Evaluation of wheat and triticale forage for stocker production in the Gulf Coast region

The Professional Animal Scientist 30 (2014):296–304

©2014 American Registry of Professional Animal Scientists

Evaluation of wheat and triticale forage for stocker production in the Gulf Coast region

M. K. Mullenix,1 S. L. Dillard,2 J. C. Lin, B. E. Gamble, and R. B. Muntifering Department of Animal Sciences, Auburn University, Auburn, AL 36849

ABSTRACT A 3-yr grazing experiment was conducted to quantify productivity, quality characteristics, and beef performance from wheat (Triticum aestivum) and triticale (× Triticosecale) forage compared with ryegrass (Lolium multiflorum) for use in the Gulf Coast region. Six 1.42-ha pastures (2 paddocks/forage treatment) were seeded in early fall of each year and stocked continuously beginning in late fall and early winter with 3 yearling steers (322 ± 10 kg initial BW). Additional put-and-take steers were used to maintain available forage mass at 1,500 to 2,000 kg of DM/ha. Steer ADG was not different between ryegrass and wheat (1.51 and 1.36 kg, respectively) but was less (P < 0.10) for triticale (1.23 kg/d). Wheat required a greater (P < 0.10) mean stocking rate (4.0 steers/ha) than ryegrass (3.2 steers/ha) and triticale (3.4 steers/ha) to maintain target forage mass, and wheat supported a greater (P < 0.10) number of grazing days per hectare (497) than ryegrass (406) and triticale (415). Forage concentrations of NDF and ADF were greater (P < 0.05) for triticale and wheat than ryegrass,

Corresponding author: clinemk@auburn. edu 2 Current address: Department of Crop Science, University of Georgia, Athens 30677. 1

and total nonstructural carbohydrates were greater (P < 0.05) for ryegrass and wheat than triticale. Steer ADG was positively correlated (P < 0.10) with forage CP and total nonstructural carbohydrate concentrations and negatively correlated (P < 0.0001) with concentrations of cell-wall constituents. Stepwise linear regression analysis revealed that forage nutritive value was not an especially important determinant of animal performance. Steer ADG and grazing days per hectare from these forages indicate a potential superiority of wheat for production of total BW gain per hectare in Gulf Coast stocker production systems. Key words: forage, Gulf Coast, ryegrass, stocker production, triticale, wheat

INTRODUCTION Small-grain forages and annual ryegrass (Lolium multiflorum) have been used for decades to support winter grazing of stocker cattle as an economically viable enterprise in the southeastern United States (Rankins and Prevatt, 2013). Planting of coolseason annuals such as ryegrass, oat (Avena sativa), and rye (Secale cereale) is common in the Gulf Coast region of the southeastern United States to provide grazing for beef cattle from November to May (Myer et al., 2008), but wheat (Triticum aestivum) and

triticale (× Triticosecale) are planted to a lesser extent than in other areas of the United States where they are well adapted for winter grazing and often followed by production of a grain crop for cash sale (Coblentz and Walgenbach, 2010). Beck et al. (2005) reported that ADG and BW gain per hectare over a 3-yr period in northern Arkansas did not differ between calves grazing wheat or ryegrass established in clean-tilled fields. In a 3-yr experiment in southwest Arkansas (Beck et al., 2007), ADG and BW gain per hectare were greater for calves grazing wheat than triticale interseeded into a bermudagrass (Cynodon dactylon L.) sod. Triticale exhibits cold and disease tolerance in southeastern variety trials (Day et al., 2013), but its use in the Gulf Coast region to date has been limited primarily to green chop or silage for dairy production systems (Blount et al., 2010). Wheat is similar to oat in herbage production, and it is less susceptible to freeze damage in the lower Coastal Plain (Blount et al., 2013). Because of these desirable agronomic traits, expanded use of triticale and wheat in Gulf Coast beef cattle production systems is desired; however, information on productivity, nutritive value, and capacity of these small-grain forages to support winter grazing by stocker cattle in the region is limited. Research is needed

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to evaluate the potential of these forage species for use in regional beefproduction systems. For this reason, the objective of this experiment was to characterize productivity, nutritive value, and beef cattle performance from triticale and wheat compared with ryegrass planted into prepared seedbeds and managed using adjustable stocking densities in response to changing forage mass.

