View Full Table | Close Full ViewTable 1.

Forage quality measurements of subirrigated meadow and upland native range grass samples taken with esophageally fistulated cows at 5 time points throughout the grazing season for Exp. 1

 
Treatment
Item1 Meadow Range SEM P-value
CP, % DM 11.9 10.0 0.74 0.10
RUP,2 % DM 1.58 1.94 0.130 0.09
TTIDP,3 % DM 1.07 1.46 0.145 0.09
RUP,2 % CP 13.4 19.7 1.49 0.02
TTIDP,3 % CP 9.3 15.0 1.88 0.06
RUP digestibility,4 % 32.8 24.3 6.66 0.72
Digested RUP,5 % DM 0.52 0.49 0.117 0.87
IVDMD, % DM 60.8 60.3 3.18 0.90
1For each variable measured n = 10.
2RUP = measured using rumen incubations equal to 75% of total mean retention time: CP weight of residue after rumen incubation (g)/DM weighed into the bags (g) = RUP (% DM). CP weight of residue after rumen incubation (g)/CP weighed into the bags (g) = RUP (% CP).
3TTIDP = total tract indigestible protein: CP weight of residue after duodenal incubation (g)/DM weighed into the bags (g) = TTIDP (% DM). CP weight of residue after duodenal incubation (g)/CP weighed into the bags (g) = TTIDP (% CP).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − TTIDP (% DM).



View Full Table | Close Full ViewTable 2.

Forage quality measurements of subirrigated meadow and upland native range grass samples taken with esophageally fistulated cows at 5 time points throughout the grazing season for Exp. 1

 
Orthogonal contrasts
Item1 May (cycle 1) June (cycle 2) July (cycle 3) August (cycle 4) September (cycle 5) SEM Linear Quadratic
CP, % DM 12.9 10.9 11.2 10.8 8.9 1.23 0.04 0.87
RUP,2 % DM 1.73 1.92 1.56 1.78 1.81 0.294 0.99 0.81
TTIDP,3 % DM 0.98 1.15 1.17 1.44 1.61 0.268 <0.01 0.40
RUP,2 % CP 13.6 17.8 14.2 17.2 20.0 3.62 0.13 0.64
TTIDP,3 % CP 7.7 10.7 10.7 13.9 17.8 3.26 0.01 0.51
RUP digestibility,4 % 41.8 39.6 25.7 19.1 10.8 3.23 0.11 0.34
Digested RUP,5 % DM 0.75 0.77 0.39 0.34 0.21 0.084 0.06 0.27
IVDMD, % DM 68.9 65.5 60.3 56.5 51.4 1.30 0.60 0.11
1For each variable measured n = 10.
2RUP = measured using rumen incubations equal to 75% of total mean retention time: CP weight of residue after rumen incubation (g)/DM weighed into the bags (g) = RUP (% DM). CP weight of residue after rumen incubation (g)/CP weighed into the bags (g) = RUP (% CP).
3TTIDP = total tract indigestible protein: CP weight of residue after duodenal incubation (g)/DM weighed into the bags (g) = TTIDP (% DM). CP weight of residue after duodenal incubation (g)/CP weighed into the bags (g) = TTIDP (% CP).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − TTIDP (% DM).



View Full Table | Close Full ViewTable 3.

Scatterplot data showing the relationship between forage quality factors in subirrigated meadow and upland native range grass samples taken with esophageally fistulated cows at 5 time points throughout the grazing season in Exp. 1

 
x axis variable1 y axis variable Regression equation (SE) r2 P-value
IVDMD, % DM CP, % DM y = 0.19(0.07)x − 0.33(4.40) 0.453 0.03
IVDMD, % DM RUP,2 % DM y = 0.001(0.001)x + 1.67(1.07) 0.001 0.94
IVDMD, % DM TTIDP,3 % DM y = −0.03(0.02)x + 3.23(0.95) 0.349 0.07
IVDMD, % DM RUP digestibility,4 % y = 2.00(0.24)x − 95.3(14.5) 0.898 <0.01
IVDMD, % DM Digested RUP,5 % DM y = 0.03(0.01)x − 1.48(0.37) 0.785 <0.01
CP, % DM RUP,2 % DM y = −0.02(0.06)x + 2.02(0.70) 0.018 0.71
CP, % DM TTIDP,3 % DM y = −0.11(0.06)x + 2.47(0.65) 0.306 0.10
CP, % DM RUP digestibility,4 % y = 5.36(1.93)x − 32.6(21.4) 0.492 0.02
CP, % DM Digested RUP,5 % DM y = 0.08(0.04)x − 0.32(0.43) 0.322 0.09
1For each variable measured n = 10.
2RUP = measured using rumen incubations equal to 75% of total mean retention time.
3TTIDP = total tract indigestible protein: CP weight of residue (g)/DM weighed into the bags (g).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − TTIDP (% DM).



