Failure to Thrive Syndrome (FTS)

In the last few months I have had to investigate a number of alpaca herds with young alpaca (usually observed between 6 – 9 months age) that are suddenly starting to sit increasingly rather than standing indicating that they are ill. These animals are unshorn so it often comes as a surprise to the owner that the animals condition score is poor. Determination of condition score of alpaca is done by palpation rather than a purely visual examination. Condition scoring is on a scale of 0-5, and can be rapidly estimated from the amount of fat cover either side of the mid to anterior thoracic vertebrae (backbone over midchest). The condition score scale is from Score 0 (emaciated) to Score 5 (fat). Most alpaca are found in a condition score ranging from 1.5 to 4. These FTC animals have a very sharp backbone in this area with no fat and very little muscle overlying the vertebrae. Their appetite has been good up to the time that they start to increasingly sit; when it is reduced to poor .The dung quality character is apparently normal in most cases with individual pellets being passed.

Clinical examination has revealed a smaller for age, emaciated animal .The condition score is determined by feeling rather than just looking at the animal .The body temperature is normal, and the faecal pellets appear formed and “normal ”. Examination of the gums and the conjunctiva reveal they are very pale to white. Activity level will be normal to depressed. At this point, a blood and a faecal sample are collected to investigate further. Limited pathology testing was performed in hospital to determine the degree of anaemia by doing a PCV (anaemic if less than 15%), a total blood protein (TPP) (low if less than 50g/L) and a faecal floatation to check for internal parasitism. If more involved pathology investigation is required the blood sample is sent to a commercial veterinary laboratory for a full blood count and biochemical testing.

Pathology has been essential in unravelling the causes of FTC. The PCV has ranged from 5% to 11%! The plasma protein (TPP) range has been 20-48g/L. A simple faecal floatation test indicated a high level of parasitism with numerous strongyle parasite eggs present. Laboratory results confirmed severe anaemia and low blood protein and suggested accompanying iron deficiency anaemia.

All causes of FT have not been resolved. Identified causes include the following:

• Parasitism
• Abnormalities of the oral cavity
• Nutritional insufficiency
• Systemic illness
• Musculoskeletal abnormalities
• Thyroid dysfunction
• Iron deficiency anaemia
• Genetics
• Immunodeficiency

A high stocking density as is practiced in the Gloucester area due to the higher rainfall is an important consideration for parasite control. Poor quality pastures high in fibre content may have some impact on these nutritionally challenged FTC animals.

Treatment of these cases has been directed at worm control, improved nutrition with attention to oral haematinics and injectable iron, and in one case an unsuccessful blood transfusion was given (its PCV was only 5%!). More frequent monitoring of worm burden by regular faecal floatation examination and using ivomectin oral/ injection as the anthelmintic. An oral multivitamin-iron supplement (BLUD) has been given over a 120-day period, as this is the time taken for red blood cell development in the bone marrow. Additional iron has been also given by iron dextran injection as iron is poorly absorbed orally. A real improvement in nutrition is attempted with higher quality protein and improved carbohydrate feed with more alpaca nuts and Lucerne hay.

Since parasitism has been the cause in the cases investigated, more aggressive faecal monitoring has been undertaken. The reason for the timing of sample collection is that most strongyle parasites have a very short prepatent (life cycle) period of only 10-14 days depending on environmental conditions. Faecal testing has been done: -

(a) Prior to treatment – to indicate level of existing parasitism

(b) 7-10 days after treatment – to detect any anthelmintic failure/resistance

(c) 28 days after treatment – to indicate re-infection rate/pasture contamination level

Advise more conscientious faecal collection and disposal. High stocking rates seem to override the alpacas dung piling habits and faecal pellets are found scattered all over the pasture. Loss of the dung piling toileting habit increases pasture parasite larval contamination and ingestion by alpaca. Advise to use a more effective anthelmintic either ivermectin or cydectin Response to treatment is slow as body condition recovery is very gradual. Rapid reduction of parasite burden and attention to improved nutrition sees a more rapid demeanour improvement with less sitting and greater activity being observed.