3-1089 October 1969 a ock Production and Profifgkjligv GamplaYisoru i, Of Various Grazing Systems, Texas Range ftation —— s A&M UNIVERSITY Agriculturai Experiment Station i, . Kunkel, Acting Director, College Station, Texas Summary Research on the Texas Range Station, Barnhart, waslmodified in 1958 to study the effects of various grazing systems on livestock production. This study reports livestock production and profitability from 1959 through 1965 under different grazing systems with a common stocking rate of 25.6 animal units per section. The systems compared were: yearlong graz- ing with cattle only and with sheep only; yearlong grazing with both’ cattle and sheep; and a two- pasture rotation and a four-pasture rotation system of grazing, both with dual use (used by cattle and sheep simultaneously). Dual use considerably increased the production of sheep. Lamb production from the single use sys- tem was significantly lower than from the dual use system. Both average lamb weaning weights and percent lamb crop were increased when sheep were grazed in combination with cattle. Likewise, wool production was significantly greater from the dual use system than from the single use. The overall condition of the ewes in each system was best illustrated in the amount of supplemental feed required for each system. The ewes in the single use system required approximately four times the amount of feed as those in the other grazing systems, and the replacement rate (ewes culled be- cause of emaciation and death loss) was still signifi- cantly higher than that in the other systems. Rotation grazing yielded an additional increase in sheep productivity through an increase in percent lamb crop and wool production as well as in a reduc- tion in feed expense and replacement rate. Analysis of net returns per animal unit of sheep to land, labor and management revealed the impor- Content: Summary ............................................ .. 2 Introduction ....................................... .. 3 Description of Area . ..... .. 3 Procedure: .. 4 Grazing Treatment Description ................................................ .. 4 Pasture Descriptions ______ ._ 5 Livestock Nlanagement 5 Replacement Procedures 6 Supplemental Feeding G Economic Analysis .. 6 6 6 8 9 9 Results and Discussion Sheep Production .... .. Cattle Production Net Returns Sheep Cattle ..... .. l0 Total Management System l0 Economic Stability ll Additional Costs Due to Management System ............. ..ll Acknowledgments 12 Literature Cited l2 Appendix 13 tance of dual use as a means of increasin itability of sheep production. The mean to sheep in the single use system was $19. ‘ the mean net return in the dual use <4 $53.03. Rotation grazing, yielded a larger _“ although not statistically}; significant, long grazing. . In general, the effects of dual use onf duction were the reverse of the effects on f duction. In comparison to single use, ca , tion significantly decreased when cattle j in combination with sheep in the yearl systems. However, rotation grazing, al n- dual use, increased cattle production whe, to yearlong grazing. Neither rotation dual use appreciably affected calf wean’; but the major difference was in percent. The dual use yearlong system had the lo " calf crop and seemed to have a 2-year cy cows did not conceive. Cattle production A, the rotation systems seemed to be related‘. Comparison of total net returns favo g ing the positive effects of dual use on" duction and the positive effects of rota on cattle production. The net returns single use systems were significantly lower‘: dual use, and the returns from the rota I; were significantly higher than grazing ye I dual use yearlong system had a net return unit of $30.63 as compared to $19.52 for 7 and to $22.27 for cattle only. The net“ the two and. four-pasture rotation systems l“ and $39.03, respectively. In addition to net income was more stable in the rota 5 ; ' EDWARDS PLATEAU AREA OF TEXAS rt a longte-rm downward trend in 1r ranching enterprises. This de- “turns apparently results from the . of maximizing short term profits. ftenn profits were obtained by con- ' close grazing, but this has resulted fof the native forage-plant cover on Ylthe long term. Low producing an- ‘nials which are often weedy and i‘ have largely replaced high produc- nial grasses. As a consequence, I» efficient and are more susceptible ' . onal and extended drouth. frequently suggested as means of lerioration and improving range con- u reduce the stocking rate to proper ‘ deferred grazing and (3) to adjust _ to better use the vegetation. Most T’ indicated only the pounds of live- ‘gor changes in vegetation resulting above alternatives. To adequately involving different products, results H. yzed within an