Ruminal large and small particle kinetics in dairy cows fed red clover and grass silages harvested at two stages of growth

The objective of this study was to investigate the effects of 2 alfalfa hays differing in undigested neutral detergent fiber content and digestibility used as the main forage source in diets fed to high producing cows for Parmigiano-Reggiano cheese production. Diets were designed to have 2 different amounts of undigestible NDF [high (Hu) and low (Lu)], as determined by 240-h in vitro analysis (uNDF). Alfalfa hay in vitro digestibility [% of amylase- and sodium sulfite-treated NDF with ash correction (aNDFom)] at 24 and 240 h was 40.2 and 31.2% and 53.6 and 45.7% for low- (LD) and high-digestibility (HD) hays, respectively. The 4 experimental diets (Hu-HD, Lu-HD, Hu-LD, and Lu-LD) contained 46.8, 36.8, 38.8, and 30.1% of alfalfa hay, respectively, 8.6% wheat straw, and 35.3% corn (50% flake and 50% meal; DM basis). Soy hulls and soybean meal were used to replace hay to balance protein and energy among diets. Eight multiparous Holstein cows (average milk production = 46.0 ± 5.2 kg/d, 101 ± 38 d in milk, and 662 ± 42 kg of average body weight) were assigned to a 4 × 4 Latin square design, with 2 wk of adaptation and a 1-wk collection period. Dry matter and water intake, rumination time, ruminal pH, and milk production and composition were measured. Diets and feces were analyzed for NDF on an organic matter basis (aNDFom), acid detergent fiber, acid detergent lignin, and uNDF to estimate total-tract fiber digestibility. Dry matter intake and rumination times were higher in HD diets compared with LD diets, regardless of forage amount. Rumination time was constant per unit of dry matter intake but differed when expressed as a function of uNDF, aNDFom, or physically effective NDF intake. No differences were found among treatments on average ruminal pH, but the amount of time with pH <5.8 was lower in Hu-HD diets. Milk production and components were not different among diets. Total-tract aNDFom and potentially digestible neutral detergent fiber fraction digestibility was higher for the LD diets (88.3 versus 85.8% aNDFom in HD), for which lower feed intakes were also observed. The Hu-HD diet allowed greater dry matter intake, longer rumination time, and higher ruminal pH, suggesting that the limiting factor for dry matter intake is neutral detergent fiber digestibility and its relative rumen retention time.

Section: Resultssupporting

confidence: 87%

Section: Resultssupporting

confidence: 87%

Effect of undigested neutral detergent fiber content of alfalfa hay on lactating dairy cows: Feeding behavior, fiber digestibility, and lactation performance

Fustini

Palmonari

Canestrari

et al. 2017

“…In contrast, effects of advancing grass silage maturity on passage kinetics have been rather extensively studied but are ambiguous and seem to depend on the plant material and resulting specific particle size. Although some studies reported reduced or unchanged K 1 values for late compared with early maturing grass (Mambrini and Peyraud, 1994;Lamb et al, 2002;Lund et al, 2006;Kuoppala et al, 2009;Bayat et al, 2010Bayat et al, , 2011, other studies showed increased K 1 values with advancing maturity of grass silage (Gasa et al, 1991;Bosch et al, 1992a;Rinne et al, 1997aRinne et al, , 2002. In our study, K 1 was generally higher and passage kinetics faster (higher K 2 ; lower PCT, transit time, and TMRT) for the high fertilized N90 treatment.…”

Section: Effect Of Maturity Stage and Fertilizationsupporting

confidence: 50%

“…Previous studies based on external or inert markers suggest that grass silage quality affects passage kinetics, although effects were not clear and results from literature range from slightly negative or no effects (Mambrini and Peyraud, 1994;Lamb et al, 2002;Lund et al, 2006;Kuoppala et al, 2009;Bayat et al, 2010Bayat et al, , 2011 to clearly positive effects (Gasa et al, 1991;Bosch et al, 1992a;Rinne et al, 1997aRinne et al, , 2002 of advancing plant maturity on K 1 . Effects of N fertilization were not specifically investigated with regard to passage kinetics, but results from in situ degradation studies indicate clear effects of N fertilization level on fractional degradation rates and the potentially rumen digestible fraction (van Vuuren et al, 1991;Valk et al, 1996;Peyraud et al, 1997).…”

Section: Introductionmentioning

confidence: 81%

Passage of stable isotope-labeled grass silage fiber and fiber-bound protein through the gastrointestinal tract of dairy cows

