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‘Giant’ (Reg. no. CV‐348, PI 701902) is a southern root‐knot nematode (Meloidgyne incognitarace 3 and race 4)–resistant forage cowpea [Vigna unguiculata(L.) Walp.] developed by Texas A&M AgriLife Research at Overton, TX. Giant is intended for use as a warm‐season cover crop, a forage and hay crop, and supplemental browse for white‐tailed deer. Giant is an indeterminate, forage type cowpea that produces biomass from May through September in northeast Texas but also flowers 25 days earlier than ‘Iron & Clay’ cowpea, allowing seed production in northeast Texas before the first average frost date. Single nucleotide polymorphism analysis confirmed the variety mix Iron & Clay as the parental source population for Giant. Forage production of Giant at Overton, TX, in 2019 and 2020 was 5.3 and 6.0 Mg dry matter (DM) ha−1, respectively. Forage production of Giant in 2019 at Prairie and Starkville, MS, was 2.8 and 2.9 Mg DM ha−1, respectively. Protein content of Giant in 2019 at Prairie and Starkville was 21.1 and 21.2%, respectively. Forage production of Giant in 2019 at Chillicothe, TX and Lockett, TX, was 2.6 and 3.6 Mg DM ha−1, respectively. Top growth nitrogen (N) yield of Giant in 2019 at Chillicothe, TX, and Lockett, TX, was 67 and 65 kg N ha−1, respectively. Based on very low nematode reproduction, Giant is rated resistant and partially resistant to southern root‐knot nematode race 3 and race 4, respectively. Improved cultivars of forage cowpea are needed.Giant forage cowpea produces seed earlier than Iron & Clay cowpea.Giant forage cowpea is resistant to southern root‐knot nematode.

‘Ace’ (Reg. no. CV‐329, PI 691530) is a small‐seeded cultivar of forage cowpea [Vigna unguiculata(L.) Walp.] that was developed by Texas A&M AgriLife Research at Overton, TX. Ace is intended for use in wildlife supplemental plantings, cover cropping systems, and hay production systems. Forage cowpeas are widely used in Texas and the U.S. southern region as supplemental plantings for white‐tailed deer, but seed production of late‐flowering forage cowpeas is restricted in northern Texas due to freeze kill prior to seed maturity. Mass selection within two highly variable plant introduction lines was used to develop Ace. Seed from five plants with very similar phenotypes, including first bloom in late August, was bulked and tested as experimental forage cowpea. Biomass production of Ace (experimental designation TX‐3) at Overton was 2.8 and 4.7 Mg ha−1in 2013 and 2015, respectively. Biomass production of Ace at Vernon, TX, in 2015, 2016, and 2017 was 3.9, 5.9, and 6.7 Mg dry matter ha−1, respectively. Protein content of Ace biomass at Vernon in 2015 and 2016 was 16.5 and 16.4, respectively. Seed production of Ace at Vernon ranged from 106 to 670 kg ha−1. The seed size of Ace, expressed as seed weight, was 5.1 g 100 seeds−1, compared with Iron & Clay at 10.6 g 100 seeds−1. Average days to first bloom at Overton for Ace and Iron & Clay are 87 and 114, respectively. Root galling of Ace by southern root‐knot nematode (Meloidgyne incognitaRace 3) is very low, and nematode reproduction is low, relative to southern root‐knot nematode–susceptible cowpea lines. Greenhouse seed germination studies indicate about 25% of Ace seed would survive after 2 mo of simulated field conditions and that all seed would be germinated after 3 mo. The reseeding potential of Ace needs further study.

The DSSAT perennial forage model predicted bermudagrass response to N reasonably well.The model prediction accuracy was linked mainly to soil water holding capacity.Bermudagrass production in the southern United States could be impacted by El Niño‐Southern Oscillation.The La Niña (El Niño) phase was associated with above (below) normal production.The impact of El Niño‐Southern Oscillation was greater on a soil with a coarser texture. The perennial forage model in the Decision Support System for Agrotechnology Transfer (DSSAT) suite is a newly developed model. Studies involving the use of the forage model for predicting biomass production for a perennial grass such as bermudagrass [Cynodon dactylon(L.) Pers.] are few. By conducting a series of simulation investigations, we examined the DSSAT forage model for simulating ‘Coastal’ bermudagrass biomass response to N as affected by soil and climate variability in the southern United States. The simulation results indicated that the DSSAT forage model predicted the biomass response to N reasonably well. However, the accuracy of simulations was linked primarily to the water holding capacity (WHC) of the soil used. A seemingly small difference in WHC, such as 0.03 mm mm−1, made a significant difference in the biomass response to N rate by a margin of about 3 Mg ha−1. These results indicated that providing more leverage to WHC than to the soil name, texture, or type being used for simulations could provide more accurate results. The simulations further indicated that bermudagrass production in the southern United States could be impacted by El Niño‐Southern Oscillation (ENSO), with the La Niña and El Niño phases providing above‐normal and below‐normal production, respectively. The rate of increase in biomass with an increase in N rate was higher under La Niña than under El Niño. The impact of ENSO was greater on a soil with a coarser texture.

Winter wheat biomass had one‐phase exponential association with N application rate.A finer, more fertile soil produced more biomass than a coarser, less fertile soil.Biomass significantly decreased with a delay in planting for N rates ≥135 kg ha–1.The effect of the initial drought on biomass was higher with an increase in N rate.The reduction in biomass due to the terminal drought was greatest at 135 kg N ha–1. Winter wheat (Triticum aestivumL.) is an important component of pastures in the southern United States. This study examined winter wheat biomass responses to N application rate as influenced by soil type, planting date, drought, and El Niño‐Southern Oscillation (ENSO) for the Pineywoods region of Texas using a new forage wheat model that had been incorporated into the Decision Support System for Agrotechnology Transfer suite of crop models. Biomass was simulated for various scenarios comprising two soils, three planting dates, seven N rates, and 74 yr of weather data. The biomass response to N rate was represented by a one‐phase exponential association. Biomass generally peaked at 135 kg N ha−1on the finer, more fertile Lilbert soil and at 269 kg N ha−1on the coarser, less fertile Darco soil. Biomass decreased with a delay in planting date at N rates ≥135 kg N ha−1for Lilbert and ≥202 kg N ha−1for Darco. The effect of drought during September to October was greater for a higher N rate, the Darco soil, and an earlier planting date. The effect of drought during March to April was greatest at 135 kg N ha−1and greater on Darco, with up to 45% reduction in biomass compared with 35% on Lilbert. Biomass reduction was up to 45% for the mid‐October planting and 32% for the mid‐September planting. Winter wheat biomass yield was not significantly affected by ENSO. These findings might assist winter wheat forage growers in this region in identifying soil type–, planting date–, and weather‐specific N rates to optimize forage production.

Management of bermudagrass [Cynodon dactylon(L) Pers.] pastures on Coastal Plain soils in the southeastern United States incorporates multiple strategies for N fertilization, liming, and stocking rate (SR). This study documented long‐term changes in soil pH and extractable NO3–N K, Ca, and Mg in Coastal and common bermudagrass pastures continuously stocked at different intensities for 37 yr (1969–2004). Soil fertility regimens were established in 1985 and consisted of (i) inorganic nitrogen fertilizer with overseeded annual ryegrass (Lolium multiflorumLam.) (NRYG) and (ii) no nitrogen with overseeded clover (Trifoliumspp.) (NoNCLV). Soil samples (0–120‐cm depth) were collected in 1985, 1989, 1994, 1996, and 2004 and analyzed for pH and extractable NO3–N, K, Ca, and Mg levels. Fertility regimen showed significant effects on soil NO3–N concentration (0–15 cm) with greater values generally observed in the pastures receiving N (average NO3–N concentration of ∼ 4 mg kg−1in NoNCLV vs. 14.15 mg kg−1in NRYG treatments). Differences in N fertilizer application levels throughout the study period also affected soil NO3–N concentration. Conversely, bermudagrass pastures receiving no inorganic N and overseeded with clover showed relatively constant soil NO3–N concentrations during the study period. Soil K levels increased (42 to 48%) over time and were generally greater in the NoNCLV pastures. It was concluded that overseeding clover without N fertilization onto bermudagrass pastures can be a viable, long‐term management strategy to sustain adequate soil nutrient levels while achieving satisfactory forage and animal production.

Grazing systems research includes a wide array of component experimentation to assess plant–animal responses on pastures during short‐term, seasonal, and long‐term periods. Pasture‐animal experiments seek to assess forage growth responses to grazing and to quantify relationships between forage growth and nutritive value to gains per animal and per hectare. These experiments have used fixed and variable stocking rate management, continuous or rotational methods of stocking, and other stocking strategies to evaluate levels of production efficiencies. Stocking strategies require the integration of periodic and total forage mass, associated nutritive attributes, specific defoliation regimen responses, and incorporation of weather conditions to meet end‐point objectives. The flexible integration processes includes forage–animal databases, availability of land resources, and intuitive experience to accommodate erratic weather conditions. Scientists have the opportunity to develop and validate stocking strategies through long‐term, site‐specific grazing systems research as well as collaborative, ecoregion research efforts. Documenting the influence of stocking density on nutrient cycling, stand maintenance, ecotype diversity, and watersheds will further define soil–forage–animal responses and impacts. Management prerequisites for application of stocking strategies includes foundational forage–animal interface relationships, land resource limitations, animal husbandry behavior awareness, initiation and termination of stocking sequences, projections and expectations for climatic changes, and biological and economic risk–reward expectations. Scientists involved in grazing system research are challenged to integrate soil, forage, and animal databases to discover and document production efficiencies and stocking strategies for implementation by scientists, students, and stakeholders.

