From Grazing Treatments on the = T exar Experimental Ranch ivestock Production and Economic Returns TEXAS A&M UNIVERSITY ' TEXAS AGRICULTURAL EXPERIMENT STATION ' H. O. Kunkel, Acting Director, College Station, Texas Cover photo by ]0e Brown. ACKNO IVLEDGMEN TS The authors express appreciation to the T mental Ranch Committee and Swenson Land f‘; Company for their support and contributions of ' y; and materials which made this research possible. Acknowledgment is made also to W. M. ranch foreman of the Texas Experimental ' Parker, former research associate; and Mrs. W secretary, for assistance in conducting this work. Special thanks are due A. M. Sorensen, ] ‘ Morrow for time and effort spent in palpating used in the study. ' ; Plains Cooperative on Mill, Lubbock, T“ Paymaster Cotton Oil Mill, Abilene, Texas, oi of the cottonseed cake used. The information given herein is for researchi only. Reference to commercial products or f!‘ . is made with the understanding that no discr' " intended and no endorsement by the Texas Experiment Station is implied. i’ SUMMARY Studies of grazing management for cow-calf operations I native range were conducted on the Texas Experimental - ch from 1960 through 1968. The response of live- i» k to nine different combinations of stocking rates, azing systems and levels of winter supplementation was = ermined. The stocking rates studied were heavy, moder- and light which were designed to utilize 75 to 80 rcent, 45 to 50 percent and 20 to 30 percent of the 4 rent year's forage production. Three grazing systems, ntinuous grazing, Merrill system deferred-rotation and '- itchback system deferred-rotation, were compared under \ oderate stocking and a medium level of supplementation. y e three levels of supplementation were 3.0, 1.5 and 0.0 unds of 41 percent crude protein cottonseed cake per ‘i! per day, fed for 90 days during each winter. The ree rates of supplementation were tested under both 7» oderate and heavy continuous grazing. Cow weights and calf weights both increased sig- iificantly as stocking rates decreased, but cow weights ‘i owed more response to changes in stocking rates than id calf weights. Cow weights increased 36 and 38 pounds rom heavy to moderate and from moderate to light tocking, respectively, while calf weaning weights increased nly 11 and 5 pounds from heavy to moderate and from .1 oderate to light stocking, respectively. Decreasing stock- ing rates did increase production per animal unit, but production per acre decreased in proportion to the re- ductions in stocking rates. Reducing the stocking rate increased production costs per animal unit as a result of increasing land costs. Calculated net returns to capital and management per acre were $5.28 from heavy stocking, $3.03 from moderate stocking and $2.24 from light stock- ing for a landowner. Calf production per animal unit from the switchback and Merrill systems was greater than from moderate con- tinuous grazing by 17 and 46 pounds, respectively. Both deferred-rotation grazing systems also produced more pounds of calf per acre than did moderate continuous grazing. The average cow weights were 17 pounds heavier from the switchback and 33 pounds heavier from the Merrill system compared with those from moderate con- tinuous grazing. The use of different grazing systems had little effect on production costs when stocking rate was held constant. Net returns per acre to capital and manage- ment for a landowner were $3.03 from moderate continu- ous, $3.22 from switchback system and $3.81 from the Merrill system. Returns to capital and management per animal unit for a lessee were $21.19 from moderate con- tinuous, $24.97 from switchback system and $34.80 from the Merrill system. Cow weights were greatly increased by supplementation on moderate continuously grazed pastures, but on heavy continuously grazed pastures, cow weights showed only a small response to supplementation. Under both stocking rates, supplementation reduced the magnitude of annual variation of cow weights. Under heavy continuous stock- ing, the medium and high levels of supplement increased calf production per animal unit 37 and 25 pounds, respec- tively. Under moderate continuous grazing, the medium level of supplement decreased calf production per animal unit by 6 pounds; the high level increased production by 13 pounds. The medium level of supplement on heavy continuous grazing yielded a net return to capital and management of $3.41 per animal unit above that of no supplement. Net returns to the high level of supplement on heavy stocking were lower than from no supplement. Under moderate continuous grazing, both the medium and high levels of supplement had lower net returns than did no supplement. Among the nine treatments studied, heavy continuous stocking with the medium level of supplementation yielded the highest net returns for the 8-year period. The lowest returns were from light continuous stocking. Deferred- rotation grazing systems increased net returns compared with continuous grazing at the same stocking rate. Since precipitation was near average or above for the duration of the study, it would be hazardous to make long term recommendations based only on this study. The effects of drouth could greatly alter the response of livestock to the treatments studied. CONTENTS Acknowledgments .............................................. .. ' Summary ............................................................ -- Introduction ....................................................... .. ' Experimental Area ........................................... .. Location .................................................... .. Climate ....................................................... -. Soils and Range Sites ................................ .. Vegetation .................................................. .. Vegetation and Range Site Relationships.. Procedure .......................................................... .. Treatments ................................................ .._. Stocking Rate ......................................... Supplemental Feeding ........................... .- Grazing Systems ..................................... -. tatistical Analyses ................................. -. Results and Discussion .................................. .. Stocking Rates and Grazing Systems ..... .. Cow Weights ................................. .. Levels of Winter Supplement ............... -. Calf Production ............................. .. Cow Weights ................................. -. Calf Production ............................. .. Longevity of Cows ................................. .. Economic Evaluation .................................. .. Discussion .................................................. .. Literature Cited ................................................. .. Appendix ........................................................... .. HE ROLLING Prams REGION OF TEXAS is among the p most important in the United States for the production A f feeder and stocker calves and yearlings. Approximately $90 million or about 41 percent of the total agricultural ' come of the region is derived from cow-calf operations producing stocker and feeder cattle. Most of these animals ire produced on ranches which depend upon native vege- tation for the bulk of their forage. Sixty-eight percent of the 15.8 million acres in the Rolling Plains is in rangeland. Continuous heavy grazing by domestic livestock for over three-quarters of a century has decreased the productivity and seriously deteriorated much of this rangeland (5). _ Prior to the establishment of the Texas Experimental Ranch in 1959, no facilities were available for a range research program in this region. The nearest sources of research information pertaining to range problems were the Texas A8zM University Agricultural Research Station at Sonora, Texas, and the U. S. Southern Great Plains Field Station near Woodward, Oklahoma. Ranchers in the Rolling Plains were interested in starting a program of range research. This interest resulted lin a; cooperative agreement between ranchmen and the Texas Agricultural Experiment Station by which the ranch- men provided the land, livestock and improvements and the Experiment Station conducted the research. This report covers livestock production from the first .9 years of grazing management research on the Texas *Respectively, assistant professor, Department of Range Science; research associate, Texas Experimental Ranch, Throckmorton; superintendent, Texas A&M University Agricultural Research Station at Spur; and former associate range scientist, Texas Experimental Ranch, Throckmorton. Livestock Production and Economic Returns From Grazing Treatments on the T exar Experimental Ranch M. M. KOTHMANN, G. W. MATHLS, P. T. MARION AND W. j. WAL1>R1P* Experimental Ranch. Vegetational changes resulting from the different grazing treatments will be reported in a separate publication. The objectives of this study were 1. To determine effects of the following treatments upon livestock, vegetation and soil and water conservation: Different rates of stocking—light, moderate, heavy; Different systems of grazing management; and Different levels of nutrition for winter maintenance. 