GRAZING ANNUAL FORAGES

Grazing Annual Forages
- Animal Performance Summary -

W.W. Poland, P.M. Carr and L.J. Tisor

NDSU Dickinson Research Extension Center

Impact Statement

Research has demonstrated that barley, oat, pea and Siberian millet can be used to provide productive annual pastures when grazed singularly or in sequence during the summer in the Northern Great Plains.

Summary

Beef cattle have grazed annual forages at the Dickinson RE Center for eight years (4 yrs. with cow/calf pairs; 4 yrs. with bred heifers). Stocking rate (animal unit/mo; AUM) and animal performance varied from year to year and crop to crop. Seasonal stocking rate averaged .9 AUM/ac; individual animal performance averaged 2.5 lb/d for suckling calves and 2.0 lb/d for bred heifers; and live weight gain averaged 71 lb/ac. Although the potential for grazing cattle on annual forages is quite promising, further research is needed to identify promising forage species for grazing and establish potential forage sequences and optimal seeding dates, initial grazing dates, stocking rates, and grazing management appropriate for annual forage pastures.

Introduction

Prices received for agricultural commodities are often low compared to the high costs of production. This results in relatively low net returns per acre for the amount of capital invested. Traditional cropping systems in the Northern Great Plains include continuous small grains or a small grain-fallow rotation. However as governmental control of agricultural production recedes, producers are being given greater flexibility in the development of unique farming plans. As producers contemplate possible cropping decisions, crop rotations involving annual forages are gaining in popularity among diversified operations that manage both crops and cattle enterprises.

Annual forage production can provide a basis for establishing an integrated system between crop and cattle production. Annual forages offer crop producers a wider variety of alternative crops that can be included in a rotating crop sequence. In addition to diversified agricultural operations, when cattle and crops are produced in close proximity, local livestock can create a readily-available market for excess forage production.

Cattle enterprises can also benefit from integrated crop-livestock systems. Expanding annual forage production within the region would expand the total feed base available to cattle producers. Using this forage within the context of a grazing system should help reduce costs of beef production, while simultaneously generating revenue on crop acreage.

These experiments were designed to evaluate the potential of using annual crops and intercrops as grazable forage for beef cattle during the summer months within the context of an integrated crop-livestock system. In addition to documenting livestock production, forage production and quality and economic returns to various harvesting options have been evaluated and being reported elsewhere.

Materials and Methods

In each of four years (1993-1996), crossbred cow/calf pairs (animal unit [AU]=cow/calf pair) grazed on sequences of annual forages. Eight paddocks (8.3 ac/paddock) were arranged into two, 4-pasture blocks. Within each block, annual forages were randomly seeded (Table 1) into individual paddocks and grazed sequentially with a constant stocking rate (2.05, 1.45 and 1.2 AU/ac in 1993, 1994 and 1995/1996, respectively). Annual forages selected for grazing evaluation included: winter rye, cereal/pea intercrop, and millets (Siberian and Pearl). Use of Pearl millet was discontinued in 1994 due to agronomic difficulties and replaced by barley in 1995 and 1996. Within each year, the desired grazing management involved grazing rye in May, cereal/pea in June, Pearl millet or barley in July and Siberian millet in August. Calves were weighed at the initiation and termination of grazing in each pasture. Average daily gain, gain per acre and accumulated grazing days (AUM/ac) were used to evaluate the grazing potential of each forage type. A complete description of grazing evaluations between 1993-1994 and 1995-1996 is given in Manske and Nelson (1996) and Poland et al. (1996), respectively.

Table 1. Seeding and grazing dates and stocking rates for beef cattle grazing annual forages at Dickinson RE Center.

Year/Forage Type

Seeding date

Grazing dates

Days

AUM^a/acre

1993^b

01June - 30September

.96

OP intercrop^c

Pearl millet

Siberian millet

Pearl millet

24April

Early May

Early June

Mid July

13July - 27July

not grazed

01September - 15September

08October - 14October

15September - 08October

.94

1.34

1.54

1994

01June - 30September

.79

Winter rye

OP intercrop

Pearl millet^d

Siberian millet

August, 1993

07May

not seeded

Early June

15June - 13July

14July - 08August

23August - 06September

.64

1.23

.66

1995

15May - 31August

.76

Winter rye

CP intercrop^c

Barley^d

Siberian Millet

August, 1993

03May

01June

12June

15May - 30May

29June - 26July

27July - 11August

12August - 30August

.59

1.07

.62

.75

1996

15May - 31August

.67

Winter rye

CP intercrop

Barley

Siberian Millet

May, 1995

20April

24May

29June

28May - 10June

14June - 01July

16July - 06August

07August - 23August

.52

.68

.83

.68

1998-1999

15June - 15August

.89

Oat and Pea

Barley and Lentil

Late April

Early June

17June - 18July

20July - 18August

28^e

.93

.84^e

2000

01July - 29July

1.10

Barley

Oat

16May

03July - 31July

1.10

2000-2001

01August - 29August

1.02

Barley

Millet

Millet/Alfalfa

Millet/Sweetclover

Alfalfa

Sweetclover

Pea

Early June

Mid May

Early June

02August - 04September

02August - 12September

02August - 08September

02August - 06September

02August - 30August

02August - 02September

02August - 03September

.99

1.23

1.11

1.05

.84

.93

.96

^a Animal unit month or the equivalent of one cow-calf pair grazing for one month. Bred heifers were considered to be .75 animal unit. ^b Stocking rates were 2.05, 1.45, 1.2, 1.2 and .9 animal units per acre in 1993, 1994, 1995, 1996 and 1998, respectively. ^c OP and CP refer to oat-pea and oat-pea-winter rye intercrops, respectively. ^d Use of Pearl millet discontinued in 1994; replaced by barley in 1995 and 1996. ^e Grazing initiated in lentil pastures on August 5 resulting in 12 grazing days in 1998. Grazing terminated in lentil pastures on August 5 resulting in 15 grazing days in 1999. Table numbers reflect on grazing days and stocking rate for barley and intercrop.

