CATTLE AND SHEEP DIETS 425

their reaction under moderate graz- Trend of carbohydrate reserves in SPRAGUE, V. G., AND J. T. SULLIVAN. ing use. Physiol. 10:727-738. alfalfa, smooth bromegrass, and tim- 1950. Reserve carbohydrates in or- MCCARTY, E. C., AND R. PRICE. 1942. othy grown under various cutting chard grass clipped . periodically. Growth and carbohydrate content of schedules. Crop Sci. 2: 333-336. Plant Phvsiol. 25:92-102. important mountain forage in ROBISON, G. D., AND M. A. MASSEN- TROUGHTO;, A. 1957. The under- central as affected by clipping GALE. 1968. Effect of harvest man- ground organs of herbage grasses. and grazing. U. S. Dep. Agr. Tech. agement and temperature on forage Commonwealth Bur. Pastures and Bull. 818. 51 p. yield, root carbohydrates, plant den- Field Crops Bull. 44. 163 p. MCCONNELL, B. R., AND G. A. GARRI- sity and leaf area relationships in WEINMANN, H. 1943. Root reserves SON. 1966. Seasonal variation of alfalfa (Medicago sati-cra L. cultiver of South African highveld grasses in available carbohydrates in bitter- “moapa”). Crop Sci. 8: 147-15 1. relation to fertilizing and frequency brush. J. Wildlife Manage. 30:168- SAMPSON, A. W,> AND E. C. MCCARTY. of clipping. J. South African Bot. 10: 172. 1930. The carbohydrate metabo- 37-54. PAULSEN, G. M., AND D. SMITH. 1968. lism of Sti@ pulchra. Hilgardia 5: WEINMANN, H. 1947. Determination Influence of several management 61-100. of total available carbohydrates in practices on growth characteristics SMITH, D. 1962. Carbohydrate root plants. Plant Physiol. 22:279-290. and available carbohydrate content reserves in alfalfa, red clover, and WEINMANN, H. 1961. Total avail- on smooth bromegrass. Agron. J. birdsfoot trefoil under several man- able carbohydrates in grasses and le- 60: 375-379. agement schedules. Crop Sci. 2:75- gumes. Herbage Abst. 3 1: 255-26 1. PRIESTLY, C. A. 1962. Carbohydrate 78. WOLF, D. D., K. L. LARSON, AND D. resources within the perennial plant. SMITH, D., G. M. PAULSEN, AND C. A. SMITH. 1962. Grass-alfalfa yields Commonwealth Bureau of Hort. and RAGUSE. 1964. Extraction of total and food storage of associated alfalfa Plantation Crops Tech. Communica- available carbohydrates from grass as influenced by height and fre- tion 27. 116 p. and legume tissue. Plant Physiol. 39: quency of cutting. Crop Sci. 2:363- REYNOLDS, J. H., AND D. SMITH. 1962. 960-962. 364.

9 %

Botanical and Chemical La Composition Botanica y Quimica de las Dietas de1 Ganado Bovino y Ovino en una Pradera Tipo Composition of Cattle and Pinyon- Juniper Sheep Diets on Pinyon- Juniper Resumen3 Grassland Range1 Se llevo a cabo el estudio en el Estado de New , E.U.A. Las dietas de1 ganado ovino constituyeron en mas hierbas que gramineas con la exception de 10s meses de FRANK 0. THETFORD,a REX D. PIEPER, AND Junio, Julio y Agosto. Las m&s importantes hierbas fueron ARNOLD B. NELSON Artemisia curruthii, Verbena spp. y Sphaerulceu coccinea. Las dietas de1 ganado bovino constituyeron en mas grami- Research Assistant, Associate Professor of Range Science, neas que hierbas con la exception de1 mes de Abril. La and Professor of Animal Science, State graminea mas importante fue Boutelouu grucilis. Boutelouu University, Las Cruces. curtipendulu, Lycurus phleoides y Aristidu spp. fueron secundarias en importancia. Las dietas de1 ganado bovino Highlight tuvieron mas proteina cruda. No hubo diferencia en 10s contenidos de fibra cruda ni de la digestibilidad entre las Diets collected by use of esophageal fistulated steers and dietas de1 ganado bovino y ovino. sheep on foothill range in southcentral New Mexico where Common use or dual grazing by more than one compared botanically and chemically. Sheep diets were class of livestock offers possibilities for increasing generally higher in forbs and lower in grass than cattle diets livestock production without increasing land areas. and contained more forbs than grass except during June, July and August. Important forbs in sheep diets were car- Such practices are becoming increasingly more im- ruth sagewort, vervain, and globemallow. Cattle diets con- portant as production costs increase and opportuni- tained more grass than forbs in all periods except April, ties for acquiring additional land decrease. with blue grama the most important grass followed by Some rangelands are better suited for grazing by sideoats grama, wolftail, and threeawns. Sheep diets were one class of livestock than another, but many ranges consistently higher in crude protein and ash content than may be better utilized by cattle and sheep grazing cattle diets, but there were no significant differences in together (Cook, 1954; Smith, 1965; Stoddart and cell-wall constituents and in vitro dry matter disappearance Smith, 1955). Rangelands with diverse topography among dates or between cattle and sheep diets. and vegetation are more suitable for dual use by sheep and cattle than for single species use (Cook, l Journal article 372, Agricultural Experiment Station, New Mexico State University, Las Cruces, New Mexico 88001. 1954; Merrill et al., 1966; Merrill and Young, 1954; Received December 1, 1970. 2 Present address: A and M Experimental Ranch, 3 Por Donald L. Huss y Benjamin Lopez, Dep. de Zootecnia, Throckmorton, Texas. I.T.E.S.M., Monterrey, Mexico. 426 THETFORD, PIEPER, AND NELSON

