Comparison of Ruminal Degradability, Indigestible Neutral Detergent Fiber, and Total-Tract Digestibility of Three Main Crop Straws with Alfalfa Hay and Corn Silage

Abstract

Three main crop straws including corn straw (Zea mays, CS), rice straw (Oryza sativa, RS), and wheat straw (Triticum aestivum, WS), and two forages including alfalfa hay (Medicago sativa, AH) and corn silage (Zea mays, CSil) were analyzed in order to compare their ruminal degradability, indigestible neutral detergent fiber (iNDF), intestinal digestibility (ID), and their total-tract digestibility (TTD) of crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) using both an in situ nylon bag technique and a mobile nylon bag technique. The forage samples were incubated in the rumen for 6, 12, 16, 24, 36, 48, 72, and 288 h, respectively, to determine their ruminal degradability. Prior to intestinal incubation, forage samples were incubated in the rumen for 12 h and 24 h to determine the ruminal degradable content of CP, NDF, and ADF, respectively, and for 288 h to determine their iNDF288 content. Residues from the ruminal undegradable fractions (12 h for CP, 24 h for NDF and ADF) were subsequently inserted into the duodenum through a cannula to determine their intestinal digestible content. Here, the TTD of CP, NDF, and ADF were determined as the ruminal degradable content + intestinal digestible content. The results showed that AH had the highest iNDF2.4 (calculated as acid detergent lignin content × 2.4) and iNDF288 values (379.42 and 473.40 g/kg of NDF), while CS and CSil had the lowest iNDF2.4 values (177.44 and 179.43 g/kg of NDF). The ruminal degradability of CP, NDF, and ADF for CS, RS, and WS were lower than those of AH and Csil during the first 48 h of incubation. The potential degradation fraction of CP, NDF, and ADF for CSil was the highest; CS, RS, and WS were intermediate; and AH was the lowest (p < 0.05). CS, RS, and WS had a lower intestinal digestibility with respect to their rumen undegradable content of NDF (p < 0.05), and lower TTD of CP, NDF, and ADF (p < 0.05) compared to AH and CSil. General regression equations with satisfactory accuracy (R2 ≥ 0.828) were derived to predict iNDF288 and TTD based on their chemical compositions and the ruminal degradation kinetics of different forages. Incorporating this information into rations could improve our ability to optimize main crop straws utilization and milk production.

Nutritional Values of Industrial Hemp Byproducts for Dairy Cattle

“…The higher NDICP of industrial hemp ethanol extraction byproducts and industrial hemp seed meal will make them have more slowly degraded proteins and provide more rumen bypass proteins for ruminants. Compared with the results of Wang et al [ 15 ], the nutrient composition of alfalfa hay in this experiment showed that CP content was low, and NDF and ADF content was high, which may be caused by the late harvest period. Although the NDF of industrial hemp ethanol extraction byproducts in this study was 471 g/kg DM and 460 g/kg DM, respectively, less than alfalfa hay, they could also provide abundant carbohydrates for ruminants.…”

“…The appropriate content of NDF and CP can stimulate rumination and saliva production, thus buffering the rumen and promoting rumen health [ 14 ]. The in situ nylon bag technique (ISNBT) and three-step in vitro method (TSIVM) are often used to simulate the prediction of nutrient degradability and digestibility in animal production and feed value [ 15 , 16 ]. Alfalfa hay and soybean meal are used as common conventional feed in dairy farms.…”

A Combination of Novel Microecological Agents and Molasses Role in Digestibility and Fermentation of Rice Straw by Facilitating the Ruminal Microbial Colonization

“…It was suggested to conjugate with the aromatic structure (Zhao et al, 2010), representing the ether bonds of the lignin structure were hydrolyzed by MA or MA + M pretreatment. Importantly, the NDF content of feed affects feed intake and ADF affects digestibility (Wang et al, 2021). Here, our study proves that MA or MA + M pretreatments decreased the NDF and ADF of rice straw, which suggests that the rice straw pretreated by MA or MA+ M had a positive effect on digestion.…”

“…Importantly, the NDF content of feed affects feed intake and ADF affects digestibility (Wang et al, 2021 ). Here, our study proves that MA or MA + M pretreatments decreased the NDF and ADF of rice straw, which suggests that the rice straw pretreated by MA or MA+ M had a positive effect on digestion.…”

Comparison of coated and uncoated trace elements on growth performance, apparent digestibility, intestinal development and microbial diversity in growing sheep

“…1. After removal from the rumen, the nylon bags were repeatedly rinsed under cold running water to remove adhesions and subsequently placed in cold water for soaking while the nylon bags were repeatedly kneaded by hand gently until the filtered water was clear ( Wang E. et al, 2021 ). The cleaned nylon bags were dried to constant weight at 65°C for 48 hours, and the weight after drying was recorded and the rumen disappearance rate of the coated trace elements was calculated by the difference from the initial weight.…”