Alternative Forages for Dairy Cattle

 

Dr. L.E. Chase

Department of Animal Sciences

Cornell University

 

A wide variety of forages can be utilized in formulating rations for dairy cattle. Many of these forages fit well as emergency or substitute forages in rations. The advice of an agronomist should be used to determine which forage types fit your specific soil, fertility and climatic situation.

 

Table 1 contains typical nutrient composition for these forages. The values in this table are from samples analyzed at the Dairy One Forage Testing Lab. These values are averages for each type of forage. There will be large variations in nutrient content of each forage type due to soil type, water availability, growing season, fertilization program and maturity at harvest.

 

Table 1. Nutrient Composition of Selected Foragesa

 

Forage

Crude Protein

 

ADF

 

NDF

 

Ca

 

P

 

NE-1
 

- - - - - - - - - - - - (% of DM) - - - - - - - - - - - -

Mcal/lb

Barley Silage

11.7

35.5

56.0

.47

.30

.55

Oat Silage

13.7

39.1

58.7

.56

.31

.50

Rye Silage

14.3

36.9

57.8

.41

.36

.53

Millet Silage

16.9

34.2

59.6

.58

.28

.27

Sorghum Silage

9.4

37.8

59.6

.47

.21

.54

Sudangrass silage

12.1

38.6

62.1

.59

.26

.51

Sorghum-sudan silage

12.1

38.8

62.4

.63

.25

.50

Triticale silage

15.4

37.9

57.0

.65

.32

.52

aSource: Dairy One Forage Testing Lab

 

One example of the variation for oat hay is in Table 2. Tom Kilcer who is a Cooperative Extension agent in Renssalaer County has done similar work with Japanese millet. He has found crude protein levels ranging from 9 to 22% depending on stage of maturity, nitrogen fertilization and water availability.

 

Table 2. Nutrient Composition of Oat Haya

Maturity

Crude

Protein

 

ADF

 

NDF

 

NE-1
 

- - - - - - -(% of DM) - - - - - - -

Mcal/lb

Boot

17.5

35

58

.75

Heading

14.0

39

62

.61

Dough

11.5

34

56

.54

aPioneer Forage Manual, 1990

 

A trial was conducted at the Dairy Forage Research Center to examine the feeding value of some of these forges. Rations were formulated with a constant level of NDF in the total ration. The results of this trial are in Table 3. Note that the ratio of forage to concentrate varied due to the NDF content of each forage. Milk production was similar for all 5 forages. However, the levels of grain fed varied from 24 to 31 lbs per day.

 

 

Table 3. Milk production of dairy cows fed silages at similar ration NDF levelsa

 

Sorghum-Sudan

Silages

Orchardgrass

Silages

Alfalfa

Silages

Wheat

Silage

Corn

Silage

Forage Composition

          

DM, %

40.2

44.8

57.9

51.7

42.1

CP, %

12.8

15.5

17.2

10.2

8.3

NDF, %

54.8

48.4

45.2

54.4

41.6
           

Ration Composition

          

DM, %

55.0

57.4

64.9

64.2

57.6

CP, %

18.5

17.7

17.7

19.0

19.1

NDF, %

31.0

31.1

31.4

30.3

30.5

Forage, %

44.2

51.5

57.2

43.6

63.6
           

Animal Data

          

DMI, lbs

48.5

51.4

52.0

50.0

48.5

DMI, % BW

3.75

3.82

3.98

3.63

3.62

Total, NDF, lbs

15.0

16.0

16.3

15.2

14.8

Total, NDF, % BW

1.16

1.19

1.25

1.10

1.10

Forage NDF, lbs

11.75

12.8

13.4

11.86

112.8

Forage NDF, % BW

.91

.95

1.03

.86

.96

Milk, lbs/day

71.3

74.1

73.9

73.7

76.1

Milk fat, %

3.6

3.8

3.6

3.4

3.5

Milk protein, %

3.1

3.1

3.0

3.0

3.1

aMertens, 1996

 

 

Forage quality is the key to successfully using alternative forage sources in dairy cattle rations. Small grain silages are usually harvested at the milk to soft-dough stage of maturity to maximize energy yield per acre. The highest level of protein will be in the boot stage but this will decrease the yield per acre.

 

The following points should be considered relative to the use of alternative forages in dairy rations:

 

  1. Work closely with your field crop advisor to select the forages best suited to your soil and fertility conditions. This individual can also assist with guidelines on cultural practices and fertilization programs.
  2. Forage testing should be used to determine actual nutrient composition due to the large variations which exist within forage type. Analysis based on wet chemistry may be more accurate than NIR for these forages.

    3.  

  3. If these crops are to be ensiled, a moisture content of 65 to 70% will result in a better fermentation. This will require a field wilting period in most cases.

    4.  

  4. Rations can be balanced using NDF. Forage NDF in the total ration of 0.85-0.95% of bodyweight is a good starting point for formulation.

    5.  

  5. Be aware of the potential prussic acid concerns with sorghum-sudangrass forages. This risk can be minimized by waiting until plants are at least 30 inches tall before harvesting. Silages should be allowed to ferment for 3-4 weeks before feeding.

    6.  

  6. Timely harvest is critical to using these forages in rations for lactating dairy cows. The digestibility of many of these decrease rapidly with advancing maturity. If harvest is delayed, feed intake, digestibility and milk production will be depressed.