MATERIALS AND METHODS Research-Site Characteristics The 3-yr grazing experiment was conducted at the Wiregrass Research and Extension Center in Headland, Alabama (31.35°N, 85.34°W). Soils (sandy, fine-loamy, kaolinitic, thermic Plinthic Kandiudults) and climatic conditions (warm to hot, humid, maritime) at the research site are characteristic of the lower tier of the eastern Gulf Coastal Plain that encompasses portions of 5 states (GA, FL, AL, MS, and LA) from southwestern Georgia across the Florida panhandle and west to southeastern Louisiana. Monthly total and 30-yr average monthly total precipitation at the research site between September and May of each year are presented in Figure 1, and corresponding monthly mean and 30-yr average monthly mean temperatures during these same periods are presented in Figure 2.

Pasture Establishment Six 1.42-ha pastures (experimental unit; 2 pastures per treatment) of wheat (Triticum aestivum L.), triticale (× Triticosecale Wittmack), and ryegrass (Lolium multiflorum L.) were established annually in a cleantilled, prepared seed bed. Experimental units were seeded with SS8641 wheat (Southern States, Richmond, VA), Trical 2700 triticale (Resource Seeds Inc., Gilroy, CA), and Marshall ryegrass (Wax Seed Company, Amory, MS) at recommended seeding rates of 140, 125, and 32 kg/ha, respectively. Pastures were disked and chisel-plowed beginning in September

of each year and were planted on 26 October 2009, 5 October 2010, and 25 October 2011. Before establishment of small grains and ryegrass in early fall, the experimental area was planted in summer-annual grasses {pearl millet (Pennisetum glaucum L.), sorghumsudangrass [Sorgum bicolor (L.) Moench], and corn (Zea mays L.) in 2009; pearl millet in 2010 and 2011} and grazed from July until September during each year of the experiment. Before 2009 the experimental area had been in a crop rotation consisting of winter-annual grazing of small grains and annual peanut (Arachis hypogea L.) during the late spring until harvest in early fall for 5 yr. Pastures were randomly assigned to forage treatments in yr 1 of the experiment and again in yr 2 with the restriction that pastures could not receive the same treatments as in yr 1. In yr 3, pastures were assigned by default to treatments that they had not received in either yr 1 or 2. Thus, each pasture was assigned to each forage treatment once over the 3-yr experiment. In 2009 and 2010, pastures initially received 40 kg of N/ha, 45 kg of P/ ha, and 45 kg of K/ha as NH4NO3, P2O5, and K2O, respectively, at planting according to soil test recommendations of the Auburn University Soil Testing Laboratory. Initial application rates were 25 kg of N/ha and 67 kg of K and P/ha, respectively, in 2011. Ammonium nitrate and ammonium sulfate were applied in December and March 2009 at rates of 67 kg of N/ ha and 11 kg of S/ha, respectively. In 2010 and 2011, a liquid fertilizer mixture (18-0-0-3) was applied in December at a rate of 90 kg of N/ha and 15 kg of S/ha, and urea was applied in late February at a rate of 67 kg of N/ha.

Animal and Pasture Management Animal handling and management procedures were conducted according to a research protocol that had been approved by the Institutional Animal Care and Use Committee of Auburn University. Pastures were stocked

initially with 3 yearling Angus × Simmental test steers (average initial BW of 340 ± 7.1, 302 ± 19.6, and 324 ± 19.1 in 2009, 2010, and 2011, respectively) per pasture. Steers were born in the fall before the experimental year and were maintained on bermudagrass (Cynodon dactylon L.) pasture after weaning until the beginning of the experiment. When forage mass became limiting during the late summer, steers were given ad libitum access to bermudagrass hay. Steers were treated with moxidectin pour-on (Pfizer Animal Health, New York, NY) dewormer at the beginning of the grazing experiment in 2009 and 2011 and with doramectin pour-on (Zoetis Inc., New York, NY) in 2010. All steers had ad libitum access to salt-mineral mix (Cattlemen’s HiMag Beef Mineral, Southern States Cooperative Inc., Richmond, VA) and water. Grazing was initiated when forage mass in each treatment had achieved 1,000 to 1,200 kg of DM/ha (Table 1). Steers were weighed full every 28 d, and grazing was terminated when herbage mass and quality could no longer support satisfactory animal performance. Pastures were managed under continuous stocking throughout the experiment to maintain a target herbage mass of 1,500 to 2,000 kg of DM/ha, which is intermediate to values of 1,220 and 2,230 kg of DM/ ha that Hafley (1996) reported should result in maximum animal performance and forage DMI, respectively, by steers grazing ryegrass. Stocking densities were adjusted using put-andtake steers as described by Sollenberger and Burns (2001). Stocking density adjustments were made on the basis of calculations of forage mass and animal use at the time of sampling as described by Mullenix et al. (2012).

