Ring test for the determination of digestibilities of raw nutrients of hay, dairy concentrates and palm kernel expeller using wethers

Reliability of digestibilities was determined using wethers that were tested in a ring test across 13 experimental stations in Germany, Austria and Switzerland. Samples of indentical batches of hay, compounded dairy concentrates and palm kernel expeller were studied roughly at the same time following official protocols. Analyses of feeds and faeces were carried out in the respective laboratories. Good agreement was found for crude ash crude protein and crude fat, whereas determination of fibrous fractions was problematic, especially for the palm kernel expeller compound. Digestibility of organic matter was 61.4 ± 1.5 % in hay and 83.2 ± 1.2 % in dairy concentrates, which only showed little deviations between the institutes. Within the institutes, the range of digestibilities of OM was 1.8 ± 0.9 %-units for hay and 1.6 %-units for dairy concentrates. Determination of digestability problematic for palm kernel expeller due to substantial individual variations between wethers. Influences on fibre digestibility caused by the effects of palm kernel expellerson ruminal fermentation are discussed. More research is recommended as a basis for future standardizations.

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