Download Grazing Management for Forage Turnips

GRAZING MANAGEMENT FOR FORAGE TURNIPS
S.M. Jones, K.J. Simon, J.A. Jennings1
Brassicas are annual crops which grow during the fall and into the winter. They are highly
productive, digestible and contain relatively high levels of crude protein and energy. They can be
grazed 70 to 90 days after seeding, depending on the species and weather. Demonstrations
conducted in Fall of 2011showed that forage turnips planted between late August and early
September can provide green forage for grazing by the end of October. The two forage brassica
varieties used in our demonstrations in 2011 were Appin and Pasja (Ampac Seed Company). The
third brassica variety used was Seven-top. The seeding rate was 5 pounds per acre. In addition to
the brassicas, Marshall ryegrass was over seeded at 22 lbs/acre on each demonstration farm.
Under variable management among farms, acceptable dry matter yields were produced. At the
time of sampling and the start of grazing (approximately November 1) the ryegrass had not
reached adequate forage height to sample or graze. The crude protein and TDN exceeded the
nutritional requirements for all classes of livestock. Demonstrations were grazed by small
ruminants and beef cattle. A total of 15.7 acres of brassicas produced 942.4 AU grazing days.
Most livestock had not grazed forage brassicas and appeared to refuse grazing them at first turnin. On the demonstration farms we observed that the animals were reluctant to start grazing the
turnips, but grazed them readily in four or five days. Rotational or controlled grazing increased
forage utilization over continuous grazing by 40%. The amount of forage produced will depend
upon soil fertility and fertilization. The number of grazing days provided by forage turnips and
other forage brassicas will be influenced by the type of grazing method implemented.
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1
Associate Professor- Animal Science, Animal Science Forage Program Associate, ProfessorExtension Forages, respectively, University of Arkansas Division of Agriculture, Little Rock,
AR, 72204.
GRAZING MANAGEMENT FOR FORAGE TURNIPS
S.M. Jones, K.J. Simon, J.A. Jennings1
Abstract
Brassicas are annual crops which grow during the fall and into the winter. They are highly
productive, digestible and contain relatively high levels of crude protein and energy. They can be
grazed 70 to 90 days after seeding, depending on the species and weather. Proper grazing
management is important to optimize the true potential of these crops. Four on-farm
demonstrations were established in 2011 with the objectives of 1) evaluating potential forage
turnip yield; 2) evaluate the potential of extending fall and winter grazing with turnips and 3)
measure the cost of production. Demonstrations were planted from the last week of August
through the third week of September. The two forage brassica varieties used in our
demonstrations in 2011 were Appin and Pasja (Ampac Seed Company). The third brassica
variety used was Seven-top, commonly used as a vegetable crop, but has a history of being used
as a forage crop for small ruminants and in deer food plots in Arkansas. The seeding rate was 5
pounds per acre. In addition to the brassicas, Marshall ryegrass was over seeded at 22 lbs/acre on
each demonstration farm. Under variable management among farms, acceptable dry matter
yields were produced. Appin turnips yielded 2482 pounds of dry matter per acre, crude protein
was 27.94% and TDN was 77.45. (With recommended fertilization, Appin produced 2992
pounds of dry matter/acre). Pasja turnips yielded 1615 pounds of dry matter per acre, crude
protein was 31.44% and TDN was 75.3%. The Seven-Top turnips yielded 2049 pounds of dry
matter per acre, crude protein was 31.02% and TDN was 78.5%. One note, the seven-top was
fertilized, while some plots of Appin and Pasja were not. At the time of sampling and the start of
grazing (approximately November 1) the ryegrass had not reached adequate forage height to
sample or graze. The crude protein and TDN exceeded the nutritional requirements for all classes
of livestock. Grazing was initiated when the plants reached 12-18 inches tall and livestock
terminated when the forage was grazed to 6-10 inches in height. Forage production was
calculated as animal unit (AU) grazing days per acre based on the number, weight and nutrient
requirements of animals on each farm. Demonstrations were grazed by small ruminants and beef
cattle. A total of 15.7 acres of brassicas produced 942 AU grazing days. Mean of cost savings per
AU was $179.10. Cost savings were calculated by subtracting total cost of seed and fertilizer
___________________
1
Associate Professor- Animal Science, Animal Science Forage Program Associate, ProfessorExtension Forages, respectively, University of Arkansas Division of Agriculture, Little Rock,
AR, 72204.
from the total cost of hay and/or grain supplement that would have been fed without the
brassicas. Most livestock had not grazed forage brassicas and appeared to refuse grazing them at
first turn-in. On the demonstration farms we observed that the animals were reluctant to start
grazing the turnips, but grazed them readily in four or five days. Proper grazing management is
important to optimize the true potential of these crops. Rotational or controlled grazing
increased forage utilization over continuous grazing by 40%. Grazing large areas increased
trampling and waste of the available forage. Strip grazing small areas provided the most
efficient utilization. Forage turnips can produce high yields of palatable and nutritious forage for
livestock during periods when perennial forages have limited production. The digestibility of the
forage remains high over a relatively longer period than perennial crops. To improve forage yield
potential, apply fertilizer according to soil test recommendations. Proper grazing management
can increase the number of grazing days by 40% percent over continuous grazing. Plan for a
transition and adjustment period to allow livestock time to accept this new forage.