2. To make an economic analysis of the treatments ap- plied in order to determine the influence of grazing practices, range improvement measures and winter maintenance practices upon the economy of range calf production. EXPERIMENTAL AREA Location The Texas Experimental Ranch, located in Throck- morton County in the eastern portion of the Rolling Plains, comprises approximately 7,000 acres of native rangeland owned by Swenson Land and Cattle Company (Figure 1). The area has been managed for experimental purposes since 1959 by the Texas Agricultural Experiment Station under a cooperative agreement with the owners. Climate The average annual precipitation for Throckmorton County is 24.83 inches (7). However, the 8-year average at the ranch headquarters was 27.51 inches. Annual rainfall is generally quite variable in this area, but only 2 of the past 8 years were below the county average (Figure 2). 5 B Continuous Moderate Use —"_“"N "-9 Supplement l Continuous Heavy Use Supplement l Range Improvement Studies Reserve D Continuous Moderate Use Supplement 2 Continuous Light Use E Supplement 2 Four-pasture deferred rotation Supplement 2 _ Continuous Heavy Use F \ ‘I Supplement 2 K J Trgy Continuous Heavy Use House, Earn’ G Supplement 3 Pens, etc. Switchback:two-pasture deferred rotation Continuous Moderate Use H Supplement 3 a? Supplement 2 I; I Figure 1. ‘ Map of the Tf mental Ranch.» long and 3 U. S. Highway l83 to Seymour Supplement l - Nothing Supplement 2 - l% pounds cottonseed cake per day Supplement 3 - 3 pounds cottonseed cake per day Most of the precipitation occurs as rainfall, but occasionally some moisture is received in the form of snow during the winter months. Average monthly rainfall for the ranch during the 8-year period is shown in Figure 3. September had the highest average, 4.84 inches, and other peak months in- cluded April, May and ]une. The lowest monthly average 6 containing 11 . ""'* N was 0.83 inch, recorded during December. tribution in some years varied considerably amounts being received in 1 month followed; months of limited rainfall (Appendix Table 1)tfi_ The average frost free period is approx‘ days with the last average freeze date in the sp will March 31 and the first in the fall occurring l 40' AVERAGE ANNUAL PRECIPITATION DROUGHT ‘W40 THROCKMORTON COUNTY- 24.33" (25% BELOW AVERAGE) so. " | u - 32.63 3,35 33.24 3° V g], " u ll _ I 20 250' 27.5: 27.10 2o g 2 ---_-_--,..------__---__-_-_- -_,,--------~ a ' 2i.32 2|.92 "’ F. 7 igure _. Annual precipitation meas- Io’ ‘I0 ured on the Texas Experi- mental Ranch from 1961 through 1968. I96l I962 I963 I964 I965 I966 I967 I968 YEARS Average maximum and minimum temperatures recorded TABLE 1. LAND AREA OF THE EXPERIMENTAL PAS- i at the ranch during the study period were 80.2 and 483° F, TURES CONTAINED IN EACH RANGE SITE respectively, resulting in a mean annual temperature of Range Sim <= _ 1 0° ' p643 F Temperatures above ‘O occur frequently duriong Deep Rolling ShaHOW Rocky the summer months, and occasionally temperatures of 0 1* pasture Upland Hllls Redlands Hills vallq, or below are recorded during the winter months. Percent _ Soils and Range Sites A 5Q 18_ L 48_ 3_ Soils on the Texas Experimental Ranch are mostly B 22. 23. 0. 47. 8. clays and clay loams that vary from deep alluvial creek D 56 46- 5- 19- 0' bottoms to shallow rocky slopes. According to surveys f; 1315' made ‘by ‘the Soil (‘Ionservatio-n Service, these. soils were G 8‘ H 12: 43: O: 54: 11: classified into 1O malor soil series and grouped into 5 range l 55g 4l_ 4_ 2_ o, ' sites The percentage of area contained in each range site J 53. 37. 0. 10. 0. for the experimental pastures is shown in Table 1. K, L» M> N 66- 28- 6 0' 0' 5.0’ " 4_5_ 4.83 4.0- 3.5’ ma” u 3.4| n n I“ i‘ 3.03 3.07 Z94 52.3- E 2.0- lts. _ Figure 5. u i1.- ii Average monthly distribu- LO _ L45 ‘u L47 L43 tion of precipitation on the l.Il ,, Texas Experimental Ranch Q5. 0,83 for the 8-year period 1961- 68. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC. M 0 N T H S The Abilene, Crawford, Rowena and Tobosa series were grouped into the Deep Upland site. This is the predominant site on the ranch and comprises 41 percent of the total experimental area. Characteristically, these soils are dark clays and clay loams, moderate to slowly permeable and well drained. Depth of top soil above parent material ranges from 20 to 80 inches. Slope varies from O to 3 percent. All soils in these series generally have high fertility levels and high available water capacities. They differ mainly in distribution of calcareous material in the soil horizons. Grouped into the Rolling Hills site, which includes 34 percent of the area, were the Mereta and Throck series. Surface soils of these series are dark, greyish brown, silty clay loams, ranging in depth from 15 to 20 inches, with a slope of 1 to 5 percent. They are highly calcareous, and out-croppings of flat limestone pebbles occur frequently on the surface. These soils are moderately permeable and highly fertile, but water storage is restricted because of their shallow depth. Soils of the Owens-Tarrant complex were designated as Rocky Hills site. These soils are shallow, stony clays and are characterized by limestone rocks on the surface that vary in size from small cobbles to large boulders. Depth of soil above parent material ranges from 5 to 20 inches. Fertility level is generally high, but permeability is moderate to very slow. These areas occur on steep slopes and rocky ridges where surface runoff is rapid. Water erosion is a hazard particularly on areas that have been closely grazed. Seventeen percent of the experimental ranch is contained in this site. The Owens-Vernon soils were grouped into a Shallow Redland site containing 4 percent of the area. These soils consist of reddish to olive brown calcareous clays that range in depth from 5 to 20 inches. The subsoil is under- lain by shaley clays. Surface runoff is rapid, and soil erosion is generally active because these areas are sparsely vegetated. Included in the remaining 4 percent of the area were soils of the Spur series. These soils were designated as Valley site and occur in the valleys or depressions adjacent to primary or secondary drainages. Slope is normally less than 0.5 percent. Depth of soil above parent material is greater than 6O inches. Surface soils are dark brown, cal- careous, clay loams with stratified layers of silt and fine sandy loam occurring at lower depths. These soils are slowly permeable and have a high fertility level and high available water capacity. Vegetation The original native vegetation of the Rolling Plains area included tall and mid grasses Due to continuous close utilization by livestock, this climax vegetation has 8 been reduced primarily to short and mid gr ,_ Appendix (Table 2) lists the scientific and co w of many of the plant species found on the T mental Ranch. Numerous short and mid gras on the ranch, but Texas wintergrass, buffalograss? oats grama accounted for approximately 73 per‘ vegetation at initiation of the