economic frame- All net benefit of each alternative not A’ t for the additional economic re- products, it must also include the ' ch as additional fencing, differences p; and practices, livestock investment j_ and culling rates. This study was 'ne the effects of yearlong and rota- ind both dual and single use at a Q; rate of 25.6 animal units per sec- ,_ production and profitability in the F Plateau. IPTION OF AREA Range Station is located in northeast- nty, approximately l0 miles south 19 miles north of Ozona. The sta- i approximately 3,160 acres‘ of land , niversity of Texas. if _ nt professor and graduate research assistant, gc Science, Texas A8cM University. g k Production and Profitability Coinparironr 1 Q‘ Various Grazing Syrtemir, T exar Range Station DONALD L. Huss AND JERRY V. ALLEN* Extensive ecological studies by Thomas (1951, 1954) and Potts (1946) give an accurate description of the climate, topography, soils and vegetation on the Texas Range Station. The mean annual precipi- tation approaches the 18-inch rainfall belt (Appendix Table 1). May and June are the wettest months; midsummer tends to be dry with precipitation in- creasing in October. The winter months are dry. The rainfall is often of a localized torrential nature and varies greatly from year to year. The most abundant grasses are buffalograss, Buchloe dactyloides; curlymesquite, Hilaria belan- geri; and tobosagrass, Hilaria mutica. Species of lesser abundance are: sideoats grama, Bouteloua cur- tipendula; threeawn grasses, Aristida spp.; Vine mesquite, Panicum obtusum; hairy tridens, Tridens pilosus; fall witchgrass, Leptoloma cognatum; muhly, Muhlenbergia arenacea; tumblegrass, Schedonnardus paniculatus; hairy grama, Bouteloua hirsuta; and Panicum halii. In years of good rainfall, winter annual grasses and forbs are abundant. Most of these, especially forbs, are palatable to sheep and constitute a major portion of their winter diet. A major problem of the area is the presence of the poisonous bitterweed, Hymenoxys odorata. This winter annual usually occurs in abundance with average fall or early spring rainfall. The species is poisonous mainly to sheep and contributes to the ranching risks of the area. Mesquite, Prosopis juli- flora, is also another problem. The land is gently rolling with occasional dry lake beds. The soil profile has a heavy calcium carbonate accumulation and is underlain by hard limestones. The major soil series are Ozona, Valera, Tobosa, Irion and Randall. The soils of the Sta- tion have been grouped into three range sites: shal- low upland, tobosa flat and lakebed. A shallow upland site is a ridge of 1 to 3 percent slope containing shallow, moderately permeable clays of the Ozona series. The soils are l0 to 20 inches deep to limestone. A Tobosa flat site contains soils of both the Tobosa and Ozona series. The site has a 0 to l percent slope and a slowly permeable clay series which is 20 to 40 inches deep to limestone. j3 The deep phase of Ozona clay is included in this site because of soil and topographic similarity to the Tobosa clay and because both soils support a similar type of vegetation. A lakebed site is a depressed area composed of either Randall or Irion clay soils subject to inundation for short periods following tor- rential rains. The transitio-n between a shallow upland and tobosa flat represents a microsite with above-average moisture conditions. Apparently, the surface runoff from the shallow site accumulates in this zone and increases the available soil moisture. The first signs of an upward trend in range condition, as evidenced by the occurrence of sideoats grama, is in this zone. The species then spreads into other sites with con- tinued favorable management. An abundance of microsites can considerably influence grazing capacity. A lakebed usually supports a sod of buffalograss. Vine mesquite increases with proper management, and bitterweed occurs in abundance, particularly fol- lowing summer inundation. Tobosagrass is the dominant species of a tobosa flat. Buffalograss is in lesser amounts. The site supports an abundance of annual winter forbs and grasses, particularly bitterweed, and mesquite is also abundant. A shallow upland supports a sod of buffalograss and curlymesquite. Since stolons of the two species usually intertwine and are difficult to identify, the mixture is classified as “turf” for vege- tation analysis.