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Abstracts of the
2023 American Dairy Science Association®
Annual Meeting
Journal of Dairy Science®
Volume 106, Supplement 1
74
J. Dairy Sci. Vol. 106, Suppl. 1
Ruminant Nutrition 3: Carbohydrates and Lipids
2304 Dietary fiber source and direct fed microbial supplemen-
tation effects on performance of high-producing dairy cows. M. R.
Pupo*, E. C. Diepersloot, C. Heinzen Jr., M. P. Rodrigues, and L. F.
Ferraretto, University of Wisconsin–Madison, Madison, WI.
Sixty-four multiparous Holstein cows (76 ± 22 DIM) were randomly
assigned to 1 of 4 treatments in a completely randomized design with a
2 × 2 factorial arrangement for an 11-wk trial (1 wk acclimation, 2 wk
covariate, and 8 wk treatment periods). Treatments were forage inclusion
in the diet, 45% (LOW) or 60% (HIGH) of DM, and without (CON)
or with the supplementation of a direct-fed microbial containing herbal
extracts, L. plantarum, L. buchneri, and Saccharomyces cerevisiae (75
mL/head/day; AD). Data were analyzed with a covariate and using a
mixed model with week of treatment as repeated measures. The model
included fiber source, direct fed supplementation, week, and all 2- and
3-way interactions as fixed effects, and cow (treatment) as a random
effect. Three-way interactions were observed for dry matter intake (P
= 0.001) and feed efficiency (P = 0.001). Dry matter intake was 2 to 3
kg/d greater for LOW-AD than HIGH-CON and HIGH-AD during
wk 2, 3, 5, and 8 of the treatment period. Feed efficiency was 0.2-units
greater for LOW-CON than HIGH-CON during wk 4 and 7, whereas
did not differ from other treatments during wk 4. Milk production was
greater (P = 0.002) for LOW than HIGH forage diet (56.9 vs. 54.8
kg/d, respectively), which affected (P = 0.01) lactose yield (2.7 vs. 2.6
kg/d, respectively). Milk fat (P = 0.02; 3.52% and 3.34% DM, respec-
tively) and MUN (P = 0.02; 11.9 mg/dL and 11.4 mg/dL, respectively)
concentrations were greater for HIGH than LOW. Conversely, milk
protein concentration was lower (P = 0.04) for HIGH than LOW (2.95
vs. 3.01% DM, respectively). Morning respiration rate (P = 0.02) was
3.2 breathes/min lower with AD supplementation. Daily rectal tem-
perature (P = 0.02) was approximately 0.1°C greater for LOW than
HIGH forage diets. Moreover, TMR containing AD had (P = 0.01) 1 h
greater aerobic stability than TMR without AD. Feeding a low forage
diet increased actual milk yield but not component-corrected milk yields
by dairy cows. In addition, AD supplementation reduced respiration
rate during the summer.
Key Words: direct-fed microbial, forage, feed efficiency
2305 Eects of isoacids supplementation in lactating cows’ diet
varying in forage ber level on performances, feed eciency and
milk fatty acids prole. S. Ahmed*1, M. R. A. Redoy1, M. L. Bulnes1,
J. B. Urbina1, D. H. Kleinschmit2, and M. E. Uddin1, 1Dairy and Food
Science Department, South Dakota State University, Brookings, SD,
2Zinpro Corporation, Eden Prairie, MN.
Our objective was to determine the eects of isoacids (ISO; IsoFerm,
Zinpro Inc.) on the lactation performances, feed eciency and milk
fatty acids (FA) prole of Holstein cows under 2 forage neutral deter-
gent ber (NDF) levels (FL). For a 10-wk long (2-wk for covariate)
randomized complete block design study, 64 mid-lactation cows [662
± 71 kg body weight, 119 ± 51d in milk (DIM), 2 ± 0.9 parity] were
blocked by parity, DIM, and prior milk yield (MY) or genetic merit.