study. ‘Other gr’, contributing appreciably to the composition were; curlymesquite, Texas cupgrass, the threeawns, h, seed, tumble windmillgrass and hairy tridens. ‘i: decreaser species, once a major part of the it climax community, were still present at the s study, but they made up only a very small part off composition. These grasses include big and little Indiangrass, switchgrass, blue grama, western ~ Canada wildrye and vine-mesquite. The most abundant forbs were bitterw' broomweed, silverleaf nightshade, curlycup i filaree, plains beebalm and snow-on-the-moun A_ of these forbs were present each year, but the - as bitterweed, filaree and Texas broomweed uni greater abundance when moisture conditions were. during the fall and winter months. i’ The brush species included mesquite, lotebu a pricklypear and tasajillo. Mesquite and lotebushi dominant woody species and were present on sites. The original stand of mesquite on the ex, area" was chained in 1948, and the regrowth w aerially with 2,4,5-T in 1964. Resprouting ofi has occurred since the aerial spraying, but the 1968 was not great enough to materially redu production. i‘ Vegetation and Range Site Relationships Sample plots within the test pastures certain species were consistently more abundant: range sites under all of the grazing treatmeni wintergrass and buffalograss occurred more fr w‘ the Deep Upland site while sideoats grama and; awns tended to favor the shallow soils contai Rocky Hills and Rolling Hills sites. Western was present only on the Deep Upland and primarily in depression areas that received from slopes above. Although low in frequency rence, big bluestem occurred on all sites in -" managed pastures. It was most abundant, howevi Rocky Hills site. Switchgrass and Indiangrass w in some of the pastures on the Valley sites primary and secondary streams. . In years of favorable moisture conditi populations of Texas broomweed and bitterweedf“ on the Deep Upland and Valley sites. Curlycup, preferred the Rolling Hills site and silverleaf was more abundant on the Deep Upland site. Although mesquite and pricklypear occurred on all sites, greatest densities prevailed 0n the deeper soils of the Deep Upland and Valley sites. Lotebush was widely established on all sites except the Rocky Hills site. PROCEDURE Initially the Texas Experimental Ranch consisted of 7,000 acres fenced in one pasture. An intensive soil and range survey was made on the ranch, and the fence lines were placed so that the experimental pastures were as imilar as possible. This resulted in some irregular pasture boundaries. Fence construction began in October 1959 and was completed in March 1960. Figure 1 shows the location, size and grazing treatment of the pastures, and Table 1 gives the percentage of the area in each range site within the pastures. It was not possible to include all of the range sites in all of the pastures, but the major sites, Deep Upland and Rolling Hills, are well represented in all treatments. Bred Hereford heifers were obtained and randomly allocated to the treatments. These heifers had their first calves as 3-year-olds during the winter of 1959-60. Records were not obtained on this calf crop. Bulls were placed with the cows March 14 and removed ]une 15 of that year and of each successive year. All bulls were fertility tested just prior to breeding, and at least two bulls were used in each pasture. The cows were pregnancy tested in September of each year, and any cow that was open 2 consecutive years was permanently removed from the herd. A reserve herd of comparable cows was kept on the ranch to provide replacements. Dry cows were removed from the treatment pastures and placed in reserve pastures. ilf they calved the following year in the reserve pasture, they were then returned to the treatment pasture. These cows were not included in the production records the first year after returning to the treatment. Wet cows from the reserve herd were placed in the treatment pastures in place _of those removed to maintain the specified stocking rates. The purpose of this practice was to maintain a constant grazing pressure from producing cows on all treatments. Individual records were kept on all cows and calves. Cows were tattooed in the ear and also identified with a neckchain and tag for easier recognition. Numbered plastic tags’ were placed in the calves’ ears for identification. The calving date was recorded for each cow, and the cows and calves were paired so that calves could be identified with their cows. Calves were tagged, dehorned, castrated and earmarked during February. All cows and calves were weighed individually in late March, mid-June and Septem- ber. At the March weighing, the calves were branded and vaccinated for blackleg. The calves were usually removed from the cows in early October. Salt and bonemeal were provided free choice in weatherproof feeders, and the cattle were treated for lice and flies. Stocking rate Grazing system Level of supplement Pasture lb/ day A Heavy Continuous none F Heavy Continuous 1 . 5 j Heavy Continuous 3.0 B Moderate Continuous none D Moderate Continuous 1.5 I Moderate Continuous 3 .0 E Light Continuous 1.5 G-H Moderate Switchback 1.5 K-L-M-N Moderate Merrill 1.5 Figure 4. Experimental treatments assigned to pastures on the Texas Experimental Ranch. Treatments The main effects and interactions of three treatments were studied using three levels of each treatment. The treatments were: stocking rates at three levels——heavy, moderate and light; grazing systems——continuous, 2-pasture deferred-rotation (switchback system) and 4-pasture de- ferred-rotation (Merrill system); and protein supplementa- tion at three levels during the winter—none, 1.5 pounds per cow per day and 3 pounds per cow per day. The nine combinations of treatments and the respective pastures used are shown in Figure 4. Stocking Rate Three stocking rates were studied under a continuous grazing system. Three pastures were heavily stocked, three were moderately stocked and one was lightly stocked. The initial stocking rates in 1961 were 14.0 acres, 23.0 acres and 32.5 acres per animal unit for heavy, moderate and light stocking, respectively. The stocking rates were planned to utilize 75-80 percent, 45-50 percent and 20-30 percent of the current year's forage production. The actual per- centage of the forage utilized under each stocking rate varied somewhat from year to year as the end-of-season use could not be predetermined. Generally, the actual percent utilization appeared to be lower than the desired levels for all stocking rates. As a result of plentiful rain- fall and slightly understocked pastures, the stocking rates were increased several times (Table 2). The average stock- ing rates in 1968 were 11.1 acres, 16.4 acres and 23.9 acres per animal unit for heavy, moderate and light stock- ing, respectively. Supplemental Feeding Three levels of protein supplement were fed to the cows during the winter. Cottonseed cake (41 percent crude protein) was fed at the rate of 3.0, 1.5 and 0.0 pounds per cow per day. Of the three heavily stocked pastures, no supplement was fed on pasture A, the 1.5-pound rate was fed on pasture F and the 3-pound rate was fed on 9 pasture The cows on the moderately stocked, continu- ously grazed pastures were supplemented as follows: pasture B, no supplement; pasture D, 1.5-pound rate; pasture I, 3-pound rate. The lightly stocked pasture and both deferred- rotation grazing systems were supplemented at the 1.5- pound rate. ' Supplement was fed on Monday, Wednesday and Friday mornings for 9O days during the winter. Cows fed the 1.5-pound rate received a total of 135 pounds of cottonseed cake per cow per winter, and those on the 3-pound rate received 270 pounds. Grazing Systems A comparison of three grazing systems was made using a moderate stocking rate and a 1.5-pound-per-day level of supplement. The continuous grazing system was 10 Weighing time g Texas Experimental Individual records-j; kept for each calf. (Photo by ]oe that used by the majority of landowners in the Plains. Under this system, a pasture was grazed y, at a constant stocking rate. The switchback