STOCKPILING FORAGES FOR FALL GRAZING

 

Greg Cuomo, Bill Head, Dennis Johnson, and Margot Rudstrom

West Central Research and Outreach Center, University of Minnesota

 

            Small profit margins in animal production systems have highlighted the need for more extensive use of pastures by livestock producers.  A major problem with pastures in the North Central region is the relatively short growing season.  Hay or silage has traditionally been used to feed livestock when green growing pastures are not available.  In many situations, stockpiled pastures offer an excellent alternative to more expensive hay or silage feeding programs.  This paper will discuss some of the advantages and disadvantages of using stockpiled forage.  It will also discuss some preliminary findings from stockpiled forage research from the West Central Research and Outreach Center (WCROC) near Morris, Minnesota.

 

Stockpiling forage is accomplished by removing grazing animals from a pasture at some time during the growing season and allowing forage accumulation for later grazing.  Stockpiling forage can also be achieved on a field cut for hay and allowed to regrow.  

 

            The smooth brome and orchardgrass that often dominate pastures in this region generally produce the majority of their seedheads by late June.  If stockpiling is initiated after that date, a much greater percentage of the forage produced will be leaf material.  Leaf material is more readily eaten, and is of higher quality than stem material.  In addition, stems can reduce the intake of grazing animals.  When growing forage for stockpiling (or anytime forage is grown), the goal should be to provide the greatest amount of leaf material possible to grazing animals.

 

            Kind and class of livestock is an important factor when considering if stockpiling forage will be beneficial on your farm.  Generally, stockpiled forage is of moderate to poor quality.  Stockpiled forage may not meet nutrient requirements for growing or lactating animals.  However, it can economically maintain dry cows or ewes.

 

            Stockpiling has not been as widely used in the North Central States as it has in the South.  Regional growing conditions require that different forages and management strategies may be needed.  If desirable forage species and management strategies can be identified, stockpiled forage has the potential to increase the length of the grazing season and decrease the length of the hay or silage feeding in this region.

 

            The following information is from three research trials being conducted at the West Central Research and Outreach Center near Morris, MN.  The objectives of these trials were to evaluate pasture management options and animal performance for fall stockpiled forage.  One study examined stockpile initiation date and nitrogen fertilization effects on smooth bromegrass.  Stockpile initiation dates were 6/1, 6/15, 7/1, 7/15, 8/1, and 8/15.  Nitrogen fertilizer rates were 0, 50, and 100 lb. N/ac.  This trial was conducted in 1996 and 1998.  On the date of stockpile initiation, the experimental area was mowed to leave a stubble height of 3 in and N treatments were applied.  Electric fence was used to exclude cattle from the area.  Stockpiled forage was harvested in mid-October.   

            Table 1 shows the effect of stockpile initiation date on total yield and leaf yield.  Total yield generally declined as stockpile initiation date progressed later into the growing season.  However, forage stockpiled on July 1 produced just as much leaf yield as the two June dates.  By initiating stockpiling July 1 instead of June 1, there was no loss in leaf material available for fall grazing and the pasture could be used for an additional month (June) during the summer.  Initiating stockpiling after July 1 reduced total and leaf yield.

 

Table 2 shows the effect of nitrogen fertilization on stockpiled bromegrass.  There was an increase in forage and leaf yield with 50 lb. N/ac compared with unfertilized bromegrass.  In addition, stockpiled leaf yield was 40% greater for bromegrass with 50 lb. N/ac compared with unfertilized bromegrass.  One hundred pounds of nitrogen per acre did not significantly increase forage or leaf yield above 50 lb. N/ac. This is in agreement with other research that suggests that it is unlikely that an economic response to N fertilizer occurs beyond 50 lb. of N/ac when stockpiling forage for fall grazing.  From this data it appears that initiating stockpiling in early July and applying 50 lb. N/ac  results in optimal levels of forage leaf yield.