Warner

Dijkstra

Hendriks

et al. 2013

Fractional passage rates are required to predict nutrient absorption in ruminants but data on nutrientspecific passage kinetics are largely lacking. With the use of the stable isotope ratio (δ) as an internal marker, we assessed passage kinetics of fiber and fiberbound nitrogen (N) of intrinsically labeled grass silage from fecal and omasal excretion patterns of δ 13 C and δ 15 N. In a 6 × 6 Latin square, lactating dairy cows received grass silages [455 g/kg of total diet dry matter (DM) ] in a 2 × 3 factorial arrangement from ryegrass swards fertilized at low (45 kg of N/ha) or high (90 kg of N/ha) levels of N and harvested at 3 maturity stages. Feed intake (16.7 ± 0.48 kg of DM/d; mean ± standard error of the mean) and milk yield (26.7 ± 0.92 kg/d) increased at the high level of N fertilization and at decreasing maturity. Nutrient digestibility decreased with increasing plant maturity, particularly at the high level of N fertilization, essentially reflecting dietary treatment effects on the nutritional composition of the grass silage. Fractional rumen passage rates (K 1 ) were highest and total mean retention time in the gastrointestinal tract (TMRT) was lowest when based on the external marker chromium mordanted fiber (Cr-NDF; 0.047/h and 38.0 h, respectively). Fecal δ 13 C in the acid detergent fiber fraction ( 13 CADF) provided the lowest K 1 (0.023/h) and the highest TMRT (61.1 h) and highest peak concentration time (PCT; 24.3 h) among markers. In comparison, fecal fiber-bound N ( 15 NADF) had a considerably higher K 1 (0.032/h) and lower TMRT (46.4 h) than 13 CADF. Total N (measured with 15 NDM) had a comparable K 1 (0.034/h) to that of 15 NADF but provided the highest fractional passage rates from the proximal colon-cecum (K 2 ; 0.37/h) and lowest PCT (17.4 h) among markers. A literature review indicated unclear effects of grass silage maturity on K 1 and unknown effects of N fertilization on K 1 . Our study indicated no effect of advancing maturity on fecal K 1 and a trend for K 1 to increase with the high level of N fertilization. Parameter K 2 increased, whereas PCT and TMRT generally decreased with the high level of N fertilization. Omasal digesta sampling largely confirmed results based on fecal sampling. Results indicate that the use of δ 13 C and δ 15 N can describe fiber-specific passage kinetics of forage.

“…Digesta passage from the rumen is affected by numerous feed and animal factors. Legumes and grasses have different ruminal kinetic parameters (Voelker Linton and Allen, 2008;Bayat et al, 2010;Krizsan et al 2010) and increases in DMI result in a decrease in the percentage of small particles in the rumen (Okine and Mathison, 1991). Therefore, the effects of forage family and level of feed intake on ruminal passage rates are of interest in this study.…”

Section: Introductionmentioning

confidence: 99%

Rates of particle size reduction and passage are faster for legume compared with cool-season grass, resulting in lower rumen fill and less effective fiber

Kammes

Allen

2012

Effects of forage family on rates of particle size reduction in, and passage from, the rumen and the relationship of these effects with preliminary dry matter intake (pDMI) were evaluated using 13 ruminally and duodenally cannulated Holstein cows in a crossover design with a 14-d preliminary period and two 18-d treatment periods. During the preliminary period, pDMI of individual cows ranged from 19.6 to 29.5 kg/d (mean = 25.9 kg/d). Experimental treatments were diets containing either a) alfalfa silage (AL) or b) orchardgrass silage (OG) as the sole forage. Silages were chopped to 10-mm theoretical length of cut and contained 42.3 and 58.2% neutral detergent fiber (NDF) for alfalfa and orchardgrass, respectively. Both diets contained approximately 25% forage NDF and 30% total NDF. Feed, orts, rumen, and duodenal samples were wet sieved to fractionate particles above (large) and below (small) 2.36 mm. Indigestible NDF (iNDF) was used as a flow marker. Preliminary DMI, an index of nutrient demand, was determined during the last 4 d of the preliminary period when cows were fed a common diet and used as a covariate. Main effects of forage family and their interaction with pDMI were tested by ANOVA. Approximately 75% of the NDF consumed was large and 25% was small for both treatments, but cows fed AL consumed more iNDF and less potentially digestible NDF (pdNDF) than cows fed OG. The AL diet increased the reduction rate (large to small) compared with OG despite less rumination per unit of forage NDF for AL than OG, suggesting alfalfa NDF was more fragile than orchardgrass NDF. Over 55% of particles in the rumen were below 2.36 mm for AL and OG, indicating that particle size was not a limiting constraint to passage. Passage rates (k(p)) of large iNDF and large pdNDF were similar for AL and OG, but AL increased k(p) of large pdNDF and OG decreased it as pDMI increased. The AL diet increased k(p) of small iNDF and small pdNDF compared with OG, resulting in lower rumen fill for AL than OG. The k(p) of small iNDF and small pdNDF were similar within forage family, suggesting buoyancy was not limiting passage. The OG diet increased rumen pool size of large NDF compared with AL, which likely retained small NDF, contributing to the slower k(p) of small iNDF and small pdNDF observed for OG. Particle size reduction was a prerequisite to ruminal passage but not a constraint. Selective retention of small particles was less for alfalfa than orchardgrass, resulting in lower rumen fill and less effective fiber.