Cancer of the eye in cattle with white faces occurs less frequently in cattle with pigmented eyelids. Corneoscleral pigmentation is related to eyelid pigmentation and occurrence of lesions that may precede cancer. Objectives of this study were to assess 1) variation in the proportion of eyelid and corneoscleral pigmentation in Hereford, Bos taurus,and Bos indicuscrossbreds and 2) the occurrence of lesions with the presence of pigmentation in those areas. Hereford and Bos indicuscrosses (Brahman or Nellore with Angus and Hereford and straightbred Brafords) and Bos tauruscrosses (Angus-Hereford) were included in the study (n =1,083). Eyelid pigmentation proportions were estimated by pixel quantification and were evaluated as total proportions and for upper and lower eyelids distinctly for each eye. Fixed effects included breed type, age categories, and sex of the animal. Lesion presence (1) or absence (0) was obtained by visual appraisal of image and was assumed to be binomially distributed. Eyelid pigmentation proportions (overall, upper, and lower eyelids) for Hereford ranged from 0.65 ± 0.03 to 0.68 ± 0.03 and were significantly lower than Bos indicus(range from 0.93 ± 0.02 to 0.95 ± 0.02) or Bos taurus(ranged from 0.88 ± 0.02 to 0.92 ± 0.02) crosses. Corneoscleral pigmentation in Hereford cows (0.17 ± 0.06) did not differ (P= 0.91) from Hereford calves and yearlings (0.16 ± 0.07). Bos indicusand Bos tauruscrossbred cows had larger corneoscleral pigmentation (0.38 ± 0.05 and 0.48 ± 0.04 for left eyes and 0.37 ± 0.05 and 0.53 ± 0.04 for right eyes, respectively) than all calves (P< 0.001), and their corneoscleral pigmentations were greater than that of Hereford cows (P< 0.003). Bos indicusand Bos tauruscows had greater proportions of left eye corneoscleral pigmentation (0.38 ± 0.05 and 0.48 ± 0.04, respectively) than Hereford cows (0.17 ± 0.06) and all young animal breed types (P< 0.05). Right eye proportions differed for all cow groups (P< 0.05; 0.53 ± 0.04, 0.37 ± 0.05, and 0.17 ± 0.06). Among calves and yearlings, Hereford had a lower right eye corneoscleral pigmentation proportion (0.16 ± 0.07) than Bos taurus(P= 0.02). The lesion proportion for Hereford (0.08 ± 0.03) was significantly greater than that of either Bos indicus(0.01 ± 0.005) or Bos taurus(0.01 ± 0.003). Crossbreeding with Bos taurusor Bos indicusanimals appears to increase eye pigmentation, which may help reduce the occurrence of cancer in eyes of cattle with white faces.

Field observations revealed greater retention of green leaf area and growth of ‘Tifton 85’ compared to common and ‘Coastal’ bermudagrass [Cynodon dactylon(L.) Pers.] under water stress. Our objective was to compare phenotypic and physiological responses to increased water stress between Tifton 85 and Coastal and between Tifton 85 and ‘Tifway’ bermudagrass under greenhouse conditions. Bermudagrass green leaf area, shoot and root dry weights, leaf CO2exchange rate (CER), H2O exchange rate (WER), and conductance were measured under well‐watered and reduced watering in two experiments. Tifton 85 retained greater green leaf area than Tifway under water stress in Exp. 1. The CER, WER, and conductance were less for Tifton 85 than Tifway, but water stress over 8 d reduced each variable for Tifway only. In Exp. 2, soil water content and green leaf area declined more for Tifton 85 than for Coastal bermudagrass over 14 d after watering ended. Greater root dry weight below the 13‐cm depth indicated Tifton 85 depleted water content of the finite pot volumes more rapidly than Coastal under reduced watering. After 14 d without watering during Exp. 2, mean CER of green leaves was less than well‐watered pots for Tifton 85 but not for Coastal bermudagrass. Similar to phenotypic traits, leaf CER, WER, and conductance responses of Tifton 85 differed between experiments. These greenhouse experiments documented variation of responses to reduced soil water supply among bermudagrass and revealed the need to evaluate traits affecting water access and use for Tifton 85 and other bermudagrass under field conditions.

‘Nelson’ ryegrass is a newly released variety of annual ryegrass that will be used as a forage crop for grazing livestock in the southern USA. Nelson (Reg. No. CV‐257, PI 658137) Italian ryegrass (Lolium multiflorumLam.) was developed by the Texas Agricultural Experiment Station—now Texas AgriLife Research—as a forage‐type annual ryegrass. Plant breeding of Nelson was conducted at what is now the Texas AgriLife Research and Extension Center at Overton, Texas. Nelson is a tetraploid where 2n= 4x= 28 chromosomes. Nelson is an open‐pollinated three‐way cross from ryegrass breeding lines TXR2000‐T2, TXR2002‐T17, and the cultivar ‘Jumbo’. Both TX breeding lines were from ‘TAM 90’ germplasm that had its chromosome numbers doubled from 14 to 28. Adjacent rows, which were replicated, were grown in an isolation block and allowed to cross‐pollinate and produce seed. Subsequent generations were grown and selected for high forage‐yield potential and crown rust (caused by Puccinia coronateCorda) resistance at Beaumont, Texas. Seed from these populations was increased in Oregon and was later tested for forage yield across the southern USA. Nelson has high forage‐yield potential, good crown rust resistance, and good cold tolerance for the southeastern USA. Nelson is improved for forage yield potential compared with most commercial cultivars in East Texas. The predominant use is projected to be in overseeding warm‐season pastures for winter production of forage for grazing animals. Seed production of Nelson will be in Oregon. Nelson was tested as TXR2006‐T22 and released in 2009.

The objective of this study was to characterize residual feed intake (RFI) and to estimate phenotypic and genetic correlations with performance and ultrasound carcass traits in growing heifers. Four postweaning feed efficiency trials were conducted using 468 Brangus heifers. The complete Brangus pedigree file from Camp Cooley Ranch (Franklin, TX), which included 31,215 animals, was used to generate genetic parameter estimates. The heifer progeny from 223 dams were sired by 36 bulls, whereas the complete pedigree file contained 1,710 sires and 8,191 dams. Heifers were individually fed a roughage-based diet (ME = 1.98 Mcal/kg of DM) using Calan gate feeders for 70 d. Heifer BW was recorded weekly and ultrasound measures of 12th- to 13th-rib fat thickness (BF) and LM area (LMA) obtained at d 0 and 70. Residual feed intake (RFIp) was computed as actual minus predicted DMI, with predicted DMI determined by linear regression of DMI on mid-test BW0.75(MBW) and ADG with trial, trial × MBW, and trial × ADG as random effects. Overall means for ADG, DMI, and RFI were 1.01 (SD = 0.15), 9.51 (SD = 1.02), and 0.00 (SD = 0.71) kg/d, respectively. Stepwise regression analysis revealed that inclusion of gain in BF and final LMA into the base model increased the R2(0.578 vs. 0.534) and accounted for 9% of the variation in DMI not explained by MBW and ADG (RFIp). Residual feed intake and carcass-adjusted RFI (RFIc) were strongly correlated phenotypically and genetically with DMI and FCR, but not with ADG or MBW. Gain in BF was phenotypically correlated (P< 0.05) with RFIp (0.22), but not with FCR or RFIc; however, final BF was genetically correlated (P< 0.05) with RFIp (0.36) and RFIc (0.39). Gain in LMA was weakly phenotypically correlated with FCR, but not with RFIp or RFIc; however, gain in LMA was strongly genetically correlated with RFIp (0.55) and RFIc (0.77). The Spearman rank correlation between RFIp and RFIc was high (0.96). These results suggest that adjusting RFI for ultrasound carcass composition traits will facilitate selection phenotypically independent of growth, body size, and carcass composition; however, genetic relationships may still exist between RFI and carcass composition.

Forage-animal production agriculture is implementing infrastructure changes and management strategies to adjust to increased energy-related costs of fuel, feed grains, fertilizers, and seeds. The primary objectives of this position paper are to assess future research and extension scientific needs in forage utilization, financial support for the discipline, and changing status and number of scientists. A survey questionnaire returned from 25 land-grant universities in the eastern half of the United States rated the top 4 research needs as 1) pasture systems and efficiency of production; 2) interfacing with energy concerns; 3) forage cultivar evaluations and persistence; and 4) environment impacts. Plant-animal future research needs at 11 USDA-ARS regional locations are targeted at sustainable management and improved livestock performance, ecophysiology and ecology of grasslands, environment impacts, and improved technologies for nutritive value assessments. Extension scientists from 17 southern and northeastern states listed the top 3 needs as forage persistence, soil fertility and nutrient management, and pasture systems and efficiency of production. Grant funds currently provide more than 40% of land-grant university research and extension efforts in forage utilization, and scientists estimate that this support base will increase to 55 to 60% of the funding total by 2013. Reduced allocation of state and federal funding has contributed to a reduction in the number of full-time equivalent (FTE) scientists engaged in forage utilization research and extension activities. The current 25 state FTE conducting research number about 2.8 per state. This includes 10 states with >3, 11 states with <2, and 3 states with <1 FTE. Increased interest in cellulosic energy, climate change, and environmental impact may offer new opportunities for these FTE to participate in integrated cross-discipline research Extension programming, and technology transfer methods will change to accommodate reduced funding but with increasing numbers of novice, recreation-oriented landowners.

Large and repeated manure applications can exceed the P sorption capacity of soil and increase P leaching and losses through subsurface drainage. The objective of this study was to evaluate the fate of P applied with increasing N rates in dairy wastewater or poultry litter on grassland during a 4‐yr period. In addition to P recovery in forage, soil‐test phosphorus (STP) was monitored at depths to 180 cm in a Darco loamy sand (loamy, siliceous, semiactive, thermic Grossarenic Paleudults) twice annually. A split‐plot arrangement of a randomized complete block design comprised four annual N rates (0, 250, 500, and 1000 kg ha−1) for each nutrient source on coastal bermudagrass [Cynodon dactylon(L.) Pers.] over‐seeded with ryegrass (Lolium multiflorumL. cv. TAM90). Increasing annual rates of N and P in wastewater and poultry litter increased P removal in forage (P= 0.001). At the highest N rate of each nutrient source, less than 13% of applied P was recovered in forage. The highest N rates delivered 8 times more P in wastewater or 15 times more P in poultry litter than was removed in forage harvests during an average year. Compared with controls, annual P rates up to 188 kg ha−1in dairy wastewater did not increase STP concentrations at depths below 30 cm. In contrast, the highest annual P rate (590 kg ha−1) in poultry litter increased STP above that of controls at depth intervals to 120 cm during the first year of sampling. Increases in STP at depths below 30 cm in the Darco soil were indicative of excessive P rates that could contribute to nonpoint‐source pollution in outflows from subsoil through subsurface drainage.