Stoddart and Smith, 1955). Studies in Utah and Table 1. Botanical composition (%) of area grazed by Texas have shown that stocking with two or more esophageal fistulated sheep and cattle at Fort Stanton, classes of livestock in the same pasture increased 1969-70. gains per head and per acre, maintained or im- Species1 Composition2 proved range condition, increased carrying capac- ity, reduced supplemental feeding, resulted in more Grasses uniform use overall, and increased gross and net Blue grama (Bouteloua gracilis, (H.B.K.) Lag.) 66.4 returns when compared to single use by sheep or Sideoats grama (B. curtipendula, (Michx.) Torr.) 4.6 cattle (Cook, 1954; Huss and Allen, 1969; Merrill Hairy grama (B. hirsu ta Lag.) T Threeawns (Aristida spp.) 0.8 and Miller, 1961; Merrill et al., 1966; Merrill and Galleta (Hilaria jamesii (Torr.) Benth.) 1.0 Young, 1954). Wolftail (Lycurus phleoides H.B.K.) 16.7 Hull et al., (1957) and Meyer et al. (1957) showed Mat muhly ( richardsonis (Trin.) that sheep and cattle select diets which are quite Rydb.) 3.0 different in plant parts, botanically and chemically, Ring muhly (M. torreyi (Kunth.) Hitchc.) 1.2 when animals grazed on adjacent pastures of a Halls panic (Panicum hallii Vasey) T single species or adjacent pastures consisting of two Bottlebrush squirreltail (Sitanion hystrix (Nutt.) species. Other investigators working with animals J. G. Smith) - on native range reported that cattle diets consisted Forbs mainly of grasses, with forbs and browse of lesser Carruth sagewort (Artemisia carruthii Wood) 5.5 dietary importance. While sheep readily eat Locoweeds (Astrugalus spp.) T grasses, they generally consume greater amounts of Broom snakeweed (Gutierrezia sarothrue (Pursh.) forbs and browse than cattle (Cook, 1954, 1956; Britt. and Rusby) T - Cook et al., 1963, Cook et al., 1967; Cook and Har- Vervains (Verbena spp.) Globemallow (Sphuerulceu coccineu (Pursh.) ris, 1950; Cook et al., 1965; Smith and Julander, Rydb.) - 1953). For example, Cook et al. (1963) reported Bladderpod (Lesquerella gordonii (Gray) Wats.) - cattle diets contained 55% grass, 25% forbs, and Lemonweed (Pectis papposa Harv. and Gray) - 207, browse whereas the diets of sheep grazing the Browse same areas were composed of 35% grass, 40% forbs, Wavyleaf oak (Quercus undulatu Torr.) - and 25% browse. One-seeded juniper (Juniperus monosperma Several studies have shown that sheep select diets (Engelm.) Sarg.) - which are significantly higher in total protein and Pinon pine (Pinus edulis Engelm.) - digestible protein than cattle diets, whereas cattle Red barberry (Berberis haematocurpa Wooten) - diets are significantly higher in cellulose. Sheep Fourwing saltbush (A triplex canescens (Pursh.) diets also contained more ether extract and lignin Nutt.) - than cattle diets (Cook et al., 1963; Cook et al., 1 Nomenclature follows Kearney and Peebles, 1960. 1967; Van Dyne and Heady, 1965b). These dif- 2 Those species for which no percentages are listed appeared on ferences in diets may be due to the fact sheep select the area but were not sampled on the transects. T < 0.1% diets high in browse, forbs, and plant parts which are high in protein, ether extract, and lignin, but The major forage species is blue grama which cattle consume large quantities od grass stems, is dominant or codominant on all sites. Other im- which are high in cellulose (Cook et al., 1963; Van portant grass species are shown in Table 1. Dyne and Heady, 1965b). The average annual precipitation for 94 years of The objective of this study was to compare bo- record (1856 to 1969 with some gaps) is 15.30 inches tanical and chemical composition of diets of cattle (U. S. Weather Bureau) of which about 62% falls and sheep grazing together on the same range. during the growing season of June, July, August, and September (Grace and Pieper, 1967). The Materials and Methods climate of the area is generally mild but some rela- The Fort Stanton Cooperative Range Research tively cold winter temperatures occur. The mean Station is located in the foothills between Sierra annual temperature for Fort Stanton is 52 F, with Blanca and the Capitan Mountains in southern a mean minimum of 36 F and a mean maximum of Lincoln County, New Mexico. The topography is 65.5 F (U. S. Weather Bureau). characterized by deep canyons, arroyos, and mesas The study pasture was stocked two-thirds with with elevations varying from 6200 to 7500 feet. cattle and one-third with sheep. There were 34.5 Fort Stanton is in a transition zone between the acres per animal unit yearlong. The pasture is on grama-galleta steppe and juniper-pinyon woodland a mesa at an elevation of approximately 6800 feet, vegetation types (Kuchler, 1964). The vegetation convenient to corrals and water. is open grassland on the mesas, canyon floors, and The botanical composition of the study areas lowlands with woody species on the slopes (Grace was determined in October, 1969, by the step- and Pieper, 1967). point method of Evans and Love (1957). CATTLE AND SHEEP DIETS 427