‘ The threeawns, muhly, hairy grama- and hairy tridens are usually found on this site. The site does not support an abundance of bitterweed or mesquite. PROCEDURES Grazing Treatment Description Although this study began in 1958 and a lamb crop was produced that year, a calf crop was not pro- duced until 1959. Therefore, the livestock production compared is that from 1959 through 1965. All grazing systems were grazed at an equivalent rate of 25.6 animal units (hereafter referred to as A.U.’s) per section. The grazing systems compared in the study are summarized in Table 1. The design confuses the effects of deferred grazing and dual use. Any bene- fits derived from deferred grazing probably result from both dual use and deferred grazing, and the exact effect of each cannot be isolated. However, certain suppo-sitions are made. Descriptions of the various grazing systems follow. “Single use” is the practice of grazing only one kind of animal, whereas “dual use” is the practice of grazing more than one kind of animal. This study includes single use by cattle and by sheep and dual use at an approximate ratio of 15.4 A.U.’s of cattle to 10.2 A.U.’s of sheep. An A.U. is defined as one mature cow or five mature ewes. 4 TABLE 1. SUMMARY OF GRAZING SYSTEMS Q IN THIS ANALYSIS‘ Number Description ewes Single use — yearlong 64 Single use — yearlong Dual use — yearlong 28 Dual use — four-pasture rotation 51 Dual use- two-pasture rotation” 52 ‘All systems are grazed at the equivalent stockingl A.U.’s per section. (An A.U. is defined as a u A five mature ewes.) Dual use is at an approxi of 60 percent cattle and 40 percent sheep. ’ Yearlong grazing is considered as grazing from March 1 of one year to M following year except with cattle. It was f divide all cattle on the Station into thr herds during the March 1 to May l5 bree The cattle were rotated in such mann pasture was grazed for approximately the ‘ ber of cow days that it would have been the cattle not been removed and placed in l herd. No pasture was deferred from longer than 1O days, and no pasture i‘ completely, except the one grazed by If, cause all sheep remained in their pasture Two rotational grazing systems are the study: a four-pasture deferred rot’ two-pasture rotation. The four-pasture s1 same as the one first developed by Leo M at the Texas A8cM Agricultural Resear L» Sonora. ' In the four-pasture system, the eqi 102.4 A.U.’s was divided into three h, A.U.’s each. A pasture was grazed by but, because of the nature of the rotation, l equivalent was 25.6 A.U.’s per year. J pasture was grazed 12 months and rest deferment periods were March 1 to Jul to November l and November 1 to M ~ rotational order is given in Table 2. In the two-pasture system, livestock 'J tures were combined into one herd of _; TABLE 2. THE FOUR-PASTURE DEFERRED TESTED ON THE TEXAS RANGE STATIONJV Deferment periods I March 1 to July 1 to Year July 1 November 1 1964-65 Pasture l Pasture 2 1965-66 Pasture 4 Pasture 1 1966-67 Pasture 3 Pasture 4 1967-68 Pasture 2 Pasture 3 1968-69 Pasture 1 Pasture 2 and so forth and so forth ETHE TWO-PASTURE ROTATION TESTED ON t RANGE STATION, BARNHART Deferment periods i March 1 to June l to December 1 to June l December I March l Pasture 1 Pasture 2 Pasture 1 Pasture 2 Pasture 1 Pasture 2 Pasture 1 Pasture 2 Pasture l é and so forth and so forth and so forth asture being grazediwas stocked at this e nature of the rotation caused each "have a grazing equivalent of 25.6 A.U.’s he rotational order is given in Table 3. Pasture Descriptions aimize vegetational influence on livestock due to past use, grazing history was con- assigning treatments to specific p-astures * earch was modified and this study begun ‘ter of 1958. In effect, the grazing treat- in 1958 were, with few exceptions, a f» of similar treatments. In addition, all re removed from the Station in 1957 due A’ drouth. Undoubtedly this drouth in- e trend toward pasture equalization. i. ibility of range site influence upon yand livestock performances is recognized fl site is represented in each treatment, iThe near equal ratio of shallow upland at in the two-pasture rotation created a s. of the transitional site previously men- i: is type of site could have had some in- i‘ the livestock responses within this treat- A ever, this situation was prevalent in only two pastures; the other was more similar the remaining treatments. ' proportionate distribution of the lakebed "treatments could also have had an influ- vegetation and livestock responses. The i ed yearlong with cattle had the lowest per- ebed, and the one grazed yearlong with ;~sheep had the largest percent of lakebed. itVERAGE PERCENTAGE OF RANGE SITES . CH GRAZING TREATMENT ._ Shallow Tobosa a tment Lakebed upland flat ‘yearlong - sheep i ' 11.9 20.0 68.1 yearlong — cattle‘ 2.3 22.5 69.3 i - rlong 17.4 26.8 55.8 ur-pasture rotation 7.6 23.3 69.1 A o-pasture rotation 6.3 47.2 46.5 l percent Ector stony clay loam creating a shallow, A“ occurs only in this pasture. The 1957 turf frequency was low for all sites and pastures. The greatest variation between graz- ing treatments was on the lakebed site, Table 