In the Gulf Costal Plain adapted summer annual forages such as pearl millet [Pennisetum typhoides(Burm.) Stapf and C. E. Hubb] are generally higher in energy content than perennial grasses and are capable of producing higher rates of gain. However, practically no data are available which define animal performance at different levels of forage utilization. The lack of definitive data on which to base a grazing program with pearl millet prompted this study which determined liveweight gains of weanling cattle grazing ]pearl millet and evaluated the relationships between gain, forage yield, forage quality, grazing pressure, and profitability. A hybrid pearl millet ‘Millex 23’ was seeded at the rate of 15 kg/ha on Thenas (Fluvaquentic Eutrochrept; coarse, loamy, mixed, thermic) soil and fertilized with 112 kg/ha each of N, P2O5, and K2O in each of 2 years. Weanling crossbred beef calves were used as tester animals and grazed at stocking rates ranging from 3.73 to 11.35 animals/ha. Liveweight average daily gains (ADG) from 0.27 to 1.01 kg were shown to be a non‐linear function of forage availability and a positive linear function of percent in vitro dry matter disappearance (IVDMD) available forage. Percent IVDMD of available forage varied from 36.29 to 63.57% and was inversely related to length of trial. Neutral detergent fiber values for available forage were negatively correlated with ADG (r= −0.84). Maximum profitability, expressed as return per ha, was found at intermediate grazing pressure and was dependent upon the magnitude of positive or negative margin between the time of purchase and the time of selling. Maximum profit occurred at greater grazing pressures as the positive margin between selling and purchase price increased. The most important factor affecting the profitability of grazing pearl millet was the differential between buying and selling price of the cattle. Aside from this factor, which the farmer seldom controls, grazing pressure is the most important determinant of profit. It was concluded that the greatest profit or least loss occurs at medium grazing pressures which, in this study, was approximately 2 kg of available forage per kg of animal liveweight.

As part of an evaluation of Tuli crossbred cattle, forage intake, digesta kinetics, and grazing behavior were estimated in two Texas environments. In humid east Texas, Tuli × Brahman heifers were compared with purebred Angus and Brahman and Angus × Brahman heifers. Fecal output, forage intake, compartmental mass, and compartmental residence time did not differ among breeds. Angus and Brahman heifers had different (P< . 02) gastrointestinal residence times (51.1 ± 1.56 vs 43.1 ± 1.56 h, respectively), but values for the purebreds did not differ from those for Tuli × Brahman or Angus × Brahman heifers. Angus heifers had shorter (P< .05) 24-h grazing times (398 ± 15.4 min/d) and fewer (P< .05) grazing periods (7 ± .4) than Tuli × Brahman (552 ± 16.8 min/d and 10 ± .4), Angus × Brahman (507 ± 18.4 min/d and 9 ± .5), and Brahman (560 ± 16.8 min/d and 9 ± .4, respectively) heifers. In semiarid southwest Texas, Tuli × Angus heifers were compared with purebred Angus and Brahman and Brahman × Angus heifers. Fecal output and forage intake were similar in Tuli × Angus and Brahman × Angus heifers (14.2 ± .69 and 14.9 ± .91 g fecal DM/ [d.kg BW] and 24.5 ± 1.33 and 25.6 ± 1.75 g/d of forage DMI, respectively) but higher (P< .05) than those of purebred Brahman heifers (12.2 ± .64 and 20.3 ± 1.23 g/[d.kg BW] of fecal DM and forage DMI, respectively). Grazing times did not differ among breeds. We conclude that Tuli-sired heifers are likely to be as productive as Brahman crossbred heifers in Texas, based on the similarities in intake, digesta dynamics, and grazing behavior.

Yearling heifer growth data were obtained during 4 yr for 524 heifers allotted to either humid bermudagrass pastures (Overton) or semiarid rangeland (Uvalde). Each year, heifers were allotted on April 15 to four forage availability levels (400 to 2,800 kg of DM per 100 kg of BW at Uvalde and 80 to 260 kg of DM per 100 kg of BW at Overton) maintained by varying the stocking rate monthly until mid-October of each year. Forage availability and yearling heifer characteristics (weight, condition score, and height at hooks, taken on April 15) were treated as continuous variables in regression analyses. Final heifer weight, height, and condition responses to increased forage allowance were related to yearling phenotypes differently for the two locations. Generally, at Overton, forage availability influenced final characteristics to a greater extent than did yearling variables, whereas the trend was the opposite at Uvalde. At Uvalde, the yearling characteristic that had the largest effect on performance was height at hooks. Yearlings with large frames benefited from increased forage allowance by accumulating body fat at a faster rate than those with small frames. In contrast, at Overton, the yearling characteristic that had the largest effect on performance was condition. Fat heifers responded to increased forage availability to gain even greater advantages in fatness at the expense of potential growth in height and, thus, achieved early maturation. Yearling phenotypes were more broadly adapted to arrays of forage availability for humid, improved pastures than for semiarid rangeland.

Brahman-Hereford F1dams have been used to evaluate the influence of grazing pressure on forage attributes and animal performance at the Texas A&M University Agricultural Research Center at Overton. Data for this study were compiled from 1,909 records of Simmental-sired calves born to Brahman-Hereford F1cows from 1975 to 1990. Birth weight and weaning weight were analyzed independently to estimate the influence of year, season of birth, dam age, weaning age, and sex of calf. The effect of stocking rate as represented by levels of forage availability on weaning weights and subsequent birth weights was measured. Within the fall and winter calving seasons, lactating dams grazing at a high stocking rate produced calves with the lowest subsequent birth weights. Lactating dams assigned to creep-fed treatments had calves with the heaviest subsequent birth weights. Although dams that were < 3.5 yr of age had calves with the lightest birth weights, there was no apparent decline in birth weight of calves from dams 12 to 17 yr old. Year, sex of calf, age of dam, stocking rate, season of birth, age at weaning, and birth weight were significant factors affecting weaning weight (P< .01). Fall-born calves grazing cool-season annual pastures were heavier at weaning (267.6 kg) than either winter- (252.0 kg) or spring-born calves (240.9 kg). A stocking rate × season-of-birth interaction was observed for birth weight and weaning weight (P< .05). Differences in weaning weight from low-vs high-stocked pastures were greater for fall-born calves (61.6 kg) than for winter-born calves (48.7).(ABSTRACT TRUNCATED AT 250 WORDS)

Summary Arrowleaf clover (Trifolium vesiculosum Savi) is an annual forage legume that is sown in south-eastern USA when temperature and moisture conditions may not be suitable for survival of inoculant rhizobia. Survival of two antibiotic-resistant strains of rhizobia on seed or quartz particles was evaluated under controlled conditions in the laboratory. At 30°C and 75% r.h., lime coating of inoculated seed, soil pH (4.2 and 6.7), and surface or subsurface sowing of inoculated seed did not significantly (P = 0.05) affect the survival of either rhizobial strain. The use of gum arabic as an inoculant adhesive resulted in better rhizobial survival than sucrose or water, but even with gum arabic treatment the population of strain 162Y10 declined fromc. 10,000/seed to less than ten/seed in six days. Survival of strain 162Y15 appeared better andc. 200 rhizobia/seed survived for six days. When inoculated seed were incubated at 45°C, soil pH, method of sowing, lime coating of the seed, and r.h. (75% and 100%) did not influence rhizobial survival. The gum arabic adhesive enhanced survival over the use of sucrose but survival was still poor. No viable rhizobia were detected after two days of incubation. High r.h. (100%) and 30°C favoured survival and growth of both rhizobial strains when inoculated onto quartz particles placed on, or mixed into, soil at pH 4.2. Coating inoculated quartz particles with lime increased the growth of rhizobia under these conditions, but sucrose and gum arabic were equally effective as inoculant adhesives.

The Texas A&M Cattle Production Systems Model was used to study herd productivity under several management plans open to cow-calf producers in the southeastern United States. An east Texas farm herd was simulated as a self-contained unit where all hay fed in the winter months was harvested from hay pastures or as surplus forage from grazed pastures. Management options examined involved (1) variation in the amount of forage fed as hay, and (2) spring vs fall calving. All forage was produced on well fertilized, intensively managed Coastal bermudagrass pastures. The winter feed options consisted of hay fed (1) ad libitum, and at (2) 80, (3) 60 and (4) 40% of the ad libitum level. The hay feeding period was November 15 through April 15. Overall herd productivity decreased as level of winter feeding decreased. Higher levels of hay feeding resulted in fewer cattle/unit land area but higher production/breeding cow. Herd size increased by 2.9, 11.9 and 32.5% as winter hay levels were reduced from ad libitum to 80, 60 and 40% of ad libitum, respectively, under spring calving management, whereas herd productivity measured as total live weight sold/herd (fixed land area) declined by 2.2, 9.4 and 10.3% with the respective feed levels. Spring-calving herds were approximately 3.2% larger in number than corresponding fall-calving herds on the same land area, but fall-calving herds produced an average of 3.6% more live weight sales.