Esophageal-fistulated steers and wethers were used to obtain forage samples from the study area. Sheep!?$%$E% The animals were placed in the pasture to be Cattle sampled one week prior to sampling for each col- lection date except the January, 1970 collection when the animals were put on the sampling area the first day of sampling. Samples were collected with two steers and two sheep on two consecutive days for each sampling period. Most of the samples were taken early in the morning after the animals had fasted overnight, but some samples were taken in the afternoon after April June August October January the animals had fasted for approximately three hours. Collection periods lasted from 45 minutes to one hour. The collected samples were drained of excess saliva, place in an insulated chest containing dry ice and returned to the Animal Nutrition Labora- tory at New Mexico State University, where they were stored in a freezer. Prior to analyses, the samples were thawed and the samples for each species of animal were composited for each collec- tion day. The composited samples were thoroughly mixed and dried in a forced-air oven for 24 hours at 65 C. They were then ,ground through a ZO- mesh screen in a Wiley mill and stored in plastic containers. The sheep samples for August and Browse October, 1969, were combined for each collection h IO- 2 ~ ‘9 h period because the sample for each day was in- . ,z gti h! WV cx WC? L c\i sufficient for a complete analysis. 0 $6 d 3Lr 0 April June July August October January Botanical analysis of each composited sample was conducted according to a procedure similar FIG. 1. Percent of grass, forbs and browse in diets of sheep and to that described by Sparks (1968) and Sparks and cattle collected at different times of the year. Malecheck (1968). Whole plant samples of each plant species growing on the study area were col- the analysis of variance indicated significant dif- lected for references. ferences among means. Histological characteristics such as size and shape of cells, cell inclusions, cell wall variations, varia- Results and Discussion tions in the various specialized epidermal cells Botanical Composition of the Study Area such as cork, guard, and silica, and the size and shape of hairs, if present, were used to identify The composition of the plant cover of the grazed plant species (Davies, 1959; Brusven and Mulkern, area is presented in Table 1. Blue grama is the 1960; Storr, 1961) in the diet. dominant species, contributing 66.4% of the basal Each sample was analyzed in duplicate for cover, with wolftail contributing 16.7%, the second Kjeldahl nitrogen, dry matter, ash, and silica by largest amount. Other grasses contributing signifi- procedures of the A.O.A.C. (1965). The fibrous cant amounts to the composition of the area were portion was assayed as cell-wall constituents sideoats grama, mat muhly, ring muhly, and galleta. (CWC) according to the procedures of Van Soest The most important forb was carruth sagewort, and Wine (1967). Each sample except the April 3 with locoweeds and broom snakeweed contributing steer sample, was assayed in triplicate for organic insignificant amounts. These data do not show matter disappearance by the procedure described seasonal availabilitv of different snecies but give a by Tilley and Terry (1963). Protein, cell-wall general indication’ of the specie’s present.” The constituents, and in vitro dry matter disappearance other species listed in the table were present on the are expressed on an organic matter basis because of area but were not encountered on- the sampling possible contamination with inorganic material. transects. They contributed minor amounts to Data were analyzed by the analysis of variance the plant cover. Wavyleaf oak formed the periph- procedures appropriate for each phase. Duncam’s ery of the g-razed area, with a few plants scattered multiple range test was used to test means where thoughout. Pinyon pine and juniper plants were 428 THETFORD, PIEPER, AND NELSON

