Beef Cow-Calf Productivity as Influenced by Forage-Management Systems
Published by the Office of Agricultural Communications, Division of Agriculture, Forestry, and Veterinary Medicine, Mississippi State University. Edited by Keith H. Remy, Senior Publications Editor.
A 4-year study was conducted at the Pontotoc Ridge-Flatwoods Branch Experiment Station in north Mississippi to compare three forage systems, each stocked with 15 cow-calf pairs. The forage systems were System 1, 30 acres (2 paddocks); System 2, 15 acres (3 paddocks); and System 3, 15 acres (4 paddocks, with two available for creep grazing by calves). Cow production efficiency (pounds of calf weaned per cow weight at weaning) was above 50% for all groups. Conception rates of cows averaged 87% and average calving interval was 369 days with no treatment differences (P>.05). Calf weaning weights were above 500 pounds for all three treatment groups. Cost of calf production was lowest ($0.31/pound) and total net income was highest ($2,205) for System 1, but profit per acre was greatest for System 2 ($116/acre).
As reported at the American Forage and Grassland Council annual meeting (Thompson, 1995), beef cattle and calves are the largest commodity, in terms of gross sales, of any agricultural commodity in the United States. Of the estimated 41,000 farms in Mississippi, 28,000 have a livestock component.
With the fluctuations in prices paid for livestock, it is imperative for ranchers to produce beef as cheaply and efficiently as possible. Pogue et al. (1996) reported that grazed forages are approximately one-third the cost of stored forages, based on per pound of TDN. Several studies have been conducted to measure increases in cow-calf productivity by utilizing legumes in the grazing system (Hoveland et al., 1978; Morrow et al., 1988; Stricker et al., 1979); by altering beef cow stocking rates and utilizing relatively high rates of nitrogen fertilizer (Bagley et al., 1987a); by utilizing large-frame breeds of cattle in grazing systems (Oliver, 1978; Knox et al., 1982; Gregory et al., 1978); and by utilizing a fall calving season (Bagley et al., 1987b; Gaertner et al., 1992; Ivy et al., 1995). Each of these management tools can have an impact on forage-livestock system productivity. However, because of the differences of cattle types, soil types, available forages, and climatic conditions, the effects of forage-livestock management systems need to be evaluated over a wide variety of climates, cattle types, and soil conditions.
The objectives of this experiment were to measure the effects that different forage management systems had on cow-calf production characteristics, forage production characteristics, and estimated economic returns (both per cow and per acre) for the forage-based cow-calf management systems.
Materials and Methods
Three forage-animal management systems were compared in a study initially utilizing 45 Angus-Hereford cows with an average initial weight of 878 pounds. The initial weight was taken in the spring of the first year, shortly after all cows had calved. Cows were bred to calve between January 20 and April 1 of each year. This is typically the time of year when spring-calving cows have their lowest body weight (Bagley et al., 1987a, b). These young cows had calves at side that had been sired by Angus bulls. The 45 cow-calf pairs were divided into three equal groups in year 1 and assigned to one of three forage-management systems for the remainder of the study.
Two pastures were comprised primarily of common bermudagrass (Cynodon dactylon L.) and tall fescue (Festuca arundinacea Schreb.) consisting of one 20-acre and one 10-acre pasture. The 30 total acres of pasture in System 1 were stocked with 15 cow-calf pairs, or a stocking rate of 2 acres per cow-calf pair. Because of this relatively low stocking rate, no fertilizer was applied to these pastures during the spring and summer grazing periods.
In late August of each year, the 10-acre pasture of tall fescue was deferred from grazing, and 65 pounds per acre each of nitrogen (N), phosphate (P2O5) and potash (K2O) were applied to allow the accumulation of tall fescue growth (stockpiling tall fescue) for fall and winter grazing by the cow herd. This practice produces a relatively high quality forage (Bagley et al., 1978) and can reduce winter hay needs.
In late February, as weather and soil conditions would permit, an additional 68 pounds per acre of N were applied to the 10 acres of stockpiled pasture for additional grazing by cows.