sy deferred-rotation operated with two pastures of about’ carrying capacity and one herd of cattle The size; cow herd was determined by dividing the stockin“ (acres per animal unit) into the total acreage of M? pastures. This number of cows was then placed in the pastures. On March 15, June 15 and Dece of each year, the cows were moved to the other Thus, each pasture had 5, 6, 3 months of graze, rest, followed by 3, 6, 3 months of rest, graze, rest. 5* a 2-year period, each pasture was rested a total months with rest during each season. The Merrill system of deferred-rotation cons“ four pastures of approximately equal carrying cap ithree herds of cattle The stocking rate (acres per animal unit) was divided into the total acreage of the four pastures, and the total number of cows separated into three equal herds, leaving one pasture empty. Every 4 months one herd of cattle was moved into the rested moving again. This system resulted in a rotation of the livestock and a rotation of the season of deferred grazing. Four years were required to complete a cycle of rotational deferment. Within a 4-year period, each pasture was rested fa total of 12 months with deferment during each season. Livestock were moved February 15, June 15 and October 15. Statistical Analyses g Cow and calf weights from the nine treatments were analyzed statistically. Cow and calf weights from reserve or replacement cows were not used in the analysis of the fpasture where it would remain for 12 months before, Contrasting degrees of utilization under light and heavy stocking, January 1964. Abundant forage remained in the lightly stocked pasture (left), but forage was closely used in the heavily stocked pasture (right). treatments although some of these cows were in treatment pastures several years. Thus, all cow and calf data presented are from a uniform, even age cow herd. Year effects were confounded with age of cow, but neither affected. the interpretation of the data. Initially it was desired to analyze the data by using an unweighted least squares analysis on individual observa- tions. However, it was concluded that the data were poorly conditioned for this statisical technique. Therefore, an analysis of the cow and calf weights was made using the unweighted means in a factorial analysis of variance. The mean cow weights for treatment, year and weighing period were analyzed, and Duncan's multiple range test for the 5-percent level of probability was used to test for significant mean differences. The analysis of variance table for cow weights is presented in the Appendix Table 3. Calf weights from each weighing period were analyzed TABLE 2. STOCKING RATES BY YEARS FOR EXPERIMENTAL PASTURES Pasture Year 1961 1962 196s 1964 196s 1966 1967 196s Avg Acres/ animal unit A 14.1 14.7 13.2 12.8 12.8 12.7 12.7 12.1 13.1 F 13.9 A 14.3 13.1 12.7 12.6 13.0 12.2 10.8 12.8 J 13.2 A 13.5 12.4 12.2 12.1 12.3 11.7 10.5 12.2 B 23.0 23.3 21.4 20.8 20.3 20.8 19.7 16.6 20.7 D 23.0 23.4 21.5 21.1 20.3 20.9 19.7 16.3 20.8 v I 22.6 22.8 21.3 20.4 21.5 20.9 19.9 16.2 20.7 E 32.5 32.5 28.9 27.6 27.0 27.5 27.6 23.9 28.4 G-H 22.5 23.8 21.5 20.7 19.8 20.4 19.5 17.2 20.7 I K-L-M-N 22.5 22.7 20.4 19.8 19.3 19.9 18.1 15.4 19.8 _ 11 H5OF HOO- I050- |oao 00m I025 992 I009 POUNDS 95°‘ sea 900- 850- ‘r 1’ HEAVY MODERATE UGHT SWHTHBACK MERRILL Figure 5. Cow weights for three stocking rates and three grazing systems averaged across 8 years and three weighing periods per year. H5O IIOO I050 - IOOO POUNDS 950 900 separately resulting in an analysis of variance the three weighing periods. Duncan's multipl was used to test for significant mean differ“ S-percent level. The analysis of variance tab I calf weights are presented in Appendix Tables RESULTS AND DISCUSSION Seasonal and annual fluctuations in the i cow are direct indicators of her; nliltritional sta size and potential weight were assumed the i‘; cow herds when they were allocated to the vi ments in this study. Hence, any resulting dif the average weight of the cows on different would be a reflection of the quantity and nu _' of the diets ingested. The livestock data are two parts: Stocking rates and grazing systems, f of winter supplementation, second. _ Stocking Rates and Grazing Systems The five treatments considered in this _ heavy continuous, moderate continuous and ous stocking, and the switchback and Merrill Figure 6. aso - I —— HEAVY Qjjjaiufcmgw‘. _..._.. MODERATE aged across sp' mer and fall wei a’ —""' LIGHT T | n I | q | , I96I I962 I963 I964 I965 I966 I967 I968 12 H50- IIOO I050 IOOO POUNDS 950 rotation systems both with moderate stocking. All of the cows on these five treatments were fed the 1.5-pound level e of supplement. Cow Weights Stocking rates and grazing systems significantly in- fluenced the average weights of cows on the treatments during the 8-year period (Figure 5). There was no sig- "nificant difference between the average cow weights from light stocking and from the Merrill system of deferred- rotation. All other treatments differed significantly (P<.O5) with heavier stocking resulting in lower cow weights. Cows on both deferred-rotation grazing systems were significantly heavier than those on moderate continuous grazing. Cow weights from year to year showed similar trends for all three stocking rates (Figure 6), but unfavorable climatic conditions in 1964 and 1966 affected cows on the heavily stocked pasturefl more than those on the moderate and lightly stocked pastures. With the exceptions of 1964 and 1965, cow weights on the lightly stocked pasture showed little variation from year to year. The weights of cows on the Merrill system were similar to those from light stocking (Figure 7). Cows on the switchback system showed an adverse response to drouth conditions similar 900 - Figure 7. Annual cow weights for 85o ' i‘ coNTlNuous three grazing systems aver- d ' , - "" SWITCHBACK 1i aifimiirisfiiigghtsium -' "“' _‘ MERRILL T l l l | I I J |96| I962 I963 I964 I965 I966 i967 i968 to that of cows on heavy stocking; however, they responded more rapidly to favorable conditions in 1965 than did the cows on heavy stocking. Following precipitation, forage production increased rapidly on the switchback, but slowly on the heavy stocking. This probably accounts for the difference in results between these two treatments in 1965. There were significant seasonal changes in the average weights of cows on all treatments. Cows on the heavily stocked pasture lost the most weight during the winter, gained the most during the spring and lost the least during the summer (Figure 8). The greatest differences among treatments were in the early spring, and the smallest dif- ferences were in the fall. During the spring and summer months, when there was adequate rainfall, ample forage (apparently of high quality) was available even on heavily stocked pastures. As the grazing season progressed through the fall and winter, the effects of different stocking rates became more apparent. Cow weights from the Merrill system showed a seasonal pattern very similar to that from light continuous stocking (Figure 9). Average weights from the Merrill system were heavier at all three weighings than those from the switchback or moderate continuous stocking. Average cow weights under the switchback system showed 13 ||50y I050- I000- POUNDS 950- 900- 950. ——— HEAVY l ---- MODERATE ’ ---- LIGHT L. JAM FEB. MAR APR MAY JUNE JULY AUG.SEPT OCT NOV DEC Figure 8. Spring, summer and fall cow weights for three stocking rates averaged across 8 years. more fluctuation than under the other two systems. Under the switchback system, the livestock were concentrated in one pasture from June 15 until December 15 of each year. When the cows were switched to the rested pasture December 15, much of the forage in that pasture had matured. As a result, daily intake may have been less than under the Merrill system or under moderate con- tinuous grazing. Forage quality is correlated with the stage of maturity; therefore, the forage in the pasture which JHI|5OF HOO- .fi\. 