Effects of Forage Sources on Rumen Fermentation Characteristics, Performance, and Microbial Protein Synthesis in Midlactation Cows

Abstract

Eight multiparous Holstein cows (632±12 kg BW; 135±16 DIM) were used in a replicated 4×4 Latin square design to evaluate the effects of forage sources on rumen fermentation characteristics, performance, and microbial protein (MCP) synthesis. The forage portion of the diets contained alfalfa hay (AH), oat hay (OH), Leymus chinensis (LC), or rice straw (RS) as the primary source of fiber. Diets were isonitrogenous and isocaloric, and cows were fed four corn silages based total mixed rations with equivalent nonfiber carbohydrate (NFC) and forage neutral detergent fiber (NDF). Dry matter intake was not affected by the source of dietary forages, ranging from 18.83 to 19.20 kg/d, consequently, milk yield was similar among diets. Because of the numerical differences in milk fat and milk protein concentrations, 4% FCM and ECM yields were unchanged (p>0.05). Mean rumen pH, NH3-N content, and concentrations of volatile fatty acids in the rumen fluid were not affected by the treatments (p>0.05). Dietary treatments did not affect the total tract apparent digestibility of dry matter, organic matter, and crude protein (p>0.05); however, digestibility of NDF and acid detergent fiber in RS diet was higher compared with AH, OH, and LC diets (p<0.05). Total purine derivative excretion was higher in cows fed AH, OH, and LC diets compared with those fed RS diet (p<0.05), consequently, estimated MCP synthesis was 124.35 g/d higher in cows fed AH diet compared with those fed RS diet (p<0.05). The results indicated that cows fed AH, OH, LC, and RS diets with an equivalent forage NDF and NFC have no unfavourable effect on the ruminal fermentation and productive parameters.

In vitro Rumen Fermentability of the Pelleted Feed Containing Water Spinach (Ipomoea aquatica)

“…The incorporation of water spinach as the source of fiber in the pelleted feed did not impact the pH, ammonia, enzyme protein and microbial protein. This finding was in accordance with a study conducted by Al-Arif et al (2017); Li et al (2003); Xu et al (2014). Zhang et al (2019) reported that rumen pH is highly dependent on feed fermentation and its physical form.…”

Effects of forage ensiling and ration fermentation on total mixed ration pH, ruminal fermentation and performance of growing Holstein‐Zebu cross steers

“…; Xu et al . ). After obtaining approximately 200 mL of rumen fluid the pH was immediately measured (Model HI 98127 Waterproof pH meter; Fotronic Corporation).…”

“…The tubing and probe head were inserted into the rumen at a depth of 180 cm followed by 200 cm for collection. To ensure minimal saliva contamination the first 200 mL of rumen fluid extracted was discarded (Shen et al 2012;Xu et al 2014). After obtaining approximately 200 mL of rumen fluid the pH was immediately measured (Model HI 98127 Waterproof pH meter; Fotronic Corporation).…”

Relationship between forage neutral detergent fiber and non-fibrous carbohydrates on ruminal fermentation products and neutral detergent fiber digestibility in goats

“…Among the various lines of research related to ruminant nutrition, the study of the relationship between NDF and NFC is of great importance. Suitable NDF levels in a ruminant's diet during production are usually adjusted in order to maintain normal function of the rumen, maintain microbial protein synthesis (Xu et al, 2014), and optimize its intake and digestibility (Oliveira et al, 2011). Similarly, the NFC content has been considered in ruminant ration formulations as a nutritional criterion that is adjusted to obtain the appropriate fiber fraction in the feed (NRC, 2001).…”