Effects of particle size of a total mixed ration on in vivo ruminal fermentation patterns and inocula characteristics used for in vitro gas production

Evaluation of associative effects of total mixed ration for dairy cattle using in vitro gas production and different rumen inocula

“…Although it is known that fermentation is more intense in the dorsal and ventral rumen mat,7, 9 rumen material other than FRL is commonly not utilised for in vitro gas production, mostly due to the need to implement a rumen fistula with a larger diameter in donor cows. The present results indicate that there is a substantial effect of rumen inoculum on gas production kinetics and fermentation characteristics.…”

“…The concentrate comprised 340 g kg −1 wheat, 250 g kg −1 maize, 210 g kg −1 soybean meal, 80 g kg −1 barley, 80 g kg −1 sunflower grains and 30 g kg −1 mineral–vitamin premix. Grass silage varied in theoretical PS with PSs of 5.5, 11 and 25 mm as described by Taf1j et al 7 The TMRs with different PSs of grass silage were offered to each cow in a 3 × 3 randomised block design. Each experimental period lasted 18 days, with the first 15 days used for diet adaptation.…”

“…For in vitro incubation, about 200 mL of FRL was collected from the ventral rumen sac using a vacuum pump, filtered through gauze, buffered according to Menke and Steingass8 and blended in a Waring blender for 2 min at low speed. After collection of FRL, solid digesta samples (700–800 g particle fraction without free liquid) were collected for PAL from the dorsal (PAL‐D) and ventral (PAL‐V) rumen according to the sampling technique described in detail by Taf1j et al 7 In brief, the PAL‐D fraction was sampled 5–10 cm beneath the top of the particle mat, whereas the PAL‐V fraction was sampled 5–10 cm above the rumen floor 7. To obtain the necessary amount of fluid, portions of PAL‐D and PAL‐V were manually squeezed, as reported in detail by Taf1j et al 7 Afterwards, rumen particles were soaked in a fixed volume of anaerobic buffer solution, and blended with the respective squeezed fluid (Waring blender, 2 min, low speed), squeezed again, filtered through gauze and incubated.…”

“…To determine the energy value of feedstuffs, in vitro gas production techniques are widely applied 5, 6. Indeed, the amount of gas produced in vitro highly correlates to the nutrients degraded and the amount of net energy released from the fermentation of organic matter contained in the incubated substrates 7 . In vitro gas production techniques, such as the Hohenheim gas test,8 use ventral free rumen liquid (FRL) to estimate the energy value of a feed ingredient, thereby assuming that FRL represents the whole rumen.…”

Ruminal microbial responses in fermentation characteristics and dry matter degradability to TDN level of total mixed ration

“…Corn and grass silage are main components of the forage portion of TMR. They are fed as single forage components, or together, depending mainly on the region, availability, and feeding purpose (Tafaj et al, 2005).…”