- Rib fractures can be caused by increased bone fragility from nutritional deficiencies.
- Some broken ribs are caused by birth difficulties, excessive force during handling and/or incorrect equipment.
- On farm production losses due to rib fractures include slow maturation, ill thrift, infertility and weight loss.
- Fractured ribs generally heal by themselves, causing thickening or deformation at the site of the break.
- The fractured sections of rib cage are trimmed at processing, reducing carcase/dressed weights. Trimming of healed fractures, if with large calluses, can occur.
- Deficiencies e.g. in vitamin D, calcium or phosphorus, causing weak bones to break.
- Commonly in fast growing lambs on lush pastures.
- Deficiencies can be primary (dietary deficiencies) e.g. cereal and grass hays are deficient in calcium, or secondary, e.g. lush green feed contains anti-vitamin D substances or high grain diets. It should be noted that a recent South Australian study found no association between copper deficiency and the incidence of rib fractures in lambs.
- Ribs can also be broken by rough handling, e.g. lambs at birth or marking.
- Many animals show no obvious signs however some may have difficulty breathing, ill thrift, anorexia, infertility and lameness.
- The appearance of broken or deformed ribs at slaughter.
- A veterinarian can diagnose rib fractures based on examination and blood analysis (for mineral imbalances).
- Provide trace mineral mix or other oral or injectable supplement for the specific deficiency.
- Adding hay to the diet if animals are grazing rapidly growing lush winter pasture or cereal crops.
- Providing a source of calcium (e.g. stock lime, dolomite) when heavily supplementing ewes with grain in late pregnancy can ensure bones remain strong.
- Care must be taken to prevent supplement toxicity by overdosing.
- Feed livestock a complete and balanced ration.
- Undertake soil and pasture tests at laboratories to determine the need for adjustments in management or for supplements.
- Careful stock handling, e.g. ensure pneumatic settings are appropriate for stock and draft lambs into correct group size if needing to adjust the setting.