View Full Table | Close Full ViewTable 1.

Ingredient composition and chemical analysis of treatment diets

 
Treatment diets1
Item LF:C-HS LF:C-LS HF:C-HS HF:C-LS
Diet composition, % DM
Barley silage 3.7 3.7 50.6 51.0
Barley grain 53.0 53.0
DDGS-TG2 37.8 39.5
DDGS-NWT3 37.4 39.1
Supplement 1 5.6
Supplement 2 5.6
Supplement 3 9.9
Supplement 4 9.9
Supplement composition, % DM
Barley grain 34.4 36.7 57.7 58.7
Canola oil 3.2 3.2 3.9 3.9
Limestone 35.1 35.2 15.0 15.0
Ionophore/thiamine premix4 8.5 8.6 12.8 12.8
Trace mineral salt5 4.9 4.9 2.8 2.8
LS1066 11.4 11.4 6.9 6.9
Elemental sulfur 2.5 1.0
Chemical composition (mean ± SD), % DM
CP 20.8 ± 0.35 20.7 ± 0.19 21.8 ± 0.35 21.8 ± 0.29
Starch 34.1 ± 0.85 34.1 ± 0.73 16.4 ± 1.17 17.0 ± 0.85
ADF 9.2 ± 0.70 9.4 ± 0.51 20.4 ± 1.15 20.6 ± 0.20
NDF 25.6 ± 0.54 27.4 ± 0.65 36.5 ± 0.37 38.4 ± 1.25
Calcium 0.67 ± 0.17 0.76 ± 0.02 1.14 ± 0.26 0.96 ± 0.04
Phosphorus 0.56 ± 0.03 0.56 ± 0.00 0.57 ± 0.04 0.57 ± 0.02
Sodium 0.27 ± 0.05 0.26 ± 0.00 0.44 ± 0.07 0.41 ± 0.01
Potassium 0.87 ± 0.01 0.87 ± 0.00 1.59 ± 0.05 1.59 ± 0.05
Sulfur7 0.59 ± 0.05 0.29 ± 0.04 0.64 ± 0.03 0.33 ± 0.02
1Treatment diets: LF:C-HS, low forage-to-concentrate ratio (F:C), high S; LF:C-LS, low F:C, low S; HF:C-HS, high F:C, high S; HF:C-LS, high F:C, low S.
2DDGS-TG: high-S-containing wheat dried distillers grains with solubles (1.07% S DM basis).
3DDGS-NWT: low-S-containing wheat dried distillers grains with solubles (0.55% S DM basis).
4Ionophore/thiamine premix of supplements 1 and 2 contains 95% barley and 3% Rumensin premix (as monensin sodium at 200 g/kg; Elanco, Guelph, ON) and 2% thiamine (DM basis); ionophore/thiamine premix of supplements 3 and 4 contains 98% barley and 1% Rumensin premix and 1% thiamine (DM basis).
5Trace mineral salt: 95% NaCl, 12,000 mg/kg Zn, 10,000 mg/kg Mn, 4,000 mg/kg Cu, 400 mg/kg I, 60 mg/kg Co, and 30 mg/kg Se.
6University of Saskatchewan vitamin A & D supplement contains 440,500 IU vitamin A and 88,000 IU vitamin D3/kg.
7Sulfur contents of barley silage and barley grain were 0.23% and 0.13% (DM), respectively. Sulfur content of supplements 1, 2, 3, and 4 were 1.93%, 0.10%, 1.03%, and 0.11% (DM basis), respectively.



View Full Table | Close Full ViewTable 2.

Chemical composition of buffers used for washing the reticulorumen and for measurement of short-chain fatty acid (SCFA) absorption across the reticulorumen epithelia

 
Chemical Washing buffer,1 mM Incubation buffer,1,2 mM
NaCl 105 5
KCl 5
CaCl2 2
MgCl2 2
Na acetate 30
K acetate 35
Na propionate 20 35
Na butyrate 8
Butyric acid 7
NaHCO3 25 25
l-Lactic acid 5
Co-EDTA 2
Na2S 0.2
Acetic acid 10
1The pH of the buffer was adjusted to 6.2.
2Osmolality ± SD of the experimental buffer was 279 ± 9.7 mOsmol/kg.



View Full Table | Close Full ViewTable 3.

