The Nutritionist 2019

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14 February 20199:00 am EST5:00 pm ESTDr Rick Grant

The Wm H Miner Institute

Relationships between undigested and physically effective fiber in lactating dairy

cows

Relationship between undigested and physically effective fiber in lactating

dairy cows

R. Grant1, W. Smith1, M. Miller1, K. Ishida2, and A. Obata2

1William H. Miner Agricultural Research Institute, Chazy, NY2Zennoh National Federation of Agricultural Cooperative

Associations, Tokyo, Japan

Introduction• Economic, environmental, and social considerations are

encouraging use of higher fiber diets (Martin et al., 2017)

• Forage and non-forage

• NDF alone does not explain all observed variation in DMI and milk yield as dietary source and content vary

• Incorporate measures of digestibility and particle size

Current status: fiber digestion3-pool model

(Waldo et al., 1972; Mertens, 1977; Raffrenato et al., 2019)

pdNDF

iNDF2

NDF

NDS

Variable

digestion

Complete

digestionNDS

Variable

kd

Kd = 0

Complete

digestionNDS Complete

digestion

iNDF3

Kd = 0

F-NDFVariable kFast

S-NDFVariable kSlow

uNDF240

Use of uNDF240 as a benchmarking tool

• uNDF240 is sensitive to• Genetics

• Maturity at harvest

• Growing environment

• Measurement of iNDF using uNDF240 provides dynamic estimate of Kd

• In the field, nutritionists have begun to use uNDF within herds along with NDF, NDFD, peNDF…

(Nousiainen et al., 2003; 2004; Cotanch, 2015; Van Amburgh et al., 2015; Palmonari et al., 2015; 2016)

Physical effectiveness factor (pef) and peNDF

• pef = physical effectiveness factor

• % of sample retained on ≥1.18-mm screen when dry sieved; 4.0-mm screen as fed

• peNDF = physically effective NDF

• peNDF = pef x NDF%

• Recommendation:

• 21-23% of DM(Mertens, 1997; Mertens, 2007)

• Function of CHO fermentability and feeding management (Zebeli papers)

0.6

0.9

1.2

1.5

1.8

10 15 20 25 30 35 40

FCM

/DM

I (kg

/kg)

peNDF1.18 (% of DM)

12 studies using vertical dry sieving and 1.18-mm sieve

(Grant, 2008, unpublished)

Relationship between uNDF240 and peNDF(Smith et al., 2018; ADSA abstracts)

Practical feeding questions:✓What are separate and combined effects of peNDF and uNDF240 in

diets fed to lactating cows?

✓Can we adjust for lack of peNDF by adding more dietary uNDF240?

✓If forage uNDF240 is higher than desired, can we partially compensate by chopping more finely?

✓How important is particle size?

✓Answer likely affected by source of fiber.

Miner Institute StudyObjectives

Evaluate the effect of feeding different dietary concentrations of

uNDF240 and peNDF on: 1) chewing behavior,

2) rumen dynamics, and 3) lactation performance of

Holstein cows.

Dietary fiber and forage processingTwo uNDF240 concentrations:

Target: 8.5 vs 11.5% uNDF240

Adjusted forage% and NFFS

Two peNDF concentrations:

Timothy hay

Haybuster (hammer mill)

High pef: 0.58 ± 0.04

Low pef: 0.24 ± 0.01

Screens used for chopping timothy hay

Hammer mill 3 and 2 in 1/2 and 3/8 in

15.2 and 5.1 cm 1.3 and 0.95 cm

Timothy hay – as fed

Dietary ingredient composition

Low uNDF240 High uNDF240

Ingredient, % of DM Low peNDF High peNDF Low peNDF High peNDF

Corn silage 34.7 34.7 34.7 34.7

Straw, wheat 1.6 1.6 1.6 1.6

Timothy hay – short 10.5 … 24.2 …

Timothy hay – long … 10.5 … 24.2

Beet pulp, pelleted 12.9 12.9 0.4 0.4

Grain mix 40.3 40.3 39.2 39.2

Dietary carbohydrate composition

Low uNDF240 High uNDF240

Item, % of DM Low peNDF High peNDF Low peNDF High peNDF

% Forage 46.8 46.8 60.5 60.5

Starch 24.6 24.6 23.4 23.5

Sugar 4.3 4.3 4.6 4.6

aNDFom 33.1 33.3 35.7 36.1

uNDF240om 8.8 8.9 11.4 11.6

peNDF1.18 20.1 21.9 18.6 22.0

New concept: “peuNDF240”

