View Full Table | Close Full ViewTable 1.

Ingredient and nutrient compositions of the experimental diets based on alfalfa hay (AH), corn stover (CS), or rice straw (RS)

 
Treatment
Item AH CS RS
Dietary ingredient, % of DM
    Ground corn grain 27.0 27.0 27.0
    Wheat bran 5.1 5.1 5.1
    Soybean meal 12.7 12.7 12.7
    Cottonseed meal 4.3 4.3 4.3
    Beet pulp 1.0 0.0 0.0
    Corn silage 15.0 15.0 15.0
    AH 23.0 0.0 0.0
    Chinese wild grass hay 7.0 0.0 0.0
    CS 0.0 30.0 0.0
    RS 0.0 0.0 30.0
    Urea 0.0 1.0 1.0
    Premix1 4.9 4.9 4.9
Nutrient composition, % of DM
    OM 92.0 ± 2.26 91.7 ± 1.69 90.6 ± 1.64
    CP 16.7 ± 0.22 16.2 ± 0.29 16.0 ± 0.46
    NDF 31.1 ± 1.73 36.3 ± 1.11 36.9 ± 1.26
    ADF 18.9 ± 1.07 19.5 ± 2.21 21.9 ± 2.53
    Nonfiber carbohydrate2 40.6 ± 3.29 36.0 ± 2.29 34.6 ± 3.66
    Na+ 0.28 0.25 0.26
    K+ 1.05 1.05 1.14
    Cl 0.49 0.61 0.54
    NEl, Mcal/kg 1.57 1.45 1.43
1Formulated to contain (per kilogram of DM) 174 g of zeolite powder, 1.25 g of yeast, 25 g of mold adsorbent (Solis Mos; Novus International Inc., St. Charles, MO), 21.44 g of KCl, 41.25 g of MgO, 150 g of NaCl, 187.5 g of NaHCO3, 84 g of Ca, 15 g of P, 125,000 IU of vitamin A, 750,000 IU of vitamin D3, 937.5 IU of vitamin E, 1,750 mg of Zn, 17.5 mg of Se, 28.75 mg of I, 375 mg of Fe, 15 mg of Co, 556.5 mg of Mn, and 343.75 mg of Cu.
2Nonfiber carbohydrate = 100 − % NDF − % CP − % ether extract − % ash.



View Full Table | Close Full ViewTable 2.

Rumen fermentation characteristics (3 h after the morning feeding) in dairy cows1 fed 3 experimental diets based on alfalfa hay (AH), corn stover (CS), or rice straw (RS) for 14 wk

 
Treatment
Item AH CS RS SEM P-value
pH 6.62 6.34 6.42 0.096 0.15
Ammonia nitrogen, mM 10.4b 13.1a 13.3a 0.69 0.02
Total VFA, mM 81.8a 66.5b 72.3ab 4.91 0.12
Acetate, mM 59.6a 45.6b 54.7ab 4.22 0.10
Propionate, mM 16.4a 15.0ab 13.0b 1.03 0.09
Butyrate, mM 5.82 5.85 4.62 0.60 0.28
Molar proportion, %
    Acetate 73.0ab 67.3b 75.9a 2.02 0.03
    Propionate 19.9ab 23.2a 18.0b 1.39 0.06
    Butyrate 7.07ab 9.52a 6.18b 1.02 0.10
    Acetate:propionate ratio 3.65ab 3.14b 4.22a 0.24 0.02
    Propionate:butyrate ratio 2.87 2.94 2.99 0.26 0.94
a,bMeans in the same row not bearing a common superscript letter are significantly different (P < 0.05).
1The number of cows for each group is 10.



View Full Table | Close Full ViewTable 3.

Average plasma glucose concentrations measured from 8 sampling times over a 24-h period (every 3 h) across mammary gland of dairy cows1 fed 3 experimental diets based on alfalfa hay (AH), corn stover (CS), or rice straw (RS)

 
Treatment
Glucose AH CS RS SEM P-value
Arterial, mM 3.04 2.97 2.89 0.053 0.18
Venous, mM 2.48a 2.46a 2.25b 0.069 0.05
AV difference,2 mM 0.55ab 0.51b 0.64a 0.044 0.13
Uptake,3 mol/d 10.2a 5.58b 5.96b 0.870 <0.01
Clearance rate,4 L/h 171.3a 95.9b 112.8b 15.71 0.01
a,bMeans in the same row not bearing a common superscript letter are significantly different (P < 0.05).
1The number of cows for each group is 10.
2AV = arterial–venous.
3Uptake = AV difference (M) × mammary plasma flow (L/d).
4Clearance rate = AV difference (mM) × mammary plasma flow (L/h)/venous concentration (mM) × 100.



View Full Table | Close Full ViewTable 4.