1050- _/,' *\\\-\, w I000- D Z D O O. 950» 900- 650 - —— CONTINUOUS j --—- SWITCHBACK - —-—~ MERRILL TL . . . . . . . . . JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT OCT. NOV. 05c. Figure 9. Spring, summer and fall cow weights for three grazing systems averaged across 8 years. 14 n)" y" T % had rested for 6 months was probably of than was the regrowth forage on the Merrill continuous grazing systems. Calf Production t, s Calves from the Merrill system were (P<.O5) heavier at weaning, averaged over. period, than from the other four grazing trea 10). The average weaning weights of calvesug light continuous stocking and the switchback‘: pounds. Moderate continuous stocking had a l p‘: weaning weight of 501 pounds, and heavy c0 the lowest average weaning weight. The swit '_ and especially the Merrill grazing system w. in increasing the weaning weights of CQIVCSQ/fj-l only a relatively small difference of 16 p0 i the weaning weights of calves from heavy c light continuous stocking. This probably r. good rainfall in most years and a slightly 1 of utilization than was anticipated. K’ The average annual weaning weights tend under heavy stocking as the study progressed increased under moderate and light stocking i,- The weaning weights from light stocking variation from year to year; whereas, those fr and heavy stocking showed considerable anni l‘; For 6 of the 8 years, the Merrill sys the “heaviest calves when compared with m tinuous stocking and the switchback system The switchback had the heaviest calves in >1 continuous stocking had the heaviest in 1968. _ differences among treatments were during the fit; 600 550- 500- 490 450- POUNDS 400- 350- 300- 50l 506 506 HEAVY Figure 10. MODERATE UGHT swncueAc I" Weaning weights of calves from three stocking rates? grazing systems averaged across 8 years. and in 1966. The initial response of the vegetation to deferment, when the rotation systems were started, probably resulted in their having heavier weaning weights than the continuous use system for the first 5 years of the study. The greater concentration of livestock on the switchback would lead one to expect a slightly lower weaning weight from I it than from the Merrill system. Drouth conditions during spring and summer 1966 had a greater effect on the switchback system than on the other two grazing systems. Figure 13 shows the spring, summer and fall weights of calves from heavy, moderate and light stocking. The treatments appeared to have little effect on average birth dates of calves (Appendix Table 7). The calves were approximately 2.5 months old at the time of the March weighing. In late March, warm season grasses had made little growth, and cool season plants were just starting their period of rapid spring growth. This was the time j of greatest difference in quantity of forage available under the different stocking rates and resulted in maximum treatment differences during early spring. The differences between calf weights on the heavily stocked treatment and the moderately and lightly stocked treatments were about the same in the fall as they were in the spring. The cows _ on the heavily stocked pasture gained more during the 600r S50 ' 500 spring and summer than did those on the moderately and lightly stocked pastures (Figure 8), and the calves on the heavily stocked pasture gained at a comparable rate during this period. Therefore, the nutritive intake of cows on the heavily stocked pastures must have been comparable to that of the cows on other pastures during the spring and summer. From these data it appears that the detri- mental effect of heavy stocking on livestock production occurred largely during the fall and winter. Seasonal calf weights from the three grazing systems showed the same trend as the calf weights from the stock- ing rates (Figure 14). Differences among treatments in early spring remained essentially the same throughout the spring and summer. Calves from the Merrill system were heaviest at all three weighings. Cows and calves on the switchback system were moved to the rested pasture just prior to the March weighing and again just before the June weighing. They gained more during the spring while in the pasture that received the winter rest than they did during the summer while in the spring rested pasture. Because grass in the winter rested pasture was always short as a result of the 6-month grazing period of the previous year, the spring growth was little mixed with old growth and was readily available and high in nutritive value. 450 U7 Q Z D 3 400 ' 350 - Figure 11. Weaning weights of calves 300 “ i H EAVY from continuously grazed _ _ __ MODERATE pastures stocked at three different rates. J, —'_' LIGHT ‘I’ . . . a I l 4 I96I I962 I963 I964 I965 I966 I967 I968 15 GQOF 550 500 450 ' V) Q Z 3 O Q. ’ 40C- ‘350 ' Figure 12. 300' -'—- CONTINUOUS Weaningwei ____ fmmtmxgig SWITCHBACK stocked m H; J- —-—- MERRILL t l | l I I Q I l I96l I962 I963 I964 I965 I966 I967 I 968 The spring rested pasture had been rested for 6 months the previous year, and forage was rank and starting to mature when the cows were rotated in June. This probably ‘Jresulted in lower quality forage and slightly lower gains for the switchback system during the summer. Calves on all treatments tended to gain at a little lower rate during the summer than during the spring. The percent calf crops weaned from the five treat- ments followed about the same pattern as the weaning weights (Figure 15). One discrepancy to be noted is that the data showed heavy stocking resulting in a higher per- cent calf crop weaned than did moderate stocking. Prior to the 1968 calf crop, the averages we're 90 percent on moderate and 89 percent on heavy. In 1968 the cows on heavy stocking weaned a 95-percent calf crop and those on moderate stocking weaned a 75-percent calf crop. A possible explanation for this is that more calves were born and lost on the moderately stocked pasture during the severe ice storms which occurred frequently that winter. With this exception, the percent calf crops weaned fit the pattern of the previous data. The pounds of calf produced per cow (weaning weight times percent calf crop) varied more among treatments than l6 g .2 did the weaning weights (Figure 16). Moderg ous stocking showed no advantage over heavy stocking, and light continuous stocking res , increase of only 25 pounds. The switchback duced 17 pounds more calf per cow than tinuous stocking, and the Merrill system pounds more calf per cow than moderate use. 05 On an annual basis, there was a great deal I among stocking rates in the pounds of calf p I T cow (Figure 17). No clear trend resulted u rates. The cyclic production on moderate con '8 was very marked, but, other than random chance, explanation could be found for it. i For 7 of the 8 years during the study, I: system produced more pounds of calf per cow the switchback or moderate continuous st '9: 18). Production per cow varied more from the; use system than from the deferred-rotation weather during 1966 caused a drop in produ treatments. A combination of cold, wet wea i; winter 1967-68, a tremendous population of T, weed and low soil moisture during August ‘P; e. L 1 Pouuos in a marked drop in production for that year. Although total rainfall was low in 1967 (Appendix Table 1), the winter was dry and mild, and near ideal rainfall distribution during the spring and summer resulted in a high level of ' production. Calf production per acre differed markedly among treatments (Figure 19). The production per acre increased in direct proportion to the stocking rate with heavy stock- v ing having the highest production. Production per acre was very low from light stocking. The switchback system _ produced 0.9 pound more calf per acre than did moderate continuous use, while the Merrill system produced 3.4 pounds more calf per acre than did moderate continuous use. Heavy stocking, however, still produced almost 1O ’ pounds more calf per acre than did the Merrill system. On an annual basis, calf production per acre showed less variation than did weaning weights or production per cow (Figure I20). There was a gradual increase in production from all treatments as the study progressed, but the differ- ence between heavy and moderate stocking was as great or 550 - 500 ' 450* 400 - 350 - 300 - 250' '50‘ ' M -——— HEAVY i -——— MODERATE " — —-uenr T l l A l l I J l l JAN. FEB. MAR.APR. MAY JUNE JULYAUGSEPT. OCT NOV. DEC. Figure 13. Spring, summer and fall weights of calves from three stocking rates averaged across 8 years. 