In each of two years (1998-1999; Poland et al., 1998), 12 paddocks (2.5 ac/paddock) were blocked into two, 6-paddock groups (2 paddocks/forage type). One group was seeded to pea, oat or oat-pea intercrop, while the other group was seeded to lentil, barley or barley-lentil intercrop. Paddocks were grazed by bred beef heifers (.75 AU/heifer) at a constant stocking rate of .9 AU/ac. Paddocks seeded (Table 1) to pea/oat combinations were grazed first (mid June to mid July), followed by paddocks seeded to the barley-lentil combinations (mid July to mid August). Grazing potential of each forage type was evaluated as in earlier experiments. Portions of this material is based upon work supported by the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture, under Agreement No. 96-34216-2539.

In one year (2000; Poland et al., 2001), six paddocks were seeded to either oat or barley (3 paddocks/forage type) and grazed by bred beef heifers in July (Table 1) at a constant stocking rate of 1.2 AU/ac. Grazing potential of each forage type evaluated as in earlier experiments.

In each of two years (2000-2001; Poland et al., 2000; Poland and Carr, 2002), 18 paddocks were seeded to either barley, Siberian millet, alfalfa, sweetclover, field pea, Siberian millet/alfalfa or Siberian millet/sweetclover (4 paddocks/forage type for Siberian millet and pea and 2 paddocks/forage type for remaining types). Paddocks were grazed in August (Table 1) at a constant stocking rate of .9 AU/ac. Grazing potential of each forage type evaluated as in earlier experiments. Portions of this material is based upon work supported by the North Central Region - Sustainable Agriculture Research and Education, U.S. Department of Agriculture, under Project No. LNC99-153.

Results and Discussion

Seeding and grazing dates and accumulated grazing days per acre are presented in Table 1. With the exception of 1993, most paddocks were grazed between 15 May and 31 August. Under the grazing management imposed, sequences of annual forages accumulated an average of .9 AUM/ac. A hypothetical, 640-ac pasture seeded to an appropriate sequence of annual forages would be expected to support 165 animal units for 3.5 mo (approximately 15 May - 31 August).

Suckling calf performance (4 years; 1993-1996) is summarized in Table 2. Although there was considerable variation within forage types both among and between years, annual performance averaged 2.48 lb/head/d and 66.0 lb/ac. The 165-cow herd in the previous example would be expected to add 260 to 280 lb per calf over the summer period (3.5 mo). A calf with a 75 lb birth weight that had gained 120 lb (60 days of age gaining at 2.0 lb/d) prior to moving to annual forage pastures would weigh approximately 465 lb (75+120+270) by the end of August.

Bred heifer performance (4 years; 1998-2001) is also presented in Table 2. Heifers averaged 2.0 lbs./d from mid June to early September. Typical summer grazing performance for bred heifers at DREC is 1.0 lb/d (Ringwall et al., 1998). Heifer live weight gain per acre (75.4 lb/ac) was slightly greater than average suckling calf performance reported in previous years. The hypothetical pasture (640 ac) would support 220 yearling beef heifers (165 AU) for 3.5 months and produce approximately 210 to 220 lb of live weight gain per heifer over the summer grazing period.

Table 2. Cattle performance while grazing annual forages at Dickinson RE Center.

Year/Forage Type

Average daily gain

lb/d

SE^a

Gain per acre

lb/ac

--------------------------- Suckling calf performance -------------------------

1993^b

2.46

--^c

91.0

OP intercrop^d

Pearl millet^e

Siberian millet

3.01

1.29

3.07

86.3

61.0

125.6

1994

2.16

57.8

Winter rye

OP intercrop

Siberian millet

1.20

2.48

2.81

23.4

93.1

56.9

1995

2.50

.002

58.0

.0005

Winter rye

CP intercrop

Barley^e

Siberian Millet

2.22

2.02

3.61

2.48

.071

.060

.442

.335

40.2

65.6

69.5

56.8

1.27

1.98

8.49

7.71

1996

2.79

.179

57.2

3.68

Winter rye

CP intercrop

Barley

Siberian Millet

2.22

2.53

3.18

3.03

.240

.046

.202

.329

34.7

51.9

80.4

62.0

3.75

.92

5.16

6.72

----------------------------- Bred heifer performance ----------------------------

1998-1999

1.82

59.4

Oat

Pea

OP intercrop

Barley

Lentil

BL intercrop

1.30

1.24

1.17

2.68

1.93

2.63

.45^g

48.7

46.2

45.0

91.2

36.1

88.9

13.4^g

2000

1.91

85.5

Barley

Oat

1.89

1.93

.15^g