Low uNDF240 High uNDF240

Item, % of DM Low peNDF High peNDF Low peNDF High peNDF

uNDF240om 8.8 8.9 11.4 11.6

pef 1.18-mm 0.61 0.66 0.52 0.61

peuNDF240 5.4 5.9 5.9 7.1

peuNDF240 = pef x uNDF240om

✓ pef measured using Ro-Tap/1.18-mm screen or PSPS/4.0-mm sieve.

✓ uNDF240 uniformly distributed above and below 1.18-mm screen.

Treatment TMR

Dry matter and NDF intake

Low uNDF240 High uNDF240

Item Low peNDF High peNDF Low peNDF High peNDF SE P-value

DMI, kg/d 27.5a 27.3a 27.4a 24.9b 0.6 <0.01

DMI, % of BW 4.02a 4.04a 3.99a 3.73b 0.10 0.03

NDF, kg/d 9.12b 9.06b 9.74a 8.96b 0.19 0.008

NDF, % of BW 1.33b 1.34b 1.42a 1.34b 0.03 0.017

abc Within a row different superscripts differ (P ≤ 0.05).

uNDF240 and peNDF intakeLow uNDF240 High uNDF240

Item Low peNDF High peNDF Low peNDF High peNDF SE P-value

uNDF240, kg/d 2.41c 2.43c 3.11a 2.87b 0.05 <0.001

uNDF240, % of BW 0.35c 0.36c 0.45a 0.43b 0.01 <0.001

peNDF1.18, kg/d 5.56b 5.94a 5.07c 5.44b 0.11 <0.001

peuNDF240, kg/d 1.47c 1.59b 1.61b 1.74a 0.03 <0.001

abc Within a row different superscripts differ (P ≤ 0.05).

Q: Does lactation performance track with peuNDF240 intake?

Milk yield and composition

Low uNDF240 High uNDF240

ItemLow

peNDF

High

peNDF

Low

peNDF

High

peNDFSE P-value

Milk, kg/d 46.1a 44.9ab 44.0bc 42.6c 0.9 <0.01

Fat, % 3.68b 3.66b 3.93a 3.92a 0.10 0.03

Fat, kg/d 1.70 1.62 1.71 1.64 0.05 0.12

True protein, % 2.93a 2.88ab 2.96a 2.84b 0.06 0.04

True protein, kg/d 1.35a 1.27b 1.29ab 1.19c 0.03 0.001

Urea nitrogen, mg/dL 8.5c 9.4bc 10.1ab 11.0a 0.6 <0.01

abc Within a row different superscripts differ (P ≤ 0.05).

ECM and efficiency

Low uNDF240 High uNDF240

ItemLow

peNDF

High

peNDF

Low

peNDF

High

peNDFSE P-value

ECM, kg/d 47.0a 45.7ab 46.4ab 44.6b 0.9 0.03

ECM/DMI, kg/kg 1.71ab 1.68b 1.70ab 1.79a 0.04 0.02

abc Within a row different superscripts differ (P ≤ 0.05).

✓ Milk and ECM track with peuNDF240✓ Milk fat % tracks with uNDF240✓ Interpret gross dairy efficiency carefully…

Chewing responses

Low uNDF240 High uNDF240

ItemLow

peNDF

High

peNDF

Low

peNDF

High

peNDFSE P-value

Eating time, min/d 255b 263b 279ab 300a 12 <0.01

Eating time, min/kg DMI 9.09c 9.62bc 10.08b 11.86a 0.51 <0.01

Rumination time, min/d 523 527 532 545 16 0.36

Rumination, min/kg DMI 18.59b 19.29b 19.25b 21.69a 0.80 <0.01

abc Within a row different superscripts differ (P ≤ 0.05).

Meal patterns

Low uNDF240 High uNDF240

ItemLow

peNDF

High

peNDF

Low

peNDF

High

peNDFSE P-value

DMI, kg/d 27.5 27.3 27.4 24.9

Meal length, min 27.7c 32.8b 32.6b 37.7a 2.5 <0.001

Meal bouts, /d 11.3a 10.5ab 10.7ab 10.0b 0.5 0.03

abc Within a row different superscripts differ (P ≤ 0.05).