500 - 450- 400- 350- POUNDS 300- 250- 200 ' '5°' -—-connuuous ---- SWITCHBACK ,4: _'_‘ MERRILL "P l l 1 l l a l n l 1 JAN. FE B. MARAPRMAY JUNE JULYAUGSEPT. OCT. NOV. DE C. Figure 14. Spring, summer and fall weights of calves from three grazing systems averaged across 8 years. greater at the end of the study as it was at the start. This increase in production resulted from increases in stocking rates (Table 2). Each time stocking rates were increased, they I00’ 90' 93.7 92.l 893 90.5 88.2 PERCENT Q O 70- 60- ‘r T HEAVY MODERATE LIGHT SWITCHBACK MERRILL Figure 15. Percent calf crop weaned from three stocking rates and three grazing systems averaged across 8 years. 17 POUNDS BOO - soo I 550- 500- 440 400- 350 - J- L 44l 465 45B 487 HEAVY Figure 16. Pounds of calf produced per cow bred from three stocking rates MODERATE LIGHT SWITCHBACK and three grazing systems averaged across 8 years. POUNDS 18 600T 550 ' 5OO ' 450 4oo MERRILL were increased by the same percentage on each Heavy stocking was influenced more than the o l; ments by the short drouth during 1966. a Productig light stocking was almost constant from year to y; Production per acre was similar for the three?- systems all stocked at the moderate rate (Figure 21){ ever, the Merrill system always produced more - 5? calf per acre than did the switchliack system or c0 c" use. The switchback system produced at about ° level as continuous use for 5 years, and in 3 produced more. Potential differences among gr terns lie in their influence on kinds of volunteer vei they develop over a long period and in resulting y‘; of carrying capacities and stocking rates. The - rotation grazing systems improved the vigor of I vegetation, and over another decade significant I in vegetative composition are expected. The eff‘ deferred-rotation grazing systems used in this not as immediately noticeable as were the effects of if rates. However, the long term potential for f“ the range resource is the real test of a grazing syst 3 50 - Figure 11. Pounds of calf p ' 30o i —-- H E AVY IIIDJIIIIOSSTZ’ Ztrfiaieilfroi J- ;i:i“:.‘;?.i“"" iii“d“‘ ‘l; - - - . . . . l96I I962 I963 I964 I965 I966 I96? I968 600 - 550 500 450 U) O Z D O O. 400 350 - Figure 18. - P‘ d f 1f d d 30o ' coNTlNuous pgrunccfwobrefd frgrho tlllmcrtee ..___ swn-CHBACK grazing systems stocked at a moderate rate. _L, '-"-' MERRILL f I l l I l l Q |96| i962 I963 I954 I965 |966 i967 i968 Levels of Winter Supplement Cow Weights Cows on heavily stocked pastures reacted differently to supplementation than did the cows on moderately stocked pastures (Figure 22). With moderate stocking, supplement markedly increased the average cow weight. .50- 4o- so- 34.4 U) 0 = z . Du: 8 zo- 24.6 2|.2 221 |s.4 l0- HEAVY MODERATE usnr SWITCHBACK MERRILL Figure 19. Calf production per acre from three stocking rates and three grazing systems averaged across 8 years. However, on heavy stocking, cows on the high level (3 pounds) of supplement weighed significantly less than those on the medium level. At all levels of supplementa- tion, cows on moderately stocked pastures weighed more than those on heavily stocked pastures. The mean cow weights for all treatments differed significantly (P<.05) 50F 40- X‘ 3o- U) 2 3 ,’\\ /’. ~ \ “ ~ __. E ’)\\ /// \\ /’/ 2o _ ,»’ \\ l,’ ‘\,/’ ~‘_“\0// .-~'“:l§ g J“"'-.-‘-J Zn? ~c€_‘ Z_z ‘X ~\,,/ _ ___'_, 10- ' — HEAVY ---- MODERATE —~—- LIGHT I A | I l l 1 |9s| |9s2 1963 1964 uses 196s 19s? |9sa Figure 20. Annual calf production per acre from continuously grazed pastures stocked at three different rates. 19 POUNDS to O 50- 40- OJ O IO ' '—'—' CONTlNUOUS """ SWITCH BACK ""—' MERRILL l96l I962 I963 I964 I965 I966 I967 with the exception of the medium level (1.5 pounds) on heavy stocking and the low level (O pounds) on moderate stocking (Appendix Table 3). On the heavily stocked pastures, the cows fed the high level of supplement were lighter than the other two groups at the beginning of the study (Figure 23). The difference between the medium and high-level cows nar- rowed progressively until in 1965 the high level cows were heavier. Average cow weights on all three levels of supplement differed very little in most years. These data suggest that the high-level treatment may have had smaller type cows than the medium-level treatment. Whether or not this was true, supplement had less effect on the average body weight of the cows on heavily stocked pastures than on moderately stocked pastures. On the heavily stocked pastures, the quantity of forage available probably limited intake of forage at various times of the year other than during the winter. The quantity of supplement fed for a limited time during the winter did not contain an adequate supply of , energy to maintain body weight at a high level. ' On the moderately stocked pastures, an adequate supply of forage was always available. Since range forage pro- vided adequate nutrition for the cow to meet her mainte- nance and production needs in most years, the nutrients provided by the supplement were used to increase the body weight (Figure 24). During good years such as 1965, all of the cows gained a considerable amount of weight, but those receiving no supplement gained the most. The annual weights of cows from all three of these moderately 20 I968 Figure 21. :1 Annual calf prod acre from three] systems stocked at? crate rate. r’ stocked pastures follow fairly closely a normal a The cows were 4 years old in 1961 and hit weight during a good year at the age of 8 y checks showed that some cows were losing teeth and 1968. y’; . 13. Seasonal fluctuations of cow weights fr “is levels of supplement on heavily stocked pastures HSOF HOO- I050- I000- POUNDS 950' 900- 850- 968 956 969 Figure 22. ll/2 HEAVY 0 | v2 moosaxig Average weights of cows fed three levels of protein s i‘ on heavily and moderately stocked pastures. ll50[ IIOO I050 IOOO POUNDS 950 900 Figure 25. Average annual weights of 85o ' O cows fed three levels of ___.. | V2 protein supplement on A, heavily stocked pastures. T _ . .-_- 3 I l l n | 1 4| I96I I962 I963 I964 I965 I966 I967 I968 I200 I nso- _/'\ IIOO I050 o) o 5 |ooo- O n. 950 _ 900' Figure 24. -‘ Average annual weights of cows fed three levels of protein supplement 0n moderately i- Q stocked pastures. 852 _ ___ I V2 t I l l L I i i iII3 J I96I I962 I963 I964 I965 I966 I967 I968 21 H50‘ ll00 I050- I000 POUNDS 950 900 - 850- J»- t l | | . n | l JAN. FEB. MAR. APR. MAY JUNE JULY in Figure 25. These data also indicate that the cows on the high level of supplement were smaller type cows than those on the other two treatments. Seasonal fluctuations in the weights of cows on the low and medium levels of sup- plement were almost identical. The low level cows were about 4O pounds lighter at each weighing period. Cows on > H5O lI0O- I050- I000- POUNDS 950- 900- 850- i -----| v2 n 1.1.3 JAN. FEB. MAR. APR. MAY JUNE JULY AUG SEPT. ocr NOV. 05c. Figure 26. Spring, summer and fall weights of cows fed three levels of protein supplement on moderately stocked pastures. 22 Figure 25. Spring, summer and fall weights if fed three levels of protein suppl p; heavily stocked pastures. -——— o ---- ||/2 --¢1-¢3 AUG. SEPT. OCT. NOV. DEC. w '- the high level lost less weight during the winterfi less during the spring and lost more during the i than those on the low and medium levels. This same trend that was observed among the three rates (Figure 8) and among the three levels of sup‘ on moderately stocked pastures (Figure 26). A 600- 550- 500- 490 492 450" 464 POUNDS 400- 350- 300- 501 0 ll/2 3 HEAVY Figure 27. 