 

 

Table 1. Date of stockpiling initiation effects on total and leaf yield of smooth bromegrass harvested in mid-October 1996 and 1998.  Data presented is averaged across nitrogen fertilization treatments.  West Central Research and Outreach Center, Morris, MN.               

Stockpile initiation                    

            date                              Total yield                    Leaf yield                     Leaf content    

                                                 ----------------- lb./ac ------------------                         -- % --

June 1                                           2390b1                        1540b                              65b         

June 15                                         2600a                         1750a                              68b         

July 1                                            1890c                         1590ab                            83a         

July 15                                          1320d                         1120c                              83a

August1                                           640e                           570d                              85a                     

August 15                                        620e                           520d                              84a         

1 Within a column, means followed by the same letter are not significantly different from each other [LSD (0.05)].

 

 

Table 2. Nitrogen fertilization effects on total and leaf yield of stockpiled smooth bromegrass harvested in mid-October 1996 and 1998.  Data presented is averaged across stockpile initiation dates.  West Central Research and Outreach Center, Morris, MN.                                                   

 

Nitrogen fertilization                  Total yield                      Leaf yield                   Leaf content    

       ------------------------------ lb./ac ---------------------------------                          -- % --

            0                                       1240b1                          910b                              77b

           50                                      1670a                          1280a                             80a         

          100                                     1820a                          1350a                             78ab       

1 Within a column, means followed by the same letter are not significantly different from each other [LSD (0.05)].

            In the second trial, plots of six grass (smooth brome, orchardgrass, reed canarygrass, tall fescue, timothy, and quackgrass) and two legume species (alfalfa and birdsfoot trefoil) were evaluated for season long and stockpiled yield.  Yield by harvest and total growing-season yield is presented in Table 3.  Stockpile total and leaf yields are presented in Table 4.  Late-summer growth was greatest for tall fescue followed by orchardgrass, reed canarygrass, and birdsfoot trefoil.  When evaluating for total leaf material available for fall grazing (Table 4), tall fescue produced the most leaf material followed by orchardgrass.  Tall fescue grows well in fall and is widely used in the mid-south for stockpile grazing.  However, tall fescue can be susceptible to winter-kill in this region.  Tall fescue has persisted better in areas that have consistent snow cover (insulation) in winter.  Of the species that are frequently grown in this region, orchardgrass produces the most late-season growth for fall grazing.  Therefore, orchardgrass pastures may make a good choice for stockpiling for fall growth.   

 

Table 3. Yield by harvest and season total yield of six grass and two legume species stockpiled beginning July 15 and harvested in mid-September 1997 and 1998 at the West Central Research and Outreach Center near Morris, MN.                              

Stockpiled                   

species                                     6/1                   7/15                 8/15                 9/16        Season total  

                                                 ------------------------ lb./ac ---------------------------             --- t/a ---

Alfalfa                                    2840                  1420              1260                  1210             3.3

Birdsfoot trefoil           2170                  1210                -                      2240             2.8         

Orchardgrass                          1800                    980                -                      2580            2.7         

Quackgrass                            2760                    780                -                      1670             2.6         

Reed canarygrass                  2380                     940                 -                      2680             3.0

Smooth bromegrass              3820                      880                -                      1820             3.3         

Tall fescue                            2330                      970                 -                      3260             3.3

Timothy                                  2720                    750                 -                      1930             2.7

 

LSD 0.05                                 560                    300                -                         570             0.4         

 

 

In the third trial, Targhee cross yearling ewes were used to evaluate animal performance on stockpiled forage in 1998.  Ewes were either fed good quality smooth bromegrass hay (13.2% CP and 56.7% TDN) or strip grazed smooth bromegrass, orchardgrass, or reed canarygrass forage that had been stockpiled from 7/15 to the initiation of grazing on 9/29.  All stockpiled pastures were mowed to leave a stubble height of 3 in. and received 50 lb N/ac in mid-July.  The stockpile grazing period lasted 42 days (9/29-11/10).  During the first 21 days, ewes gained weight on the still green orchardgrass, maintained weight on the smooth bromegrass, and lost weight on the relatively coarse reed canarygrass (Table 5).  During the last 21 days, animal performance declined dramatically on all stockpiled forages.  Over the entire 42 day grazing period ewes lost 1/3 lb/day grazing stockpiled smooth bromegrass or reed canarygrass.  Ewes fed hay or grazing stockpiled orchardgrass lost about 1/10 lb/hd/d.  These results were surprising, as the forage was visually similar between the two periods.  It is hypothesized that perhaps the decaying forage on or near the soil surface reduced intake on the pastures during the last 21 days.  

