In situ evaluation of hen mortality meal as a protein supplement for dairy cows

A study was conducted to evaluate the nutritional composition and in situ degradation of hen mortality meals. There were four treatments: control autoclaved hen meal (C-HM), enzyme-treated, fermented, autoclaved hen meal (E-HM), NaOH-treated, fermented, autoclaved hen meal (NaOH-HM), and soybean meal (SBM). For the E-HM or NaOH-HM, hen mortality was treated with a feather digesting enzyme or NaOH to improve digestibility of feathers on the carcass. After the enzyme or NaOH treatment, treated hen mortality was preserved by a fermentation procedure. The crude protein levels of the C-HM and SBM were higher than the E-HM and NaOH-HM, and the concentration of fat in the C-HM was higher than the other treatments. Levels of Lys, Thr, Arg, Ile, Leu, Val, and Phe for the C-HM and SBM were higher than in the E-HM and NaOH-HM. The Met, Cys, and Gly levels in the C-HM were higher than the soybean meal. In situ ruminal degradation data showed that the C-HM had lower dry matter and crude protein degradation than the other treatments, whereas the E-HM or NaOH-HM was more susceptible to ruminal degradation. These results indicate that the C-HM has higher levels of crude protein, amino acids, and resistance to ruminal degradation, whereas the E-HM or NaOH-HM was more digestible to ruminal microorganisms.