Monday, July 30, 2012

To Do the IgG Test or Not?

I no longer do a routine IgG test after the birth of an alpaca cria. Here is some information about the test and why I don't do it anymore:

The IgG Test measures the Immunoglobulin G transferred from the mother to the cria thru the colostrum. It is the most abundant of the different types of antibody and is found in all body fluids and protects against bacterial and viral infections. The antibody produced by the mother and passed to the cria against a specific antigen, provides the cria with some protection should that antigen enter their body within the first three weeks (after which the transferred IgG is not longer present). From birth the cria also begins to develop their own IgG response. The cria's immune system "remembers" its response to an antigen and has a better chance of fighting it.

Why don't I do the test anymore? I used to do it and all my crias tested had outstanding, high IgG levels. Then I had one that had a reading that was on the low side of acceptable. I was given the option of doing a plasma transfer or watching the cria. Since the plasma would take a few days to get I decided to watch. The cria was vigorous and never had an issue. Then a year later I had one that had an incredibly high IgG and she crashed on day two. She was is really bad shape, near death. The vet gave her a plasma transfusion and it did nothing to help her, she continued to decline. A very experienced alpaca breeder told me the best I could do for her would be to get an IV inserted and also treat with antibiotics. She had a shunt put into her neck and I gave her IV fluids around the clock for 3 days. She responded almost immediately to this treatment.

So as a livestock breeder one has to decide which tests and treatments are really necessary and will be a worthwhile expense against the sale of that animal. Paying for a vet visit, blood withdrawal and test is expensive and to my small operation, not a worthwhile expense. If a cria is going to crash, I am going to see it and treat that cria with excellent care to get it through the challenge. Knowing the IgG only lets you know that "maybe" if the cria encounters a challenge, "maybe" the cria will be able to fight it on its own. Or in the case where the cria has a lower IgG that that cria "maybe" will have a problem. So that is not really useful information to me. Knowing what IgG was transferred from my dam to her cria would have done me/her no good. She did not have any infection at birth but was slow to get up and nurse. Once she did (24hours) she was fine on her own indicating that she was not experiencing an antigen challenge. By the time she had her next episode (around 2 months) she was of an age where she would no longer have protection from mother's transfer and should have developed her own IgG.

I have also learned from what the other, more established, livestock breeders are doing (goat, beef, sheep, etc) as they have learned over the years what is necessary and what is an expense that doesn't pay off. 

Male Alpaca Sniffing the Manure Pile

This is called the Flehmen Response. This strange pose occurs when a male alpaca smells the urine of another alpaca and often occurs at the alpaca poop piles.  The alpaca doing the smelling will throw his head back and curl his upper lip back at the same time which helps to seal his nostrils and draw the scent over a receptor on the roof of the alpacas mouth called the Jacobsen’s Organ.  As the scent is drawn over the Jacobsen’s Organ the alpaca can detect if the urine he is scenting is from a female alpaca who is receptive to breeding.