Animals

Nena Nepia, Wellsford Vet Clinic https://wellsfordvet.com/

Common diseases in sheep

Sheep make an excellent choice of animal for the lifestyler with their tidy grazing habits, small feet that cause little pugging, and charming lambs come spring. But, being a prey animal, it can be tricky spotting a sick sheep. It can seem like the flock is perfectly healthy and then, the next day you wake to a dead sheep. There are a couple of diseases we commonly see during the late summer/autumn period which are worth highlighting: Facial eczema: This is a fungus that grows at the base of grass and causes liver toxicity to ruminants when ingested in sufficient quantities. Being a fungus, it thrives in warmth and humidity, and the number of spores can climb exponentially over a couple of days of ideal conditions. The fungal spores are taken in as sheep graze, causing liver damage and a reaction somewhat akin to sunburn. A sheep suffering from facial eczema will often have a crusty, weepy nose and eyes, and swollen, hanging ears with crusty margins. They will separate from the flock, hang their head and seek shade. Prevention is the best treatment – zinc boluses can be administered to sheep, which act to ‘mop up’ the damaging action of the spores and protect the liver. The boluses take some skill (and a decent set of yards) to administer, but will give several weeks of protection. Secondly, reduce the number of spores taken in by avoiding overgrazing the paddock too long so sheep are forced to nibble the grass right down. Also, know that kikuyu grass is less hospitable to fungal spores so try timing grazing of these paddocks for when conditions favour spore growth.

Barbers pole: Also known as Haemonchus, this is a worm infection of sheep that results in excessive blood loss (anaemia). The egg and larvae stage of the worm lifecycle take place on the pasture rather than in the sheep and, like fungus, favour warm and humid conditions. Forcing sheep to graze paddocks right down will increase the uptake of worm larvae so the worm burden that a sheep carries can become quite high over the autumn period. The adult worm attaches itself to the stomach wall and consumes blood, causing damage in the process. In sheep, of which younger, smaller sheep are more susceptible, the predominant symptom is slowness and weakness, caused by the anaemia. A telltale sign is very pale or white conjunctiva (the inside of the eyelids), as opposed to a healthy pink colour. Occasionally you can see scouring (loose faeces), but don’t rely on this as a symptom alone. The treatment for Barbers pole is timely drenching (most drench products will kill Haemonchus), and grazing practices that aim to reduce the number of worm eggs on the pasture over time.