Forage Sampling and Laboratory Analyses Herbage mass and nutritive value were determined by clipping representative 0.25-m2 quadrats (8/pasture) immediately before grazing was initiated and every 2 wk during each

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grazing season. Forage within quadrats was clipped to an aboveground stubble height of approximately 5 cm. Fresh-cut forage was then placed into plastic, zip-closure bags and stored on ice for transportation to the Ruminant Nutrition Laboratory at Auburn University. Samples from each pasture were placed in a paper bag, oven dried at 60°C for 72 h, and weighed to a constant weight. Herbage mass was calculated for each pasture based on dry-weight data, and forage allowance was calculated as kilograms of forage DM per pasture divided by kilograms of total animal liveweight per pasture at each forage sampling date (Sollenberger et al., 2005). Dried, air-equilibrated forage samples were ground in a Wiley mill (Thomas Scientific, Swedesboro, NJ) to pass a 1-mm screen. Forage concentrations of CP and DM were determined according to procedures of AOAC (1995), and concentrations of NDF, ADF, and ADL were determined sequentially according to procedures of Van Soest et al. (1991). Samples were analyzed for total nonstructural carbohydrate (TNC) according to a modification of the Weinmann (1947) procedure for fructosan accumulators as described by Mullenix et al. (2012).

Statistical Analyses

Figure 1. Monthly and 30-yr average monthly total precipitation from September through May by year at the Wiregrass Research and Extension Center in Headland, Alabama.

Performance data for test steers, but not put-and-take steers, were used in calculations of mean initial BW, final BW, and ADG. Data for all steers were used in calculations of mean forage allowance, grazing days, and stocking rate. Data were analyzed using the PROC MIXED procedure (SAS Institute Inc., Cary, NC) for a completely randomized design. Forage treatment was considered a fixed effect and year as a random effect in the absence of year × treatment interactions. Forage metrics and nutritive value parameters quantified throughout the growing season were treated as repeated measures. The PDIFF option of LSMEANS in SAS (SAS Institute Inc.) was used for

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separation of treatment means when protected by significant F-test at α = 0.10. Forage data from all biweekly harvests and steer performance data from all monthly weigh periods were used to determine Pearson correlation coefficients between steer ADG and forage characteristics by the PROC CORR procedure, and stepwise linear regression analysis was conducted according to the PROC REG procedure to detect predictive statistical associations between forage characteristics and steer ADG.

RESULTS AND DISCUSSION Animal Performance

Figure 2. Monthly mean and 30-yr average monthly mean temperatures from September through May by year at the Wiregrass Research and Extension Center in Headland, Alabama.

Ryegrass and wheat provided a longer grazing season than triticale from December 2010 to May 2011 (Table 1). During yr 2, the length of the grazing season was 134 d for all forage treatments. Triticale and wheat had a 117-d grazing period during yr 3 compared with 126 d for ryegrass. Initial BW of steers was not different (P > 0.41) among forage species, but final BW was greater for steers (P = 0.037) grazing ryegrass than triticale; no differences (P > 0.26) were observed for final BW of steers between wheat and triticale or between wheat and ryegrass (Table 2). Ryegrass pastures supported greater (P = 0.084) ADG than triticale, and ADG of steers grazing wheat pastures was not different (P > 0.34) from ryegrass or triticale. Ryegrass has been suggested to be the ideal winter-annual forage crop for stocker production systems in the southeastern USA (Ball et al., 2007), and it is commonly used for this purpose in Alabama and the surrounding Gulf Coast region (Rankins and Prevatt, 2013). Parish et al. (2013) reported ADG values similar to those in the present experiment for spring stocker production systems in Mississippi. When Marshall ryegrass was managed under rotational stocking using 14-d rest periods, British-Continental crossbred steers had similar ADG (1.17 kg) to those grazing chicory (Cichorium intybus L.)