Table 2. Average botanical composition (yO dry weight) of sheep and cattle diets at Fort Stanton, 1969-70.

April June July August October January Species Sheep Cattle Sheep Cattle Sheep Cattle Sheep Cattle Sheep Cattle Sheep Cattle

Grasses Blue grama 15.5 21.7 9.8 35.5 34.5 35.4 27.4 50.1 20.3 28.6 22.1 34.0 Sideoats grama 1.7 2.4 2.6 7.7 4.0 7.4 2.2 10.0 3.8 5.0 4.9 5.1 Wolftail 3.4 2.3 2.5 7.3 8.2 9.6 4.5 19.2 1.3 6.6 0.7 5.9 Threeawns 5.9 5.1 6.5 8.3 8.3 4.4 16.9 0.0 1.9 15.9 3.5 16.5 Halls panic 3.2 1.3 0.5 1.1 3.0 5.7 4.5 4.4 1.9 2.4 0.0 0.2 Bottlebrush Squirreltail 0.4 0.0 0.3 1.5 0.0 1.1 0.0 5.2 1.2 0.3 0.0 0.2 Sand dropseed 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Ring muhly 0.0 0.3 0.0 0.0 0.0 1.3 0.0 0.0 0.0 0.0 0.0 0.2 Total 32.5 33.1 22.2 61.4 58.0 64.9 55.5 88.9 30.4 58.8 31.2 62.1

Forbs Carruth sagewort 42.3 42.0 31.2 10.9 10.3 0.0 8.7 1.1 25.6 14.1 18.5 9.4 Globemallow 3.6 0.5 16.0 14.2 7.7 29.3 2.8 2.2 16.1 3.8 3.5 0.2 Vervains 8.8 2.0 20.8 4.2 19.1 0.0 13.3 0.0 16.9 8.7 23.1 4.9 Locoweeds 4.6 0.3 8.3 0.4 0.0 1.4 15.4 0.0 7.2 1.9 21.2 14.0 Broom snakeweed 1.7 1.4 1.2 4.2 3.4 0.2 2.2 5.6 1.9 7.3 0.7 3.2 Bladderpod 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 Lemonweed 0.0 0.8 0.0 1.4 0.6 0.4 1.6 0.0 0.0 0.9 2.0 0.2 Total 61.0 47.0 77.8 35.3 41.1 31.3 44.0 8.9 67.7 36.7 69.0 32.1

