Twelve early lactation Holstein cows (4 fistulated) were used in replicated 4x4 Latin squares with 4-wk periods to determine the effective neutral detergent fiber (NDF) content of wet corn gluten feed and to measure the effect of forage particle size on ruminal mat consistency and passage rate of wet corn gluten feed. Diets were 1) 23.3% NDF (17.4 percentage units of NDF from alfalfa silage), 2...

In order to determine of physical characteristics of rice straw as an effective source of fiber in ruminants, alfalfa hay, four varieties of rice straw (Taroum Neda, Taroum Neamat, Taroum Sangi, and Asgari), and four rations that contained four varieties of rice straws were investigated. The chemical (dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), nonfiber carbohydrates (N...

We quanti®ed the effect of dietary non®ber carbohydrate (NFC) concentration (30, 35, 40, or 45% of DM) on in vitro digestion kinetics of neutral detergent ®ber (NDF) from alfalfa and corn silages at pH 5.8 or 6.8. The objective was to simulate the effect of diets differing in effective ®ber content on the optimal NFC-to-NDF ratio that resulted in maximal ®ber digestion. Ash-free NDF was determi...

Physically effective neutral detergent fiber (peNDF) is the fraction of neutral detergent fiber (NDF) that stimulates chewing activity and contributes to the floating mat of large particles in the rumen. Multiplying dietary NDF by particle size has been used as an estimate of peNDF. In re-evaluating the concept of peNDF, we compared the use of peNDF as dietary NDF × particle size with the use o...

Data from recent research studies were analyzed quantitatively, and the random effect of experiment was assessed to define the physiological responses of dairy cows in early lactation to intake of physically effective neutral detergent fiber (peNDF). All studies were conducted with lactating Holstein cows (84.8 +/- 3.54 days in milk) in Latin square designs, and feeds were offered ad libitum as...

Twenty-four lactating Holstein dairy cows (12 first lactation and 12 multiparous; day in milk = 11 ± 5 days) were allotted to a randomised complete block design in a 2 × 3 factorial with four replicates per treatment to evaluate the effects of two methods of alfalfa feeding (dry and reconstituted to achieve a theoretical dry matter (DM) content of 350 g/kg) and three geometric mean (GM) particl...

The objective of this study was to determine whether the amount of forage in a total mixed ration influences feed sorting by cows and whether the extent of this sorting changes as they adapt to a new diet. Six lactating Holstein cows, individually fed once per day, were provided each of 2 diets in a crossover design (dry matter basis): 1) a higher forage diet (HF; 62.3% forage), and 2) a lower ...

An experiment was carried out to determine the effect of corn silage particle size and fat supplements on performance, solid passage rate through the digestive tract, and chewing behavior in dairy cows. The forages were coarse or fine corn silage with geometric means of 8.8±2.7 and 5.6±2.8 mm, and alfalfa with geometrics means of 7.0±3.3 mm, and fat supplements were neutral fat (palm) and soy-o...

This study was conducted to evaluate the ensiling characteristics and the in situ degradability of a by-product feed (BF)-based silage. Before ensilation, the BF-based mixture was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial inoculant on a wet basis and ensiled for up to 4 weeks. The ...

Mertens (1997) defined physically effective NDF (peNDF) as the fraction of NDF that stimulated chewing and contributed to a ruminal digesta mat. He also proposed a standard laboratory method for measuring peNDF that involved dry sieving and measuring the fraction of sample NDF retained on the ≥1.18-mm sieve. This large particle pool requires rumination and has a high resistance to escape from t...