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Table 1. Grazing initiation and termination dates for forage treatments from 2010 to 2012 Forage treatment Year

Ryegrass

Triticale

Wheat

Winter to spring 2010   Grazing initiation   Grazing termination   Length of season, d Fall 2010 to spring 2011   Grazing initiation   Grazing termination   Length of season, d Winter to spring 2012   Grazing initiation   Grazing termination   Length of season, d

  Jan. 14 May 5 118   Dec. 8 Apr. 21 134   Jan. 3 May 8 126

  Jan. 26 May 5 106   Dec. 8 Apr. 21 134   Dec 15 Apr. 10 117

  Jan. 14 May 5 118   Dec. 8 Apr. 21 134   Dec. 15 Apr. 10 117

from April to June (1.16 kg/d) over a 2-yr experimental period (Parish et al., 2012). Bransby et al. (1999) reported that, across several grazing experiments in Alabama evaluating oat, wheat, and rye forage for stocker production, ryegrass was superior for producing steer ADG. In an evaluation of steer performance from wheat pasture without supplementation, Horn et al. (1995) reported steer ADG ranging from 0.80 to 0.97 kg over a 3-yr period. When bermudagrass pastures were overseeded with wheat, Beck et al. (2007) reported steer ADG of 0.56 kg from December to March and 1.14 kg from March to May; final BW of cattle grazing wheat tended to be greater (322 kg) than the average of

oat (300 kg) and rye (309 kg). Few experiments have reported beef cattle performance from grazed triticale. Vendramini et al. (2013) compared herbage production, nutritive value, and performance of early-weaned beef calves (~100 kg initial BW) from continuously stocked Jumbo ryegrass and Jumbo ryegrass + Trical 2700 in south Florida. Calves were supplemented daily with concentrate at 1% of BW and, although the ryegrass– triticale mixture tended to promote greater herbage mass production than ryegrass monocultures, no differences were observed for animal performance (mean, 0.83 kg/d) or BW gain per hectare (mean, 1,138 kg). DiLorenzo (2012) evaluated overseeding mixtures of Trical 342 or Florida 401 rye with

Table 2. Steer initial BW, final BW, and ADG from ryegrass, triticale, and wheat pastures Forage treatment Item Initial BW, kg Final BW, kg ADG, kg

Triticale

330 523a 1.51c

318 474b 1.23d

Wheat

Mean

SE

319 498ab 1.36cd

322 498 1.37

10.5 15.3 0.11

Within a row, means without a common superscript differ (P < 0.10). Within a row, means without a common superscript differ (P < 0.05).

a,b c,d

Ryegrass

Diamond R ryegrass into Pensacola bahiagrass (Paspalum notatum) for winter feeding of beef heifers. In the 1-yr evaluation, the triticale and ryegrass mixture supported greater ADG (1.57 kg) than the rye and ryegrass mixture (0.88 kg). Myer et al. (2011) observed ADG of 1.11 kg for steers and heifers grazing Trical 342 compared with 1.0 kg for Wrens Abruzzi rye. When triticale was grown in mixtures with Venture ryegrass, ADG increased to 1.20 kg (Myer et al., 2011). Based on these observations, ADG values for triticale in the present experiment fall within the range of profitable levels of beef production achievable from grazed small-grain forages and exceed the value of 0.9 kg that Beck et al. (2013) have indicated many stocker operators set as their goal to enable costs of stocker ownership to be prorated over multiple units of gain. There was no advantage of triticale over wheat in terms of animal performance in the present experiment.

Forage Mass and Allowance, Grazing Days, and Stocking Rates Forage mass did not differ (P > 0.128) among ryegrass and smallgrain forages (Table 3). Soares and Restle (2002) reported similar values for continuously stocked triticale and annual ryegrass under various levels of N fertilization. Also, there were no differences (P > 0.57) among treatments for forage allowance achieved by maintaining forage mass at a target mass of 1,500 to 2,000 kg of DM/ ha with put-and-take steers. Redmon et al. (1995) reported a decline in forage intake and estimated daily gain of cattle grazing wheat pastures when forage allowance was less than 0.21 to 0.24 kg of DM/kg of BW. McCollum et al. (1992) suggested that peak intake occurs at 0.30 kg of DM/kg of BW and that intake is limited around a forage mass of 1,100 kg of DM/ ha from an evaluation of the effect of forage mass on cattle grazing wheat pastures. Scaglia et al. (2009) report-

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Table 3. Forage mass, forage allowance, grazing days per hectare, and stocking rates for ryegrass, triticale, and wheat pastures Forage treatment Item

Ryegrass

Triticale

Wheat

Mean

SE

Forage mass, kg of DM/ha Forage allowance, kg of DM/kg of BW Grazing days per hectare Stocking rate, animals/ha