Browse Wavyleaf oak 5.0 19.0 0.0 1.7 0.0 3.7 0.0 2.2 1.9 4.0 0.0 0.7 Four-wing saltbush 0.0 0.6 0.0 1.0 0.6 0.0 0.0 0.0 0.0 0.3 0.0 0.5 Red barberry 0.9 0.0 0.0 0.0 0.0 0.0 0.5 0.0 0.0 0.3 0.0 1.5 Total 5.9 19.6 0.0 2.7 0.6 3.7 0.5 2.2 1.9 4.6 0.0 2.7 - few and scattered, and red barberry grew under the than did sheep for all collection periods except in pinyon. There were approximately five or six July, when the sheep diets contained as much blue fourwing saltbush plants on the area. grama as the cattle diets (Table 2). Cattle consist- ently selected a higher proportion of sideoats Botanical Composition of the Diets grama than did sheep throughout the year and the The analysis of variance showed a significant analysis of variance showed that the difference be- difference (P < .Ol) in the amount of grass and tween cattle and sheep diets was significant at the forbs in the diets between species but no differences .06 level. Except in ,4ugust, wolftail was present in browse. Cattle diets were consistently higher in in lower percentages in both cattle and sheep diets grasses than sheep diets except in April, while than in the vegetative composition of the area. The sheep diets were consistently higher in forbs than analysis of variance showed no significant dif- cattle diets (Fig. 1). Grasses have been reported to ference in wolftail content of the diets among dates be the most important component of cattle diets or between sheep and cattle. The content of three- by several workers (Galt et al., 1969; Cook et al., awn in the diets was variable with sheep selecting 1963; Van Dyne and Heady, 1965a). In general for larger amounts in April, July, and August and both cattle and sheep, forbs were most important cattle selecting larger amounts in June, October, during the fall and spring and grasses during the and January. These inconsistencies may account summer. During the spring of 1969, soil moisture for the nonsignificant difference between threeawn conditions were good and there was good growth content of cattle and sheep diets for the whole of many forbs while the grass was still dormant. year. Threeawn comprised less than 1% of the Browse contributed small amounts to the diets vegetative cover of the area (Table l), but the of sheep and cattle except for cattle in April when animals seemed to select it because threeawn ap- wavyleaf oak comprised 19% of the diet. This was peared in amounts greater than 1% in all diet because the cattle grazed into the oak at the edge samples except one. of the grazed area when the oak had begun new Halls panic was the most important of the other growth. grasses. Sheep and cattle diets contained equal Cattle selected significantly more blue grama proportions of Halls panic in August while sheep CATTLE AND SHEEP DIETS 429

diets were higher than cattle diets in April and cattle diets higher than sheep diets in the other four collection periods. Bottlebrush squirreltail con- tributed minor amounts to the diets of sheep and cattle except in cattle diets in August when it con- tributed 5.2%. Ring muhly was found in cattle diets in minor amounts in April, July, and January. The most important forb in the sheep and cattle diets was carruth sagewort. Sheep consistently se- lected higher proportions of carruth sagewort than did cattle throughout the year. The analysis of variance showed that the difference between car- ruth sagewor’t in cattle and sheep diets was signif- icant at the .06 level. In April, sheep and cattle 01 selected significantly higher amounts of carruth A’M ‘J ‘J ‘A’ S’O’ N’D’J’ A’M’J ’ J’A’S’O’N’D’J’ sagewort, 42.3% and 42.0% respectively, than at any other collection period. The analysis of variance showed a highly significant difference (P < .Ol) among collection dates in carruth sagewort content of the diets. It was much more important in fall, winter, and spring samples than in summer samples and most important in spring samples. Except in the July and August samples, it formed a higher percentage of the diets than of the plant cover of the area. The amount of globemallow in the diets was nonsignificant among dates and between sheep and A’M’J ‘J ‘A’S’O’N’D’ J