The effect of dietary sulfur concentration and forage-to-concentrate ratio (F:C) on ruminal pH, ruminal short-chain fatty acid (SCFA) concentrations, and sulfur metabolites in beef heifers

 
Dietary treatments1
P-value
Item LF:C-HS LF:C-LS HF:C-HS HF:C-LS SEM F:C S F:C × S D2 F:C × D S × D F:C ×S × D
Ruminal pH
    Minimum pH 5.53 5.49 6.09 5.81 0.087 <0.01 0.08 0.17 0.86 0.02 0.89 0.43
     6.11 5.92 6.43 6.17 0.060 <0.01 <0.01 0.60 0.39 <0.01 0.04 0.18
    Maximum pH 6.72 6.54 6.84 6.64 0.053 0.05 <0.01 0.90 0.65 0.02 0.68 0.21
    Duration pH < 5.53 60.0 268.7 3.0 7.9 60.2 0.02 0.10 0.11 0.01 0.02 0.05 0.1
    Area pH < 5.54 7.12 49.30 0.48 0.34 12.17 0.04 0.11 0.11 0.01 0.01 0.01 0.01
Total SCFA,5 mM 150.0 156.3 143.8 169.5 7.86 0.77 0.05 0.18 0.85 0.35 0.51 0.79
Acetate, mM 54.4 54.1 61.1 68.9 3.21 0.01 0.26 0.24 0.95 0.03 0.72 0.79
Propionate, mM 27.3 30.5 21.7 30.2 1.89 0.14 0.01 0.19 0.39 0.26 0.05 0.36
Butyrate, mM 17.8 19.5 10.6 13.9 1.21 <0.01 0.06 0.53 0.02 0.46 0.40 0.88
H2S, g/m3 3.46 0.44 3.44 0.96 0.260 0.34 <0.01 0.31 0.22 0.19 0.42 0.71
S2–, µM 2.98 1.29 1.41 0.51 0.27 <0.01 <0.01 0.19 0.01 0.11 0.34 0.22
Serum sulfate, mg/L 174.0 141.7 169.0 135.2 3.67 0.13 < 0.01 0.81 0.11 0.48 0.69 0.90
1Dietary treatments: LF:C-HS, low F:C, high S; LF:C-LS, low F:C, low S; HF:C-HS, high F:C, high S; HF:C-LS, high F:C, low S.
2Day of sampling effect.
3Duration < 5.5 = min pH below 5.5 over 24 h.
4Area < 5.5 = min × pH below 5.5 over 24 h.
5Total SCFA = acetate + propionate + isobutyrate + butyrate + isovalerate + valerate + isocaproate + caproate.



View Full Table | Close Full ViewTable 4.

Effects of dietary sulfur concentration and forage-to-concentrate ratio (F:C) on daily urine and urinary sulfate output of beef heifers

 
Dietary treatments1
P-value
Item LF:C-HS LF:C-LS HF:C-HS HF:C-LS SEM F:C S F:C × S D2 F:C × D S × D F:C ×S × D
Urine output, L/d 9.6 13.2 13.2 15.0 1.29 0.07 0.06 0.52 1.00 0.20 0.62 0.70
Urinary sulfate, g/L 8.49 3.38 6.58 3.17 0.51 0.06 <0.01 0.11 0.07 0.19 0.42 0.30
Urinary sulfate output, g/d 80.6 44.6 86.4 47.8 5.78 0.49 <0.01 0.82 0.96 0.29 0.59 0.70
1Dietary treatments: LF:C-HS, low F:C, high S; LF:C-LS, low F:C, low S; HF:C-HS, high F:C, high S; HF:C-LS, high F:C, low S.
2Day of sampling effect.



View Full Table | Close Full ViewTable 5.

The effect of dietary sulfur concentration and forage-to-concentrate ratio (F:C) on short-chain fatty acid absorption in beef heifers

 
Dietary treatments1
P-value
Item LF:C-HS LF:C-LS HF:C-HS HF:C-LS SEM F:C S F:C × S
Fractional rate of absorption, %/h
    Acetate 32.0 50.8 14.2 25.6 6.1 <0.01 0.04 0.56
    Propionate 44.6 67.2 24.6 37.9 4.3 <0.01 <0.01 0.31
    Butyrate 46.6 67.2 32.9 48.4 4.8 <0.01 <0.01 0.61
Absolute disappearance rate, mmol/h
    Acetate 267 468 152 273 70 0.06 0.05 0.58
    Propionate 193 319 130 195 30 0.01 0.01 0.33
    Butyrate 85 136 71 101 14 0.11 0.02 0.45
1Dietary treatments: LF:C-HS, low F:C high S; LF:C-LS, low F:C low S; HF:C-HS, high F:C high S; HF:C-LS, high F:C low S.