

===Non-infectious Causes===

These can be considered if infectious causes have been eliminated.  

These can be considered if infectious causes have been eliminated.  

They include: '''inadequate nutrition and trace element deficiencies, pregnancy toxaemia, stress, poor handling, vaccination, transport, dog worry, concurrent disease, pasteurellosis, chronic fluke.'''

They include: '''inadequate nutrition and trace element deficiencies, [[Pregnancy Toxaemia|pregnancy toxaemia]], stress, poor handling, vaccination, transport, dog worry, concurrent disease, pasteurellosis, chronic [[Fascilolosis|fluke]].'''

===Infectious causes===

===Infectious causes===

Some infectious agents are '''primarily placentotrophic''', such as: ''Chlamydophila abortus'' (Enzootic Abortion of Ewes), ''Toxoplasma gondii'', ''Salmonella abortus ovis''.

Some infectious agents are '''primarily placentotrophic''', such as: ''[[Chlamydophila abortus]]'' (enzootic abortion of ewes), ''[[Toxoplasma gondii]]'', ''[[Salmonella|Salmonella abortus ovis]]''.

Others cause more generalised disease with abortion the result of '''septicaemia''': ''Salmonella typhimurium'', ''Salmonella dublin'', tick-borne fever (''Erlichia phagocytophila'').

Others cause more generalised disease with abortion being the result of '''septicaemia''': ''Salmonella typhimurium'', ''Salmonella dublin'', [[Tick-Borne Fever|tick-borne fever]] (''Erlichia phagocytophila'').

Other bacterial agents include: ''Campylobacter fetus fetus'', ''Campylobacter jejuni'', other ''Salmonellae'' species, ''Listeria monocytogenes'', ''Leptospira interrogans'', ''Coxiella burnetti'' (Q fever).

Other bacterial agents include: ''Campylobacter fetus fetus'', ''Campylobacter jejuni'', other ''Salmonellae'' species, ''Listeria monocytogenes'', ''Leptospira interrogans'', ''Coxiella burnetti'' (Q fever).

The bedding and abortion products should be disposed of and the area '''disinfected thoroughly'''.

The bedding and abortion products should be disposed of and the area '''disinfected thoroughly'''.

'''Antibiotic therapy''' can be intitiated if the ewe is unwell or has retained foetal membranes.

'''Antibiotic therapy''' can be initiated if the ewe is unwell or has retained foetal membranes.

Lambs should not be fostered onto ewes that have aborted due to the risk of Enzootic Abortion of Ewes.

Lambs should not be fostered onto ewes that have aborted due to the risk of Enzootic Abortion of Ewes.