cattle diets, possibly because of the inconsistencies FIG. 2. Ash, cell-wall constituent, protein content and dry matter in the amount taken. The amount selected varied disappearance of cattle and sheep diets on Ft. Stanton, 1969-70. widely among dates and between sheep and cattle. Sheep consistently selected larger percentages of vervain than cattle in all collection periods. Ver- than cattle diets throughout the year. Even con- vain contributed 23.1y0 to the sheep diet in Jan- sidering the ash contamination of the esophageal- uary, when it was one of the three noticeably g-reen fistula-collected samples, these values appear to be forbs on the grazed area, along with locoweeds and high, especially for sheep, when compared to data carruth sagewort. Vervain contributed relatively on the ash content of some hand-clipped Fort Stan- large amounts to the forb component of sheep diets ton grass (Hatch, 1968; Boggino, 1970). Sheep are in all periods except April when it comprised 8.8% able to graze close to g-round level and may pick up of the diet. soil particles. The high ash value of 20.1% in the Locoweeds were the most important of the July sheep diet sample was possibly due to soil other forbs for sheep, which selected larger propor- contamination or to high variability in the ash tions than did cattle in all periods except July. contents of the plants. Locoweeds contributed 14.0% to the cattle diets in The ash content of the cattle diets decreased January when they were green. For cattle, broom from April through the growing season to a low snakeweed was the most important of the other point in August and then increased rapidly with forbs. Cattle ate more broom snakeweed than did the onset of dormancy in October. sheep in all collection periods except April and The analysis of variance indicated a highly signif- July. Bladderpod was found in one sample for icant difference (P < .Ol) in crude protein content sheep in June and one sample for cattle in Jan- of the diets among dates and between species. uary. Lemonweed contributed variable and small Sheep diets were higher in crude protein content amounts to the sheep and cattle diets throughout than cattle diets for all periods (Fig. 2). Other the year. workers have found sheep diets to be consistently higher in crude protein than cattle diets (Cook et Chemical Composition of the Diets al., 1963; Cook et al., 1967; Van Dyne and Heady, Sheep diets were significantly higher (P < .05) in 1965b). This was probably due to the higher per- ash content than cattle diets. This agrees with data centage of forbs in sheep diets (Table Z), because presented by other researchers (Cook et al., 1963; the parts of forbs consumed by cattle are usually Van Dyne and Heady, 1965b). Figure 2 shows that higher than grasses in crude protein (Nelson, et al., sheep diets were consistently higher in ash content 1970). The protein content of both sheep and 430 THETFORD, PIEPER, AND NELSON cattle diets was lowest in April when the vegetation tion on nutritive intake of sheep on summer ranges. J. was dormant and increased rapidly when the grow- Range Manage. 18:69-73. ing season began. The sheep diets contained the COOK, C. WAYNE, LORIN E. HARRIS, AND MELVIN C. YOUNG. largest percentage of crude protein in June when 1967. Botanical and nutritive content of diets of cattle and sheep under single and common use on mountain the forb content of the diet was highest and de- range. J. Anim. Sci. 26: 1169-l 174. creased slightly through July. Protein content of DAVIES, I. 1959. The use of epidermal characteristics for the cattle diets reached a peak in July when nearly the identification of grasses in the leafy stage. J. Brit. all vegetation was green. Both sheep and cattle diets Grassland Sot. 14:7-16. decreased in crude protein content after July with EVANS, R. A., AND R. M. LOVE. 1957. The step-point increasing maturity of the vegetation. Based on the method of sampling-a practical tool in range research. National Research Council (NRC, 1970) nutrient J. Range Manage. 13:58-65. requirement levels, the crude protein content of GALT, H. D., BRENT THEURER, J. H. EHRENREICH, W. H. the diets was sufficient to maintain sheep and cattle HALE, AND S. CLARK MARTIN. 1969. Botanical composi- through the gestation and lactation periods under tion of diet of steers grazing a desert grassland range. J. Range Manage. 22: 14-19. normal ranching conditions. These requirement GROCE, V. L., AND REX D. PIEPER. 1967. Cover, herbage levels assume that total intake of dry matter suf- production, and botanical composition on foothill range ficient. sites in Southcentral New Mexico. New Mexico Agr. Exp. The fibrous portion of the diets was assayed as Sta. Res. Rep. 128. 6 p. cell-wall constituents because this analysis is re- HATCH, CARL F. 1968. Chemical composition and nylon portedly more indicative of the indigestible portion bag digestibility of range grasses. (Unpublished M.S. of the diet than the A.O.A.C. crude fiber analysis thesis) New Mexico State University, Las Cruces. 71 p. (Van Soest and Wine, 1967). The cell-wall constit- HULL, J. L., J. H. MEYER, G. P. LOFGREEN, AND A. STROTHER. uents (CWC) content of the sheep and cattle diets 1957. Studies on forage utilization by steers and sheep. J. Anim. Sci. 16:757-765. was highly variable with no significant differences Huss, DONALD L., AND JERRY V. ALLEN. 1969. Livestock among dates and between species. Figure 2 shows production and profitability comparisons of various graz- that the CWC content of the sheep diets varied ing systems, Texas Range Station. Tex. Agr. Exp. Sta. widely from one collection period to another Bull. 1089. 14 p. while the content in cattle diets remained relatively KEARNEY, T. H., AND R. H. PEEBLES. 1960. Flora. stable for all periods except the November collec- Univ. of Calif. Press, Berkeley and Los Angeles. 1085 p. tion when it was low. KUCHLER, A. W. 1964. Potential natural vegetation of the The organic matter disappearance (in vitro) of conterminous United States. Amer. Geogr. Sot., New the diets is presented in Figure 2. The variability York. 38 p. was considerable and the analysis of variance indi- MERRILL, LEO B., AND JARVIS E. MILLER. 1961. Economic cated no significant differences among dates or analysis of year-long grazing rate studies on substation No. 14, near Senora, Tex. Agr. Exp. Sta. Misc. Pub. 484. between animal species. 8 P* MERRILL, LEO B., PATRICK 0. REARDON, AND C. L. LEIN- Literature Cited WEBER. 1966. Cattle, sheep, goats-mix’em up for higher ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS, 1965. grains. Texas Agr. Prog. 12: 13-14. Official methods of analysis (10th edition). Assoc. Offic. MERRILL, LEO B., AND VERNON A. YOUNG. 1954. Results Agr. Chem., Washington, D. C. 957 p. of grazing single classes of livestock in combination with BOGGINO, ELOY, J. A. 1970. Chemical composition and in several classes when stocking rates are constant. Tex. vitro dry matter digestibilty of range grasses. (Un- Agr. Exp. Sta. Prog. Rep. 1726. 6 p. published M.S. thesis) New Mexico State Univ., Las MEYER, J. H., G. P. LOFGREEN, AND J. L. HULL. 1957. Se- Cruces. 134 p. lective grazing by sheep and cattle. J. Anim. Sci. 16:766- BRUSVEN, M. A., AND G. M. MULKERN. 1960. The use of 772. epidermal characteristics for the identification of plants NELSON, A. B., C. H. HERBEL, AND H. M. JACKSON. 1970. recovered in fragmentary condition from the crops of Chemical composition of forage species grazed by cattle grasshoppers. North Dakota Agr. Sta. Res. Rep. No. 3. on an arid New Mexico range. New Mex. State Univ. 11 p. Agr. Exp. Sta. Bull. 561. 33 p. COOK, C. WAYNE. 1954. Common use of summer range NATIONAL RESEARCH COUNCIL. 1970. Nutrient require- by sheep and cattle. J. Range Manage. 7:10-13. ments of farm animals. No. 4 Revised. Nutrient require- COOK, C. WAYNE, JOSEPH E. BLAKE, AND JAY W. CALL. ments of beef cattle. National Research Council, Wash- 1963. Use of esophageal-fistula cannula for collecting ington, D. C. 55 p. forage samples from both sheep and cattle grazing in SMITH, ARTHUR D. 1965. Determining common use graz- common. J. Anim. Sci. 22:579-581. ing capacities by application of the key species concept. COOK, C. WAYNE, AND LORIN E. HARRIS. 1950. The nutri- J. Range Manage. 18: 196-201. tive content of the grazing sheep’s diet on summer and SMITH, JUSTIN G., AND ODEL JULANDER. 1953. Deer and winter ranges of Utah. Utah Agr. Exp. Sta. Bull. 342. sheep competition in Utah. J. Wildl. Manage. 17: 101-104. 66 p. SPARKS, DONNIE R. 1968. Diet of black-tailed jackrabbits COOK, C. WAYNE, MERTYYN KOTHMANN, AND LORIN E. on Sandhill rangeland in . J. Range Manage. HARRIS. 1965. Effect of range condition and utiliza- 21:203-208. SOILS AND UTILIZATION 431