4. The pasture grazed yearlong with cattle had a turf frequency of 32.4 percent compared with 0.1 percent in the pasture grazed yearlong with cattle and sheep. The comparative high frequency of 32.4 percent is probably due to the pattern of grazing prior to the study in which this pasture was grazed with cattle only for several years. Wright (1962) found that cattle do not prefer to graze a lakebed site as fre- quently as do sheep. The 1957 turf frequency on the shallow site was nearly equal for all pastures except the pasture grazed yearlong by sheep only. This inequity also probably was caused by prior grazing since this pasture previ- ously had been grazed yearlong by sheep only as a result of their preference for grazing on a shallow upland site. This preference had apparently reduced the turf frequency. The 1957 turf frequency also was low on the tobosa flats of all pastures. The frequency varied from 3.1 percent on the yearlong dual use pasture to 11.0 percent on the yearlong-sheep only pasture. A considerable increase in turf frequency from 1957 to 1958 was caused mainly by increased rainfall. The amount of increase expressed in percentage points was nearly equal for all pastures on the shal- low upland site, indicating a greater rainfall influ- ence than grazing treatment influence on this particu- lar site. However, the amount of increase was more variable on the to-bosa flat and lakebed site. As expected, the 1957 tobosagrass frequency was not as low as the turf frequency. Thomas (1951, 1954) showed that tobosagrass frequently is reduced less by drouth than buffalograss and curlymesquite. There was also greater variability among pastures in tobosa frequency than in turf frequency. This was probably caused by past management. Cattle generally utilize tobosagrass at a greater rate than do sheep. This is partially reflected by the difference in tobosagrass frequency on the tobosa flat within pastures previously grazed by the two kinds of animals. The pasture grazed by cattle had a fre- quency of 28.2 percent, whereas the pasture grazed by sheep had 42.0 percent. Grazing preference by site is also reflected in this difference. Tobosagrass increased on all sites and pastures in 1958. As with turf, this was due mainly to an increase in rainfall. Livestock Management The study was initiated with 2-year-old commer- cial Hereford cows bred to calve at 3 years of age during December, January and February. Breeding ability of the original cow was unknown. A dry cow during the first calf crop could have been a 5 "result of either poor ‘breeding ability or of pasture treatment. Therefore, a dry cow was left in her respective herd and was bred to produce the follow- ing year. If the cow produced a calf the following year, she was assumed dry the previous year because of grazing treatment and was included in the calf crop calculations for that treatment. If the cow was dry the second year, she was assumed to be a poor breeder and was not included in the calf crop of either year. The original plan was to replace all culled cows with producing cows of the same age. However, since such cows were not always available, younger cows had to serve as replacements. Proportionately aged herds were maintained between the grazing treatments being compared. The ewes were of a commercial Rambouillet type, and all flocks were maintained at the same age. The ewes were bought at 2 years of age and were replaced at 6 years of age. The ewes were bred to lamb during April and May. They were sheared in June. All dry ewes were kept in their respective flocks and rebred. Dead and culled ewes were replaced by ewes from a reserve herd. If the dead or culled ewe had a lamb, her lamb was removed from the grazing treatment, and she was replaced with a ewe and lamb. If the ewe was dry, she was replaced with a dry ewe. All ewes were bred by rams of near equal medium gainability except those within the four- pasture deferred rotation. Because of a cooperative project with the Department of Animal Science, one of the three herds within this system was bred to a high-gaining ram, one to a medium-gaining ram and one to a low-gaining ram. However, average produc- tion of the three herds was theoretically equal to that obtained by a medium-gaining ram. Replacement Procedures Reasons for cow replacements were advanced age, death, poor breeding ability, disease, bad eyes and wildness. There was no apparent relationship be- tween grazing treatment and the cattle replacement rate. Only four cows died during the study. Initial culling because of poor breeding ability was an effort to establish a herd ofknown breeders. Cull- ing since that time was primarily due to age. The ewes were replaced because of death, emacia- tion and disease. Ewes were culled for emaciation only when they were near death or when it was obvious they could not survive for another breeding period. Supplemental Feeding Supplemental feed for cattle was equal among all treatments. Condition of cattle in the yearlong grazing treatment was used as the criterion for supplementation. 