Protein Degradation and Fermentation Characteristics of Red Clover and Alfalfa Silage Harvested with Varying Levels of Total Nonstructural Carbohydrates

Abstract

Extensive degradation of protein during fermentation of high‐protein crops reduces efficiency of dietary N utilization in ruminants. Evidence suggests that enhanced levels of fermentable carbohydrates can reduce proteolysis. Our objective was to evaluate whether delaying daily cutting time, to allow total nonstructural carbohydrates (TNC) to accumulate, would inhibit protein degradation by way of greater acid production in the silo. Red clover (Trifolium pratense L.) and alfalfa (Medicago sativa L.) were harvested at 0600, 1000, 1400, and 1800 h in 1993, 1994, and 1995 and wilted to a dry matter (DM) content of 350 g kg−1 before ensiling. The level of TNC in fresh forage of both species increased throughout the day. Starch accounted for most of the daily change in TNC in fresh alfalfa, whereas in red clover, quantitative increases in sugar and starch impacted TNC similarly. Level of TNC at initiation of ensiling did not consistently affect protein degradation during fermentation as confirmed by generally insignificant correlation coefficients. The extent of proteolysis in the silo was consistently greater in alfalfa than red clover. Silage pH typically decreased and starch increased as cutting time was delayed from 0600 to 1800 h. While the extent of proteolysis was largely unaffected by inherent increases in TNC, lower silage pH and higher starch concentrations indicate that silage from the afternoon cuttings may be better preserved and higher in quality.

Proteolysis in alfalfa silages made from different cultivars

“…Silage NPN concentrations in the present study were comparable to those of Makoni et al (1997) and Owens et al (1999), but concentrations of NH 3 were higher and FAA were lower than those of Makoni et al (1997). Their study reports NPN, NH 3 , and FAA concentrations of 659, 47, and 385 g kg -1 of TN for first cutting 20% DM alfalfa silage, 601, 120, and 374 g kg -1 of TN for first cutting 28% DM For personal use only.…”

The effect of cultivar, wilting and storage period on fermentation and the clostridial community of alfalfa silage

“…Crude protein (CP) content was analysed according to the method of the AOAC (1990). The WSC content was determined using the method of Owens et al (1999). Buffer capacity (BC) value was measured by the method of Layne and McDonald (1966).…”

Nutritional Evaluation of Fresh and Wilted Mixed Silage of Naked Oats (Avena nuda) and Alfalfa (Medicago sativa)

“…Dried samples were crushed and passed 40 mesh sieve, the content of Ash was measured by a high temperature burning, the content of CP was measured by Kjeldahl nitrogen method, the content of WSC was measured by anthrone -sulfuric acid colorimetric method (Owens et al, 1999), the contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were determined by ANKOM A200i fiber analyzer and Fan fiber Law, and the content of hemicellulose (HC) should subtract the content of ADF from NDF's, namely HC = NDF-ADF (Zhang, 2007).…”