SPARKS, D. R., AND J. C. MALECHECK. 1968. Estimating data: New Mexico section, summaries, and annual re- percentage dry weight in diets using a microscopic tech- ports. Albuquerque, New Mexico. nique. J. Range Manage. 21:264-265. VAN DYNE, GEORGE M., ANDH. F. HEADY. 1965a. Botani- STODDART,LAURENCE A., AND ARTHUR D. SMITH. 1955. cal composition of sheep and cattle diets on a mature Range management. McGraw-Hill Book Co., New York, annual range. Hilgardia 36:465492. N. Y. 433 p. VAN DYNE, GEORGEM., ANDH. F. HE~Y. 1965b. Dietary STORR, G. M. 1961. Microscopic analysis of feces, a tech- chemical composition of cattle and sheep grazing in nique for ascertaining the diet of herbivorous mammals. common on dry annual range. J. Range Manage. 18: 7% Austral. J. Biol. Sci. 14: 157-164. 86. TILLEY, J. M. A., AND R. A. TERRY. 1963. A two-state VAN SOEST, P. J., AND R. H. WINE. 1967. Use of deter- technique for the in vitro digestion of forage crops. J. gents in the analysis of fibrous feeds. IV. Determination British Grasslands Sot. 18: 104-l 11. of plant cell wall constituents. J. Assoc. Official Agr. UNITEDSTATES WEATHER BUREAU. 1856-1969 climatological Chem. 50:50.

