Nutrition
Calcium and Phosphorous.
These two minerals form a very important part of a bird’s diet. Calcium is used for the formation of bones and eggs. It is also needed for adequate nervous and muscle function. Phosphorous is also important in bone and egg formation. The uptake of both of these minerals (from the bird’s intestine) is dependent on vitamin D3.
In birds that are on a calcium deficient diet then the natural hormone systems have to work harder over time. These hormone systems regulate the level of calcium in the bloodstream. Excessive levels of phosphorous or a lack of vitamin D3 can make this worse by reducing the availability of calcium from the intestine, but also the amount that can be used from the blood.
The result of this dietary imbalance leads to a number of clinical conditions. Birds may become weak, drink excessively, vomit or refuse to eat.
Breeding females may have further complications when egg laying. These birds may lay fewer eggs or eggs which are ‘soft shelled’. Some females may be unable to pass these eggs as their oviduct (the reproductive tract) may be unable to push on the shell due to poor muscle contraction (as well as the soft-shell). Fragile bones are another long-term complication. Most hens have sufficient calcium reserves (in bone) but are unable to mobilise this fast enough when it is needed for eggshells. They cannot rely on food sources at this time as in most cases they are brooding the eggs in the nest! ). If left untreated these birds will die. An egg bound bird is an emergency.
African grey parrots are particularly prone to calcium deficiency. In this species the main presenting sign is fitting. This is because the low blood calcium leads to nerve endings becoming more excitable and so the bird’s muscles contract leading to the fit. Most birds are two to five years of age when these fits start.
Young birds can suffer growth deformities as a result of imbalances of this nature. Bird’s can have deformities in their long bone structures, which can be incompatible with an adequate life. Surgical correction is possible in some cases.
So what can we do? Firstly we need to confirm a diagnosis, so treatment can be given properly. This is quite simple by taking a blood screen, this can be performed conscious or under anaesthesia, depending on the nature of the patient! Once the sample is obtained then tests can be run on our ‘in house’ blood analyser or sent to a laboratory. This will demonstrate the low blood calcium and in most cases a high blood phosphorous.
In egg bound birds we need to solve the secondary problem of the stuck egg first. In these the egg needs to be removed manually, with or without anaesthesia. Fluids, calcium and oxytocin (a hormone to contract the womb down) are needed. Once recovered, then we can deal with the calcium deficiency long term.
The underlying cause is diet. The ideal ratio of calcium:phosphorous in a birds diet is about 2:1. Millet seeds and sunflower seeds have a ratio about 1:7.
SO THE WORST DIETS ARE ONES THAT ARE SEED BASED.
Seed is high in phosphorous and low in calcium. What calcium is available is often poorly absorbed into the bird, due to the nature of the calcium and in some cases a combined vitamin D3 deficiency as well. Some seeds are also high in fat, which may also reduce calcium uptake.
Is there any hope? Well there are many ways that the calcium levels in a bird's diet can be addressed: -
| Adding water-soluble calcium to the bird’s drinking water. This must be easily absorbed from the intestine and ideally also contain vitamin D3. Many supplements may be inadequate. We recommend 'Calcivet’ from the Birdcare Company. We normally have some in stock. This can also be given in softfoods. |
| High calcium containing foods such as cheese can be given in small quantities. |
| Complete diets are available specifically for African Grey Parrots to prevent this problem. |
| Supplement all livefood given to young birds (especially softbilled species). |
| Vary the diet for all carnivorous species. Mice, Rats or Quail have a better calcium:phosphorous ratio than dead day old chicks. |
All birds that are deficient need to be supplemented, but it should be noted that excessive levels of calcium are harmful as well. Acute cases can be given injections of calcium directly.
Wed Feb 10, 2010 5:04 pm
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