Gastrointestinal parasites cause significant welfare harm in grazing cattle, particularly in young stock during their first grazing season. Strategic targeted treatment programs balance welfare with antimicrobial resistance management by treating only animals showing clinical need rather than entire groups.
Calves and yearlings heavily parasitised during their first grazing season experience diarrhoea, protein loss, reduced growth rates, and in severe cases death from protein-losing enteropathy. The condition is often sub-clinical — causing welfare harm and production loss without obvious clinical signs. Strategic targeted treatment based on faecal egg counts reduces unnecessary treatment while maintaining effective parasite control when animals show genuine welfare need. The development of anthelmintic resistance through overuse threatens future treatment efficacy — resistance means that when animals genuinely need treatment, drugs may no longer be effective, creating future welfare emergencies.