Relationship between analysed and theoretical content of diethylether extractable fat in standardised commercial feed mixtures for farm animals

Three feed mixtures for ruminants, four for pigs and seven for poultry have been tested for discrepancies between analysed and stated content of diethyl ether extractable fat (i.e. crude fat; EE). In spite of great investments in staff and technology during the last 30 years, the mean fault frequency in the mixtures increased apparently throughout the surveyed period. For `Sw3ʹ, the most important and greatest (by volume) of the feed mixtures for pigs, the increase was statistically significant (p = 0.04). Nine of the mixtures had mean fault frequencies less than 3%. The most faulty mixtures were CowC (31.5%) for ruminants; Hen2 (10.4%) and Broiler (8.8%) for poultry and the mixture SwP (8.9%) for pigs. The mean value was 5.8%. There was a positive linear relationship (p = 0.014) between fault frequency and maximum allowable level of fat supply in the mixtures. 97% (p < 0.001) of the faulty samples were deficient in fat. Only 3% had fat in excess. The low frequency of double faults (CP + EE) could mean that the faults in crude protein (CP) and the faults in fat varied independently. No significant correlation was found between faults in EE and faults in CP or between faults in CP and faults in CP + EE. When ignoring the high fault frequency in the CowC mixture from factory F1, no regional differences in fault frequencies could be observed.