Fifteen cow-calf pairs were placed in a forage-management system that contained a total of 15 acres, subdivided into three 5-acre pastures. The three pasture subdivisions included one 5-acre paddock of primarily common bermudagrass and two 5-acre paddocks containing primarily a mixture of common bermudagrass and tall fescue. The stocking rate utilized in System 2 was one cow-calf pair per acre.
All three of the paddocks annually received 65 pounds per acre each of N, P2O5, and K2O in March, and two additional applications of 68 pounds per acre of N (as ammonium nitrate) in June and again in October. Cow-calf pairs assigned to this system were rotationally grazed between paddocks of this system during the grazing season.
A total of 15 acres subdivided into four paddocks was utilized by the 15 cow-calf pairs yielding a stocking rate of one cow-calf pair per acre. Two of the 5-acre paddocks were primarily common bermudagrass and tall fescue and were available for grazing by the cow-calf pairs in a rotational stocking system. One of the remaining 2.5-acre paddocks was planted annually to a commercially available pearl millet (Pennisetum typhoides); the second 2.5-acre paddock was established as alfalfa (Medicago sativa L., variety Vanguard) in the initial year of the study. These two 2.5-acre paddocks were primarily used for creep grazing by calves. Creep grazing was accomplished by using a creep gate (opening 14 inches wide and 4 feet high) between pastures that would allow passage by calves, but not by cows, into the millet or alfalfa paddocks.
The two 5-acre permanent pastures were fertilized with 65 pounds per acre each of N, P2O5, and K2O in March of each year. In both June and October of each year, pastures received an additional application of 68 pounds per acre of N. At establishment, land to be seeded to alfalfa received 75 pounds per acre of P2O5 and 150 pounds per acre of K2O. These fertilization rates for alfalfa were also applied each spring prior to the initiation of grazing. Millet pastures were disked and seeded each year in April. Shortly after seeding, millet pastures received 65 pounds per acre each of N, P2O5, and K2O. In July of each year, an additional application of 68 pounds per acre of N was applied to stimulate millet forage production for grazing.
During times of the year when adequate amounts of forage were not available to meet the dry matter consumption (NRC, 1976) demands of the livestock (primarily winter), cattle were moved to a single central winter feeding area in a pasture away from the study site. This procedure was done to assure that location or hay quality differences did not affect animal performance during the wintering period. While in the central hay feeding area, cattle were given ad libitum access to hay and were group-fed a cottonseed meal (41% crude protein) supplement at 2 pounds per head daily. As adequate forage dry matter became available in pasture systems, cattle were placed back into their assigned pasture-management treatment groups for grazing.
Cows and calves were provided shade, water, and mineral supplements at all times. Animals were under the care of staff from the Mississippi State University College of Veterinary Medicine. Routine health procedures, including vaccination against diseases endemic to the area and the control of internal and external parasites, were performed by veterinarians.
Cows and calves were weighed starting in April of each year and at monthly intervals until weaning. Calves were weaned in early October each year at an average age of 7-8 months. Cows were culled for failure to rebreed or because of a physical impairment significant enough to adversely affect the performance of the cow and/or calf. The average culling rate for cows assigned to the three systems was approximately 15% over the duration of the study. Replacements for culled cows came from a pool of first-calve heifers available at the station specifically for that purpose.
Fertilizer rates and times of application were as previously described. Pastures were managed to produce optimum output in terms of grazeable forage along with the possibility of some hay production. Pasture management included rotational grazing to allow for optimal animal performance while attempting to allow for hay to be produced from some pastures by restricting grazing during optimum forage producing opportunities. Weeds were controlled as needed using approved herbicides in the early spring each year. Because of the close proximity of agronomic and horticultural crops, herbicide applications were not made in pastures after mid-spring.
Animal performance variables measured included monthly weights for both cows and calves, records of hay production, and visual calf scores at weaning time. Animal production variables were analyzed using a statistical package (SAS, 1993). Individual animals were used as the experimental units, and years were used as replications for the study. Calving interval was measured only for cows that had been assigned to the study since their prior calf was born and for all subsequent calves born while the cows were still assigned to that treatment group. All animal performance variables are reported as least squares means. Differences among means were determined by least significant difference procedures when the treatment F test was significant (P<.05).
