Sheep Abortion SDL Scenario Review

Breeding Goals: The farm aims to achieve a higher scanning rate and a lower barren rate. Target breeding goals include:

  • Target scanning percentage: 200%

  • Barren rate target: <2-3%
    To meet these goals, effective breeding management and selection strategies must be implemented.

Ram Management: Two 4-year-old Texel rams are utilized in the breeding program, and there have been no reported issues with their health or performance. A breeding performance review has been conducted to analyze their effectiveness, which highlights the critical nature of regular assessments in maintaining quality stock to meet breeding goals.

Sheep Health Monitoring: Regular health checks and vaccinations are essential to prevent diseases that can affect reproductive efficiency. Indicators of good health include optimal body condition scores and absence of infectious diseases.

  • High empty rate: This indicates a lower-than-desired level of conception among the ewes.

  • High abortion rate: Current statistics indicate an abortion rate of 6%, which is higher than the targeted goals and requires immediate attention.

  • Low scanning percentage: The farm must investigate potential causes, including management and health factors.

  • Insufficient rams: The recommended ratio of 1 ram for every 40-80 ewes is not being met, potentially affecting breeding outcomes.

  • Low true lambing percentage: While many lambs are born alive, their survival rate could be improved through better management practices.

Causes of Abortion:

Primary Differentials:

  1. Toxoplasma gondii: This parasite is responsible for approximately 25% of infectious abortions in sheep. Its transmission typically occurs through contact with cat feces that contaminate feed or pasture. The effects can vary with the gestational stage, leading to early-pregnancy loss, mid-pregnancy mummification, and late-pregnancy stillborn or weak lambs.

  2. Enzootic Abortion of Ewes (EAE): Caused by Chlamydia abortus, this disease yields similar outcomes to Toxoplasma gondii, primarily through sheep-to-sheep transmission, especially during lambing season.

  3. Campylobacter infection: This bacteria accounts for about 9% of infectious abortions, transmitted from sheep to sheep, indicating the critical need for good biosecurity measures on the farm to prevent spread.

Other Concerns:

  • Salmonella: This pathogen can lead to severe illness in ewes, resulting in abortions and adversely affecting overall flock health.

  • Borders Disease (BDV): Infection occurring in the early stages of pregnancy (less than 60 days) can lead to fetal death, and infections afterward (more than 85 days) might result in live lambs with complications.

  • Listeria: Can cause abortions at any stage of pregnancy without significant ill effects on the ewe, highlighting the importance of monitoring flock health.

  • Coxiella brunetti: This bacterium generally causes abortion late in pregnancy, emphasizing the need for vigilant health management throughout gestation.

Testing and Diagnosis:

Ideal Samples for Testing: To effectively diagnose the cause of abortions, tests should focus on aborted materials such as placenta and fetus. If these are unavailable, ewe serology may provide useful insights.

Toxoplasmosis Testing: The latex agglutination test is employed for maternal sera; however, its interpretation can be challenging due to the presence of long-lasting antibodies in sheep.

Border Virus: Testing 10% of the flock via serology is recommended to monitor for this virus, allowing for timely interventions.

Management Recommendations:

Improvement Strategies:

  • Ram Power: To enhance breeding outcomes, increasing the number of rams is critical. Aiming for a ram to ewe ratio of 1:50 is ideal. The expected cost for new rams is estimated between £450-£500 each.

  • Tightening Lambing Block: Synchronizing ewes to cycle together can improve management efficiency. Options for synchronization include the use of vasectomized rams or hormonal synchronization through sponges, though the latter option is noted to be more costly.

  • Monitor Breeding Performance: Using colorful raddle aids can help identify served ewes, allowing for better tracking of breeding activities.

Flushing of Ewes: This process involves a pre-breeding nutritional boost for 3 weeks to achieve the desired body condition score (BCS) of 3.0. This phase is crucial for optimal ovulation rates and contributing to improved sperm production in rams.

Vaccination Costs: The estimated cost for vaccinations is around £3 per dose, providing lasting immunity and positively influencing fertility outcomes for the flock.

Handling Abortions:

Standard Operating Procedures for Aborted Ewes:

  1. Isolate and mark the affected ewe to prevent further contamination and monitor her health.

  2. Implement strict biosecurity measures and sanitize all areas contaminated by aborted materials.

  3. Collect samples for veterinary testing to establish the cause of abortion.

  4. Safely dispose of any infected materials to minimize disease spread.

  5. Consult with a veterinarian for tailored advice and further action.

  6. If a vaccine is available, vaccinate the flock to bolster protection against identified pathogens.

Economic Impact of Abortion:

Abortion in the sheep industry leads to significant financial losses, with Toxoplasma abortion costing approximately £12 million and Enzootic abortion costing around £20 million annually. For Matt's flock of 200 ewes, a 6% abortion rate equates to an estimated 12 ewes aborted, representing a potential loss of 24 lambs, which directly impacts farm profitability and sustainability.