View Full Table | Close Full ViewTable 4.

Forage quality measurements of warm-season grass samples taken with esophageally fistulated cows at 8 time points throughout the grazing season for Exp. 2

 
Orthogonal contrasts
Item1 Early June (cycle 1) Late June (cycle 2) Early July (cycle 3) Late July (cycle 4) Early August (cycle 5) Mid-August (cycle 6) Early September (cycle 7) Late September (cycle 8) SEM Linear Quadratic
CP, % DM 13.4 12.6 11.4 10.0 9.8 10.9 11.4 10.4 0.68 <0.01 0.46
RUP,2 % DM 3.09 4.20 5.04 4.13 3.84 5.04 5.30 3.85 0.377 0.21 <0.01
TTIDP,3 % DM 1.36 1.74 2.08 1.86 1.73 2.64 2.79 2.22 0.247 0.20 0.06
RUP,2 % CP 23.5 33.2 43.0 39.4 39.4 50.5 46.3 38.1 5.11 0.02 0.07
TTIDP,3 % CP 10.3 13.8 17.7 17.7 17.8 26.5 24.5 22.0 3.20 0.04 0.25
RUP digestibility,4 % 55.7 58.6 58.9 55.0 55.0 47.5 47.3 42.5 2.92 0.67 0.43
Digested RUP,5 % DM 1.73 2.46 2.96 2.27 2.12 2.40 2.51 1.63 0.206 0.40 0.01
IVOMD,6 % OM 58.3 54.6 51.6 55.2 49.6 55.3 48.8 53.8 0.04 0.24 0.86
1For each variable measured n = 16.
2RUP = measured using rumen incubations equal to 75% of total mean retention time: CP weight of residue after rumen incubation (g)/DM weighed into the bags (g) = RUP (% DM). CP weight of residue after rumen incubation (g)/CP weighed into the bags (g) = RUP (% CP).
3TTIDP = total tract indigestible protein: CP weight of residue after duodenal incubation (g)/DM weighed into the bags (g) = TTIDP (% DM). CP weight of residue after duodenal incubation (g)/CP weighed into the bags (g) = TTIDP (% CP).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − TTIDP (% DM).
6IVOMD = in vitro OM disappearance.



View Full Table | Close Full ViewTable 5.

Scatterplot data showing the relationship between forage quality factors in warm-season grass samples taken with esophageally fistulated cows at 8 time points throughout the grazing season in Exp. 2

 
x axis variable1 y axis variable Regression equation (SE) r2 P-value
IVOMD,2 % OM CP, % DM y = 12.5(6.25)x + 4.53(3.35) 0.223 0.06
IVOMD, % OM RUP,3 % DM y = −7.64(3.68)x + 8.39(1.97) 0.235 0.06
IVOMD, % OM TTIDP,4 % DM y = −4.83(2.38)x + 4.63(1.28) 0.228 0.06
IVOMD, % OM RUP digestibility,5 % y = 21.6(32.9)x + 41.1(17.7) 0.146 0.52
IVOMD, % OM Digested RUP,6 % DM y = −2.77(2.47)x + 3.74(1.32) 0.097 0.47
CP, % DM RUP,3 % DM y = −0.21(0.15)x + 6.70(1.67) 0.129 0.17
CP, % DM TTIDP,4 % DM y = −0.16(0.09)x + 3.88(1.04) 0.182 0.10
CP, % DM RUP digestibility,5 % y = 1.43(1.20)x + 36.6(13.6) 0.092 0.25
CP, % DM Digested RUP,6 % DM y = −0.05(0.09)x + 2.82(1.05) 0.022 0.49
1For each variable measured n = 16.
2IVOMD = in vitro OM disappearance.
3RUP = measured using rumen incubations equal to 75% of total mean retention time.
4TTIDP = total tract indigestible protein: CP weight of residue (g)/DM weighed into the bags (g).
5RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
6Digested RUP = RUP (% DM) − TTIDP (% DM).



View Full Table | Close Full ViewTable 6.

