Bec Cameron, Dairy Industry Development Officer, Ellinbank
Dairy farmers are encouraged to take proactive steps to protect herd health as humid, wet conditions increase disease, affect growth rates of young cattle and decrease productivity.
Infectious diseases
The risk of infectious diseases increases in wetter conditions. The risk of mastitis rises when cows lie in muddy environments, allowing bacteria to enter the udder. Leptospirosis, a zoonotic disease, can spread through contaminated water, posing risks to both cattle and humans. Clostridial diseases such as blackleg and pulpy kidney may also emerge after flooding or soil disturbance.
Pinkeye in cattle is a common summer and autumn issue in Victoria, mainly caused by bacteria and spread by flies, dust and grass seeds. It leads to tearing, squinting, swollen eyelids and cloudy corneas that can progress to ulcers and blindness, reducing weight gain and milk production. Treatment includes antibiotic eye ointments or injections and veterinarians can help identify the bacterial strain affecting the animal.
Controlling flies, slashing pastures to reduce seed heads, providing shade, vaccinating before fly season and maintaining good nutrition (vitamin A, copper and selenium) can help reduce the risk. Early detection and isolating affected animals help limit spread and protect herd productivity.
Facial eczema and liver disease
Facial eczema is prevalent in humid weather conditions, alongside the liver disease caused by cattle ingesting spores. The spores thrive in dead pasture during warm, humid conditions. The toxin damages the liver and can lead to photosensitisation, reduced milk yield and weight loss. Subclinical cases may go unnoticed but still affect productivity.
Prevention is essential and includes monitoring spore counts through your vet, supplementing with zinc in consultation with your nutritionist or feed company and managing grazing to reduce exposure.
Hoof health
Lameness caused by softened hooves from prolonged exposure to moisture can increase. Wet laneways and paddocks increase the risk of bruising, footrot and white-line injury. These conditions reduce mobility, feed intake and milk production, which can lead to early culling.
Preventative measures include maintaining dry walking surfaces, regular hoof checks and prompt treatment of injuries.
Parasites
Parasite burdens can increase during humid conditions, as worm larvae survive longer on pasture. Calves are especially vulnerable to gastrointestinal parasites like coccidia and cryptosporidium, which cause scours and dehydration. Flystrike may also affect cattle with open wounds or irritated skin.
Regular faecal egg counts, strategic drenching and fly control are key management tools.
Water quality
Water quality may also decline due to contamination from floods, increasing the risk of algal blooms, meaning regular water testing and access to clean water are vital.
Proactive management of troughs and water sources helps protect herd health and maintain productivity during challenging weather.
Nutrition
Wet conditions can reduce pasture quality through waterlogging and lower dry matter, affecting cattle nutrition, especially the energy and protein needed for milk production. Supplementing with silage or concentrates helps maintain dietary balance. Moisture also increases disease spread between farms, so limiting movement of animals and equipment is important.
Regular monitoring and record-keeping, including tracking hoof health, parasite treatments and water quality supports early intervention and protects herd productivity.
