Proficiency testing of animal nutrition laboratories

The Embrapa Cattle-Southeast research unit conducts a program to compare the results provided by laboratories that perform animal feed analyses. Fifty-two laboratories, representing all the Brazilian regions, have participated in the program. The assays included are those normally carried out by animal nutrition laboratories on animal feed and mineral supplements, a total of 22 different analyses. Four rounds of the program are performed annually. Each package provided to the laboratories for testing contains three kinds of animal feed (three each of forage and commercial feed), along with three mineral supplements. For the evaluation of assigned values and standard deviation, the median and robust standard deviation of the participants’ results are used. This paper reports the experience in coordinating the Brazilian interlaboratory comparison exercise.