Forage quality measurements of subirrigated meadow grass samples taken with esophageally fistulated cows at 10 time points throughout the grazing season for Exp. 3

 
Orthogonal contrasts
Item1 Mid-May (cycle 1) Late May (cycle 2) Early June (cycle 3) June 12–13 (cycle 4) June 20 (cycle 5) Late June (cycle 6) Early July (cycle 7) Mid-July (cycle 8) Late July (cycle 9) Early August (cycle 10) SEM Linear Quadratic
CP, % DM 16.0 13.2 11.3 11.5 10.8 12.1 11.0 11.2 11.4 11.5 1.29 0.43 0.32
RUP,2 % DM 0.98 1.04 1.74 1.52 1.68 1.64 1.62 1.59 1.77 1.71 0.121 <0.01 0.15
TTIDP,3 % DM 0.40 0.72 0.73 0.94 0.97 0.82 0.85 1.03 1.19 1.11 0.113 <0.01 0.40
RUP,2 % CP 6.2 7.9 15.4 13.3 15.7 13.6 14.8 15.0 16.2 15.5 2.25 <0.01 0.35
TTIDP,3 % CP 2.5 5.4 6.5 8.2 9.1 6.9 7.7 9.6 11.0 10.1 1.69 0.02 0.61
RUP digestibility,4 % 58.5 31.5 57.5 38.5 42.5 50.0 47.5 35.5 33.0 35.0 4.51 0.11 0.34
Digested RUP,5 % DM 0.58 0.32 1.01 0.59 0.71 0.83 0.78 0.56 0.58 0.60 0.080 0.06 0.27
IVDMD, % DM 60.0 64.1 63.7 59.6 56.1 54.3 52.7 47.2 51.3 56.2 4.70 0.43 0.32
1For each variable measured n = 20.
2RUP = measured using rumen incubations equal to 75% of total mean retention time: CP weight of residue after rumen incubation (g)/DM weighed into the bags (g) = RUP (% DM). CP weight of residue after rumen incubation (g)/CP weighed into the bags (g) = RUP (% CP).
3TTIDP = total tract indigestible protein: CP weight of residue after duodenal incubation (g)/DM weighed into the bags (g) = TTIDP (% DM). CP weight of residue after duodenal incubation (g)/CP weighed into the bags (g) = TTIDP (% CP).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − (TTIDP (% DM).



View Full Table | Close Full ViewTable 7.

Scatterplot data showing the relationship between forage quality factors in subirrigated meadow grass samples taken with esophageally fistulated cows at 10 time points throughout the grazing season in Exp. 3

 
x axis variable1 y axis variable Regression equation (SE) r2 P-value
IVDMD, % DM CP, % DM y = 0.02(0.07)x + 11.0(3.79) 0.004 0.80
IVDMD, % DM RUP,2 % DM y = −0.01(0.01)x + 1.86(0.56) 0.019 0.56
IVDMD, % DM TTIDP,3 % DM y = −0.01(0.01)x + 1.48(0.45) 0.093 0.19
IVDMD, % DM RUP digestibility,4 % y = 0.004(0.003)x + 0.22(0.20) 0.062 0.29
IVDMD, % DM Digested RUP,5 % DM y = 0.004(0.01)x + 0.41(0.37) 0.025 0.51
CP, % DM RUP,2 % DM y = −0.10(0.03)x + 2.76(0.31) 0.475 <0.01
CP, % DM TTIDP,3 % DM y = −0.08(0.02)x + 1.81(0.27) 0.397 <0.01
CP, % DM RUP digestibility,4 % y = 0.02(0.01)x + 0.24(0.15) 0.089 0.20
CP, % DM Digested RUP,5 % DM y = −0.03(0.02)x + 0.96(0.27) 0.068 0.27
1For each variable measured n = 20.
2RUP = measured using rumen incubations equal to 75% of total mean retention time.
3TTIDP = total tract indigestible protein: CP weight of residue (g)/DM weighed into the bags (g).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − TTIDP (% DM).



View Full Table | Close Full ViewTable 8.

Forage quality measurements of smooth bromegrass samples taken with ruminally fistulated steers at 5 time points throughout the grazing season for Exp. 4

