Ruminal fermentation characteristics and related feeding values of compound feeds and their constituting single feeds studied by using in vitrotechniques

Abstract

Single concentrate feeds are mixed together forming compound feeds for cattle. However, knowledge regarding the potential interactions (associative effects) between the feeding values of single feeds in compound feeds is lacking. The main objective of the present study was to evaluate ruminal fermentation characteristics and feeding values of eight industrially produced compound feeds in mash form from their constituent single feeds for dairy cows through in vitro assays. Additivity was given for gas production (GP), digestibility of organic matter (dOM) and utilisable CP at the duodenum (uCP). Additivity of CP fractions (determined using the Cornell Net Carbohydrate and Protein System (CNCPS)) was dependent on the fraction and compound feed type; however, the effective degradation calculated from CP fractions (ED CNCPS ) showed additivity. Additivity was not given for intestinal digestibility of rumen-undegraded protein (ID RUP ) for five out of eight compound feeds. Precise calculation of metabolisable energy (ME) of compound feeds from ME of single feeds was possible when using the same ME equations for all single and compound feeds. Compound feeds are often provided in pellet form; therefore, our second objective was to evaluate the effects of pelleting on ruminal fermentation characteristics and feeding values of compound feeds. Pelleting affected GP at 24 h (GP 24 ; up to 2.4 ml/200 mg DM), dOM (up to 2.3 percentage point (pp)) and ME (up to 0.3 MJ/kg DM), but these differences were overall small. More considerable effects of pelleting were observed for uCP, which was increased in all compound feeds except the two with the highest CP concentrations. The IDRUP was lower in most compound feeds following pelleting (up to 15 pp). Pelleting also affected CP fractions in a non-systematic way. Overall, the effects of pelleting were not considerable, which could be because pelleting conditions were mild. Our third objective was to compare in situ ruminal CP degradation (ED IN_SITU ) of compound feeds with ED using two prediction methods based on CP fractions. EDIN_SITU reference data were obtained from a companion study using the same feeds. Prediction accuracy of EDIN_SITU and EDCNCPS was variable and depended on the compound feed and prediction method. However, future studies are needed as to date not enough data are published to draw overall conclusions for the prediction of EDIN_SITU from CP fractions.

Effects of guanidinoacetic acid on in vitro rumen fermentation and microflora structure and predicted gene function

“…In vitro rumen-simulated fermentation techniques are commonly used to evaluate the extent of rumen microbial fermentation and the utilization of diets ( Yejun et al, 2019 ; Grubješić et al, 2020 ; Choi et al, 2021 ). Rumen microorganisms ferment carbohydrates to produce rumen gasses (H 2 , CH 4 , CO 2 , etc.)…”

The associative effects of sunflower straw, sunflower plate, sunflower seed shells associated with concentrate and alfalfa evaluated by using an in vitro gas production technique

“…In most cases, granulation results in the more efficient degradation of crude protein and starch in the rumen in some compound feeds than in the crushed form of compound feed, which may be due to the departure of ungraded finer feed particles from the bag (Grubjesic et al 2019). Afterwards, the single feed data on GP 24h , metabolic energy, OMD and available CP in the duodenum have additivity, however the data are not additive on intestinal digestibility of undegraded protein in the rumen, so the degradation of CP in compound feed in the rumen cannot be forecasted reliably by CP fractions (Grubjesic et al 2020). Yuan and Wan (2019) reported that when peanut shell was combined with concentrate and alfalfa, the best combinations of single-factor and multiple-factor associative effects index were 30 : 10 : 60 and 40 : 30 : 30 (concentrate/peanut shell/alfalfa ratios).…”

Study on the associative effects of different proportions of soybean pod, alfalfa and concentrate on the diets at different ratio of concentrate to roughage in vitro

“…However, Grubjesic et al (2019) suggested that in most cases, pelleting led to the greater effective ruminal deg-Czech Journal of Animal Science, 65, 2020 (10): 389-401 https://doi.org/10.17221/165/2020-CJAS radation of crude protein and starch in some compound feeds than in compound feeds in mash form, probably due to undegraded finer feed particles which leave the bags. Afterwards, Grubjesic et al (2020) concluded that when formulating compound feeds for cattle, single feed data for GP 24 h , OMD, metabolizable energy (ME) and utilizable CP in the duodenum are additive, while those for intestinal digestibility of rumen undegraded protein are not, therefore, using CP fractions did not reliably predict the in situ ruminal CP degradation of compound feeds. The above four reports showed once again that the AE between feeds is widespread, but the mechanism of the AE between feeds is very complex.…”