1,493 1.35 406b 3.2a

1,464 1.33 415b 3.4a

1,769 1.40 497a 4.0b

1,575 1.36 439 3.5

140.1 0.09 56.7 0.34

a,b

Within a row, means without a common superscript differ (P < 0.10).

ed a range in forage allowance of 0.60 to 1.14 kg of DM/kg of BW for steers grazing annual ryegrass over a 105-d grazing period. The exceptionally satisfactory animal performance achieved from forage allowance maintained in the present experiment suggests that neither forage mass nor allowance were limiting to forage DMI, and this is consistent with the concept that ADG from grazing of high-quality forage plateaus at low forage mass or allowance (Sollenberger and Vanzant, 2011). Steer ADG across all forage treatments (1.37 kg) from a mean forage allowance of 1.36 kg of DM/ kg of BW was considerably greater than would be predicted from the model developed by Beck et al. (2013) for cool-season annual pastures in Arkansas, presumably because their data set included observations from interseeded warm-season systems and fall grazing that were not components of the present experiment. Number of grazing days per hectare differed (P = 0.09) among forage species when they were maintained at a common target mass of 1,500 to 2,000 kg of DM/ha throughout the grazing season. Wheat required a 25 and 18% greater (P < 0.10) stocking rate than ryegrass and triticale, respectively, to maintain available forage DM at the target mass, which resulted in 91 and 82 more (P < 0.10) grazing days per hectare for wheat than ryegrass and triticale, respectively. Values in the present experiment are in agreement with grazing days per hectare recorded by Pereira (2009) for ryegrass, oat, and rye (315, 388, and 369 d/ha,

respectively) in a 3-yr grazing trial in Headland, Alabama. Barnett et al. (2002) suggested that, if triticale is to make a significant contribution to winter grazing programs, extending the production season and selecting for rapid regrowth following a defoliation event would enhance the use of the crop in southern production systems. Planting blends of small grains and ryegrass may also extend the grazing season compared with monocultures (Myer et al., 2011; Mullenix et al., 2012).

Forage Chemical Composition and Nutritive Value Ryegrass had a lower concentration of NDF (Table 4) than triticale (P = 0.009) and wheat (P = 0.040), but NDF concentration in triticale and wheat was not different (P = 0.580). Hafley (1996) reported similar NDF values for Marshall ryegrass under continuous stocking over a 2-yr experiment. In an evaluation of forage sampling methods on in situ DM disappearance kinetics, Coblentz et al. (2002) reported mean values of 52% NDF and 28% ADF for whole-plant wheat samples collected during mid-March and April. A similar pattern was observed for concentration of ADF, with ryegrass having less ADF concentration than triticale (P = 0.003) and wheat (P = 0.049), but there were no differences (P = 0.296) between triticale and wheat. Concentration of ADL in ryegrass was less (P = 0.029) than in wheat, but no differences were

observed between triticale and wheat (P = 0.252) or between triticale and ryegrass (P = 0.297). These values are slightly less than those observed by Coblentz et al. (2002) for wheat pasture and by Muir and Bow (2009) for cool-season annual forages grown under nutrient-rich conditions. During the first year of the trial, mean concentration of ADL was less than 3% for barley, oat, triticale, rye, and ryegrass from September to April in Stephenville, Texas (Muir and Bow, 2009); mean concentration of ADL was greater than 5% for the small grains and ryegrass in yr 2 and 3 because of increased yield compared with yr 1, as well as varying environmental conditions. Concentration of CP was not different (P > 0.212) among forage species and exceeded the requirement for growing-finishing beef steers (NRC, 1996). Concentration of TNC was less in triticale than ryegrass (P = 0.014) and wheat (P = 0.067), but TNC concentration in wheat and ryegrass was not different (P = 0.532). Forage concentration of TNC is largely influenced by time of sampling, day length, and various climatic factors, and values reported in the present experiment agree with those reported for cool-season annuals in the Coastal Plain region by Myer et al. (2010). When small grains and ryegrass monocultures were managed under 4-wk clipping intervals, these authors observed a mean watersoluble carbohydrate concentration of 25.4% for Marshall ryegrass over a 2-yr period.