6. Ewes were supplemented on the basis weed poisoning symptoms. When a herd s symptoms of poisoning, it was penned and the symptoms disappeared. This usually to l0 days. Amount of feed and number of ‘ were recorded. Economic; Analysis , A typical ranch in tlle Edwards Plate tains an uneven age herd of cattle and/or w keeps replacements. Since the experimental _ from an even age herd of sheep and did o“ maintenance of any replacement livestock, _ matical power series formula based on the ‘ death and culling rates was used to simula; even age herd of sheep based on an even I Indices developed from Campbell's (1962) production curve were used to adjust even duction to uneven age production. Cattle p data were not adjusted for age since an Ii herd was maintained. Calf production wasf to a 205-day weight and for sex. An anim- the economic analysis included a breedi five ewes plus the corresponding replaceme = .x breeding unit + .y replacement; whe _ _y)_ . A simple budgeting procedure was f0 estimate operating expenses and net returns‘ A year. Variable expenses of a ranch firm l i cording to number of producing animals y ments and percent calf or lamb crop. _ expenses such as hauling, marketing, taxes, y, shearing and investment on livestock w‘ yearly for each system. Production per a i? was determined by percent calf or lamb u ' ing weight and wool production but adjus +- maintenance of replacements. ‘ é RESULTS AND DISCUSSION a Sheep Production if Average sheep production is presented 5. An analysis of variance revealed a si ' ference in lamb production among grazing - and years (Appendix Table 4). TABLE 5. AVERAGE SHEEP PRODUCTION f THROUGH 1965 ON THE TEXAS RANGE i BARNHART A Percent‘ Lamb i lamb Lamb producti p, Grazing treatment crop weight per A.Uj.~ Yearlong — sheep 88.2‘ 65.5‘ 289.6‘ 5 Yearlong—dua1 use 105.6” 79.1” 431.7‘ '_ Two-pasture j rotation — dual use 111.5” 82.0” 443.9‘ l Four-pasture f rotation — dual use 113.7” 79.4“ 455.6‘ ‘Any two means followed by the same letter are; cantly different at the 5-percent level of probabili j g and twopasture rotation systems had yeans of 455.6 and 443.9 pounds of lamb ,pectively. The dual use yearlong sys- TT-ean lamb production per A.U. of 431.7 é e the single use yearlong system had the uction of 289.6 pounds. Average lamb “rof the single use yearlong system was i lower at the 5-percent level than of the asystems. However, differences between ' the dual use yearlong and the dual use items were not significant. , for the significantly lower lamb produc- ‘IU. from the single use yearlong system A nd in both lamb weaning weights and pb crops. The mean lamb weaning weight De use yearlong system was 65.5 pounds ificantly lower than the other three n?» dual use yearlong system had a mean u weight of 79.1 pounds and the four- i". .two-pasture rotation mean lamb wean- igwere 79.4 and 82.0 pounds, respectively. (use yearlong system had a mean percent pf. 88.2 percent, significantly lower than " other three systems. The mean percent from the dual use yearlong, dual use two- Years of age 3 4 5 2 pasture rotation and dual use four-pasture rotation systems were 105.6 percent, 111.5 percent, and 113.7 percent, respectively. Although there is a trend to- ward greater lamb crops and lamb production with the more complex rotation systems, the differences are not significant even at a lO-percent level. Yearly lamb production reflected an age cycle with maximum production when ewe-s were four and five years of age, Figure 1. This cycle was evident in all grazing treatments. Lamb production showed no apparent variation in relation to ‘yearly rainfall variation but closely followed the age-production curve presented by Camp- bell (1962). This is especially true of the production from 1962 through 1965. This relationship permitted the simulation of an uneven aged herd used for eco- nomic analysis later in this report. That the four- pasture rotation system had the highest production during 3 of the last 4 years perhaps indicates a trend in favor of the four-pasture system when contrasted with the two-pasture rotation system. Average wool production per A.U. is presented in Table 5. The single use yearlong system had the lowest mean wool production of 40.9 pounds, whereas I I I 1 1 n 1 | 1959 1960 1961 1962 Year / Y Legend ____ Sheep yearlong _.._.. Dual use yearlong 1963 1964 1965 Dual use two-nasture rotation __ Dual use four-pasture rotation I ! Figure l. Average