Two trials were conducted to determine the influence of monensin on live weight gain and efficiency of forage utilization of calves grazing Bermudagrass. In trial 1, 32 calves, weaned at an average age of 238 days and 250 kg, were grazed on “Coastcross I” Bermudagrass from July 20 to October 13. Eight steers and eight heifers were randomly assigned to one of two treatments: 200 mg monensin/head/day or 0 mg monensin/head/day fed in a .91 kg/head/ day diet of pelletized 14% protein feed. Both groups were stocked at 15.3 head/ha. Monensin-fed calves gained .52 kg/head/day, while the control-fed calves gained .42 kg/head/day (P<.10). Average daily gains (ADG) of steers (.54 kg) were greater (P<.05) than those of heifers (.40 kg). Forage to gain ratio estimates were 15:1 and 19:1 for calves on monensin and control paddocks, respectively. In trial 2, 48 steer calves, averaging 265 days of age and 260 kg, were randomly assigned to each of two replicates of the following grazing treatments: common Bermudagrass only (P), Bermudagrass + .91 kg/head/day 14% protein feed (PF) or Bermudagrass + .91 kg/head/day feed + 200 mg monensin/head/day (PFM). ADG were .45, .47 and .68 kg for steers fed P, PF and PFM, respectively. The monensin-fed calves showed a 45% improvement in ADG (P<.05). Estimated forage to gain ratios for calves fed P, PF and PFM were 20.5:1, 19:1 and 13:1, respectively. The use of 200 mg monensin/head/day improved calf gains by 23 to 45% and increased estimated feed efficiencies by 21 to 36% on Bermudagrass pastures. The improvement in gain for heifers fed monensin was 28.6%, while steers gained 18.4% more when fed monensin.

Two groups of eight first-cross Brahman-Hereford cows of equal parity within groups were fed monensin and no monensin, respectively, from day 246 ± .4 of gestation. The cows were group fed Coastal bermudagrass hay ad libitumand either 0 (group NMON) or 200 mg (group MON) of monensin incorporated in 1.8 kg of standard range cube (daily per cow). The experimental purpose was to study concentration profiles of sex steroids prepartum. Blood was sampled via tail vein or artery on alternate days through day 270 of gestation and at least daily thereafter until 3 days postpartum as well as within 1 hr after calving (day 0). Progesterone (P4), estrone (E1) and estradiol-17β (Eβ) and -17α (Eα) were measured in blood serum by radioimmunoassay. The data were analyzed by least-squares and split-plot analysis of variance and by stepwise-addition multiple regression. Diet did not affect body weight and length, wither height, heart girth or condition score of cows, calving traits or birthweight and vigor of calves. Periparturiently, concentration profiles of the serum steroids were characteristic of other published data. Concentrations of the serum steroids were not different (P>.25) between groups initially, but serum P4increased (P<.01) about 3 ng/ml in cows of group NMON during the first 22 days of the feeding trial and serum P4was higher (P<.01) on day 22 than in cows of group MON. In contrast, concentrations of serum estrogens did not differ significantly between diet groups until days 2 to 0 prepartum when concentrations of serum E1and Eβ were higher (P<.05) in cows of group NMON than in cows of group MON. Concentrations of serum Eα started to decrease on either day −4 (group MON) or day −1 (group NMON). Cows carrying a female calf had higher concentrations of serum P4(P<.05) and lower concentrations of serum estrogens [E1, P>.10; Eβ and Eα, P<10] prepartum than cows carrying a male calf. Differences in concentrations of the serum estrogens associated with calf sex were most evident during the last 18 days before calving.

Previously selected plants for improved lines of kleingrass (Panicum coloratumL.) were evaluated for growth and seed production characteristics. At the initiation of this test, 13 experimental synthetic varieties were available for chemical comparisons of forage quality. This study was conducted to determine if differences existed in percent of neutral detergent fiber (NDF) and NDF components within the available synthetic varieties of kleingrass. The effects of five stages of plant maturity on NDF and its components were also evaluated for each variety. Since kleingrass has an indeterminate type of growth form, plants collected as initial and regrowth forage were harvested when a certain percent of the seed on the most mature kleingrass tillers reached the soft dough stage, but prior to the time of seed maturation. Previously nonharvested cumulative forage was collected at the same chronological age as the regrowth forage. At each of the maturity‐stage dates, plant samples were separated into leaf laminae and stems. Each plant part was analyzed for its neutral detergent solubles:neutral detergent fiber ratio (NDS:NDF). The NDF was then sequentially partitioned into hemicelluloses (HEM), cellulose (CEL), lignin (LIG), and ash. The hemicelluloses were further divided into easily hydrolyzable (EHH) and difficulty hydrolyzable hemicelluloses (DHH). Kleingrass varieties differed in NDS:NDF and NDF components. Leaf:stem ratios ranged from 1:1 to 1:4. By harvesting at a morphological stage prior to seed maturation, the NDS: NDF ratio of leaves and stems in regrowth forage did not vary throughout the study period. Leaf laminae contained approximately 34% HEM and 24% CEL; whereas, stems contained approximately 34% HEM and 34% CEL. With advancing maturity, HEM of leaf laminae increased at the expense of CEL. However, the HEM: CEL ratio of stems remained at approximately 1:1 throughout the collection period. The EHH:DHH ratio changed significantly with plant age as percent EHH increased and DHH decreased. The percent of LIG in both leaves (3.2%) and stems (6.6%) changed with plant age but the buildup of LIG was greatest in stems. Acid‐insoluble ash was influenced by the stage of growth only in leaf laminae and the leaves, with an average of 2.4%, contained four to eight times more ash than did stem sections.

Recent studies have shown that differences in neutral detergent fiber:neutral detergent solubles ratios (NDF:NDS) exist within experimental synthetic varieties of kleingrass (Panicum coloratumL.), and those varieties which had the highest NDF content were genetically closely related. This investigation was initiated to determine if selected varieties which differed in NDF:NDS also differed in in vitroand in vivodigestibility. The relationships between NDF, components of NDF, and various NDF component ratios vs. in vitroand in vivodigestibility were also studied using three synthetic varieties harvested at four stages of plant growth. Initial and subsequent regrowth forage was harvested as a certain percent of seed reached the soft dough stage, but before seed maturation had occurred. Cumulative growth forage was collected at the same chronological time as the final regrowth harvest date. At each harvest date, analyses were obtained for in vivodigestible dry matter (DDM), in vitrotrue digestible dry matter (IVDDM), neutral detergent fiber (NDF), digestibility of NDF (DNDF), and NDF components (hemicelluloses, cellulose, lignin, and ash). Percent DDM, IVDDM, and DNDF declined from 62, 74, and 60%, respectively, to 51, 65, and 47%, respectively, with plant maturity. NDF increased from 64% to 71% with plant age and accounted for approximately 92% (r = −0.96**) of the variability associated with DDM. The regression of DDM vs. DNDF resulted in a positive relationship (r = 0.99**). NDF vs. DNDF gave a highly significant negative relationship (r = −0.93**). Cellulose, lignin, and lignin:acid detergent fiber ratio were negatively related to DNDF; whereas, hemicellulose:NDF and hemicelluloses:cellulose ratios were positively related to DNDF. Regression with IVDDM and NDF components and component ratios were of the same magnitude as those relationships with DDM. The level of NDF showed a closer relationship to its digestibility than did any NDF component ratio with DNDF. NDF and DDM showed no difference between varieties, but the IVDMM analyses proved one of the varieties to be superior to the other two.

Preweaning growth data were obtained during 4 yr on 349 Braford-sired calves from Brahman-Hereford F1first-calf females. These females were allotted to either semiarid rangeland (Uvalde) or humid improved pasture (Overton) as weanlings and to one of four herbage allowance levels at each location as yearlings. Females were wintered on systems in local industry practice and maintained on various allotted herbage levels both as yearlings and during first lactation. The desired range in herbage allowance (400 to 2,800 kg of DM per 100 kg of BW at Uvalde and 80 to 460 kg of DM per 100 kg of BW at Overton) was accomplished by adjusting stocking rate monthly from April to weaning (October). Herbage allowance and yearling heifer characteristics (hook height, condition score, or weight) were treated as continuous, independent variables in regression analyses. Preweaning daily gain responded to increased herbage allowance differently for the two locations. Generally, at Overton, herbage allowance influenced suckling calf growth to a greater extent than for the F1yearling variables, but at Uvalde this trend was reversed. Heifers with larger yearling heights had first calves that grew faster to weaning for both locations and all herbage allowances, although the relationship was stronger for greater herbage allowances at Overton (herbage allowance × yearling weight interaction, P< .07). This interaction was not detected (P> .15) at Uvalde. Interactions between herbage allowance and yearling condition score were detected (P< .05) at both Overton and Uvalde, but these interactions were different (P< .15) at the two locations.(ABSTRACT TRUNCATED AT 250 WORDS)

A glasshouse study was conducted to determine and quantify direct transfer of nitrogen (N) between 3 selected warm-season annual legumes and a warm-season annual grass during the growing season, 'Tifleaf' pearl millet [Pennisetum americanum (L.) Leeke] was grown in pots as a monoculture with and without N applied as inorganic fertilizer, or with either 'Iron and Clay' cowpeas [Vigna unguiculata (L.) Walp], common alyceclover [Alysicarpus vaginalis (L.) DC.], or 'Comanche' partridge pea (Cassia fasciculata Michx.). Sixty-three percent of the N contained in pearl millet grown with alyceclover was derived directly from alyceclover as determined by the 15N dilution technique. Partridge peas and cowpeas transferred 34% and 32%, respectively, of the N contained in companion pearl millet plants. Pearl millet grown with partridge peas produced dry matter yields similar to pearl millet that received the equivalent of 112 kg N/ha. Pearl millet grown with legumes contained lower levels of neutral detergent fiber than did pearl millet that received inorganic fertilizer. Nitrogen content of pearl millet grown with legumes was not as great as pearl millet that received N-fertilizer.