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Table 4. Chemical composition (DM basis) of grazed ryegrass, triticale, and wheat pastures Forage treatment Item

Ryegrass

Triticale

Wheat

Mean

SE

41.7a 22.0a 1.5a 17.0 25.4a

48.4b 26.6b 1.7ab 17.6 18.5b

47.0b 25.0b 1.9b 16.2 23.7a

45.7 24.5 1.7 16.9 22.5

1.80 1.15 0.24 0.73 2.01

NDF, % ADF, % Lignin, % CP, % TNC,1 %

Within a row, means without a common superscript differ (P < 0.05). TNC = total nonstructural carbohydrates.

a,b 1

Table 5. Correlation coefficients1 (r) between forage metrics1 and ADG by steers grazing ryegrass, triticale, and wheat pastures Item2

r

P-value

CP FA NDF ADF ADL TNC

0.3525 0.0653 −0.4436 −0.4670 −0.4400 0.1987

0.0004 0.5290 <0.0001 <0.0001 <0.0001 0.0523

Correlation values were derived from data collected on a monthly basis across the growing season. 2 FA = forage DM allowance (kg of DM/kg of steer BW); TNC = total nonstructural carbohydrates (%); and forage concentration of CP (%), NDF (%), ADF (%), and ADL (%). 1

Statistical Associations Between Forage Metrics and Steer ADG Less ADG from triticale than ryegrass may be partially attributed to differences in nutritive value. Although lignin and CP concentrations were not different between these species, less NDF and greater TNC concentrations in ryegrass (P ≤ 0.05) may explain increased steer ADG compared with triticale. Correlation analysis (Table 5) revealed a positive relationship (P < 0.05) across all forage treatments between steer ADG and forage CP concentration, and between ADG and forage TNC concentration. Also, there was a moderately strong inverse relationship between steer ADG and forage concentrations of NDF, ADF, and ADL but no significant relationship (P = 0.53) between ADG and forage allowance.

Table 6. Multiple regression of independent variables of forage metrics1 on the dependent variable ADG by steers grazing ryegrass, triticale, and wheat pastures Independent variable ADF FA CP ADL

Intercept

P-value

r2

SE

−0.0245 −0.3084 0.0319 −0.2168

<0.001 0.0570 0.0738 0.0824

0.2206 0.0299 0.0257 0.0237

0.1358 0.0187 0.1234 0.0153

FA = forage DM allowance (kg of DM/kg of steer BW) and forage concentration of ADF (%), CP (%), and ADL (%).

1

Although the treatment structure of the present experiment was not designed to rigorously evaluate the relative importance of forage nutritive value and quantity as determinants of stocker ADG, exploration of such relationships from the data set can provide new insight into the relative roles of forage nutritive value and quantity in affecting stocker performance from cool-season annual forages under location-specific conditions (Sollenberger and Vanzant, 2011). Stepwise regression analysis (Table 6) revealed that forage allowance and concentrations of ADF, CP, and lignin collectively explained 30% of the variation in steer ADG across all forage treatments. Concentration of ADF alone accounted for 22% of the variation in ADG, whereas the other factors each contributed ≤3%, indicating that forage quality factors contributed more to variation in ADG than did forage allowance in this experiment. Because forages were managed to maintain a target DM mass and forage DM mass was not limiting to DMI, nutritive value parameters entered the multiple-regression model and contributed to 90% of the accounted variation in steer ADG. However, the influence of both forage allowance and quality factors was not as great in the present experiment as reported in other research with warm-season perennial forage systems evaluated across a wider range of forage allowance (Stuedemann and Franzluebbers, 2007; Bungenstab et al., 2011). Sollenberger and Vanzant (2011) have stated that high-nutritive-value forages produce greater ADG than low-nutritive-value forages across a wide range of forage quantity, and that ADG plateaus at lower levels of forage mass or allowance for high-nutritive-value forages, which may partially explain the relatively low model r2 value in the present experiment.

IMPLICATIONS Ryegrass and wheat produced superior ADG and greater number of grazing days per hectare, respectively, over triticale in the current experi-

Stocker production from small-grain forage

ment. Steer ADG from wheat was comparable to that from ryegrass, but the greater number of grazing days per hectare from wheat indicates that it may be superior to ryegrass for supporting total BW gain per hectare. Forage nutritive value was not an especially important determinant of stocker ADG within the ranges of relatively low forage DM mass and allowance maintained in the current experiment. Interactions of forage mass and nutritive value should be further investigated across a wider range of herbage allowances and forage species to more fully understand their relative importance as determinants of animal performance from cool-season annual forages.

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