مقالات لاتین

[Broken Angel]

عنوان مقاله :

Intake and milk production of cows fed diets that differed in dietary
neutral detergent fiber and neutral detergent fiber digestibility1

اطلاعات مختصری از سال و منبع مقاله و نویسندگان :

J. Dairy Sci. 92:313–323
doi:10.3168/jds.2008-1482
© American Dairy Science Association, 2009.
C. Kendall, C. Leonardi, P. C. Hoffman, and D. K. Combs2
Department of Dairy Science, University of Wisconsin-Madison, Madison 53706


ABSTRACT


The objectives of this study were to determine how
feeding diets that differed in dietary neutral detergent
fiber (NDF) concentration and in vitro NDF digestibility
affects dry matter (DM) intake, ruminal fermentation,
and milk production in early lactation dairy
cows. Twelve rumen-cannulated, multiparous Holstein
cows averaging 38 ± 15 d (±standard deviation) in
milk, and producing 40 ± 9 kg of milk daily, were used
in a replicated 4 × 4 Latin square design with 28-d
periods. Treatment diets were arranged in a 2 × 2
factorial with 28 or 32% dietary NDF (DM basis) and
2 levels of straw NDF digestibility: 1) LD, untreated
wheat straw (77% NDF, 41% NDF digestibility) or 2)
HD, anhydrous NH3-treated wheat straw (76% NDF,
62% NDF digestibility). All 4 diets consisted of wheat
straw, alfalfa silage, corn silage, and a concentrate mix
of cracked corn grain, corn gluten meal, 48% soybean
meal, and vitamins and minerals. Wheat straw comprised
8.5% DM of the 28% NDF diets and 16% DM
of the 32% NDF diets. Cows fed 28% NDF and HD
diets produced more milk, fat, and protein than those
consuming 32% NDF or LD diets. Dry matter intake
was greater for cows consuming 28% NDF diets, but
intakes of DM and total NDF were not affected by in
vitro NDF digestibility. Intake of digestible NDF was
greater for cows consuming HD diets. Ruminal fermentation
was not affected by feeding diets that differed
in NDF digestibility. Ruminal NDF passage rate was
slower for cows fed HD than LD. No interactions of dietary
NDF concentration and in vitro NDF digestibility
were observed for any parameter measured. Regardless
of dietary NDF concentration, increased in vitro NDF
digestibility improved intake and production in early
lactation dairy cows.

[Broken Angel]

عنوان مقاله :

Near-infrared reflectance spectroscopy prediction of neutral
detergent-soluble carbohydrates in timothy and alfalfa

اطلاعات مختصری از سال و منبع مقاله و نویسندگان :

J. Dairy Sci. 92 :1702–1711
doi: 10.3168/jds.2008-1599
© American Dairy Science Association, 2009 .
Z. Nie ,* G. F. Tremblay ,†1 G. Bélanger ,† R. Berthiaume ,‡ Y. Castonguay ,† A. Bertrand ,† R. Michaud ,†
G. Allard ,§ and J. Han *
* Department of Grassland Science, College of Animal Science and Technology, China Agricultural University, Beijing, P. R. China, 100094
† Agriculture and Agri-Food Canada, Quebec, Quebec, Canada G1V 2J3
‡ Agriculture and Agri-Food Canada, Sherbrooke, Quebec, Canada J1M 1Z3
§ Université Laval, Québec, Québec, Canada G1K 7P4


ABSTRACT


Carbohydrates in forage crops can be divided into
neutral detergent-insoluble fiber and neutral detergentsoluble
carbohydrates (NDSC); the latter includes organic
acids (OA), total ethanol:water-soluble carbohydrates
(TESC), starch, and neutral detergent-soluble
fiber (NDSF). The accurate and efficient estimation of
NDSC in forage crops is essential for improving the
performance of dairy cattle. In the present study, visible
and near-infrared reflectance spectroscopy (NIRS) were
applied to evaluate the feasibility of predicting OA,
TESC, starch, NDSF, NDSC, and all related constituents
used to calculate these 5 carbohydrate fractions in
timothy and alfalfa. Forage samples (n = 1,008) of
timothy and alfalfa were taken at the first and second
harvests at 2 sites in 2007; samples were dried, ground,
and then scanned (400 to 2,500 nm) using an NIRSystems
6500 monochromator. A calibration (n = 60) and
a validation (n = 15) set of samples were selected for
each species and then chemically analyzed. Concentrations
of TESC and NDSC in timothy, as well as starch
in alfalfa, were successfully predicted, but many other
carbohydrate fractions were not predicted accurately
when calibrations were performed using single-species
sample sets. Both sets of samples were combined to
form new calibration (n = 120) and validation (n = 30)
sets of alfalfa and timothy samples. Calibration and
validation statistics for the combined sets of alfalfa and
timothy samples indicated that TESC, starch, and
NDSC were predicted successfully, with coefficients of
determination of prediction RP
( 2 ) of 0.92, 0.89, and
0.93, and a ratio of prediction to deviation (RPD) of
3.3, 3.1, and 3.6, respectively. The NDSF prediction
was classified as moderately successful
R 88, RPD 2 8 P
( 2 = 0. = . ). The NIRS prediction of OA was unsuccessful R 38, RPD 1 3 P
( 2 = 0. = . ). All related
constituents were predicted successfully
R 9 , RPD 3 P
( 2 > 0. 0 > .0) by NIRS except ethanol-insoluble
residual OM, with R 75 and RPD 1 9 P
2 = 0. = . . Our
results confirm the feasibility of using NIRS to predict
NDSC, its fractions, and other related constituents,
except for OA and ethanol-insoluble residual OM, in
timothy and alfalfa forage samples.

[Broken Angel]

عنوان مقاله :

Substitution of Neutral Detergent Fiber from Forage
with Neutral Detergent Fiber from By-Products
in the Diets of Lactating Cows

اطلاعات مختصری از سال و منبع مقاله و نویسندگان :

J. S. ZHU,*,1 S. R. STOKES,*,2,3 and M. R. MURPHY†
*Department of Animal Science and Food Nutrition,
Southern Illinois University, Carbondale 62901
†Department of Animal Sciences,
University of Illinois, Urbana 61801


ABSTRACT


Four lactating dairy cows that were ruminally and
duodenally cannulated were used in an experiment
with a 4 ´ 4 Latin square design to determine the
effects of the substitution of neutral detergent fiber
(NDF) from forage with NDF from wheat middlings,
corn gluten feed, or a blend of distillers dried grains
and hominy. Dietary crude protein and NDF averaged
18 and 31%, respectively, for the diet with 71.2% of
the NDF from forage (control diet) and for diets with
55% of the NDF from forage (by-product diets). The
substitution of NDF from these by-products for forage
NDF did not affect dry matter intake (20.1 kg/d) or
digestibility of organic matter. Total tract digestibility
of acid detergent fiber was lower for cows fed the
diet containing a blend of distillers dried grains and
hominy than for cows fed the diet containing corn
gluten feed. Microbial crude protein synthesis, milk
production (23.9 kg/d), and milk fat percentage were
similar for all cows, regardless of diet. Cows fed the
diets containing wheat middlings or a blend of distillers
dried grains and hominy had reduced ruminal
pH compared with that of cows fed the diet containing
corn gluten feed or the control diet. Diets containing
55% of total NDF from forage with 31% of total NDF
from corn gluten feed, wheat middlings, or a blend of
distillers dried grains and hominy can supply sufficient
effective fiber to maintain normal ruminal function.