0 IVZ uoosru Weaning weights of calves from three levels of suppl two stocking rates averaged across 8 years. POUNDS 600 Iso- 500 /'\ 450 400 350 - 300 " ‘D T I I l l Figure 28. Annual weaning weights l96l I962 I963 I964 I965 a cows on the lower levels of nutrition during the winter made compensatory gains during the subsequent period of high nutritional intake during the spring. The cows fed the high level of supplement on the moderately stocked pasture were significantly heavier at all weighing periods compared with those fed the other levels (Figure 26). Fall weights of cows on the low and medium levels of supplement were almost the same, but the cows receiving no supplement lost 45 pounds more weight during the winter. As in all other cases, the March weights were the lowest and the June weights the highest. .= Calf Production While cow weights are one measure of the nutritional status of the cow, the returns from supplementation will be primarily in the form of calf production. The average weaning weights from {the three levels of supplement varied 28 pounds with.‘ heavy stocking and 14 pounds with moderate stocking (Figure 27). Supplement appeared to have influenced weaning weights more on the heavily stocked pastures than on the moderately stocked pastures. Calves weaned from the low level on heavy stocking were significantly lighter than from all other treatments, and O of calves from cows fed _._.._ | V2 three levels of supplement _ .___ 3 on heavily stocked pastures. I966 I967 I968 the weaning weights from the high level on moderate stocking were significantly higher than from all other treatments (Appendix Table 6b). Failure to feed supplemental protein to cows on heavily stocked pastures appeared to have an accumulative adverse effect on weaning weights of the calves as the study progressed (Figure 28). For the first 2 years the amount of supplement showed little effect on the weaning weights, but starting in 1964 and throughout the remainder of the study, supplement significantly increased the weaning weights. However, the 3-pound level of supplement showed little additional response compared to the 1.5-p0und level. Weaning weights on moderately stocked pastures did not show an accumulative effect of supplement; supplement appeared to have almost no effect (Figure 29). Only in 1961 and 1964 did the treatments respond to supplement as they might be expected to. In 5 of the 8 years, weaning weights from the no-supplement treatment were as heavy or heavier than from one or both of the other treatments. The differences among the three levels of supplement were greater during the first 4 years of the study than during the last 4 years. Improving range condition under the moderate stocking rate may have been responsible. 23 $OOy 550- 500 - 450 ' (D Q Z D O O. 4C0 ' 350 ' Figure 29. t Annual weaning -- vi of calves from -- i 300 ' i’ o three levels of supply - '- -- l l/Z on moderately stocked J ______ 3 tures. , y L l l | n n v l J l96| I962 I963 I964 I965 I966 I967 I958 Calves on the heavily stocked pasture where no supplement was fed were significantly (P<.O5) lighter at all three weighing periods compared with those receiv- ing the medium and high levels of supplement (Figure 30 and Appendix Tables 4b, 5b and 6b). Calf weights from the medium and high levels of supplement did not differ significantly at any of the weighing periods. A small re- sponse to the high level of supplement was noted at the March weighing, but at the summer and fall weighings, only two pounds separated the average calf weights from the medium and high levels of supplement. Calves from the zero level of supplement gained at a slightly lower rate during the spring and summer than those from the medium and high levels. ' On the moderately stocked pastures, calf weights showed little response to different levels of supplement at the spring weighing (Figure 31 At the summer weigh- ing, calves from the high level weighed significantly (P<.O5) heavier than those that received no winter sup- plement (Appendix Table 5b). At the fall weighing the calves from the high level were significantly heavier than both the low and medium level groups (Appendix Table 6b). No explanation is available for this response; it may be a result of the supplement fed or of differences in the 24 vegetation of the pastures. To fully interpret this res’: would require a more intensive investigation. i The percent calf crop weaned from the trea: showed little response to the level of supplement (Figure 32). The highest average percent calf crop o six treatments was from the LS-pound level of suppll with heavy stocking. On both the heavily and mod stocked pastures, the percent calf crops were the same; the low and high level groups. With heavy stocking,‘ medium level of supplement had the highest percent: crop, whereas, with moderate stocking, the medium ' had the lowest. The percent calf crops from mode stocked pastures tended to be higher than from the head, stocked pastures. '7 On the heavily stocked pastures, the medium l_ of supplement produced 37 more pounds of calf per (weaning weight times percent calf crop) than no i, plement, but the high level of supplement produced than the medium level (Figure 33). Production on‘ heavily stocked pastures was lower than on the mode t; stocked pastures. On the moderately stocked pasturesyi high level of supplement produced 13 pounds more per cow than no supplement, whereas the medium POUNDS 550 - 500 - 450 - 400- 350 - 300 - 250 - 200 - l50- -——— O ---- I l/Z .._._-. 3 JAN. FEB. MARAPRMAY JUNE JULY AUG.SEPT. OCT.NOV. DEC. 4 i Figure 30. Spring, summer and fall weights of calves from cows fed three levels of protein supplement on heavily stocked pastures. of supplement produced an average of 6 pounds less calf per cow than no supplement. Calf production per cow on the heavily stocked pastures varied relatively little for the first 3 years of the i study (Figure 34). Supplement appeared to have little ‘effect on calf production until 1964. Production dropped sharply in 1964 and 1965 on the no-supplement treatment. A 67-percent calf crop weaned on the high level of sup- plement in 1966 greatly reduced production that year; however, in 1967 the same treatment weaned a 100-percent calf crop resulting in an increase in production of 218 pounds of calf per cow. Production from the heavily stocked pastures varied more from year to year on all three levels of supplement as the study progressed. No consistent differences among levels of supplement were observed. Production from the lfcows receiving no supplement was significantly lower than from those receiving the medium and high levels for 4 years, but for 2 years, the low level of supplement produced more pounds of calf per cow than either the medium or high levels. In only 2 of the 8 years did the high level of supplement produce the most pounds of calf per cow. 550' 500 * 450* 400 - 350- POUNDS 300 - I50- i Q --—- | v2 T n n | a I l i 1 I JAN. FEB. MAR.APR.MAY JUNE JULY AUG.SEPT. OCT. NOV. DEC. Figure 51. Spring, summer and fall weights of calves from cows fed three levels of protein supplement on moderately stocked pastures. On the moderately stocked pastures, calf production per cow varied less on the low level of supplement than on the medium and high levels (Figure 35). Calf pro- duction increased almost linearly for the first 4 years on I00- 90- 89~9 89.8 89.6 86.9 88.9 882 PERCENT ~| m o o O ll/2 3 O I I/2 3 HEAVY MODERATE Figure 52. Percent calf crop weaned from three levels of protein supplement and two stocking rates averaged across 8 years. 25 soo I 550' 500' 450- POUNDS 400- 403 350» 300- 440 428 447 44I 460 O Figure 33. Pounds of calf produced per cow bred from three levels of protein II/2 HEAVY II/2 3 MODERATE supplement and two stocking rates averaged across 8 years. 600* 550 56o 450 POUNDS 400 350 300 - ‘L l96l Z6 I962 I963 I964 I965 L . the high level of supplement but then dropped during 1965 and 1966. The high level of su“ produced fewer pounds of calf per cow in 1966 v the low and medium levels. This was the s observed on the heavily stocked pastures in 1966 34). In only 1 year (1963) did the cows receii supplement produce significantly fewer tpounds g per cow than those receiving supplement. 