Tuesday, May 7, 2013

 Caution: Research Findings may not be Valid!

In the most recent issue of the Journal of Dairy Science you can find an article, "Effect of feeding maternal colostrum or plasma-derived or colostrum-derived colostrum replacer on passive transfer of immunity, health, and performance of preweaned heifer calves." JDS 96:3247-3256
 
Hey, just what we need. A comparison of three sources of immunity for our newborn calves. 
 
Tucked into the description of treatments is this short sentence:
"...a decision was made to standarize the volume of solution fed to all calves to eliminate volume fed as a confounder (Jones et al., 2004) and because mass of IgG fed is more important than concentration (Stott and Fellah, 1983)." 
 
Thus, rather than following the manufacturers' mixing directions to use either 1.3 or 1.5 quarts of water the colostrum replacer products were prepared to result in 4 quarts of solution. This way all calves would be fed 4 quarts of either maternal colostrum or 4 quarts of colostrum replacer.
 
I went back and read both of the articles cited in that sentence. Jones and others in their study fed the colostrum replacer mixed with volumes recommended by the manufacturer - so, I cannot see how that citation supports mixing up the colostrum replacer to equal 4 quarts when the manufacturers recommend using between 1.3 and 1.5 quarts of water.
 
Stott and Fellah's article reports a strong positive linear relationship between concentration of antibodies and the rate of absorption - so, I cannot see how the citation supports mixing up the colostrum replacer to equal 4 quarts when the manufacturers recommend using between 1.3 and 1.5 quarts of water. This procedure creates a solution that has a low concentration of antibodies.
 
In my humble opinion this study was badly biased in favor of maternal colostrum by setting up the two colostrum replacers for impaired antibody absorption.
 
Moral of the story: the devil is in the details - if you can, ask about how the research was done before you accept the findings as valid.  

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