Effects of Soils The purpose of this study was to determine the effects of selected soil and plant characteristics on on Forage Utilization in the the utilization by cattle of two key grass species on three different soils in the desert grassland of south- Desert Grassland1 eastern Arizona.

JERRY L. VANDERMARK, ERVIN M. SCHMUTZ, Study Area and Methods AND PHIL R. OGDEN The study was conducted in 1968 in a 30-acre pasture on Science Teacher, Benson Union High School, Benson, the Elgin Ranch, located one mile west of Elgin, Arizona. Arizona; and Professors of Range Management, Department The pasture is open desert grassland at an elevation of of Watershed Management, The University of Arizona, 4700 ft. Precipitation during the summer of 1968 was 8.2 Tucson. inches, slightly below the average summer precipitation of 10 inches. The pasture was grazed by 4 head of 500-lb. Highlight weaner steers and 1 cow from July 16 to October 11. The desert grassland is characterized by low annual This study was made in southeastern Arizona to deter- precipitation, short erratic rainy seasons, high temperatures, mine some of the factors affecting utilization by cattle of high wind velocities and rapid evaporation (Humphrey, two key species on three desert grassland soils. Results 1968). Most of the grass species belong to the three genera, showed that macronutrient content of the soil and the Bouteloua, Hilaria, and Aristida. The species investigated plants, and corresponding utilization of blue grama (Boute- loua grucilis) and curlymesquite (Hiluriu belangeri), were in this study were blue grama (Bouteloua gracilis) and curly- always significantly greater on the Pima bottomland soil mesquite (Hilaria belangerz). These species are palatable than on the two upland soils, but they were not always and nutritious grasses in the desert grassland (Humphrey, significantly different between the two upland soils. No 1970). consistent relationships were found between forage utiliza- Soils in the study area were developed from mixed tion and micronutrient, sugar or starch content in the alluvium under high temperature and low rainfall condi- plants. tions (Bud, 1965 & 1966). Topsoils are generally dark colored, medium to moderately fine textured, and usually contain 1 to 2% organic matter. Subsoils are moderate to El Efecto de Suelos Sobre el Consumo de Forraje fine textured and contain appreciable amounts of carbonate. en una Pradera Desertica The three soil series in the study area-Bernardino, Hatha- Resumen2 way and Pima-are described in detail in the 1970 National Cooperative Soil Series Descriptions.3 The predominant El estudio se llev6 a cabo en una zona desertica en el Bernardino series has a shallow dark brown gravelly clay Estado de Arizona, E.U.A. H ubo una correlation significa- loam A horizon 1 to 3 inches thick, a dark reddish-brown tiva entre el consume de forraje y 10s contenidos de nit&- gravelly clay B horizon 10 to 20 inches thick, and a gravelly geno, f&for0 y potasio. No hubo una correlation entre el C horizon high in calcium carbonate at 15 to 20 inches. The consume y 10s contenidos de azucar, almidon, micro- nutrientes ni humedad. El consume fue mucho mas signifi- pH ranges from 7.5 at the surface to 8.0 in the subsoil. cativo en cuanto al forraje en 10s valles con suelos profundos Hathaway has a dark grayish-brown gravelly loam A horizon que en 10s suelos de las dos mesetas. 7 to 16 inches thick over a light gray C horizon that ranges from gravelly loam to a very gravelly loamy sand 10 to 40 inches thick. It is calcareous throughout, ranging from 1 Paper No. 1669 Arizona Agricultural Experiment Station, pH 8.0 to 8.2, and has a layer of caliche at 7 to 16 inches. Tucson. Study financed in part by the National Science Foundation. Received July 8, 1970; accepted for publica- tion June 6, 1971. 3 Soil series description for Bernardino, Hathaway and 2 Por Donald L. Huss and Benjamin Lopez, Dep. de Zoo- Pima Series approved in 1970, National Cooperative Soil tecnia, ITESM, Monterrey, Mexico. Survey, USA.