lamb production per A.U. as related to years and age of ewes. 7 TABLE 6. MEAN EWE WEIGHTS FOR EACH WEIGHT DATE BY GRAZING MANAGEMENT SYSTEM ON THE TEXAS RANGE STATION, BARNHART Grazing management system Dual use Dual use two- four- Single use Dual use pasture pasture Weight yearlong, yearlong, rotation, rotation, date pounds pounds pounds pounds March 1 107 119 119 121 July 1 104 117 120 118 November 1 107 121 120 122 Yearly mean 106 119 120 120 the mean wool production for the dual use year- long, dual use two-pasture rotation and dual use four- pasture rotation systems were 46.5, 52.8, and 46.5 pounds per A.U., respectively. The two-pasture rota- tion system was statistically superior to the fo-ur- pasture system but there was no significant difference between the means of the four-pasture system and the dual use yearlong systems, Appendix Table 3. How- ever, the means from the dual use yearlong system and dual use rotation systems were all significantly higher than the single use yearlong system. Wool production also significantly varied between years, Appendix Table 3. Mean ewe weights by management systems are presented in Table 6. All ewes were randomly selected from a herd of similar genetic potential and weight at the beginning of the study when the 6-year- old ewes were replaced with 2-year-olds. However, those in the single use yearlong system soon became the smallest and those in the other treatments the largest because of additional growth. There was no apparent difference between the mean weights of ewes grazed yearlong (dual use) and those grazed in a rotation system. Ewe weights did not reflect sea- sonal changes in vegetation since ewe weights did not fluctuate greatly between weighing dates. The absence of weight fluctuation can be attributed largely to the practice of feeding each herd according to physical condition. Comparison of the mean ewe replacement rates, Table 7, revealed a large difference between single use and dual use. The mean ewe replaceme the single use yearlong system was 16.7 perce as the dual use yearlong system had a 7. replacement rate. The two-pasture and f0 ' rotation systems had replacement rates of 5. percent, respectively. The replacement ra single use yearlong system was significant! than that of the 3 remaining systems, but 1 no statistically significant" difference bet means from dual use yearlong grazing and grazing. Cattle Production The average cattle production is pr, Table 8. Single use yearlong has a mean? pounds of calf per A.U., but calf production to 294.2 pounds per A.U. when cattle w yearlong in combination with sheep. C tion appeared to be greater when cattle W in a rotation management system. The two. pasture system had means of 354.8 and 342 per A.U., respectively. a The yearly calf production per A.U. i Table 9. Calf production varied consid A systems, particularly within the yearlong I system. Within this system, production v, a low of 181.1 pounds to a high of 417.9 f’ a difference of 236.8 pounds. Production i than from any other system in 3 of th‘ Production varied in the other systems, t this extent. The yearlong single use sysk from a low of 228.5 pounds per A.U. to 37f and in no years was production above three. Production varied from 287.3 to 4 l in the two-pasture rotation system and 266 pounds in the four-pasture system. A Since the mean calf production per expression of botl1 weaning weight and '2 calf crop, further comparisons were made any differences among the treatment Q dual use yearlong system had the lowest ~ crop, Table 9, (72.0 percent) and ranged f. TABLE 8. AVEILAGE CATTLE PRODUCTION- THROUGH 1965 ON THE TEXAS RANGE j BARNHART , " TABLE 7. COMPARISON OF MEAN PERCENT REPLACE- Calf MENT RATE OF SHEEP AS INFLUENCED BY GRAZING ,Percent‘ weaning MANAGEMENT SYSTEMS Grazing system calf crop weight Death Culling Pound; Grazing system loss rate Total‘ yearlong _ came 845. 387.9. A Yearlong-dual use 72.0” 407.0‘ ' Yearlong —- sheep 10.2 6.5 16.7‘ Two-pasture Yearlong-dual use 6.3 1.3 7.6“ rotation-dual use 87.1‘ 406.5‘ Two-pasture rotation — dual use 4.6 0.6 5.2” Four-pasture Four-pasture rotation -— dual use 4.2 .3 4.5” rotation —dual use 86.4“ 395.5‘ ‘Any two means followed by the same letter are not signifi- cantly different at the 5-percent level of probability. ‘Any two means followed by the same letter a cantly different at the 10-percent level of probabi -“ VMPARISON or AVERAGE CALF PRODUC- . AS INFLUENNCED BY GRAZING MANAGE- AND YEARS Management system _; Dual use Dual use little Dual use two-pasture four-pasture long yearlong rotation rotation Pounds 12 345.9 351.2 292.1 . 