✓ Greater intake and more meals with lower uNDF240 diets, and high uNDF240 diet chopped shorter.

Rumen Dive –Something to chew on…

✓ Emptied the rumen✓ Fed each TMR✓ Collected the swallowed

bolus

✓ Assess particle size reduction due solely to chewing while eating

Sieve size: 19 mm 13.2 mm 9.5 mm 6.7 mm 4.75 mm 3.35 mm

Mean

particle

size (mm)

Diet

Low/Low peNDF, uNDF240

3 % 27 % 33 % 20 % 10 % 7 % 9.36

High/Low peNDF, uNDF240

12 % 27 % 29 % 16 % 9 % 6 % 10.42

Low/High peNDF, uNDF240

9 % 21 % 23 % 22 % 14 % 11 % 9.19

High/High peNDF, uNDF240

32 % 13 % 17 % 20 % 11 % 7 % 11.55

Bolus

Low/Low peNDF, uNDF240

1 % 11 % 38 % 26 % 14 % 10 % 7.96

High/Low peNDF, uNDF240

3 % 11 % 22 % 29 % 20 % 16 % 7.46

Low/High peNDF, uNDF240

2 % 11 % 26 % 29 % 19 % 13 % 7.51

High/High peNDF, uNDF240

5 % 12 % 19 % 28 % 21 % 14 % 7.78

Particle size reduction during eating

Particle size of ingested feed(Schadt et al., 2011)

Forage typeNDF,

% of DM

Feed

size,

Bolus

size,

Chews

/g NDF

mm mm

Long rye grass hay 57.1 … 10.3c 2.6

50-mm rye “hay” 58.6 42.2a 9.9c 3.5

19-mm PSPS hay 57.9 43.5a 10.7bc 2.2

8-mm PSPS hay 59.1 25.1b 10.8bc 1.7

1.18 PSPS hay 54.2 9.7f 8.1d 1.9

Grass silage 53.1 13.8c 11.6ab 0.4

Corn silage 48.1 12.0e 11.2bc 0.7

TMR 37.7 13.1d 12.5a 0.6

Forage fiber and feeding behavior (Grant and Ferraretto, 2018)

• Greater eating time and possible lower DMI associated with:

• Higher forage content (Cotanch et al., 2012; Jiang et al., 2017)

• Corn silage and haycrop silage

• Lower NDF digestibility (Miron et al., 2007: Cotanch et al., 2012)

• Corn silage, sorghum silage

• Longer particle size (Fernandez et al., 2002; Kononoff and Heinrichs, 2003; Miller et

al., 2017)

• Alfalfa silage, corn silage, wheat straw

Chewing meta-analysis(Krentz et al., 2018)

◼ n = 117 trials; 431 treatment means

◼ As eating time increases:◼ Reduced milk protein, milk yield, and ECM yield

◼ As rumination time increases:◼ Increased milk fat% and yield

◼ As total chewing time increases:◼ Increased milk fat%, but decreased milk yield

Eating time between 3-5 h/d encourages natural feeding behavior

Dietary forage (% of DM) and behavior responses (Jiang et al., 2017)

Item 40% 50% 60% 70% Difference

DMI, kg/d 22.4 21.5 20.3 18.7 -3.7 kg/d

Eating, min/d 286 292 342 393 +107 min/d

Rumination, min/d 426 454 471 461 +35 min/d

Total chewing, min/d 712 745 813 853 +141 min/d

Resting, min/d 728 695 627 587 -141 min/d

✓ Corn silage and alfalfa hay, primarily.✓ Increased chewing time (mostly longer eating time) at expense of resting time.

Suggested PSPS targets:Miner Institute (2017)

