From challenge to advantage: Managing parasites when it matters most

As the dairy calendar turns towards the drying-off period, farmers face a critical window to safeguard herd health and prepare for a productive next season.

Drying off isn’t just a pause in milking – it’s an opportunity to reset, protect cows from disease, and ensure optimal conditions for calving.

The dairy sector is always evolving, with innovations in herd management, animal health, and sustainability taking centre stage. Farmers are increasingly adopting new technologies, yet some challenges remain stubbornly old-fashioned. Internal parasites, for example, continue to threaten cow and calf health, milk yields, and farm profitability. The dry-off period is a prime time to address these issues, especially as cows may have compromised immunity from infections and poor condition in the lead up to this period. The health and wellbeing of your cows during this time lays the foundation for a successful calving season and, ultimately, a productive milking year.

Internal parasites can sap a cow’s energy, reduce feed efficiency, and impact immune function. Parasite larvae are at their peak on pasture in late autumn and early winter – just as feed covers are decreasing. External parasites (lice) are often seen in stressed herds or immunocompromised animals and irritate cows who then scratch on and can damage infrastructure. Lice begin to breed once it gets cold, building up over winter where they are protected in thicker winter coats, ending with peak numbers and itching, in spring. Being aware of options and treating animals who are most in need can make economic sense in addition to improving cow health.

One tool available to dairy farmers for parasite management around dry-off is Cydectin^® Pour-On. This anthelmintic is designed to control a broad spectrum of important internal and external parasites, including roundworms, lungworms, and lice. By reducing parasite loads, cows can better absorb nutrients from pasture and gain weight or produce milk more efficiently.

Cydectin Pour-On is one of the few drench treatments with proven persistent activity against parasites, meaning it can control newly ingested larvae for several weeks after treatment. It controls Ostertagia for 35 days, Trichostrongylus for 28 days and lungworm for 42 days, allowing cows to utilise the protein and energy they gain from feed for production, rather than wasting it fighting a parasite challenge. When larval challenge is high in autumn this is a useful benefit. It also has zero meat, milk and bobby calf withholding times, so it can be used to support the health of any cow, whether she is still lactating or not. New Zealand field studies¹ have demonstrated an average increase of over 4kg milk solids, when cows were treated with Cydectin Pour-On compared to their untreated herdmates, in trials started in late lactation, dry-off or calving. Parasites are an invisible cost to both cows and profits.

Modern dairy farming is constantly evolving, with farmers facing new pressures. One of the challenges is the rise in resistance to anthelmintics and as a result, a different approach to parasite management is needed. Tips to reduce resistance developing include only treating cows that need it; providing adequate refugia (the prior point will help with this); minimising exposure of susceptible stock to larvae (such as young stock, sick or stressed cows) and monitoring worm burdens in calves.

At the end of the day, every farm is unique with its own challenges. Focusing on practical, science-backed approaches to parasite management and using quality proven treatments like Cydectin Pour-On, can ensure your cows and farm continue to thrive.

Investing in cow health at dry off isn’t just about this season – it’s about supporting your herd and its future. Speak with your local TSR about options on how to best control and manage parasites today.

1. Murphy, A. The effect of treatment with moxidectin, a long acting endectocide, on milk production in lactating dairy cows Buiatrics World Congress, 1998.

Zoetis New Zealand Limited. Tel: 0800 963 847; www.zoetis.co.nz. Cydectin is a registered trade mark of Zoetis. ACVM No. A6203.

Article supplied by Zoetis