Effects of direct-fed Bacillus subtilis and Clostridium beijerinckii on total-mixed ration apparent digestibility and ruminal degradability of alfalfa haylage and whole-plant corn silage in Holstein cows

Garcia, Lizet

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https://hdl.handle.net/2142/122102 Copy

Description

Title

Effects of direct-fed Bacillus subtilis and Clostridium beijerinckii on total-mixed ration apparent digestibility and ruminal degradability of alfalfa haylage and whole-plant corn silage in Holstein cows

Author(s)

Garcia, Lizet

Issue Date

2023-12-05

Director of Research (if dissertation) or Advisor (if thesis)

Cardoso, Felipe C.

Committee Member(s)

• Murphy, Michael R.
• Drackley, James K.
• Smith, Alexandra

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Apparent digestibility
• degradability
• C. beijerinckii
• B. subtilis

Abstract

The use of direct-fed microbials has been proposed to alter rumen and lower gut microbial populations along with rumen fermentation patterns, which can improve cow performance through improved feed digestibility. Therefore, we aimed to determine the apparent digestibility (AD) of a total-mixed ration (TMR) and the ruminal degradability of alfalfa haylage (AH) and corn silage (CS) in response to feeding 2 strains of Bacillus subtilis (2.0 × 109 colony forming units (CFU)/day); 6 strains of environmental Clostridium beijerinckii (4 × 106 CFU/day), or both in lactating Holstein cows. Forty multiparous Holstein cows, blocked by parity, previous 305-d milk production, and expected calving date were assigned to 1 of 4 dietary treatments in a randomized, complete block design. Treatments were: TMR top-dressed with B. subtilis (BAC; CERTILLUSTM, Arm & Hammer and Food Production, Waukesha, WI; 2.0 × 109 CFU/day), C. beijerinckii (BJE; 0.001% of dietary DM), both (BBJ), and neither (CON). Cows were fed from -21 d relative to expected calving until 70 days in milk. Samples of TMR were collected on d 63 to 65 and orts were collected on d 64 to 66 and analyzed for dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and starch. Feeding was at 1400 h daily. Fecal samples (ca. 120 mL) were collected directly from the cow’s rectum at 8 time points across d 63 to 65. Undegraded NDF was used as an internal marker. A subgroup of rumen-cannulated cows [(n = 3 per treatment) was also blocked by parity, previous 305-d milk production, and expected calving date and used to determine in situ degradability of alfalfa haylage and corn silage. Samples (8 g) of dried and ground AH and CS were placed into (4 replicates/feed) polyester bags on d 65 and incubated for 0, 2, 4, 12, 24, or 48 h in the rumen. Nutrient disappearance data from the bags were used to fit a nonlinear function to model digestion. A dataset was created for results including estimates of soluble (S), degradable (D), and indigestible (I) fractions of each nutrient, fractional rate of digestion (Kd), and an estimate of effective degradability (ED). Statistical analysis was performed using the MIXED procedure in SAS. Contrasts were CON vs BJE; CON vs BAC; and BAC vs BBJ. Cows in CON tended to have lower AD of OM (69.9%) and NDF (48.1%) than cows in BAC (78.3, and 59.1%, respectively). Cows in BAC had greater AD of ADF (57.2%) than cows consuming BBJ (44.1%). The AD of starch tended to be lower for cows in CON (96.5%) than cows in BAC (98.6%). Cows in BAC had greater soluble DM (0.48 vs. 0.32%), CP (0.63 vs. 0.55%), starch (0.72 vs. 0.62%), and OM (0.47 vs. 0.31%) for CS when compared to cows in CON. Degradable fraction of starch for CS was greater for cows in CON (0.37%) than cows in BJE (0.26%) and BAC (0.26%). Starch (0.37 h-1) and OM Kd (0.13 h-1) for CS tended to be higher for cows in CON in comparison with those in BJE (0.17 and 0.04 h-1, respectively) and BAC (0.16 and 0.02 h-1, respectively). Amount degraded and proportion remaining of fiber components for CS were greater for cows in CON compared to cows in BAC. There was a tendency for cows in CON to have a greater amount of NDF degraded (-0.010 vs. -0.008 h-1) and a greater proportion remaining of NDF (0.97 vs. 0.91) for CS than cows in BJE. Degradable fraction of DM (0.55 vs. 0.38%), and OM (0.58 vs. 0.40%) for AH was greater for cows in CON than cows in BAC. Contrasts did not differ in effective degradability of DM or OM; however, cows in BJE had greater effective degradability of CP (0.86) than those in CON (0.81) for AH. Cows in CON had a greater amount of NDF (-0.013 vs. -0.007 h-1) and ADF (-0.016 vs. -0.009 h-1) degraded for AH than cows in BJE. Proportion remaining of ADF for AH tended to be greater for cows in CON (0.97) in comparison with cows in BJE (0.76). Rumen pH throughout the experimental period tended to be lower for cows in CON (5.58) than cows in BAC (5.78). Cows in BJE had higher butyrate (13.5 vs. 11.7%) and valerate (2.53 vs. 1.77%) as a proportion of total volatile fatty acid (VFA) concentration than those in CON. There were no differences in propionate and isobutyrate as a proportion of total VFA. In conclusion, feeding B. subtilis improved TMR AD of OM, NDF, ADF and slowed the rate of degradation for AH and CS. Feeding cows with C. beijerinckii improved degradation of fiber components for AH and CS and altered the rumen fermentation pattern.

Graduation Semester

2023-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Lizet Garcia

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