Forty fall-born calves (steers and heifers) were divided into four preweaning treatments and slaughtered when weaned at an avereage age of 262 d. Preweaning treatments consisted of grazing a Bermuda grass-arrowleaf clover-ryegrass pasture at three stocking rates with both a creep fed and noncreep fed group on the lightly stocked pastures. Average stocking rates during the 133-d trial were 2.0, 2.0, 3.4 and 6.7 cow-calf units/ha for lightly stocked plus ad libitum creep feed (LSC); lightly stocked pasture only (LSP); medium stocked (MS) and heavy stocked pastures (HS), respectively. Weaning weights and corresponding average daily calf gains, respectively, were 358 and 1.30 (LSC); 333 and 1.16 (LSP); 295 and 1.05 (MS) and 271 kg and .77 (HS) kg•head−1•d−1. After slaughter, the left side of each carcass was electrically stimulated (ES) while the right side served as a nonstimulated (Non-ES) control. Calves from the LSC group had (P<.05) heavier carcasses, but did not differ (P>.05) from calves from the LSP group with respect to USDA yield grade, longissimus muscle area, fat thickness, percentage kidney, pelvic and heart fat or fat color. Calves from the LSC and LSP groups, however, had higher (P<.05) numerical values for the aforementioned traits than did calves from the HS group. Fat color did not differ (P>.05) among groups. Steaks from Non-ES USDA Good-Choice steer carcasses were more palatable than those from certain Non-ES calf sides; however, there were no palatability differences (P>.05) between steaks from Non-ES USDA Good-Choice steers and steaks from ES calf sides. Retail steaks from ES calf sides had brighter (P<.05) muscle color on all days of display and were more desirable (P<.05) on d 0 of display than steaks from Non-ES calf sides.

Twelve heifers and 12 steer calves born in the fall were slaughtered at weaning at an average age of 259 days. Before weaning, calves grazed a bermudagrass-ryegrass-arrowleaf clover sward at three levels of forage availability (FA). Average daily gains (ADG) of cows and calves on the low, medium and high FA paddocks were −.25 and .67, −.02 and .76, and .47 and .97 kg (P<.05), respectively. The low, medium and high FA paddocks supported stocking rates of 6.27, 4.52 and 2.72 cow-calf units/ha (P<.05) and calf weaning weights of 236, 251 and 289 kg (P<.05), respectively. Carcasses of calves that had grazed high FA paddocks were fatter (P<.05) than carcasses of calves that had grazed low FA paddocks (5.08 vs1.27 mm over the longissimusmuscle) and their longissimusmuscle areas were more than 18% larger (P<.05). Marbling scores and quality grades of carcasses from calves on high FA paddocks were 33 and 27% higher (P<.05), respectively, than those of calves on low FA paddocks. There were few significant differences in palatability-related traits of loin steaks from carcasses of calves on the three levels of FA. Also, except for juiciness, steaks from 22 grain-fed steers generally received higher (P<.05) taste panel scores and had lower shear force values than did steaks from carcass of any of the three FA groups of calves. Steer carcasses showed higher (P<.05) ADG and weaning weight and larger longissimusmuscle areas than did heifer carcasses, whereas heifer carcasses had greater (P<.05) fat thickness over the longissimusmuscle, more (P<.05) kidney, pelvic and heart (KPH) fat and a higher (P<.05) yield grade number (lower cutability). There were no differences (P>.05) in other carcass characteristics or in any of the palatability-related traits of loin steaks from steers and heifers.

During the past few years stands of ‘Coastal’ Bermudagrass (Cynodon dactylonL. Pers) have been reduced even though recommended rates of fertilizer have been applied. Many of the soils tested have been low in potassium. The objectives of this study were to determine (i) if the recommended fertilization rates of K were sufficient for optimum yield, (ii) the effect of single and split applications of K on forage yield, and (iii) the advantages of sulfur‐coated KCl or K2SO4on forage yield production of Coastal Bermudagrass. Coastal bermudagrass was fertilized with nine potassium treatments on Cuthbert fine sandy loam (Typic Hapludult; clayey, mixed, thermic) and Darco fine sand (Grossarenic Paleudult; loamy, siliceous, thermic) soils for 3 years at Overton, Tex. Potassium treatments included rates of 0, 139, and 278 kg K/ha as KCl in single and split (four) applications. In addition, sulfur‐coated muriate of potash (S‐KCl) and sulfur‐coated potassium sulfate (S‐K2SO4) were applied at both 139 and 278 kg K/ha. On the Cuthbert soil a slight forage yield increase due to the K treatments was measured in the 1st year. Highly significant forage yield responses were noted on this soil in both the 2nd and 3rd years. On the Darco soil, small but insignificant increases in forage yield were measured in the 1st and 2nd years. Forage yield was not significantly higher at 278 than at the 0 kg K rate until the 3rd year. Forage yield responses tended to occur late in the growing season usually at harvest three or four, indicating a depletion of available K reserves. Improved yields were not observed for split applications of K. Sulfur‐coated KCl tended to produce highest forage yields annually and at several of the harvest dates. The S‐coated treatments generally resulted in lowest soil pH values. Available K was reduced significantly in the surface 15 cm after 3 years on both the 0 and 139 kg K/ha rates. The 278 kg K/ha treatment resulted in exchangeable‐K levels of 146 and 104 kg K/ha at the 0‐ to 15‐cm depth for the Cuthbert and Darco soils, respectively, at the termination of the study. These K levels were below the original soil K levels for both soils. Results indicate that in the long term, soil K would be depleted by high yields of Coastal bermudagrass with the K rates used in this study.

Growth data were collected over 4 yr from 349 Brahman-Hereford F1, first-calf, lactating females that had been allotted as weanlings to either semiarid extensive rangeland (Uvalde) or humid improved Bermudagrass pasture (Overton) and to one of four herbage allowance levels at each location as yearlings. Heifers were wintered according to systems in local practice and maintained on allotted forage levels both as yearlings and during their first lactation. Heifers were bred to Braford bulls to calve as 2-yr-olds in January to March. Herbage allowance (400 to 2,800 kg of DM/100 kg BW at Uvalde and 80 to 460 kg of DM/100 kg BW at Overton) was maintained by adjusting stocking density monthly from April to weaning (October). Herbage allowance and yearling heifer hook height, condition score, or weight (taken on April 15) were continuous independent variables in regression analyses. Final heifer weight, height, and condition responses to increased herbage allowances were related to yearling pheno-types differently (P< .01) for the two locations. At Uvalde, yearling condition score interactions were especially important in that heifers that had more condition (especially those > 5 for 1 to 10 with 10 = fattest) as yearlings retained more (P< .05) weight and condition and grew more (P< .05) in height than did those of lower yearling condition. These females also responded to increased herbage allowance by gaining advantage (P< .05) in these variables, whereas those of lower yearling condition made smaller advances. At Overton, yearling condition played little role in subsequent growth. The yearling variable that had the greatest interactive effect was height. Shorter yearling heifers (< 123 cm) responded (P< .07) to increased herbage allowance so that they had greater final condition and grew more rapidly in height than those taller as yearlings.

The effects of four levels of continuous stocking rate on herbage allowance level (HAL, units of herbage DM/unit of grazer BW and growth, morphology and dietary attributes of Coastal bermudagrass (Cynodon dactylonL. pers) were evaluated. Single pastures were stocked to achieve mean herbage allowances of 8.9, 34.5, 80.7 and 148.3 kg DM/100 kg BW of cattle from June 1 through September 17. Daily net herbage growth rate decreased linearly (P< .01) with advancing date and was not affected by HAL. Quadratic interactions existed (P< .05) between HAL and date for the proportion of leaf in herbage and diet. The proportion of dietary leaf declined quadratically (P< .01) at each HAL with advancing date. Linear and quadratic interactions between HAL and date existed (P< .01) for the NDF content of herbage and dietary leaf. Dietary leaf NDF increased linearly (P< .01) with increased HAL at all dates. Within date and HAL, the NDF content of herbage leaf was similar to that of stem. Grazing selectivity for diet leaf of lower NDF content (diet leaf NDF/herbage leaf NDF) increased as HAL was reduced. Decreasing HAL via increasing grazing pressure reduced the mean age of the herbage mass by responses in the morphology and growth of the herbage and reduced the fraction of herbage mass prehensible by the animal.

Three groups of 1/2 Simmental × 1/4 Brahman × 1/4 Hereford bull calves were used during two different years to study effects of zeranol on sexual development. At 154 d of age, half the calves were implanted with 36 mg zeranol and half, not implanted, served as controls. Implanted calves were reimplanted at 90-d intervals throughout the trial (9 mo) each year. Trial 1 was conducted with 24 calves and Trial 2 was conducted the following year with 10 bulls. Twenty-four days after weaning (200 d of age) and at 28-d intervals thereafter, bulls in drylot in Trial 1 were weighed, scrotal circumference (SC) was measured and an ejaculate of semen was collected by electroejaculation to determine puberty. At these times, bulls were given 200 µg of GnRH i.m. and blood was collected at 0, 1, 2, 3, 4 and 5 h after GnRH. Serum concentrations of LH and testosterone (TEST) were determined. At slaughter, testis weight, length and circumference and pubertal status were recorded. Bulls implanted with zeranol had smaller SC than control bulls during the entire 9-mo period (P< .0001). More control bulls reached puberty than did implanted bulls (82.4 vs 23.5%, respectively; P< .001). Control bulls had larger testis measurements at slaughter (P< .0001). Implants did not alter total weight gain or ADG (P> .10). Overall, the LH response to GnRH was greater in implanted bulls than in control bulls (P< .02), but testosterone response to GnRH-stimulated LH release was greater in control than in implanted bulls (P< .02). At the end of the 9-mo period, however, there were no differences in LH or TEST responses to GnRH between control and implanted bulls (P> .10). Zeranol administered at 150 d of age inhibited testicular growth and function in bulls, but the effects were overcome with increasing age.

Ability to compete for mineral N effects stand stability of arrowleaf clover (Trifolium vesiculosumSavi) and annual ryegrass (Lolium multiflorumLam.). Two field experiments were conducted on a Darco soil (loamy, siliceous, thermic Grossarenic Paleudult) to investigate the competitive ability of ‘Yuchi’ arrowleaf clover and ‘Gulf’ ryegrass for uptake of 15N‐depleted ammonium nitrate when seeded into dormant bermudagrass (Cynodon dactylonL. pers.). When N was applied in February, ryegrass in pure stand recovered more than two times as much fertilizer N as did clover in pure stand and more than 80% of the fertilizer N when in a mixture with clover. The April application of N resulted in the clover in pure or mixed stand recovering as much or more fertilizer N as did the corresponding ryegrass in pure or mixed stand. Growing clover in mixed stand with ryegrass increased the percentage of the N in the clover derived from N fixation by an average of 23%. Application of fertilizer N reduced the percentage of total N in the clover derived from N fixation by an average of 19%. Total N in the clover from N fixation was either unchanged or reduced when clover was grown with ryegrass and when fertilizer N was applied. Efficiency of fertilizer‐N usage by either plant species ranged from a low of 5 to 70%, depending on timing of application and plant species.