Cows were randomly assigned to 1 of the 4 diets (n = 16) which were
arranged as 2 × 2 factorial, with 2 FL containing 18 (LF) and 23% forage
NDF (HF) without (WIA) or with ISO (IA, 40 g/d per cow). Diets were
formulated to meet NASEM (2021) requirement containing similar crude
protein (16.5%), NDF (28%), and net energy for lactation (1.72 Mcal/
kg DM). Dry matter intake (DMI) and MY were recorded daily, and
milk composition were analyzed weekly. Data were analyzed in R using
lme4 where nal model included wk, FL, ISO, and FL × ISO as xed
eects and block as random eect. The ISO did not aect DMI which
was greater in LF than HF (27.1 vs. 25.8 kg/d, P = 0.048). Compared
with HF, LF cows had greater MY (36.6 vs. 32.9 kg/d, P = 0.001) and
fat-and-protein corrected milk (FPCM, 37.6 vs. 35.1 kg/d, P = 0.001),
whereas ISO increased MY (14%, P < 0.001) and FPCM (10%, P =
0.003) in HF but not in LF diet (i.e., FL × ISO interaction). We only
found a FL × ISO interaction for feed eciency (MY/DMI and FPCM/
DMI) i.e., ISO increased feed eciency in HF but decreased in LF diet
regardless of expressions. Treatment did not aect milk protein, but milk
fat was lower in LF than HF (4.1 vs. 4.4%, P = 0.007) and tended to be
lower in IA than WIA group (4.1vs. 4.3%, P = 0.092). Compared with
HF, LF also had lower total and de-novo FA whereas ISO only decreased
total FA (P = 0.007). The FL did not aect milk urea nitrogen but was
decreased by ISO (12.8 vs. 14.0 mg/dL, P = 0.001) under LF diet only
(i.e., FL × ISO) suggesting a lower urinary urea nitrogen excretion. In
conclusion, IA supplementation improved lactation performances and
eciency depending on FL.
Key Words: Holstein, milk fat, de-novo fatty acid
2306 Fiber evaluation methods of novel feed ingredients for
dairy cows: The case of macroalgae. E. Chasse*1, M. V.
Curtasu1, K. E. Bach Knudsen1, A. Bruhn2,3, and M. O. Nielsen1,3,
1Department of Animal and Veterinary Sciences, Aarhus University,
Foulum, Den-mark, 2Department of Ecoscience, Aarhus University,
Aarhus, Den-mark, 3Center for Circular Bioeconomy, Aarhus
University, Foulum, Denmark.
Macroalgae have attracted significant attention as potential feeds or
additives, since their cultivation is not associated with use of arable land
suitable for human food production, and because of the ability of some
species to reduce enteric methane formation from ruminants. There is
only limited information available on rumen degradability of macroal-
gae CHO fractions, specifically the non-starch polysaccharides
(NSP). Traditionally, CHO analyses of ruminant feeds provide
information about contents of starch and sucrose, and insoluble fiber
classified into neutral detergent fiber (NDF), acid detergent fiber
(ADF) and lignin. The conventional fiber analysis does not provide
any information about the actual composition of fibers or their
physiochemical properties. The aim of this project was to compare
fiber content of seaweed samples determined by both the NDF
(Ankom 2000 Fiber Analyzer) and NSP (Bach Knudsen, 1997)
methods. We analyzed 20 macroalgae species (12 brown, 2 green
and 6 red) from Denmark and Australia. Samples were analyzed in
triplicates. Data were analyzed using correlations between
variables. Results showed that fiber content of seaweeds was
overestimated by 28% on average when using the NDF method com-
pared with the NSP method. The difference between NDF and total
NSP content positively correlated with total galactose (r = 0.5238, P
= 0.004), soluble galactose (r = 0.5698, P = 0.002), total arabinose (r
= 0.4940; P = 0.008), soluble arabinose (r = 0.5350; P = 0.003) and
insoluble mannose (r = 0.5396; P = 0.003). Galactose, arabinose and
mannose are all components of side chain ramifications in
macroalgae fibers. Moreover, galactose is the main component of
agar which has structural resemblance to pectin. The NDF method is
known to give poor estimates of fiber content of pectin-rich
ingredients because pectins are washed away with the detergent. In
conclusion, the NSP method is more appropriate to determine fiber
content of macroalgae compared with