printStock Journal Feature - August 2024
Author: Dr Sean McGrath, Millicent and Kingston Veterinary Clinics
Leading into spring and weaning time for lots of producers means a focus on animal health requirements for young stock. Young stock can be more prone to disease than adults due an immune system that is still developing, a higher demand for certain minerals or nutritional components and periods of stress. Stress is an important consideration in young stock as it can be experienced through different forms such the stress of weaning, nutritional stress (where the diet is inadequate) or the stress of forming new social hierarchies in their new post weaning mobs. These stresses all can have the same impact of lowering the effectiveness of the immune system and making them susceptible to diseases.
Still the most common cause of production loss, and at times death, in young stock is intestinal worms. Good worm control is a year round and whole of farm program, and preventing losses in young stock from worms is set up by good control in adults along with grazing management. However consideration for treatment of young stock especially at weaning is essential. As with all drenches, using an effective drench for your property is essential. For young sheep we want to have a really high kill rate by the drench to ensure there is no residual worm burden to affect their growth.
In terms of vaccinations, still the most important to consider in young stock are the clostridial vaccines, either 3in1, 5in1 or 6in1. The primary diseases that are being protected for here are pulpy kidney and tetanus. Pulpy kidney commonly affects young stock when they graze or are fed diets high in soluble energy and carbohydrates (such as grain or clover). This may be common place if people are weaning lambs early this year, but is also common practice for those prime lamb producers that generally wean onto fresh spring feed. Tetanus causes paralysis, and occurs secondary to wounds and contamination, such as mulesing or shearing. The other disease that can be protected with 6in1 and enter through shearing wounds is cheesy gland. This can have implications for carcase quality when they reach slaughter.
To ensure growth and immune function is maintained in young stock, trace minerals can be an essential consideration. This depends on where you farm is located and if you are in a deficient zone or soil type. The most important and common trace mineral deficiencies are Cobalt, Copper and Selenium. If you are unsure about the status on your farm then testing of the animals can be done, with late winter being a good time to do so. Once again supplementation at weaning is important as it ensures there is adequate levels in the animals to ensure their immune function is adequate and to also ensure their growth rates are maintained. A final consideration around vitamins for young stock is that of Vitamin E. Vitamin E is supplied by green feed and if sheep do not have access to any green feed for more than 3-4 months then Vitamin E deficiency can lead to lost growth rates. This can be especially important for merino weaners that are weaned in early summer and may not see green grass until the following Winter. Once again given they are growing, they are particularly susceptible to any deficiency.