Pearl millet [Pennisetum americanum(L.) Leeke] forage, which had been previously reported to become unpalatable under drought stress conditions, also contained high levels of nitrate and total alkaloids. This study was conducted to determine the effect of irrigation, drought stress, and drought stress elimination, as well as fertilization with 0 and 56 kg S ha−1, and 112, 224, and 336 kg N ha−1, on alkaloid and nitrate levels in pearl millet. ‘Millex 24’ hybrid millet was grown in the field during a hot, dry summer on a Darco soil (loamy, siliceous, thermic Grossarenic Paleudult) in East Texas. Chemical analyses for nitrate and total alkaloid levels were conducted on leaf blades and stems plus sheaths of vegetative plants. Alkaloid levels increased in pearl millet after extended drought and with increasing N fertilization rate. Total alkaloid concentration was higher in leaf blades (46 mg kg−1) than in stems plus sheaths (16 mg kg−1). Nitrate levels increased with improving plant water status and with increasing N fertilization. At the lowest N fertilization rate, nitrate concentrations were similar in irrigated and nonirrigated millet. At the highest N fertilization rate, nitrate was nearly two times higher in irrigated than in nonirrigated millet due to accumulation in stem portions. Nitrate concentration was higher in stems plus sheaths (14 g kg−1) than in leaf blades (5.1 g kg−1), but nitrate levels were highly correlated (r=0.90**; n=48) among plant parts. Sulfur application had no effect on either alkaloid or nitrate levels. A significant interaction between S and N rate occurred in stem plus sheath nitrate concentration (P<0.01). Whole plant alkaloid and nitrate levels were significantly correlated under N fertilization and irrigation but were not correlated under moderate drought stress or under drought stress elimination.

A field study was initiated to quantify growth attributes of loblolly pine (Pinus taeda L.) when intercropped with warm-season annual legumes. In addition to main treatments, subplots of phosphorus (P) and a cool-season annual legume were also evaluated as factors contributing to growth of pine trees. After 3 years, pine seedlings grown with 'Iron and Clay' cowpea [Vigna unguiculata (L.) Walp.] had grown to a height of 315 cm and had a diameter of 63 mm which was a substantial increase when compared to plants receiving other treatments. Phosphorus application had no effect (P>.10) on pine growth parameters. The addition of 'Tibbee' crimson clover (Trifolium incarnatum L.) affected height (P<.10) of pine trees grown with 'Comanche' partridge pea (Cassia fasciculata Michx), and pine trees grown alone (control). Regression analyses indicated no correlation between rate of growth in height of pine trees and warm-season legumes over a three-year period. Growth rate in diameter during this period, however, was greatest for pine trees growing with cowpeas. Pine seedlings grown as a control or with alyceclover had similar diameter growth rate, but then grew slower than pines with cowpeas, and faster than pines grown with partridge peas.

A study was conducted to determine the effects of legume companion crops and phosphorus (P) fertilizer on the growth and survival characteristics of newly established loblolly pine (Pinus taeda L.) seedlings. At 12 months post-establishment, there was no legume effect (P>0.05) on root lateral development or ropting depth for pine seedlings. Likewise, there was no legume effect (P>0.05) on aboveground biomass production of pine seedlings. Partridge pea (Cassia fasciculata Michx.) had a negative effect (P<0.05) on pine seedling total root biomass compared to other treatments. Pine seedlings grown with legumes allocated less resources to root development compared to pine seedlings grown alone. Pine seedlings grown alone or with cowpea [Vigna unguiculata (L.) Walp.] were subject to less mortality (P<.05) than seedlings grown with alyceclover [Alysicarpus vaginalis (L.) DC] or partridge pea. Phosphorus fertilization enhanced dry matter (DM) yield of legumes but had no effect on rooting depth of pine seedlings during the first 12 months of growth. After 12 months post-establishment, the most pronounced effect of P fertilization was that of increased nitrogen (N) content of leaf, stem, and roots of pine seedlings. Native, annual herbaceous grass biomass in the control plots (no legume) reduced the amount of soil N to below pre-planting levels, while soil N levels in all legume plots exceeded pre-trial levels.

Studies were conducted to determine the influence of N, P, and K fertilization and different stages of growth on the nutritional quality of kleingrass (Panicum coloratumL.) forage. Nitrogen rates ranged from 28 to 560 kg/ha with additions of 24 and 73 kg/ha P, and 0, 46, and 139 kg/ha K. Leaf‐stem separations were made at each harvest date and cellular (neutral detergent extract; NDE) and cell wall constituents (neutral detergent fiber; NDF) were determined on the plant parts. The NDF fraction was then sequentially partitioned into hemicellulose, cellulose, lignin, and ash. Levels of N or P were significantly negatively correlated with percent NDF of leaf laminae. Chemical components of stem fiber were not altered by fertility levels. On a whole‐plant basis percent NDF was reduced about 5 percentage units by additions of N. Percent NDF in leaves and stems increased with chronological and morphological age. The holocellulose content of leaves remained relatively constant throughout the study period; with advancing maaturity, however, the hemicellulose fraction accounted for a greater portion of the NDF than did cellulose. The hemicellulose:cellulose ratio increased to approximately 1.7:1 in leaves, but remained at 1:1 in stems with increasing maturity. The leaves apparently had more influence on decreasing NDF of the whole plant under fertilization, whereas, stems were the dominant factors involved in increasing NDF of the whole plant with advancing maturity.

A field experiment was conducted to determine recovery efficiencies for applied N, P, and K under a system of total removal of forage (Cynodon dactylonL. Pers. ‘Coastal’) over a 3‐year period. Ammonium nitrate, (NH2)2CO, and (NH4)2SO4were each applied in split applications of 0, 280, 560, and 840 kg N/ha each season. Soil levels of total N, chemically extractable P, and K were monitored each season. Results show that N recovery percentages ranged in the following order: (NH4)2SO4>NH4NO3> (NH2)2CO. Characteristic decreases in recoveries occurred with increasing N rates. Source effects on recovery efficiencies for P were as follows: NH4NO3⩾ (NH4)2SO4> (NH2)2CO. Average P recovery percentages for NH4NO3were 34, 46, and 52% for rates of 280, 560, and 840 kg N/ha, respectively. Plant recovery of applied K was greatest for (NH4)2SO4and lowest for (NH2)2CO. Average values for (NH4)2SO4were 108, 165, and 222% for the low, medium, and high rates of N, respectively. Ammonium sulfate gave greater accumulation of soil N with time than NH4NO3or (NH2)2CO while chemically extractable soil P and K were highest for NH4NO3.

The effect of two stocking rates on the recycling of N, P, and K was studied for 2 years on a Coastal bermudagrass [Cynodon dactylon(L.) Pers.] sward. Samples for chemical analysis were taken at 14‐day intervals. Available forage, forage yield, and forage consumption were estimated from samples taken at 2‐ to 4‐week intervals. Soil samples were taken prior to, during, and at termination of the grazing trial. Plant nutrient recycling on the high stocked pastures was approximately twice as great during the dry, 1969 season and about 10% higher during the 1970 season compared to that on the low stocked pastures. Recoveries of applied plant nutrients averaged over stocking rates were 84, 50, and 155% for N, P, and K, respectively, during 1969, and 180, 73, and 172% for N, P, and K, respectively, during 1970. There was a substantial soil accumulation of plant nutrients under both stocking rates with a considerable advantage in favor of the high stocked pastures. On the high stocked pastures, total soil N accumulation was slightly less than twofold, available soil P increased threefold, and available soil K increased more than twofold over the 2‐year period.

Losses of yield and stand of ‘Coastal’ bermudagrass (Cynodon dactylonL. Pers.) due to inadequate K fertility have been observed numerous times. Stand deterioration has been attributed to “winter‐kill”, disease, and lack of “physiological hardening” of the plants. Since all the aerial parts of the bermudagrass plant die when temperatures are as low as ‐2 to ‐3 C, underground stems (rhizomes) are important for maintaining and generating growth in the spring. Studies were conducted to investigate the effects of K fertility practices on rhizome production and rhizome regrowth reserve as related to certain stand and tissue characteristics. Old P and K factorial rate studies on Darco (Grossarenic Paleudult; loamy, siliceous, thermic) and Cuthbert (Typic Hapludult; clayey, mixed, thermic) soils were used. Annual fertility rates used on prior experiments were 0, 112. and 224 kg/ha K, 0 to 136 kg/ha P, and 364 to 504 kg/ha N. The influence of residual P and K fertility on stand ratings, rhizome production, and Ca, Mg, and K content of the forage was measured. Stand ratings in the spring were found to be related to rhizome production. The first increment of 112 kg/ha of K increased rhizomes 800 kg/ha on the Darco soil. Rhizome production required higher rates of K on the Cuthbert soil which gave a response of 1,500 kg/ha of rhizomes to the highest K rate used. Lowering the K rate resulted in lower K in the tissue and an observable loss of vigor in the root system. Depending on the soil K reserve, production levels ,and previous fertility practices, Coastal bermudagrass hay meadows on which K fertility levels are inadequate may exhibit the characteristics described above.

