Potential for improving fiber digestion in the rumen of cattle ( ) through microbial inoculation from bison ( ): In situ fiber degradation

Abstract

The objective of this experiment was to determine if partial replacement of cattle rumen contents with those from bison would increase in situ ruminal fiber degradation of various forages. The second objective was to examine individual variation among cattle in their ability to degrade forage and their responses to inoculation. In situ degradation of barley straw, canola straw, alfalfa hay, and timothy hay was measured in 16 ruminally cannulated heifers fed a barley straw-based diet before and after inoculation with combined rumen contents from 32 bison (performed twice, 14 d apart). Each feed was incubated in the rumen of each heifer for 0, 4, 8, 12, 24, 48, 96, and 120 h, and the degradation parameters were determined as washout fraction (), potentially degradable fraction (), rate of digestion of fraction (), and total potentially degradable fraction (). The of barley straw decreased ( = 0.04) after inoculation, whereas fraction of NDF increased ( = 0.03) and fraction of NDF and ADF decreased ( ≤ 0.02) by inoculation. In contrast, of alfalfa hay NDF and ADF decreased ( = 0.002) after inoculation, but fraction of NDF and ADF ( ≤ 0.02) increased. There were no major effects ( > 0.06) of inoculation on the fiber degradation of timothy hay or canola straw. The differential response between barley straw and alfalfa hay may have occurred because the cattle were previously adapted to a barley straw diet, whereas the bison were fed barley silage and oats. Some animals consistently ranked higher or lower for or across at least 3 of the 4 feeds incubated, but the rankings changed after inoculation. In conclusion, inoculation of cattle with bison rumen contents failed to improve degradation of fiber from barley straw, canola straw, or timothy hay in cattle well adapted to a barley straw diet, although there were small improvements in the extent of degradation of fiber from alfalfa hay. Cattle varied both in their ability to degrade various forages and in their responses to inoculation with bison rumen contents.

Comparison of the effects of rumen-protected and unprotected L-leucine on fermentation parameters, bacterial composition, and amino acids metabolism in in vitro rumen batch cultures

“…Four Xiangxi yellow cattle (Bos taurus, local breeds, Hunan, China) fitted with permanent ruminal cannulas were fed a total mixed ration containing wheat straw and concentrate mixture (4, 6; Table 1) and had free access to water. The in situ incubation was performed by described in detail by Griffith et al (2017). According to the "all in / gradual out" schedule, all of the nylon bags (pore size: 50 μm, size: 10 cm × 7 cm) with 5.00 g of the RP-Leu or RU-Leu products were tied to the end of a 40 cm polyester mesh tube and then put into the ventral sac of the rumen through a ruminal cannula after morning feeding 1 h. Two nylon bags were collected from the cannula of each cattle at 0, 2, 4, 6, 12, 16, and 24 h of incubation, respectively, with 8 replicates per time point (n = 8), immediately submerged in the ice water to stop microbial activity, rinsed with running water until the water was clear.…”

Effects of grain-based diets on the rumen and fecal bacterial communities of the North American bison (Bison bison)

“…It has been estimated that 95% of ruminal bacterial species have yet to be characterized in domesticated ruminant livestock species, highlighting that the function and metabolic potential of most rumen microorganisms remain largely unexplored (Creevey et al, 2014). Our current knowledge gap on bison gut microbial communities is even more pronounced than for domesticated ruminants, with comparatively few published studies (Towne et al, 1988;Oss et al, 2016;Bergmann, 2017;Griffith et al, 2017;Rico et al, 2021). As the effects of grain-based diets on the bison gastrointestinal environment remain largely unexplored, the main objective of this study was to compare the diversity and composition of the rumen and fecal bacterial communities of bison that were transitioned from grazing on native pastures to a grain-based free-choice diet.…”