Results and Discussion
Cow weight gains during the grazing period were greatest (P<.05) in year 1, and gains in year 2 were less than year 1 but greater than years 3 and 4 (P<.05) and equal for years 3 and 4, which were less (P<.05) than other years (Table 1). Initial cow weights were taken in year 1 during April after all cows had calved. Average cow age was lowest in year 1, so it would be expected that cow initial weight would also be lowest. This may also explain why weight gains from April to October were greatest for cows in year 1. Spring calving cow weights are generally lowest in spring just after calving (Bagley et al., 1987a,b). As these cows matured as the study progressed, weight fluctuations would not be expected to be as great from spring to fall, which would result in lower daily gains as measured from April to weaning time.
Cow production efficiency (Table 1), calculated by dividing the weight at weaning for the calf by the weight at weaning for the cow, increased (P<.05) from year 1 to 2, and (P<.05) from year 2 to 3. Production efficiency for cows in year 4 was similar (P>.05) to year 1, and both years were lower than years 2 and 3 (P<.05). This would tend to indicate a maturing of the cows, as they began to increase weaning weights of calves relative to their own body weight in year 1, while cow production efficiency declined in year 4. Production efficiency was probably lower in year 4 because of an earlier weaning date than normal caused when adverse climatic conditions caused forage production to be limited. Calf age at weaning was youngest in years 1 and 4 by an average of 2 weeks compared to years 2 and 3. Calving intervals were similar between the 3 years this variable was measured, averaging just slightly over 1 year (369 days).
Daily gains of calves (Table 2) were least (P<.05) in year 1 (1.60 lb/day) and greatest (P<.05) in year 4 (1.97 lb/day), with gains being intermediate in years 2 and 3 (1.87 and 1.84 lb/day, respectively). In year 1, cows were young and weighed only an average of 876 pounds shortly after calving. Year 1 was also the year that cow daily gains were greatest, but this corresponded to a year where their calf daily gains were the lowest (P<.05) of any of the 4 years this study was conducted. As cows reached maturity, calf weaning weights increased, which is in agreement with generally reported trends that relate cow age to calf weaning weight. Also in year 1, the forage systems were still being established and management of the systems was still being refined.
Several visual observations were made of each calf at weaning (Table 2), including body condition score (BCS; 9-point scale), feeder grade score, (FGS; 17-point scale) and frame score (5-point scale). There was considerable year-to-year variation in these scores, with BCS ranging from 7.9 (year 1) to 6.4 (year 4). Daily gains by year were opposite to the trend seen in BCS, being lowest in year 1 (1.60 lb/day) and highest in year 4 (1.97 lb/day). This would indicate that BCS probably reflected a difference in the subjective scoring by the evaluators in the different years, rather than true year-to-year differences in body condition at weaning. Feeder grade scores were highest (P<.05) in years 2 (13.2) and 3 (13.4), and lowest (P<.05) in year 4 (11.6), with their scores (12.4) in year 1 being intermediate and different (P<.05) from year 4 and years 2 and 3. Frame scores were highest (P<.05) in year 3 (3.8) and lowest in year 1 (3.1). There were no consistent trends observed for BCS, FGS, and frame score when considered across the 4 years of this study, probably indicating year-to-year variations in the subjective nature of visual scores taken one year apart from each other and sometimes by different personnel.
There were significant (P<.05) year x treatment interactions for several of the monthly weigh periods (Tables 3 and 5) for both cow and calf weights. With these interactions being present and with the high degree of variation with these monthly weights, only final weights were subjected to statistical treatment for analyzing performance variables. Initial cow weights tended to be lower (Table 3) for cows in System 3, reflecting a longer time spent on hay prior to forage being available to support full-time grazing in the spring. This system contained only 10 acres of permanent pasture for the 15 cow-calf pairs. Cows in System 3 tended to have the lowest weight gains at the May weight, also a reflection of a lesser forage supply for grazing. However, these cows tended to compensate and gain at the same or higher rate during the remainder of the grazing season as forage became available in that system. Cows in System 3 had higher (P<.05) gains from April through October than did cows in System 1 (0.55 vs 0.4 lb/day, respectively), probably reflecting a longer time on hay and a lower initial weight each April.