Table 4. Stockpile total and leaf yield of six grass and two legume species stockpiled beginning July 15 and harvested in mid-September 1997 and 1998 at the West Central Research and Outreach Center near Morris, MN.                        

Stockpiled                   

species                                     Total yield                    Leaf yield                     Leaf content    

                                                 ----------------- lb./ac ------------------                         -- % --

Alfalfa                                           1210                            750                                 62           

Birdsfoot trefoil                  2240                           1190                                53           

Orchardgrass                                 2580                           2190                                85           

Quackgrass                                   1670                           1210                                72

Reed canarygrass                         2680                            1540                                59           

Smooth bromegrass                      1820                            1440                                79           

Tall fescue                                     3260                           2990                                92

Timothy                                          1930                          1230                                64

 

LSD at 0.05                                     570                            230                                 6            

 

Stockpiled grazing, even with some weight loss can be an acceptable management option depending on your production system.  In our study, ewes lost weight, but they were dry and open.  Once removed from pastures they were flushed and bred for May lambing. Increasing energy before breeding by feeding good quality alfalfa hay provided compensatory gain.  Reproductive performance (98% conception) was similar between the ewes that grazed stockpiled forage and ewes fed in confinement.

 

Using the results from this trial, the cost of grazing stockpiled forage and supplementing corn to maintain ewes at no change in body weight was compared to purchasing hay at $50.00/ton at several corn grain prices (Table 6). Even with the low animal performance in this trial, it would cost $4.62 to $5.25 less/ewe over 42 days to maintain them on stockpiled forage with corn supplementation as opposed to feeding hay.

           

There are two basic challenges in using stockpiled forage in the North Central region.  The first challenge is that pastures can’t be used from mid-July until grazing in fall.  Generally from mid-July until fall, forage production is low and all acres are needed for grazing.  Therefore, when using land for stockpiling, forward planning is necessary to insure forage is available for grazing during mid-summer.  The second challenge to using stockpiled forage is that snow may make stockpiled forage inaccessible to grazing animals before it is totally consumed.  Thus, when deciding if stockpiled forage has a place on your farm, tradeoffs of current season pasture use, stockpile yield, stockpile forage quality, and risks associated with snow must be considered.  However if there are animals with relatively low nutrient needs on your farm during October and November, grazing stockpiled forage may be an alternative worth considering.

 

 

 

Table 5. Weight change of Targhee cross yearling ewes fed bromegrass hay or grazing forages stockpiled from 7/15/98 until 9/29/98.

 

 

- - - - - - - - - Ewe weight change - - - - - - - -

Forage

21 days

42 days

 

- - - - - - - - - - - - - - - - lb/day - - - - - - - - - - - - - - -

Hay

-0.12

-0.09

Smooth bromegrass

0.15

-0.12

Orchardgrass

0

-0.33

Reed canarygrass

-0.14

-0.39

 

 

Table 6. Net savings per ewe over 42 days of grazing stockpiled grass supplemented with corn for maintaining body weight verses feeding hay valued at $50.00/ton at different corn prices.

 

 

- - - - - - - - - - - - - - - - Price of corn/bu - - - - - - - - - - - - - - -

Stockpiled forage

$1.70

$2.20

$2.70

 

- - - - - - - - - - - - - Savings per ewe over 42 days - - - - - - - - - - - -

Orchardgrass

$5.25

$5.22

$5.19

 

Smooth brome or Reed canarygrass

 

 

$4.83

 

 

$4.67

 

 

$4.62