4.6 181.1 430.5 396.0 j- 9.9 392.8 348.5 266.6 4.2 229.8 359.0 352.0 - ~ .8 417.9 405.7 334.3 .5 235.8 287.3 354.8 1.0 256.1 321.1 400.6 i 294.2 254.8 242.4 ..g,,~ 2 i} ent. The mean percent calf crops of i_ yearlong, dual use two-pasture rotation A four-pasture rotation systems were 84.6, . percent, respectively. The percent calf I dual use yearlong system fluctuated 2-year cycle seemed evident. In years leaned calves, they did not breed back; 'on per A.U. in the following year was y‘ apparently caused by nutritional stress them by the suckling calf which in turn , to the high percent of lakebed in this ble 4, thus reducing cattle pasturage. iation in percentage calf crop of the 1 g systems was not so great. Under 2 it seemed to be affected mostly by the g 'nfall in the previous year or the year nceived thus indicating the sensitivity jption rates to vegetation conditions. I ent effects were noted from dual use or ' g on adjusted calf weaning weights. e and dual use yearlong systems had f: weaning weights of 387.9 and 407.0 _,_- ctively. The two-pasture and four- 'on averaged 406.5 and 395.5 pounds. Tjusted weaning weights fluctuated in yearly rainfall. Net Returns '01» s for each management system were ~ as to indicate the relative profitability a it of a ranch firm’s grazing capacity. does not reflect either economies or ‘of size except those associated with the _ supervision jwithin the experimental g - ore, since each management system same supervision within the experi- ,' and since the synthetic coefficients for ent system were determined in the ‘f, more reliability can be placed upon of the differences between the systems e level of the absolute values. The study also did not include any marginal analyses with- in a management system but rather a comparison of the average relative profitability per unit among systems for discrete levels or combinations of output. Sheep Increasing production from a given enterprise usually requires increased inputs or a readjustment of resources. The major costs of changing from one management system to another are additional labor, investment in livestock, fences and water facilities. These factors are discussed in the following section. Within the experimental grazing study, winter sup- plemental feed for sheep only was varied among systems. However, this was not a cost to increase production but to maintain production since ewes were fed according to their physical condition as previously explained. Since the amount of feed fed to sheep depended upon physical condition of each herd, it is a most sensitive indication, substantiated by production data, of both quantity and quality of vegetation available to sheep within each management system or grazing behavior of sheep as affected by the grazing system. The mean feed expense per A.U. of sheep is shown in Table 10. The single use yearlong system had the highest mean expense of $13.82 per A.U. but decreased tremendously when sheep were grazed in combination with cattle. The dual use yearlong system had a mean expense of $3.61 per A.U. while the feed expense for the two-pasture and four-pasture rotation systems were $2.05 and $2.78 per A.U., respectively. Mean net returns per A.U. of sheep to land, labor and management are summarized in Table 11. The single use yearlong system had a mean net return of $19.52, whereas the dual use yearlong, dual use two- pasture rotation and dual use four-pasture rotation systems had mean net returns of $53.03, $63.16 and $57.03 per A.U., respectively. The mean net returns from the single use yearlong system were statistically TABLE 10. COMPARISON OF FEED EXPENSE PER A.U. OF SHEEP AS INFLUENCED BY GRAZING MANAGEMENT SYSTEMS ON THE TEXAS RANGE STATION, BARNHART Dual use, Dual use, Single use, Dual use, two-pasture four-pasture Year yearlong‘ yearlong rotation rotation 1959 $11.55 $11.05 $ 8.65 $ 5.00 1960 19.75 3.40 0.00 5.85 1951 0.00 0.00 0.00 0.00 1962 12.10 0.00 0.00 2.20 1963 14.55 7.25 5.70 5.70 1964 30.25 0.00 0.00 0.00 1965 8.55 3.58 0.00 0.75 Mean 13.82‘ 3.61” 2.05” 2.78” ‘Any two means followed by the same letter are not signifi- cantly different at the 5-percent level of probability. TABLE ll. COMPARISON OF MEAN NET RETURNS PER A.U. OF SHEEP TO LAND, LABOR AND MANAGEMENT AS INFLUENCED BY GRAZING MANAGEMENT SYSTEMS ON THE TEXAS RANGE STATION Dual use, Dual use, Single use, Dual use, two-pasture four-pasture Year yearlong‘ yearlong rotation rotation 1959 $27.47 $43.48 $58.82 $72.02 I960 5.78 54.58 75.38 56.32 1961 24.33 56.80 65.68 47.08 1962 23.97 58.28 71.70 41.90 1963 22.12 51.65 50.18 55.40 1964 — 1.44 50.78 56.90 56.52 1965 34.39 55.65 63.48 69.95 Mean $19.52“ $53.03“ $63.16” $57 .03” ‘Any two means followed by the same letter are not signifi- cantly different at the 5-percent level of probability. lower than from the dual use systems. Although there was a substantial increase in mean net returns from rotation