Weaner deer losses
Late autumn and winter are periods in which we typically see cases of sudden death in young deer.
Potential causes include:
Parasitism is THE most important cause of ill-thrift and losses (particularly from lungworm) in weaners at this time. Drench choice is limited and development of resistance is a concern. Lungworm infection is usually noticed when moving stock, as they lag behind and may cough or pant. Gut parasites also need to be considered if animals are scouring. See next month's Vetnotes for more...
Yersiniosis is carried by birds and animals and can survive well in soil, water and pasture during the winter months, and so is a very common cause of weaner deaths in Manawatu. Management during and after weaning is vital. Stressors such as transport, bad weather, poor nutrition, trace element deficiencies or parasites can cause clinical disease. Deer weaned pre-rut may be more susceptible, so vaccination may be more important when animals are weaned early. Affected deer usually scour, lose weight, quickly dehydrate and die. In the case of an outbreak, often 20% of a mob may be affected. Vaccination, at over 12 weeks of age with a booster three to six weeks later, is the best prevention.
Johnes disease sporadically affects all ages of deer, however outbreaks involving much younger animals, eight to 20 months old, have been on the rise over recent years. Scouring and weight loss, progressing to death occurs fairly rapidly. Up to 10% of a mob may be affected and, as there is no treatment available and the disease is fatal, affected animals should be culled a soon as possible to minimise shedding of the bacteria.
Malignant Catarrhal Fever (MCF) causes a bloody scour and outbreaks can be precipitated by severe forms of stress, such as excessive yarding or mustering. MCF is caused by a virus and is always fatal. There is no treatment or vaccine available.
Leptospirosis causes deaths in weaners leading into the winter, generally following a short illness. On postmortem the carcass is usually jaundiced, the kidneys abnormal and redwater (red urine) features. This can be vaccinated against and treatment is generally very effective.
Clostridial diseases can be a problem. The most important in deer of all ages being blackleg and malignant oedema. Animals are rarely seen alive and the carcass rots very quickly. Again, this can be vaccinated against and should be part of your routine animal health treatment.
Necrobacillosis (necrotic footrot) is caused by a bacterium that is a normal inhabitant of the gut. Wounds to the lower limbs are a point of entry leading to infections in the feet, joints and tendons and potentially severe lameness. Infections can spread to the bloodstream, liver and lungs at which stage treatment is generally futile and death is inevitable.
There is often value in submitting dead stock for a post-mortem examination so call your vet for advice if you are faced with this challenging situation.