The Virginia Tech Shenandoah Valley Agricultural Research and Extension Center (SVAREC) switched from a spring-calving herd to fall-calving six years ago. At that time, a growing body of research indicating increased profitability realized by fall- vs. spring-calving herds when reliant on tall fescue forage. The AREC herd made the switch to stay relevant to Virginia production systems as a number of herds were shifting to fall-calving.
Past work at SVAREC in a spring-calving system has indicated an increase in weaning weights when calves are provided continual access to alfalfa and endophyte-free tall fescue pasture through a creep-grazing technique. However, this system is not well-suited to fall-calving herds, where calves are on cows at a time when alfalfa has largely completed its growing cycle for the year.
Alternative forage species that may be well suited to creep grazing for fall-born calves are forage brassicas and small grains. These species can produce large amounts of very nutritious forage in only 45-60 days.
Through a project funded by the Virginia Cattle Industry board, we are utilizing existing native warm season grass pastures, which can provide forage to dry cows in the summertime, to overseed winter annual forages in late summer for creep-grazing by fall-born calves through the winter and spring. We are evaluating the production potential and profitability of such a system compared to traditional rotational stocking and continuous stocking with no creep-grazing option.
In the first year of the project, the planting was slightly delayed due to external factors. In addition, deer grazing pressure significantly impacted the growth and timing of the available forage in the creep-grazing paddocks, which delayed the time that we were able to provide creep-grazing access to the calves in the appropriate treatments. However, we were able to achieve some promising results.
The four treatments that we included in this project included:
- System 1: continuously stocked, tall fescue-based pastures
- System 2: rotationally stocked, tall fescue-based pastures
- System 3: rotationally stocked, tall fescue-based pastures with one native warm season grass paddock which is overseeded with winter annual forages for calf creep-grazing
- System 4: rotationally stocked, tall fescue-based pastures with one paddock which is seeded with winter annual forages for calf creep-grazing and summer annuals for cow grazing
Each experimental unit (16 acres) was stocked with eight cows, and treatment systems 1, 3, and 4 were replicated three times while treatment system 2 was replicated twice. Treatment system 4 was sprayed with glyphosate (2 qt/ac + 0.5% surfactant) in October 2020. Creep forage (rye at 70 lb/ac and rape cv. ‘Barsica’ at 3 lb/ac) was established in the native grass and winter annual pastures between September 24 – October 5, 2020. Fertilizer (80-0-0) was spread on the native grass and winter annual pastures on October 1, 2020. Calves were provided access to creep forage in the native grass and winter annual pastures on April 8, 2021. Calves in the continuous stocking treatment occasionally would graze cool season perennial forage by slipping under the single strand of electric wire around the hay feeding area in these treatment pastures.
Calves were weaned from dams on May 4, 2021 using a fenceline weaning method. Calves in the native warm season grass and winter annual treatments were provided access to their creep-graze paddocks in addition to another cool season grass paddock. Calves in the rotational stocking and continuous stocking treatments were given access to cool season grass paddocks. Calves were removed from paddocks 16 days later and re-weighed.
While calves were provided access to the creep-grazing paddocks, there was no difference (P=0.5574) in available forage mass between the native warm season grass paddocks (1750 ± 210 lb/ac) and the winter annual paddocks (1550 ± 210 lb/ac), but forage mass increased over time (P=0.0050).
There was no difference in the percent of the sward as rye (41 ± 11%; P=0.5739), native warm season grasses (2 ± 2%; P=0.2254), clover (7 ± 6%; P=0.2153), winter annual weeds (28 ± 14%; P=0.2685), or bare ground (5 ± 1%; P=0.4226). There was significantly more (P=0.0438) cool season perennial grasses as percent cover in the native grass pastures (29 ± 2%) than in the winter annual forage pastures (13 ± 2%).
Forage crude protein tended (P=0.0593) to be slightly higher in the native grass pastures (17.5 ± 0.6%) than in the winter annual forage pastures (15.5 ± 0.6%) and declined in both pastures over time. Forage total digestible nutrients was similar (P=0.4364) in both treatment pastures (65.9 ± 0.8%), but declined over time.
Calf weaning weights were adjusted to 205-day age adjusted weaning weights (AdjWW) using the American Angus Association dam age adjustment factors. For this analysis, we calculated 205-day age adjusted weaning weights using the weaning weight collected when calves were removed from weaning paddocks (two weeks after removing from the dam).
The AdjWW of calves in the rotational stocking treatment (442 ± 13 lb) were significantly (P≤0.0220) less than the AdjWW of calves in the continuous stocking treatment (491 ± 10 lb), native grass treatment (516 lb ± 11 lb), and winter annual treatment (513 ± 10 lb). There was no significant difference in AdjWW of the calves in the latter three treatments.
Without a full year’s worth of hay feeding and production data, we are not able to finalize our economic analysis, but we can provide some preliminary figures. Using a partial budget analysis created from the costs incurred by implementing each treatment, we compared the relative profitability of the three treatments to the control treatment (rotational stocking).
We used the VDACS 10-year average prices for steers and heifers by weight class to determine the change in gross returns to calf sales using AdjWW. With an assumed value of hay of $110/ton, we assumed that the continuous stocking treatment would be fed hay for the same amount of time as the rotational stocking treatment while the native grass and winter creep treatment would be fed hay for two less weeks and the winter and summer annuals treatment would be fed hay for four less weeks.
The significant cost of establishing the summer annuals eliminated the benefit of the increased AdjWW of the calves from that treatment, while providing creep forage in native grass pastures was slightly more profitable per cow than the control treatment (Table 1). These data should be considered as preliminary, due to the assumptions noted above and the limitations of our study due to the late fall planting and the wildlife damage to the creep-paddocks.
Table 1: Relative profitability of creep-grazing treatments for fall-born calving systems using a partial budget analysis (all numbers reported as relative difference in dollars per cow-calf pair compared to rotational stocking treatment)
|Treatment||Continuous stocking||Native warm season and creep||Winter creep and summer annuals|
|Variable costs for winter annual establishment||$0||$96.42||$96.42|
|Variable costs for summer annual establishment||$0||$0||$164.23|
|Net cost/benefit to change in hay feeding days||$0||$25.03||$50.05|
|Net change in calf sales||$82.26||$85.74||$80.93|
|Net annual profitability||$82.26||$14.34||-$129.68|
Even though we were only able to provide creep-forage to the calves for about 30 days prior to weaning, we still saw an improvement in AdjWW of around 73 lb compared to the rotational stocking treatment. We are hoping to continue this project for the next two years to determine the effect of yearly weather patterns on the project results, as well as to fully account for the costs and benefits associated with each grazing system.
~ Gabriel Pent, This work was supported through a grant funded by the Virginia Cattle Industry Board. A slightly modified version of this article was first published in the Virginia Forage and Grassland Council newsletter.
The Alliance for Grassland Renewal is a national organization focused on enhancing the appropriate adoption of novel endophyte tall fescue technology through education, incentives, self-regulation and promotion. For more resources or to learn more about the Alliance for Grassland Renewal, go to www.grasslandrenewal.org