grazing over those from dual use year- long, it was not statistically significant. The analysis of the mean net returns from sheep indicated that the major economic advantage in sheep production resulted from grazing sheep in combination with cattle while rotation grazing yielded a minor increase- in net returns. It is important to note that although the order of the difference was the same as in the previous an- alyses of physical production, the magnitude of the differences was increased when animal units were simulated to represent a typical revenue producing ranch. This increase in differences was primarily due to the different death and culling rates and their effect upon the age composition of the herds, number of replacements kept, number of cull and old ewes sold and percent producing animals of the total herd. Also the inclusion of the replacement within an ani- mal unit resulted in lower absolute values. TABLE 12. COMPARISON OF MEAN NET RETURNS PER A.U. OF CATTLE TO LAND, LABOR AND MANAGEMENT AS INFLUENCED BY GRAZING MANAGEMENT SYSTEMS ON THE TEXAS RANGE STATION _ Dual use, Dual use, g Single use, Dual use, two-pasture four-pasture Year yearlong‘ yearlong rotation rotation 1959 $39.98 $40.33 $43.33 $34.73 1960 25.20 _l1.45 35.62 31.85 1961 i 22.19 25.83 23.37 15.40 1962 23.46 19.40 27.50 30.17 1963 25.04 30.93 33.40 20.37 1964 -11.88 --10.42 - .90 13.23 1965 31.87 15.25 29.52 43.47 Mean $22.27“ $15.70” $27.41“ $27.03“ ‘Any two means followed by the same letter are not signifi- cantly different at the IO-percent level of probability. .10 Cattle Comparison of mean net returns cattle by management system, Table 12, in when cattle are grazed yearlong in combing, sheep, mean net returns are reduced in w‘ to those from single use yearlong. The i yearlong system had a mean net return", whereas the dual use yearlong system h" of $15.70. This disadvantage seems to when cattle, although grazed with sheep, g in a rotation grazing system. The two-p four-pasture rotation systems had mean per A.U. of $27.41 and $27.03, respectivel Total Management System Comparisons of the net returns from _ from cattle indicated a large difference ability between the kinds of livestock. A of analysis for cattle suggests an explana restriction of selling all dry cows may realistic assumption within the time r- years. Selling all dry cows resulted in ex coefficients of weaning heifers kept for 4‘ which reduced the total pounds of calf L decreased the proportion of producing g animal unit. In contrast, ewes were not dry. Another explanation may be the; winter supplemental feeding. Sheep of agement system were fed according to ‘ condition, whereas cattle in all systems mented according to the one herd in» physical condition. This may have resul A of the rotation systems receiving more needed to maintain their body condition i tivity while feed costs for these systems w‘ as those in the other systems of ‘ma I which cattle were in poorer physical c‘ Since all systems with combination j tained the same ratio of cattle and she son of the magnitude of the differed those systems is valid. However, drawi I clusions from comparisons between ‘Q cattle yearlong and dual use grazing year , restricted. ‘3 v Comparison of mean total net reti of sheep and cattle to land, labor and; is shown in Table 13. The single long system had a mean net return of $l_ single use cattle yearlong system had a V. of $22.27 per A.U. The dual use ye_ resulted in an increased mean net ret while the rotation grazed systems yiel increase in net returns. The twopast pasture rotation systems, although with f mean net returns of $41.71 and $39. respectively. This is a most importang as it combines the positive effect of dual; MPARISON OF MEAN TOTAL NET RE- _ . OF SHEEP AND/OR CATTLE TO LAND, NAGEMENT AS INFLUENCED BY GRAZ- ENT SYSTEMS ON THE TEXAS RANGE t, Dual use, Dual use, Single use two- four- cattle, Dual use, pasture pasture yearlong yearlong rotation rotation $39.98 $41.59 $49.53 $49.65 25.20 14.96 51.52 41.64 22.19 38.22 40.29 28.07 23.46 34.95 45.18 34.86 25.04 39.22 40.11 34.38 -11.88 14.06 22.22 30.55 31.87 31.41 43.10 54.06 $22.27‘ $30.63“ $41.71” $39.03“ followed by the same letter are not signifi- the 10-percent level of probability. i‘ ‘o the positive effect of rotation grazing iuction. ‘ility if of annual income suggests stability in '1 rises. There was less variation in the ome derived from the two and four- , systems than from the three yearlong 1, 14. The dual use yearlong system also Ly than either of the single use yearlong fluctuated from a low of $22.22 high of $51.52 within the two-pasture It $28.07 to $54.06 within the four- i-o and from $14.06 to $41.59 within ual use system. There was no net loss i any year for the yearlong dual use or