1121
Influence of phenological stage on fresh forage, hay and silage on nutritional value of tall wheatgrass

Wednesday, July 23, 2014
Exhibit Hall AB (Kansas City Convention Center)
Mariano Menghini , Dto. Agronomía, Universidad Nacional del Sur, Bahía Blanca, Argentina
Hugo M Arelovich , CERZOS, Bahía Blanca, Argentina
Marcela F Martínez , Dto. Agronomía, Universidad Nacional del Sur, Bahía Blanca, Argentina
Rodrigo D Bravo , Dto. Agronomía, Universidad Nacional del Sur, Bahía Blanca, Argentina
Abstract Text:

The objective was to compare the nutritional value of two methods of forage conservation and fresh forage (type of forage=TF) of tall wheatgrass (Thinopyrum ponticum) in 5 different phenological stages (PhS). The experimental units were 5 m2 plots randomly distributed upon a uniform stand of tall wheatgrass in a complete randomized design (n=3). Clipping dates were 113, 142, 163, 190 and 211 d after regrowth related to the stages vegetative (V), booting (B), anthesis (A), milk (M) and dough-grain (D) respectively, on standing fresh pasture (P), hay (H) and silage (S). Clipping was mechanical at 10 cm height and dry matter yield (DMY) was measured. Subsamples from each experimental unit were used for: (1) DM determination of P, (2) preparation of H by drying sheltered at environmental temperature (72 h), and (3) preparation of S in PVC cylinders with 2 kg fresh forage carrying capacity (60 d). All materials were analyzed for NDF, ADF, ADL, soluble non structural carbohydrates (SNSC), IVDMD and CP. Data was analyzed by ANOVA and means compared by Tukey (α=0.05). Results are reported in the Table. A significant interaction TF X PhS was found for all variables with the exception of CP and ADL. Only A could be an adequate alternative for S. However, at B, A, M and D the H conservation method would preserve an appropriate nutritive value as well.

Table. Nutritional value (%) for tall wheatgrass at different PhS and for different TF.

PhS

TF

DM

NDF

ADF

ADL

SNSC

IVDMD

CP

DMY

V

P

38.0a

70.2

35.7

3.0

15.1a

52.4

12.6

1393a

H

91.9b

67.5

35.8

2.6

13.1a

54.3

11.3

S

41.7a

66.8

37.9

3.7

1.96b

50.9

11.2

B

P

36.1a

70.3a

36.3a

4.8

23.8a

55.4a

9.5

2047a

H

91.6b

72.8b

38.5b

5.3

12.4b

47.0ab

10.0

S

37.5a

70.9ab

40.1c

6.1

3.5c

38.9b

9.07

A

P

40.8a

72.1

38.7

5.3

24.2a

50.3

7.3

3215b

H

92.4b

73.2

39.7

5.5

12.7b

46.3

8.1

S

43.4a

71.6

41.2

6.1

1.2c

43.5

7.3

M

P

51.3a

68.4a

36.9a

5.0

18.8a

49.3a

6.6

3338b

H

92.1b

71.8b

40.4ab

5.9

16.5a

48.4a

7.0

S

50.6a

72.5b

47.0b

7.2

4.9b

40.7b

7.1

D

P

60.4a

72.1

43.7

6.3

17.7a

46.7

5.5

3812b

H

92.9c

71.2

44.4

5.9

17.2a

49.8

5.7

S

63.9b

71.4

45.3

6.0

11.8b

48.2

5.2

PhS: phenological stage; TF: type of forage.

a,b,cDiffer within each PhS (P<.05)

Keywords: forage conservation, nutritional value, Thynopirum ponticum