3f l i Calf production per acre varied more betwef ing rates than among levels of supplementation _i 36). Supplement tended to increase calf produ g acre on the heavily stocked pastures although the j rate resulted in only a slight increase above the 1. rate. On the moderately stocked pastures, supple no significant effect upon calf production per During 6 of the 8 years calf production per I lower from the heavily stocked, no supplement i_’ than from the heavily stocked, medium and high su tation levels (Figure 37). The greatest differences: treatments were observed during 1967 and u; production per acre was about the same for all thr .1 i . 1‘ Figure 34, Pounds of calf per cow bred f ~ levels of protein y ment fed on stocked pastures. ——o -—-- I I/Z i.i. 3 I966 I967 I968 8Z 996i b96l 996i 296i i96i “a: ;o spunod '8? $115M amp Jo “ma: e s12 papm qvq; asoq; pun smaunvan -‘- 11v :0; ewes sq; 91am mp asoq; om; panzxvdas ;._s;soa fiupvxaclg ‘mammal; mp2s Jo; 1pm lemme 19d ‘m: swoon} QEBJQAB aq; anqmpea o; pasn 91am smoo bpxafiuo] pun smfigam mo: ‘uogpnpold 51123 i uogpanpzmg aguuouoag 896i L96| 996i ‘ sad paapms A1919 Q u- '- 0 pa; Juawalddns ;o Z/ I I - - - - 1110.1; ama Jad o ____ 1 I v I i I I O O r0 o: SCJNflOd 10b ‘uogqmuamapidns 50 [am] qfigq sq; qqpu qqoq ‘fiuppoqs snonupuoa amJapour pue Meaq 91am Alpxafiuo] JSQMOI aq; qlgm smawwax; om aql quawalddns ou qqym fiuppms snonupuoa AAeaq pue JUQIIIQIddHS ou qggm Suppogs snonupuoa amxapow exam Aqpxafiuo] 1saq3gq amp qrggm squaunvan aql ‘uopvquawqddns 896i L96i 996i 996i 996i 996i 296i i96i V_ paapoqs AWveaq Q '_ ' _ i; JUQHJQIddHS ;o 3A | .____ r1101; e122 Jed _ o‘ 1nd m: ;o spunod o . ‘L; amfiyg - 02 ‘U O. C 2 U (D '09 50y Figure 37. Pounds of calf p, IO‘ __— o per acre from i‘ - -- "' l I/Z of supplement _ . _. 3 heavily stocked l96I I962 I963 I964 I965 I966 I967 I968 supplementation. The treatments with the highest longevity were moderate continuous stocking with no supplement and heavy continuous stocking with no supplement. The two treatments with the lowest longevity were heavy and moderate continuous stocking, both with the high level of supplementation. 4O POUNDS o: O Economic Evaluation Calf production, cow weights and longevity cows were used to calculate the average income per animal unit for each treatment. Operating costs“; separated into those that were the same for all treatments and those that varied as a result of the‘; l96l I962 I963 I964 I965 28 I966 Figure 38. t Pounds of calf p O per acre from three _ .. _. - | V2 of supplement fed ately stocked pas _ ...._. 3 I967 I968 i i i i i i s i i i E ment. The constant operating expenses, those that were the same for all treatments, included veterinary and medical, hauling to market, bull cost, pickup expense, repairs, salt and bonemeal, labor, interest and property taxes on the cow (Table 4). Some of these costs were taken from Torn Prater’s estimates for the eastern Rolling Plains (4), and E E l? the remainder were calculated from station data. Interest on herd capital was not included as a cost but was included in returns to capital and management. TABLE 4. OPERATING COST DATA PER ANIMAL UNIT FOR ALL EXPERIMENTAL TREATMENTS ON THE TEXAS EXPERIMENTAL RANCH Expenses: Cost / animal unit Veterinarian and medicine $ 2.501 Hauling to market 2.60‘ Bull cost 6.001 Pickup expense 2.50‘ Repairs 1.601 Salt and bonemeal .75 Labor (7.5 hr/cow) 11.25 Sub-total $27.20 Interest on operating expenses @ 7% (6 mo) .95 County and school property tax on cow 1.15 Total $29.30 Interest on herd capital ($140/ cow @ 5%) 7.002 Taxes County $0.53/cow $O.22/acre School 0.62/cow 0.20/acre Z ‘Cost figures taken from Estimates on Annual Beef Cow Cost by ' Areas, Tom E. Prater, AECO-5. f "If the operator uses borrowed capital, this interest will be a cost. i In this analysis it has been included in the returns to capital and management. Those costs that varied with the treatment were itemized on an animal unit basis (Table 5). Expenses were i calculated for two types of operators, landowners and lessee. Expenses for the landowner were land tax; de- .preciation on fences, pens, buildings and other improve- ments; feed cost; and replacement cost. No charge for land use was made for the landowner since net returns were calculated on the basis of returns to capital and manage- ment. Expenses for the lessee included feed cost, replace- ment cost and a land charge of $2.50 per acre per year. The land tax and depreciation would generally be borne by“’the owner and not the lessee. Replacement costs were calculated on the basis of keeping heifers and breeding them to calve as 2-year-olds. During the year the heifer was kept, the cow was sold, and the value of the cow exceeded the value of the replacement heifer for all treatments. The amount of income from the sale of the cow in excess of the value of the replacement heifer was considered the salvage value of the cow. This salvage value per cow for each treatment was divided by the average number of productive years that cows remained on that treatment to give an annual return (Table 5). All costs incurred by the replacement heifer while she was a yearling were tabulated (Appendix Tables 8 and 9). The cost of raising replacement heifers on the various treatments followed the same pattern as the operating expenses for the treatments. The replacement cost would vary considerably among individual operators and be dependent on many variable factors. For example, breeding heifers to calve at 3 years old would approximately double the replacement cost for some small operators, whereas for large operators it may be more economical. In this study an attempt was made to apply a uniform policy for calculating replacement costs to all of the treat- ments so that they could be compared objectively. The total annual costs per animal unit for a lessee were considerably higher than for a landowner (Table 5). Increasing the level of supplement fed and increasing the number of acres per animal unit were the two primary factors that resulted in increased costs. Light stocking and moderate stocking with 3.0 pounds of supplement resulted in the highest operating costs for both types of operators. The grazing system used had little influence upon the g operating expenses as long as the stocking rate and level of supplement remained the same. The value of the calf produced per cow bred on each treatment, figured at $25 per hundredweight, ranged from $100.75 from pasture A to $122 from the Merrill system (Table 5). The salvage value of the cows, when it was spread over the productive life of the cow, varied little among treatments. Therefore, total income reflected pri- marily the calf production from each treatment. Grazing systems affected income more than did the stocking rate or the level of supplement. Income from the deferred- rotation systems was higher than from the continuously grazed treatments. No attempt has been made to separate the returns to capital and to management for the treatments in this study. Table 6 gives the net returns to capital and to management combined for both landowner and lessee- type operators. These returns have been expressed in two ' ways, as returns per animal unit and as returns per acre. Returns per animal unit were calculated by subtracting the total annual cost per animal unit from the total annual income per animal unit for each treatment. Returns per acre were calculated by dividing the annual returns per animal unit by the stocking rate (acres per animal unit). The returns per animal unit for a landowner indicate several things. First, on heavily stocked pastures, the medium level of winter supplement was profitable, whereas the high level was not. On the moderately stocked, con- tinuously grazed pastures, feeding protein supplement during the winter was not profitable at either level. The stocking rate on the continuously grazed pastures had little 29 mmwwmi 8.2 ~02 0&0 00.2 20.2 02.2 8.0. 00.2 20+ 802 ~00 0.00 000 03:00 $.22 3.00 22.00 030 0000 22.00 22.02 8.20 22.20 ~82 0K E5 R808 000 3:5 MHZBOOZ0A 0052.000 00200.3 msescficee msescbcee wsescbcee 30:50.50 020200050 msescwceu msescwcee E0220 005N000 00000034 00000002 E03 00000002 00000252 00000252 250E 22003 20603 0000 050080 2-2-0-00 0-0 m 0 a m 2 0 < 0:030 IUZE 52202200020 0883 >283 B3 mcfiuoww 2-2-2-8 md m 2 Q m » w < 828.2 EUZA .688: 8m wwoU "wuwcumxm wmmhzmm HZMZMU