Farm Cattle Internal Parasite Welfare and Anthelmintic Use

Internal parasites cause chronic welfare harms in grazing cattle. Responsible anthelmintic use balances effective welfare protection with the growing problem of anthelmintic resistance.

Key Facts

Gastrointestinal nematodes cause reduced growth, weight loss, diarrhoea, and anaemia in grazing cattle
Liver fluke is a major cause of production loss and welfare harm in cattle in wet pastoral regions
Anthelmintic resistance is increasing in cattle nematodes, limiting future treatment options
Strategic targeted treatment based on faecal egg counts reduces unnecessary anthelmintic use
Pasture management including mixed grazing with sheep and rotation can reduce parasite burdens
Body condition scoring and production monitoring identify animals most requiring treatment
Some breeds including N'Dama cattle have natural resistance to certain parasite species
Refugia — maintaining some untreated animals — preserves susceptible parasites and slows resistance development

Welfare Considerations

Internal parasite welfare harms in cattle are significant and chronic. Heavy nematode burdens cause malnutrition from impaired nutrient absorption, anaemia, diarrhoea, and reduced immune function — a prolonged welfare harm that reduces body condition over months. Liver fluke causes acute fluke disease with sudden death, or chronic disease with progressive liver damage. Both conditions cause extended suffering in untreated animals. The welfare imperative to treat must be balanced against responsible anthelmintic stewardship — overuse drives resistance that will reduce future treatment efficacy, creating long-term welfare risks across the industry. Targeted selective treatment guided by faecal egg counts treats animals with welfare-significant burdens while preserving efficacy. Pasture management reduces environmental contamination and reduces treatment frequency.

What You Can Do

Advocate for anthelmintic prescribing guidelines that incorporate targeted selective treatment principles
Support faecal egg count monitoring programs that improve both welfare and anthelmintic stewardship
Choose beef and dairy from producers with documented parasite management programs
Learn about liver fluke and nematode welfare impacts to understand the scale of the problem
Support research into alternative parasite control methods including breeding for resistance
Reduce beef and dairy consumption from unverified systems with inadequate parasite management