In vitro Digestibility Measurement of Feedstuffs in Donkeys Using the DaisyII Incubator

Successful studies on in vitro digestibility measurement of feedstuffs with fecal inoculum have been reported for horses, while data on donkeys are currently lacking. In this study we evaluated the use of the DaisyII Incubator (Ankom Technology, Fairport, NY, USA) for in vitro digestibility measurement of feedstuffs using donkey feces as source of microbial inoculum. The method was tested using 7 feedstuffs commonly used in donkey diets (alfalfa, bromegrass, ryegrass and timothy hays; wheat bran and wheat straw; barley grains). Feces were obtained from 4 female donkeys and incubations were carried out at one-week intervals for 4 consecutive weeks. Two bags of each feedstuff were incubated in digestion vessels containing a buffer/feces solution (90:10). In vitro apparent dry matter digestibility (DMD), true dry matter digestibility (IVTD), and neutral detergent fiber digestibility (NDFD) were evaluated at 4 incubation times: 30, 48, 60, and 72 h. All digestibility parameters significantly increased from 30 to 72 h of incubation. At 72 h of incubation, the within-laboratory repeatability and reproducibility of the method were 2.7% and 5.0% for DMD and 1.6% and 3.9% for IVTD, respectively. The method was less repeatable and reproducible for NDFD (4.5% and 10.4%, respectively).