Sievemm

PSPS 2013

%

Miner2017

%Comments

Top 19 2-8 <5Sortable material, too long, increases time needed for eating;

especially if >10%

Mid 1 8 30-50 >50Still long and functional pef, more so than 4 mm material. Maximize amount

on this sieve, 50-60%

Mid 2 4 10-20 10-20Functions as pef sieve, no recommendation for amount to retain here other

than total on the top 3 sieves = pef

Pan --- 30-40 25-30 40-50% grain diet results in at least 25-30% in the pan

✓Keep feed in front of cow

✓Comfortable stalls

✓Part of a system

Ruminal fermentationLow uNDF240 High uNDF240

ItemLow

peNDF

High

peNDF

Low

peNDF

High

peNDFSE P-value

Daily mean pH 6.11b 6.17ab 6.22ab 6.24a 0.05 0.03

Total VFA, mM 122.8a 120.6ab 118.3ab 112.3b 4.1 0.05

Acetate, % of total VFA 63.4 63.8 63.9 64.1 0.94 0.18

Propionate, % of total VFA 22.7a 22.5a 21.5b 21.6b 0.83 <0.01

Acetate : propionate 2.83c 2.89bc 3.04a 3.01ab 0.15 <0.01

abc Within a row different superscripts differ (P ≤ 0.05).

Ruminal fiber dynamicsLow uNDF240 High uNDF240

ItemLow

peNDF

High

peNDF

Low

peNDF

High

peNDFSE P-value

Ruminal pool size, kg

OM 12.7 12.3 12.9 12.4 0.5 0.44

aNDFom 8.2 7.9 8.7 8.4 0.4 0.06

uNDF240om 3.8b 3.7b 4.5a 4.4a 0.2 <0.01

Ruminal turnover rate, %/h

OM 8.7 8.8 8.4 8.0 0.4 0.15

aNDFom 4.4x 4.4x 4.2xy 3.9y 0.2 0.04

uNDF240om 2.7 2.8 3.0 2.7 0.1 0.29

abcMeans within a row with unlike superscripts differ (P ≤ 0.05). xyMeans within a row with unlike superscripts differ (P ≤ 0.10).

Perspectives to-date…• “Book end” diets resulted in expected responses in chewing,

DMI, and ECM

• Low/high vs high/low uNDF240/peNDF diets:• Similar response in:

• DMI and ECM

• Rumen pH and VFA

• Fat %, mixed origin FA, and A:P ratio function of uNDF240

Perspectives to-date…• Reducing peNDF with high uNDF240 diet:

• Lower eating time

• Shorter meal length, more bouts

• Greater DMI

• Faster rumen NDF turnover

• Don’t forget that peNDF is important for low uNDF240 diets.

• If future research confirms relationship between dietary uNDF240 and DMI, when forage fiber digestibility is less than desired, finer forage chop length may boost DMI and ECM.

Preliminary Synthesis:uNDF240 and peuNDF240

versus DMI, ECM, and Rumen pH

(M. Miller, W. Smith, and R. Grant, 2019; unpublished)

Combined data from four studies…

• Study 1: peNDF and uNDF240 (Smith et al., 2018)

• Study 2: ~50 or 65% forage in ration DM (Cotanch et al., 2014)

• 13% haycrop silage (mixed mostly grass)

• 36 to 55% corn silage (bm3 or conventional)

• Study 3: ~42 to 60% corn silage (bm3 or conventional) and 2 to 7% fine vs coarse-chopped wheat straw (Miller et al., 2017)

• Study 4: ~55% conventional or bm3 corn silage, 2.3% chopped wheat straw (Miner Institute, unpublished, 2019)

Relationships1 between Fiber and DMI/Meal Behavior (Miller, 2018)

Fiber measure DMI, kg/d Meal duration, min Meal bouts, /d

NDF, % of DM -0.57 0.23 0.66

uNDF240, % of DM -0.84 0.66 0.13

pdNDF, % of DM -0.09 -0.25 0.86

1Pearson correlations.

✓uNDF240 related to DMI … ”ballast”✓Potentially digestible NDF related to number of meals

(fast pool of NDF)

uNDF240 and DM Intake

peuNDF240 and DM Intake

uNDF240 and ECM Yield

peuNDF240 and ECM Yield

uNDF240 and Mean Rumen pH

peuNDF240 and Mean Rumen pH

peuNDF240 and DM Intake

Future: adjust chop length based on uNDF240, digestion characteristics?

A Tale of Two Fibers

• Research needed to test relationship with:• Alfalfa-based diets

• Potential differences between grasses and legumes

• Pasture systems• Forage vs non-forage fiber sources• Feeding scenarios markedly different than high corn

silage/haycrop diets

• There appears to be value in integrating two measures of fiber - uNDF240 and peNDF - when formulating rations.

Thank you…

14 March 20199:00 am EDT6:00 pm EDT

Dr Mike Van AmburghCornell University

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