While there are no direct data generated in this study to support the following concept, it may be possible that cows in System 3 did not produce as much milk as cows in other groups. Because group 3 cows weighed less and had less forage in early spring, this could have resulted in less milk production (Bagley, unpublished data). In that prior study, cows given additional feed several months into lactation did not increase milk production but did increase weight gains and BCS compared to cows not given additional grain. Calves could compensate for the lower milk production of the cows with higher weight gains later during the year because of increased availability of both millet and alfalfa as a creep grazing crop. The possible lack of milk production would allow cows in System 3 to allocate more of their nutrient intake to increasing bodyweight rather than to maintaining milk production.
There were no differences (P>.05) in cow performance in terms of production efficiency, conception rate, or calving interval due to forage management systems (Table 4). Production efficiency averaged 54.5% for all three cow-calf groups, above the goal of 50% for a well-managed cow herd. Conception rates ranged from 84 to 90% and varied from year-to-year, probably because of the low number of cows per treatment. Calving intervals of cows on the various forage systems were similar, and were very close to maintaining the goal of averaging a 365-day calving interval for all groups (calving intervals of 373, 367, and 367 days for cows in treatment groups 1, 2, and 3, respectively).
Days on hay (Table 4) were least for cows in System 1 (84 days) and most for cows in System 3 (124 days). The amount of permanent pasture in each system for the 15 cows in a herd was 30, 15, and 10 acres for Systems 1, 2, and 3, respectively. Days on hay increased as the amount of permanent pasture acreage decreased. System 1 produced an average of 8.1 tons of hay per year, close to the approximately 12 tons of hay required to provide adequate winter feed for these cows (NRC, 1976). Systems 2 (0 tons of hay produced) and 3 (1.1 tons of hay produced) were inadequate for being self-sufficient in terms of hay production, and this is certainly a consideration in maintaining such a forage-livestock management system long-term.
Calf birth weights averaged 78 pounds and were similar for the three treatment groups (Table 5). Monthly average daily gains fluctuated by treatment group, with few consistent trends observed either by month or by forage system. Average daily gains were highest (P<.05) for calves in Systems 2 and 3 (1.86 and 1.89 lb/day, respectively) compared to calves in System 1 (1.76 lb/day).
Calf weaning weights were not different (P>.05), but tended to be higher for calves in Systems 2 and 3 (525 and 533 lb, respectively) than calves (506 lb) in System 1 (Table 6). Since there were 2.0 acres per cow-calf pair in System 1, calf production was only 253 pounds per acre for System 1 compared to 525 and 533 pounds per acre in Systems 2 and 3, respectively. Age at weaning was older for calves in System 1 than in System 2 (240.3 vs. 235.0 days) with average calf age at weaning for System 3 being intermediate (239.4 days). Date of weaning was the same for all groups each year, with the slight differences of calf age because of the calving interval of cows. No differences (P>.05) were observed between calves from the three treatments for the visual observations of BCS, FGS, and frame score.
An economic analysis (Table 7) of the various pasture systems was conducted. Results varied based upon whether costs and returns were calculated per acre or per calf. System 1 had the lowest costs per cow ($163) and the lowest cost of weaned calf production ($.31/lb). This resulted in the greatest profit per calf ($147) and the greatest profit to the entire system ($2,205) for System 1. However, when figures are based on profitability per acre, Systems 2 and 3 improved compared to System 1 because the acreage utilized was only 50% that of System 1. Estimated profit per acre was greatest for System 2 ($116) and least for System 1 ($73/acre), with System 3 being intermediate ($85/acre).