Pearl millet [Pennisetum americanum(L.) Leeke] forage has been reported to become unpalatable under drought stress conditions in east Texas. This unpalatable millet has been found to contain high levels of nitrate and total alkaloid relative to palatable, apparently unstressed, pearl millet. This study was conducted to determine if alkaloid and nitrate levels vary among pearl millet lines. Eleven lines were evaluated in the field on a Darco soil (loamy, siliceous, thermic Grossarenic Paleudult). Chemical analyses were conducted on leaf blades, and stems plus sheaths of vegetative plants. Millet lines differed for total forage alkaloid concentration as well as for total forage nitrate concentration (P < 0.05). Though alkaloid levels of the lines were relatively low, they ranged six‐fold (from 17 to 101 mg kg−1) among millet lines. Nitrate levels ranged from 2.4 to 9.8 g kg−1among the lines. Total forage alkaloid and nitrate levels were positively correlated (r = 0.45, P < 0.05). Leaf blades contained more total alkaloid than stems plus sheaths, 75 vs. 17 mg kg−1, respectively; while stems plus sheaths contained more nitrate than leaf blades, 10.8 vs. 3.9 g kg−1, respectively. It may be possible to develop lines that have both low alkaloid and low nitrate accumulations.

Supplementation of cattle on pasture is a well-known viable strategy for increased performance per animal and per ha. Ethanol has been proclaimed as a sustainable alternative to fossil fuels, and the vast supply of dried distillers' grains with solubles (DDGS) generated from ethanol production provides opportunities for addition to feedlot rations and supplementation of grazing cattle. A large percent of the cattle in the United States are located in the Southeast, where bermudagrass is the primary introduced forage species. Since relatively few research studies have been conducted using DDGS as a supplementation on actively-growing warm-season pastures, this research represents a significant and critical knowledge database for the pasture-beef industry. The first objective of this research was to evaluate performance of stocker calves grazing ‘Tifton 85’ (TIF) bermudagrass with varying rates of DDGS supplementation. Steers (n= 112, 364 ± 3.5 kg BW) were stratified by BW and allocated randomly to each of 16 pastures (0.7 ± 0.01 ha) across 2 years (2014, 2015). The TIF pastures were allocated randomly to each of 4 rates of DDGS: 0, 0.25, 0.5, or 1% BW hd-1d-1. Average daily gain was greatest (P< 0.05) from steers offered 1% BW (1.3 kg/d), and least from non-DDGS steers (0.8 kg/d), with 0.25 and 0.5% BW intermediate (1.1 and 1.2 kg/d, respectively). There were supplemental feed to additional gain ratios of 3.7, 6.0 and 9.0, respectively, for 0.25, 0.5 and 1% BW. The second objective was to evaluate performance of Bos indicusversus B. taurusstocker calves grazing ‘Coastal’ (COS) bermudagrass with varying rates of DDGS. Steers within a breed type (n= 117, 343 ± 4.5 kg BW) were stratified by BW and allocated randomly to each of 9 pastures (1.3 ± 0.17 ha) across 2 years (2014, 2015). Pastures were allocated randomly to each of 3 rates of DDGS: 0, 0.25, or 1% BW hd-1d-1. Across breed types, ADG was greater (P< 0.05) from steers offered 1% BW (1.0 kg/d) than either from non-DDGS steers or 0.25% BW (0.7 kg/d each). There was no difference (P= 0.70) in ADG between breed types. The third objective of the study was to evaluate any carryover effects in long yearling stockers previously stocked on TIF or COS with varying rates of DDGS. Following the pasture × DDGS phase in the first 2 objectives, steers were shipped 693 km to a commercial feedlot for an approximate 140-d finishing phase. At finishing, animals were transported 59 km and harvested at a commercial abattoir. There was no effect (P≥ 0.36) of DDGS for either TIF or COS during the feedlot phase. Likewise, there was no effect of DDGS on percent Low Choice for TIF (P= 0.74) or COS (P= 0.86). The fourth objective was to evaluate in vitro digestion kinetics and methane production potential of TIF or COS with varying rates of DDGS. Hand-plucked plant parts of TIF and COS were mixed independently with DDGS to represent the intake of cattle at various rates of DDGS (0, 0.25, 0.5 or 1% for TIF; 0, 0.25 or 1% for COS) in each of the first 2 objectives. Newly-generated laboratory samples were incubated in an in vitro anaerobic fermentation chamber. In vitro true degradation (IVTD) and in vitro NDF degradation (IVNDFD) were greater (P< 0.05) from TIF (69% IVTD, 57% IVNDFD) than from COS (62% IVTD, 44% IVNDFD). Treatment of DDGS did not differ (P> 0.05) within TIF for IVTD, but 1% DDGS was greater (P< 0.05) than 0%, with 0.25% DDGS intermediate to the 2 for COS. Concentration of CH4 was also greater (P< 0.05) TIF (14 mM) than COS (12 mM), and CH4:H2 ratio was less (P< 0.05) from TIF (3:1) than from COS (2:1). The fifth and final objective was to evaluate the ruminal in situ digestion kinetics of TIF as affected by forage seasonality and DDGS. Samples of TIF were harvested in June, August and October 2014. Ruminally-fistulated steers (n= 6) were stratified by BW to 3 pens, and pens were allocated randomly to 1 of 3 rates of DDGS: 0, 0.25, or 1% BW hd-1 d-1. Samples were incubated for 2, 4, 8, 12, 24, 72, and 96 h. A trend of decreasing degradation of DM, NDF, and ADF was observed with both increasing seasonality (P≤ 0.01) and increasing DDGS (P≤ 0.04). The undegraded fraction (UDG) of DM from TIF was least (P< 0.05) from June (19%), followed by August (34%), and greatest from October (41%). The UDG from TIF DM was not different (P= 0.47) based on DDGS , and averaged 31%. Low rates of DDGS may be feasible using TIF but not COS at our vegetational region. Rate of DDGS on pasture did not affect feedlot performance nor carcass characteristics. Increased rates of DDGS may increase forage digestibility and decrease CH4 production, but this was cultivar-dependent. Reduction of DM degradation was dependent upon seasonality more so than DDGS rate. Overall, DDGS represented a viable option for stocker production systems, and economic assessments for each specific operation-location will be required prior to implementation of a supplementation program.

Cool-season annuals may fill gaps in seasonal forage availability and reduce stored feed needs for beef cattle producers in the Southeast. These forages can be established during the autumn via sod-seeding or broadcasting on warm-season perennial grass pastures such as bermudagrass and bahiagrass or planted into a prepared seedbed. Opportunity exists to use small grains that vary in their individual growth distribution to extend the grazing season. Small grains adapted to the region include cereal rye (Secale cereale), wheat (Triticum aestivum), oats (Avena sativa), and triticale (×Triticosecale). These species provide bimodal forage dry matter (DM) production during the autumn and early winter months, and can be grown in monocultures or mixtures. Cereal rye generally provides forage DM earliest in the season, followed by triticale, wheat, and oats. Fall production potential of these species is primarily dependent on planting method, seeding date, fertility, and variety selection. These species provide high quality forage DM that may support animal performance in stocker and cow-calf operations with minimal supplementation, and can be grown in combination with annual ryegrass and/or legumes to further lengthen the window of grazing. Annual ryegrass and legumes in the Southeast includes cold-tolerant and rust-resistant diploid and tetraploid varieties of ryegrass, and adapted true clover (Trifolium sp.)varieties. Autumn-planted ryegrass and/or clovers including primarily crimson, arrowleaf, ball, and white clover, provide minimum to nonexistent forage mass for grazing during the fall. Naturally reseeding ryegrass or clovers will often provide earlier forage mass; however, DM is usually not adequate for stocking until late-January through May. With appropriate levels of N fertilization, ryegrass produces more forage DM, and thus allows for earlier stocking and greater stocking rates compared to clovers. Tetraploid varieties of ryegrass, when seeded into prepared seedbed, can provide adequate forage mass for fall grazing. Earliness of forage mass for stocking of clover ranges from crimson (earliest), to arrowleaf and ball (mid), to white clover (latest). White clover, however, in adapted soils and with adequate spring-summer rainfall and proper stocking rate, can provide grazing during early to mid-summer months. From the first frost event in late fall through the early spring months, cool-season annual forages provide actively growing forage to extend fall and spring grazing for cow-calf and/or stockers during winter dormancy of perennial grass pastures.

The purpose of this study was to compare the effect of residual feed intake (RFI), residual average daily gain (RADG), feed to gain (F:G) on productivity in Brahman heifers (n=242). Following a 56-d post-weaning period for six calf crops, Brahman heifers were individually fed for periods of 60-d at 2.8% of their body weight in a Calan gate system. Rations were adjusted at weekly intervals. For each contemporary group, the mean and standard deviation of RFI, RADG, and F:G was calculated. Based on the mean plus or minus ½ standard deviation for each group, heifers with the lowest RFI and F:G were classified as efficient (E), while higher RFI and F:G heifers were classified as moderately efficient (ME) or inefficient (I). For RADG, heifers with the highest RADG were classified E, while lower RADG heifers were classified as ME or I. Cow records for age at first calving (AFC), interval from the first to second calf (CI) and calf records for birth weight (BW) and 180-d adjusted weaning weight (AWW) were recorded. Data were analyzed using mixed linear models. The additive genetic effects were modeled as random in all analyses. In analyses of calf traits, maternal additive genetic effects were also random effects. For all traits, cow year of birth was investigated as a fixed effect. For calf traits, calving interval, the calf birth year was a fixed effect. Calf breed, season of birth, and sex were fixed effects in analyses of calf traits. The effects of interest were 3-level classification variables created using the upper and lower quartiles and the two middle quartiles combined of RFI, RADG, and FG. These were modeled in distinct analyses. In analyses of RADG, the high (inefficient) and low (efficient) RFI groups of heifers differed (0.03 ± 0.018 and –0.04 ± 0.02, respectively; P=0.03). In analyses of F:G all RADG groups differed (P<0.01) as expected; that is E (8.0 ± 0.25) < ME (9.5 ± 0.24) < I (12.6 ± 0.25; P< 0.01). Heifer AFC and CI were not significantly influenced by efficiency classifications for RFI, RADG, or F:G (P>0.10). As expected, male calves had greater BW (P<0.05). Classification for efficiency group did not influence either BW or AWW. RFI, RADG, or F:G did not affect reproductive or calf performance in young Brahman cows. Selection for RFI will result in selecting against RADG or F:G.