The concentrations of insulin, glucagon, and IGF-1 in the jugular vein, coccygeal artery, and mammary vein of dairy cows1 fed 3 diets based on alfalfa hay (AH), corn stover (CS), or rice straw (RS)

 
Treatment
Item AH CS RS SEM P-value
Jugular vein
    Insulin, μIU/mL 15.0 16.0 12.5 1.30 0.18
    Glucagon, pg/mL 82.1 82.6 81.5 3.39 0.97
    IGF-1, ng/mL 200.2 198.2 173.5 9.91 0.13
    Molar insulin:glucagon ratio 4.45 4.71 3.81 0.42 0.33
Coccygeal artery
    Insulin, μIU/mL 16.6 16.7 15.6 0.81 0.59
    Glucagon, pg/mL 87.5 92.6 91.8 3.52 0.32
    IGF-1, ng/mL 211.7a 207.8a 181.1b 7.03 0.03
    Molar insulin:glucagon ratio 4.63 4.34 4.04 0.21 0.17
Mammary vein
    Insulin, μIU/mL 17.9a 14.5b 14.2b 0.81 <0.01
    Glucagon, pg/mL 88.5 88.1 85.7 3.49 0.83
    IGF-1, ng/mL 194.6 174.1 196.8 10.54 0.28
    Molar insulin:glucagon ratio 4.95a 4.03b 4.04b 0.28 0.05
a,bMeans in the same row not bearing a common superscript letter are significantly different (P < 0.05).
1The number of cows for each group is 6.



View Full Table | Close Full ViewTable 5.

The mRNA abundance of genes related to gluconeogenesis and glycolysis in the liver of dairy cows1 fed 3 diets based on alfalfa hay (AH), corn stover (CS), or rice straw (RS)

 
Treatment
Genes2 AH CS RS SEM P-value
PC 17.2a 15.2a 6.73b 2.31 0.04
PEPCK-m 2.81a 2.38ab 1.61b 0.35 0.11
PEPCK-c 2.43 2.54 1.63 0.47 0.37
G6Pase 2.73 3.18 3.19 0.83 0.90
PFK-L 0.57a 0.34ab 0.17b 0.11 0.10
PFK-M 0.023a 0.014ab 0.010b 0.0031 0.06
PFK-P 0.081a 0.045ab 0.038b 0.0127 0.08
IGF-1 12.9 13.1 8.1 1.78 0.12
IGF-1R 31.9a 15.6ab 10.3b 6.39 0.09
a,bMeans in the same row not bearing a common superscript letter are significantly different (P < 0.05).
1The number of cows for each group is 6.
2PC = pyruvate carboxylase; PEPCK-m = mitochondrial phosphoenolpyruvate carboxykinase; PEPCK-c = cytosolic phosphoenolpyruvate carboxykinase; G6Pase = glucose-6-phosphatase; PFK-L = phosphofructokinase-liver; PFK-M = phosphofructokinase-muscle; PFK-P = phosphofructokinase-platelet; IGF-1R = IGF-1 receptor.



View Full Table | Close Full ViewTable 6.

The mRNA abundance of genes related to glucose transport and glucose utilization in the mammary gland of dairy cows1 fed 3 diets based on alfalfa hay (AH), corn stover (CS), or rice straw (RS)

 
Treatment
Genes2 AH CS RS SEM P-value
GLUT1 0.099 0.080 0.091 0.0119 0.58
GLUT3 0.20 0.18 0.12 0.036 0.32
GLUT8 0.66 0.67 0.59 0.056 0.56
B4GALT 49.3 43.8 49.0 6.33 0.79
α-LA 58.1a 37.3b 51.9ab 6.73 0.19
a,bMeans in the same row not bearing a common superscript letter tend to be different (0.05 < P < 0. 10).
1The number of cows for each group is 6.
2GLUT = glucose transporter; B4GALT = β-1,4-galactosyl transferase; α-LA = α-lactalbumin.



View Full Table | Close Full ViewTable 7.

The milk protein profile and ion concentrations in dairy cows1 fed 3 diets based on alfalfa hay (AH), corn stover (CS), or rice straw (RS)

 
Treatment
Item2 AH CS RS SEM P-value
Milk protein profiles, %
    κ-CN 8.74 7.97 7.52 0.602 0.37
    αs2-CN 11.63 11.18 10.51 0.589 0.42
    αs1-CN 30.28 31.92 32.48 0.835 0.18
    β-CN 34.3a 26.7b 35.4a 0.976 <0.01
    α-LA 5.23x 4.35y 5.00xy 0.360 0.23
    β-LG 9.82b 17.8a 9.07b 1.101 <0.01
Milk ions, mM
    Na+ 18.5ab 17.5b 19.7a 0.58 0.04
    K+ 44.3b 44.8b 47.2a 0.80 0.04
    Cl 27.6 27.4 27.8 0.23 0.44
    Na+ + K+ 62.7b 63.4ab 66.9a 0.84 <0.01
    CAD 35.2b 36.0b 39.1a 0.86 0.01
a,bMeans in the same row not bearing a common superscript letter are significantly different (P < 0.05).
x,yMeans in the same row not bearing a common superscript letter tend to be different (0.05 < P < 0. 10).
1The number of cows for each group is 10.
2CN = casein; α-LA = α-lactalbumin; LG = lactoglobulin; CAD = cation–anion difference ([Na+ + K+ − Cl] mM).