The influence of source and quality of water and a water treatment system on the ruminal fermentation and nutrient digestibility of a total mixed ration using an in vitro gas production measurement system
There is a wide range in water quality available in South Dakota and this variation could have an impact on the performance of lactating dairy cows. In addition, little is known regarding water treatment systems influence on ruminal fermentation. This study was to evaluate the water source and a water treatment system on the rate and/or extent of ruminal fermentation and nutrient digestibility. A standard TMR consisting of alfalfa haylage, corn silage, and a grain mix was dried at 55OC and ground through a ultracentrifuge mill having a 1.0 mm screen. One g of ground TMR was placed in a 50 um dacron bag, heat sealed, and then placed in a 500 ml Ankom Gas Fermentation Bottle (GFB) to measure rate and extent of digestion. Treatments were: Control (C): laboratory distilled water; KCU: water taken from a local SD dairy operation before the water treatment system; KCT: water taken after treatment with H2O2 product; and DRTF: Municipal water used at the SDSU Dairy Research & Training Farm. Treatments were replicated 4 times as individual GFB and study was conducted in 4 blocks. Rumen fluid was collected from a ruminally cannulated lactating dairy cow fed the same TMR and strained through 4 layers of cheesecloth. Twenty ml of rumen fluid with 200 ml of buffer prepared from each of the water treatments were added to the GFB. Bottles were incubated in a circulating water bath at 39 OC and gas measurements were collected every 5 minutes for 30 h. At the completion of 30 h fermentations, dacron bags were removed, rinsed, and dried to calculate dry matter disappearance (DMD) and NDF concentrations to calculate NDF digestibility. The rate of gas production was greater (P<0.01) for C (distilled lab water) compared to other treatments. (16.4, 9.50, 9.66 and 9.71 %/h for C, KCU, KCT, DRTF, respectively). The DMD (82.0, 81.6, 80.8 and 81.6% for C, KCW, KCT, and DRTF, respectively) tended to be lower (P<0.09) for KCT water compared to C water, with all other treatments being intermediate and similar (P>0.10). The digestibility of NDF (60.0, 59.0, 58.3, and 59.6 % of NDF) was similar (P>0.10) for all treatments. The quality of water can influence rate of ruminal fermentation and the use of a water treatment system had minimal influence on ruminal fermentation and digestibility.
Keywords: Gas Production, Nutrient Digestibility, Water Quality