Intensive Grazing/Seasonal Dairying: The Mahoning County Dairy Program

1987-1991

OARDC Research Bulletin 1190

Chapter 8: Agronomic Summary

The soils of the fields used in the study were Canfield and Ravenna silt loams, typical soils of northeast Ohio. Both soils are moderately well drained and occur on nearly level to gently sloping areas in glacial till plains.

At the beginning of the study, the soils had a moderate level of fertility, with an average pH of 6.2, lime test index (LTI) of 67, an available phosphorus level of 46 Ib/A, and potassium, 229 Ib/A. This level of fertility had been previously maintained by annual fall applications of 300 Ib/A of 0-12-46, with lime and additional phosphorus and potassium corrective applications as indicated by armual soil tests. In 1987, potash was applied to all fields at 300 lb per acre; lime was applied in the fall of 1989 at two tons per acre. Soil samples taken at the end of the study indicated that the soil fertility had been maintained at the previous level and were as follows: average pH 6.4, LTI 69, phosphorus 34 Ib/A, and potassium 249 Ib/A.

For the ten years prior to the study, seven of the ten fields had been used in a beef cow-calf pasture-hay system and were mixed grass-legume stands. Grazing was non-intensive and year-round. The original seeding was a tall fescue-birdsfoot trefoil mixture. During the ensuing ten years, other species, particularly orchard grass, white clover, and red clover, had encroached strongly into the stand. Orchardgrass was from 30% to over 50% of the stand. Good stands of legume were also present, contributing from 15 to 20% of the sward. The other three fields were in a corn-wheatalfalfa rotation, followed by four years of meadow, and seeded in 1987 to orchardgrass-alfalfa for the dairy study. In 1989 red clover was no-till drilled into the pastures in August and September to fill in bare spots resulting from dry conditions in 1988. The results of seeding were only fair to poor.

For the first year, 1987, 28 acres, divided into seven fields, were used for grazing and hay production. The three reseeded fields became available for grazing in 1988, increasing the intensively grazed and hayed acreage to 42 acres. A polywire ribbon portable electric fence was used to divide each pasture into an area sufficient for a day of grazing for the herd. The fence was pivoted from one entry point of each field and moved across the field in an arc. The daily paddocks were sized so that the mincing herd consumed about 60% of the available forage per day. It took the operator about one-half hour each day to move the fence. The plan was to graze the forage when it reached eight inches in height and graze it down to about two inches. In general, each paddock had about a 30-day recovery period, with 25 days in 1990 because of the above average rainfall. During the late springearly summer peak growth period, the recovery time was shortened to about 18 days. The grazing management provided forage that averaged about 20% crude protein, except for droughty periods of reduced growth. Heifers followed cows in most of 1988. In 1989 and 1990, heifers followed cows only in spring. In 1990, heifers were given ten of the 42 acres and rotated through it most of the year. In 1991, heifers were moved to other pasture for the entire year.

The grazing season began in mid-April and basically ended in mid-November, with the dates depending on the season, primarily early spring temperature and seasonal moisture. Some fields were harvested as hay for winter feed as large round bales, depending on grazing needs and to utilize surplus forage growth. During dry periods, this hay was also used to supplement the pasture. Fields primarily used as hay were also used as standing fall-saved forage to extend the grazing season.

The grazing periods for each year are shown below. Except for the first year, grazing began in early to mid-April and extended into November and early December. Fall-saved regrowth of hay fields cut for hay was used to extend the grazing period. Weather, particularly moisture, influenced forage production and the length of the grazing season. During periods of limited pasture, the cows were restricted to half-days on pasture with supplemental hay being fed in addition to the concentrates normally being fed. As is typical of the north-central region, occasional dry periods occurred during the grazing season. Below average rainfall occurred in 1988 and unusually high rainfall fell in 1990. Severe drought conditions occurred in 1991 as shown by the need to restrict pasture grazing in mid-summer and during the fall.

The study illustrates the value of forages in a combination grazing and hay system for smaller dairy herds under upper mid-western conditions. Asimple daily rotational grazing, using portable electric fence, enabled the operator to provide generally high quality forage for the dairy herd. During the five-year period, the operator had to cope with a range of weather conditions, from normal to unusually wet to unusually dry conditions. Despite this, good milk production was obtained.