Official website of the Victorian Eastern Region of the Australian Alpaca Association Ltd.

The Australian Alpaca Association Ltd.

Victorian Eastern Region of the Australian Alpaca Association Ltd.

Resources >> Health >> Rickets

Rickets: A Snapshot

By Elizabeth Paul Erehwon Alpacas 

Rickets is a painful, arthritic condition caused by deficiencies in the bone minerals of calcium and phosphate; a vitamin D deficiency; or occasionally by glandular dysfunction. All mammals, including humans,  can be affected by rickets, but alpacas are particularly vulnerable. Every alpaca owner needs to be aware that this condition is both intrinsic to alpacas; and may be virtually undetectable, in the early stages.

In crias under say, 12 months of age, the most obvious (but not the only) sign of rickets is crooked legs, or Angular Limb Deformity. They usually respond well to vitamin D treatment. However, rickets in older animals, is more difficult to detect, and therefore harder to correct. The symptoms are vague and may vary from animal to animal. Even when, or if, it is recognised, it may already be too late to save the alpaca.  

Signs and Symptoms: 

An alpaca with early rickets shows few signs of being ‘sick”. It continues to eat, even rapidly, although occasionally, one may lose its appetite. Generally, the alpaca stays mentally bright and alert, and its reactions are normal. Its temperature is neither elevated nor depressed. It does not present with scours, vomiting, staggers, spasms, excessive rolling or goes blind. So what does it show?


Pic 1 - Crooked legs on cria
Pic 1 - Crooked legs on cria

Lameness:

Lameness, or difficulty in walking or running, is the most obvious sign of rickets. There are, of course, many reasons for lameness. However, young crias, as mentioned, will usually display bent or crooked front legs. See Pic 1. They may be actually lame, or merely slower, more lethargic, or get left behind. Also, as the bones lose minerals and weaken, the back feet start coming under the belly, which produces the typical, humped back of rickets.  Alternatively, the back legs may become “locked” together at the hocks, so that the cria walks forward with the front legs and then picks up both back feet together. This is called the “bunny hop”. Sometimes the back legs can be so locked in that the cria can only turn in a circle. 

As the condition advances, it becomes more painful, and the cria weakens.  It may for preference sit down more often, or for longer periods of time, and start eating around itself. This might be seen as the animal being ” lazy”.  The situation becomes critical when the cria can no longer walk to its mother, or find water. An animal that has been down for too long, will die of thirst, hunger or pneumonia. 

Another name for rickets is “brittle bones’, and sometimes a cria may suffer a broken leg, for no obvious reason.  A cria born with a broken leg where no intervention was used, could well be suffering from rickets. 



Pic 2 - Straight legs on nursing female
Pic 2 - Straight legs on nursing female

Adult alpacas with rickets, usually do not show bent legs. They may sit down more often, or they may hand back, or just look a bit ‘off’. They may be lame, where the lameness shifts around from one leg to another. See Pic 2. This female has rickets, although her legs are straight. She is pregnant as well as nursing a 3 month old cria. 



Pic 3 - Same female with slight hump in the back
Pic 3 - Same female with slight hump in the back

See Pic 3. The female’s back is slightly arched, but not severely.  She was also slightly anaemic. With good grazing, she may have been able to carry on. However under drought conditions, intervention was required as all three were at risk. Females with untreated rickets, in late pregnancy, are likely to abort the foetus and then die themselves.

Stunted Growth: 

Occasionally, a cria will survive with rickets, but its growth is stunted. The body simply “makes do” with what it has available, and the animal gets along unless or until there is some other major stress.  “Miniature” alpacas, are most likely to be stunted alpacas. 

Worms. 

A cria, or even an adult, which eats normally, or even rapidly, and yet never seem to grow or put condition on, is often thought to have a worm problem. It may do, but just treating for worms, will not necessarily fix the problem. Most intestinal worms are opportunistic pathogens, meaning they are always present, and can take advantage of the time when the animal’s immune system is under attack, to increase in numbers. Crias that die “ of worms” almost certainly had something else wrong, to start with.

Loss of Condition: 

One of the most worrying signs in a female is the rapid loss of condition, especially if they are heavily nursing. Most alpacas are huacayas, so most alpacas look round and fluffy, even if underneath, they are walking skeletons. Alpacas with rickets tend to keep on eating, and this fact alone, means that a number of rickets cases are missed.



Pic 4 - Skeletal condition of nursing female
Pic 4 - Skeletal condition of nursing female

See Pic 4. This black female is 12 years old, and was nursing a five month old cria. She was noticed to be frantically and continuously eating, on good grazing, yet her condition was skeletal. She was stiff in her movements without being overly lame. She never sat down or chewed her cud during the day, until after starting rickets treatment.  In this case the first action was to remove the cria.

Regular hands-on condition checks, of all members of the herd should be routine and frequent. This is especially important, for both the weanlings and the breeding female herd.  

Serum Phosphate Levels:

The vitamin D3 level in a blood sample can be tested, but it is cheaper and easier to test for serum phosphate levels, since the two are considered to mirror each other. This is in fact not always correct, but nevertheless, a low serum phosphate sample is a good enough indication that the animal has rickets. Blood samples taken for serum phosphate levels need to be tested within the hour, or spun down for a serum sample, otherwise cell breakdown products can interfere with the result. 

Anaemia:

Alpacas with rickets, are often anaemic. An alpaca with pale membranes is unwell. An alpaca with chalkwhite membranes, is on the critical list. Checking anaemia levels, should be as routine and as regular, as checking body condition. Anaemia associated with rickets, is caused by a phosphate deficiency, not an iron deficiency.

Weather:

Normal vitamin D production is initiated in the skin by UV light from the sun, so anything which inhibits this event is likely to cause a problem. Environmental events such as bad weather, dust storms, or bushfire smoke haze can affect vitamin D production some time after the event. Dark pigmented animals are likely to be more affected than lighter ones, as pigment protects the animal from too much UV exposure. Heavily fleeced animals are also at risk. Late shearing times can affect the extent of the alpacas’ natural response to making their own vitamin D supplies.

Treatment

There are two phases to any treatment program: prevention and specific treatment of individual cases. Rickets is a preventable condition. Successful prevention requires a tailor made program and constant monitoring of changing conditions within a particular herd. Specific treatment consists of giving enough vitamin D3 and phosphate to replenish supplies, but it is not a “one size fits all” situation. Crias usually present fewer problems of treatment, unless their rickets situation has gone unnoticed for a long time. They respond well to vitamin D3 supplementation. However,  by the time rickets is well established, there could be other issues such as a heavy worm burden, coccidia or other problems. If these issues are seen as the cause, and treatment is only directed at them, the outcome is less likely to be successful.

Breeding age females with rickets invariably need the replacement of phosphate as well,  since they are often using minerals for two, whether late pregnant or nursing. This group is more difficult to treat, and more likely to die, usually because the underlying cause of their problems goes unrecognised.

Rickets is, in my opinion, not only the major cause of non-infectious disease in alpacas but is likely to be the major cause of death, in breeding age females.

References:

Paul, Elizabeth:

Health Committee Report  Sept 2005.

Rickets in Alpacas: One Breeder’s Perspective 

Part 1, Town and Country Farmer, Summer 2008 Vol 25 No 4,  

Part 2,  Town and Country Farmer Autumn 2009 Vol 26 No 1.

Vitamin D and Rickets Seminar 2005-10