Inappetence is a reduction in appetite and feed intake (see
Shy Feeders and
Inappetence/Inanition). This sub-section is confined to options for medical management of inappetence.
The objectives when trying to improve appetite are to:
- Reduce stress.
- Treat underlying health problems including pain.
- Consider feed and environmental changes where appropriate to provide the best chance of optimal rumen fermentation resuming.
The latter may be best achieved by:
- Providing substantial amounts of good quality cereal hay and coarse chopped chaff, even to the extent of removing pellets completely.
- Relocating affected animals to well ventilated pens with more space and less competition, noise and disturbance.
It may be helpful to have hay and chaff stored in locations able to be easily accessed by the crew and to try and match the energy and protein concentrations of hay and chaff to those of the pellet ration - this may mean avoiding hay and chaff made from lucerne and high quality ryegrass/clover and instead using those made from good quality cereal hay such as wheaten, oaten or barley hay.
Any decision to use injectable glucocorticoids, vitamins or vitamin/mineral combinations should be considered very carefully. They may do more harm than good. The therapeutic benefits to appetite of these preparations are uncertain, the injections may be painful, and the handling or restraint to administer them may cause extra stress. However, they may be considered as a last resort when other efforts to stimulate eating have not worked.
Treatment with antibiotics should only occur if an underlying infectious disease problem such as pneumonia is suspected. This is because appetite may be further suppressed if the injections are painful, the antibiotics disrupt the rumen microflora, or the handling and disturbance caused in order to administer the injections imposes extra stress.
There are a range of injectable preparations that have been used to treat inappetence and weight loss in exported animals.
They include:
- vitamin B1 (thiamine).
- glucocorticoids such as dexamethasone.
- combined vitamin B12 and phosphorus.
- combined vitamins A, D and E.
There is little scientific evidence to support the use of any of these products in ruminants as appetite stimulants.
B group vitamins. The B group vitamins including B1 and B12 are normally produced by microflora in the rumen. When rumen microflora have been inactivated by the animal not eating, these vitamins may become deficient. However, administration of these or other B group vitamins will not correct the primary problem. If circumstances permit, transfer of rumen fluid from an animal that is healthy and eating may be more beneficial in this situation (see below).
Glucocorticoids. The appetite-stimulating effects of glucocorticoids such as dexamethasone are uncertain in ruminants. This purported benefit has been extrapolated from the treatment of monogastrics, especially humans, where increased appetite is an unpredictable side effect to its primary use as an anti-inflammatory and immunosuppressant.
Phosphorus. The body's bone storage supply of phosphorus is long lasting ensuring availability during periods of inappetence. The cereal grains incorporated into pellets contain an abundance of phosphorus.
Vitamin A, D & E. Supplementation with vitamin A is unlikely to be beneficial. The stores of vitamin A in the liver may last for many months even when vitamin A is absent from the diet, which is unlikely in shipboard rations. Vitamin D is provided by most diets including dried forages and by body synthesis from solar radiation. Body stores can supply requirements for 6 to 15 weeks. Vitamin E supplementation may be beneficial in animals fed pellets as levels of vitamin E may be reduced in the pelleting process and if animals had previously been on dry pasture for extended periods they may have had reduced intakes of vitamin E over a period of time prior to export.
Ruminal fluid transfer. In situations of prolonged inappetence, the rumen microflora may be seriously depleted and rumen fluid transfer should be considered. Feeding hay or chaff and relocating to a less stressful pen environment should of course be tried first. The microflora in the rumen juice donated from a healthy animal may allow fermentation to resume in the microbe depleted rumen of a recipient animal. Rumen fluid transfer has been demonstrated to be an effective treatment for inappetent ruminants.
Rumen fluid collected from a healthy animal is transferred by drenching or via stomach tube to the inappetent animal. Sheep and goats should receive ~1 L and cattle at least 4 L and if possible up to 16L.
Rumen fluid may be collected from a healthy animal by siphoning via large bore stomach tube from the rumen, from abattoir sourced rumens, or from an animal that is recently dead from misadventure (unlikely to have any adverse impact on rumen health).
Best results are obtained if the donor has a similar diet as the recipient ensuring the microflora are adapted, the juice is stored anaerobically (fill container to the lid or add a thin layer of mineral oil to the top of a bucket), and transferred as soon as possible after collection (less than 2 hours). The treatment may need to be repeated daily for 3 to 4 days.