In this study, where land was substituted for improved management, very few differences were observed in cattle production characteristics. Weaning weights were acceptable in all systems, averaging over 500 pounds per calf, conception rates were acceptable (87% average), and calving intervals were approximately 1 year in duration (369 days). System 1, with a stocking rate of 2 acres per cow-calf pair, was almost self-sufficient in hay production, and cost per pound of weaned calf was lowest in that system. The higher levels of management and fertilizer in Systems 2 and 3 resulted in slightly improved weaning weights, but a higher cost per pound of gain by calves. System 2 did optimize economic productivity per acre of pasture, but the financial risks of System 3 and its slightly better estimated profitability per acre compared to System 1 may not be worth the increased financial risks. Systems 2 and 3 demanded more inputs, and a producer should calculate all these costs and labor requirements when deciding upon a forage-animal management system to utilize on his farm.
Bagley, C. P., J. C. Carpenter, Jr., J. I. Feazel, F. G. Hembry, D. C. Huffman, and K. L. Koonce. 1987b. Influence of calving season and stocking rate on beef cow-calf productivity. J. Anim. Sci. 64:687.
Gaertner, S. J., F. M. Rouquette, Jr., C. R. Long, and J. W. Turner. 1992. Influence of calving season and stocking rate on birth weight and weaning weight of Simmental-sired calves from Brahman-Hereford F1 dams. J. Anim. Sci. 70:2296.
Gregory, K. E., D. B. Laster, L. V. Cundiff, R. M. Koch, and G. M. Smith. 1978. Heterosis and breed maternal and transmitted effects in beef cattle. II. Growth rate and puberty in females. J. Anim. Sci.47:1042.
Morrow, R. E., J. A. Stricker, G. B. Garner, V. E. Jacobs, and W. G. Hines. 1988. Cow-calf production on tall fescue-ladino clover with or without nitrogen fertilizer or creep feeding: Fall calving. J. Prod. Agric.1:145.
Stricker, J.A., A. G. Matches, G. B. Thompson, V. E. Jacobs, F. A. Martz, H. N. Wheaton, H. D. Currence, and G. F. Krause. 1979. Cow-calf production on tall fescue-ladino clover pastures with and without nitrogen fertilizer or creep feeding: Spring calves. J. Anim. Sci. 48:13.
W. C. 1995. Grasslands USA: Yesterday, today, and tomorrow. Proc. Amer.
For. Grassl. Council. 4:1. Year¹ 1 2 3 4 S.E. Cow daily gain²,
lb/day Production efficiency³,
% Calf age at weaning,
days Calving interval4,
days Year¹ Item Calf daily gain,
lb/day Body condition
score² Feeder grade³ Frame score4 Forage systems¹ Item 1 2 3 S.E. Acres/cow-calf
pair 2 1 1 Initial cow wt²,
lb Daily gain,
lb May June July August September Average³ Forage system¹ Item 1 2 3 S.E. Acres/cow-calf
pair Production efficiency²,
% Cow conception
rate, % Calving interval³,
days Hay produced4,
tons Hay consumed,
tons/group Forage system¹ Item 1 2 3 S.E. Acres/cow-calf
pair Calf birth weight,
lb Calf daily gain,
lb May June July August September Average² Item 1 2 3 S.E. Calf weaning weight,
lb Calf production/A,
lb Age at weaning,
days Body condition
score³ Feeder grade score4 Frame score5 Forage system Item 1 2 3 Acres per system Cow-calf pairs
per system Pastures per system Total pounds of
fertilizer/year N, lb/A P2O5,
lb/A Specified cow
costs, $/A¹ Specified cost
of weaned calf , $/lb Estimated returns
above specified costs² per system, $ per calf, $ per acre, $
Cow daily gain², lb/day
Production efficiency³, %
Calf age at weaning, days
Calving interval4, days
Calf daily gain, lb/day
Body condition score²
Initial cow wt², lb
Daily gain, lb
Production efficiency², %
Cow conception rate, %
Calving interval³, days
Hay produced4, tons
Hay consumed, tons/group
Calf birth weight, lb
Calf daily gain, lb
Calf weaning weight, lb
Calf production/A, lb
Age at weaning, days
Body condition score³
Feeder grade score4
Acres per system
Cow-calf pairs per system
Pastures per system
Total pounds of fertilizer/year
Specified cow costs, $/A¹
Specified cost of weaned calf , $/lb
Estimated returns above specified costs²
per system, $
per calf, $
per acre, $