 
Treatment1
Item Cont Fert SEM P-value Treatment × cycle
CP, % DM 14.2 16.5 0.71 0.03 0.14
RUP,2 % DM 1.98 2.08 0.128 0.56 0.84
TTIDP,3 % DM 1.10 1.11 0.074 0.94 0.90
RUP,2 % CP 14.0 12.5 0.79 0.20 0.82
TTIDP,3 % CP 7.9 6.8 0.56 0.20 0.61
RUP digestibility,4 % 44.3 46.7 1.86 0.62 0.25
Digested RUP,5 % DM 0.87 0.97 0.074 0.35 0.34
IVDMD, % DM 59.4 60.1 1.83 0.76 0.99
1Treatments consisted of Cont [control pastures with no treatment applied and cattle initially stocked at 6.8 animal unit months (AUM)/ha] or Fert (pastures that were fertilized in the spring with 90 kg N/ha and stocked at 9.9 AUM/ha). For each variable measured n = 30.
2RUP = measured using rumen incubations equal to 75% of total mean retention time: CP weight of residue after rumen incubation (g)/DM weighed into the bags (g) = RUP (% DM). CP weight of residue after rumen incubation (g)/CP weighed into the bags (g) = RUP (% CP).
3TTIDP = total tract indigestible protein: CP weight of residue after duodenal incubation (g)/DM weighed into the bags (g) = TTIDP (% DM). CP weight of residue after duodenal incubation (g)/CP weighed into the bags (g) = TTIDP (% CP).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − TTIDP (% DM).



View Full Table | Close Full ViewTable 9.

Forage quality measurements of smooth bromegrass samples taken with ruminally fistulated steers at 5 time points throughout the grazing season for Exp. 4

 
Orthogonal contrasts
Item1 May (cycle 1) June (cycle 2) July (cycle 3) August (cycle 4) September (cycle 5) SEM Linear Quadratic
CP, % DM 18.6 13.7 13.7 15.3 15.5 1.01 0.11 <0.01
RUP,2 % DM 2.64 1.59 1.78 1.99 2.14 0.203 0.33 <0.01
TTIDP,3 % DM 1.33 0.82 0.94 1.16 1.30 0.117 0.42 <0.01
RUP,2 % CP 14.4 11.7 13.1 13.2 14.1 1.25 0.83 0.19
TTIDP,3 % CP 7.4 6.0 7.0 7.6 8.6 0.88 0.15 0.19
RUP digestibility,4 % 50.2 48.3 46.8 41.7 39.0 2.93 <0.01 0.77
Digested RUP,5 % DM 1.31 0.78 0.84 0.84 0.84 0.117 0.03 0.03
IVDMD, % DM 68.1 59.6 56.1 59.0 56.0 2.35 <0.01 0.06
1For each variable measured n = 30.
2RUP = measured using rumen incubations equal to 75% of total mean retention time: CP weight of residue after rumen incubation (g)/DM weighed into the bags (g) = RUP (% DM). CP weight of residue after rumen incubation (g)/CP weighed into the bags (g) = RUP (% CP).
3TTIDP = total tract indigestible protein: CP weight of residue after duodenal incubation (g)/DM weighed into the bags (g) = TTIDP (% DM). CP weight of residue after duodenal incubation (g)/CP weighed into the bags (g) = TTIDP (% CP).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − TTIDP (% DM).



View Full Table | Close Full ViewTable 10.

Scatterplot data showing the relationship between forage quality factors in smooth bromegrass samples taken with ruminally fistulated steers at 5 time points throughout the grazing season in Exp. 4

 
x axis variable1 y axis variable Regression equation (SE) r2 P-value
IVDMD, % DM CP, % DM y = 0.25(0.06)x + 0.67(3.90) 0.339 <0.01
IVDMD, % DM RUP,2 % DM y = 0.01(0.02)x + 1.38(0.91) 0.018 0.48
IVDMD, % DM TTIDP,3 % DM y = −0.01(0.01)x + 1.41(0.51) 0.013 0.55
IVDMD, % DM RUP digestibility,4 % y = 0.01(0.002)x + 0.15(0.12) 0.195 0.01
IVDMD, % DM Digested RUP,5 % DM y = 0.02(0.01)x − 0.02(0.52) 0.108 0.08
CP, % DM RUP,2 % DM y = 0.12(0.03)x + 0.13(0.43) 0.419 <0.01
CP, % DM TTIDP,3 % DM y = 0.04(0.02)x + 0.50(0.30) 0.134 0.05
CP, % DM RUP digestibility,4 % y = 0.01(0.01)x + 0.28(0.07) 0.164 0.03
CP, % DM Digested RUP,5 % DM y = 0.08(0.01)x − 0.37(0.23) 0.542 <0.01
1For each variable measured n = 30.
2RUP = measured using rumen incubations equal to 75% of total mean retention time.
3TTIDP = total tract indigestible protein: CP weight of residue (g)/DM weighed into the bags (g).
4RUP digestibility = 1 − [TTIDP (% DM)/RUP (% DM)].
5Digested RUP = RUP (% DM) − TTIDP (% DM).