The forage-animal interface is a vital component of agricultural systems that is often overlooked by both agronomy and animal science programs. As such, current grazing models do not always provide a satisfactory understanding of how forage species and/or cultivars respond to livestock interaction in both production and physiology, how forage can influence the animal, and how the nexus of these two entities may affect the environment. The objective of this effort was to develop a conceptual framework of a dynamic model that combined the forage and ruminant livestock interactions, and to provide the initial parameterization of a model for bermudagrass pastures. The systems dynamic methodology was used. The causal loop diagram (CLD) was first envisioned based on the hypothesis that not only can forage factors affect performance and behavior of the grazing animal, but the grazing animal, through its herbivorous behavior and selective intake, can affect and alter the physiology, growth, and performance of the forage and the pasture. Generation of a preliminary stock-and-flow diagram (SFD) with variable flight simulators was also performed. The main CLD was a composite of four sub-models that represented the agronomic, animal, atmospheric, and soil subsystems. The limitations of this model existed in the lack of meta-analytical publications in which necessary equations have been summarized that could be used in model programming. The parameterization of the model suggested that forage allowance was the driving factor in animal ADG, and forage growth rate was governed by a combination of evapotranspiration, defoliation, soil N, and precipitation. Our simulation of the bermudagrass scenario suggested that under these production conditions, most portions of the model operated in a traditional goal-seeking fashion. The initial results provided the documentation of the interface concept for the benefit of forage agronomy and animal nutrition programs as well as the foundation for advancements of the model to eventually serve as potential decision aid in production-economic strategies.

The supply of dried distillers' grains (DDG) generated from the ethanol industry provides great opportunities for feed additives and supplementation of stocker cattle. The objective of this study was to evaluate performance of stocker calves grazing ‘Tifton 85’ bermudagrass [Cynodon dactylon(L.) Pers.] when supplemented daily with varying levels of DDG. Steers (n= 96 [4 testers pasture−1yr−1], 363 ± 3.7 kg initial BW, and approximately 15 mo of age) were stratified by BW and randomly allocated to each of 16 pastures (0.7 ± 0.01 ha) across 2 yr (2014 and 2015). Pastures were randomly allocated to each of 4 levels of DDG supplementation for about 110 d at 0, 0.25, 0.5, or 1% BW hd−1d−1. Steers were group fed daily at 0800 h and weighed every 21 d. Grazer animals were added to pastures based on visual and forage mass assessments to maintain a similar forage allowance among pastures. Data were analyzed using SAS PROC MIXED or PROC GLIMMIX. Least squares means were calculated for treatments and separated using F-protected ttests with the Tukey–Kramer adjustment. Average daily gain was greatest (P< 0.05) from steers offered 1% BW DDG (1.25 kg/d) and least from non-DDG steers (0.77 kg/d), with 0.25 and 0.5% BW being intermediate (1.05 and 1.12 kg/d, respectively). Additional gain from DDG supplementation was greater (P< 0.05) from 1% BW DDG (0.68 kg/d) than from 0.25 and 0.5% BW steers (0.47 and 0.54 kg/d, respectively). There was a trend (P= 0.13) toward increased supplemental feed to additional gain ratios of 4.2, 5.4, and 7.2 for 0.25, 0.5, and 1% BW DDG, respectively, indicating that higher levels of DDG supplementation resulted in substitution of forage in the diet. There was no measurable difference (P= 0.33) in stocking rate (318 kg = 1 steer) among treatments (overall mean = 12.4 hd/ha), whereas gain per area was greatest (P< 0.05) at 1,883 kg/ha from pastures offered DDG at 1% BW followed by intermediate values of 1,268 kg/ha at 0.25% and 1,399 kg/ha at 0.5% BW. Pastures receiving no supplementation had steers gaining 906 kg/ha. Supplementation of stocker calves with DDG while grazing Tifton 85 bermudagrass is a viable management strategy to optimize gain per animal or per area.

Dried distillers' grains (DDG), a byproduct of ethanol production, can affect the digestive and fermentative function of the rumen when supplemented to cattle. The objective of this study was to evaluate the ruminal digestion kinetics of ‘Tifton 85’ bermudagrass (T85; Cynodon dactylon[L.] Pers.) as affected by chronological forage maturity and level of DDG supplementation. Samples of T85 were harvested (16 pastures at the Texas A&M AgriLife Center, Overton, TX) in June (J), August (A) and October (O) 2014. Ruminally-fistulated steers (n = 6) were stratified by BW to 3 pens, and pens were allocated randomly to 1 of 3 levels of DDG supplementation: 0.00 (C), 0.25 (L) or 1.00% (H) BW hd-1d-1. The experiment was repeated across three periods in a Latin square design. Animals were pen-fed daily and offered ad libitumaccess to T85 hay for a 7 d adaptation period. Following adaptation, duplicate samples of each chronological maturity as well as a single DDG sample were inserted into the rumen of each animal and removed at 2, 4, 8, 12, 24, 72 and 96 h. Original and incubated samples were analyzed for DM, NDF and ADF. The potential degradation (PD) of DM was greatest (P< 0.05) from C and lowest from L, with H intermediate, and was greatest (P< 0.05) from J, followed by A and lowest from O. Rate of DM degradation was greatest (P< 0.05) from C and lowest from H, with L intermediate. There was a supplement × chronological maturity interaction for PD of NDF and ADF, but overall supplementation with DDG and maturity of T85 decreased (P< 0.02) PD. Supplementation of DDG may decrease PD of DM due to reduction of fiber degradation, especially at 1% BW supplementation. Reduction of DM PD is dependent upon chronological forage maturity, which may be a greater factor in fiber digestion than DDG supplementation level.

From the eastern half of Texas and throughout most of the Gulf States below Interstate 20, warm-season perennial grasses (WSPG) such as bermudagrasses (Cynodon dactylon) and bahiagrass (Paspalum notatum) are the basic pasture unit for all grazing livestock. Sustainability of pastures are affected by management choices for variety of WSPG; level of fertilization-lime and especially nitrogen; winter-annual small grain, ryegrass, and/or clover; stocking rate; stocking method; and degree of forage utilization. Management strategies for cow-calf production includes selective choices for breedtype of cow and bull; terminal sire or replacement females; calving season(s); weaning weight objectives; and retained ownership options. Management strategies for forage-animal production efficiencies includes gain per animal; gain per unit land area; ecosystem sustainability; and economic objectives with awareness of risk-aversion for pasture systems. Forage mass of N-fertilized Coastal bermudagrass pastures, for example, can accommodate 9 cow-calf pair/ha (680 kg BW = 1 pair) during the active growing season. However, these stocking rates will result in lactating cow ADG of 0–0.90 kg/da and suckling calf ADG of about 0.60 kg/da. Reduced stocking rate of about 5 pair/ha can produce similar calf gain/ha of about 750 kg/ha as high stocking rates but without the extreme weight loss for cows. Long-term continuous high stocking rates on bermudagrass pastures can result in loss of stand and increased ecotype diversity. The degree of stocking intensity should include flexible forage utilization regimens to prevent destruction of the pasture unit. Management strategies for intensive cow-calf production must combine awareness-sensitivity to seasonality of forage production, stand-maintenance of pastures, and use of hay and/or supplementation to buffer forage deficiencies or level of total animal gain per unit land area. Overseeding bermudagrass with cool-season annual forages allows for decisions for calving season and retained ownership of weaned calves to optimize sale weights.

As funding for Land-Grant Universities has increasingly turned from Federal sources to state budgets, support for cow-calf and stocker production research and extension programs has been in constant decline. Beef production is primarily dependent on forages and grazing and the southeast region is rich in forage resources. As of 2015 the Southeast supports nearly 50% of the beef cows in the US. This reflects the importance of this segment of the beef cattle industry; however, there have been different factors negatively impacting the development of research and outreach activities. There was an average of 2.8 FTE involved in forage-related fieldsin each of the 14 southern Land-Grant universities in 2008, which is down from an average of 7.2 FTE in 1984. Increasingly, the lack of budgetary and industry support of grazing researchhas reduced the publication rate and quality of science in this field. The objective of this paper is to identify these factors and increase the knowledge of the limitations that extension and research personnel confront. A survey was prepared and submitted to all Faculty from land-grant universities and USDA-ARS personnel in the southeast region of the United States (Florida, Georgia, North Carolina, South Carolina, Kentucky, Tennessee, Virginia, Texas, Oklahoma, Arkansas, Louisiana, Mississippi, and Alabama) that have research and/or extension appointment linked to cow-calf and/or stocker production. Questions in the survey relate to availability of resources (land, animals, and personnel), objectives for the programs, degree of adoption of different practices or technologies, support (state, federal, commodity, etc.), limitations for program development, future objectives, among others. This document may serve as a framework of discussion for improvement of the present situation which would allow finding solutions to limitations in research and/or extension programs in the southeast region.

During the prolonged drought conditions of 1978, cattle throughout the East Texas area abruptly refused to graze many fields of commercial pearl millet hybrids [Pennisetum americanum(L) K. Schum.]. This study was undertaken to characterize the occurrence of the lack of palatability, investigate some plant factors associated with reduced palatability, and verify that drought was involved in the development of the palatability problem. Forage was sampled from a pasture on an upland site where plants exhibited visual drought stress, and from a bottomland site where plants did not show drought stress symptoms. Analyses were conducted for total alkaloids and nitrate. Two management treatments, shredding and irrigation, were used in an effort to increase palatability of the drought stressed pearl millet. Total alkaloid concentration of non‐drought stressed forage, which was readily consumed, ranged from 10 to 20 mg/kg throughout the August sampling period. Drought stressed forage, which was not consumed, had total alkaloid contents of 180 to 460 mg/kg. The total alkaloid concentration in the drought stressed plants was reduced to 20 mg/kg 4 days after a 1.8 cm rain. Re‐growth forage from previously shredded areas in the drought stressed pasture was not consumed. Forage taken within the drought stressed pasture which was irrigated was readily consumed. The total alkaloid concentration of irrigated forage ranged from 10.0 to 16.7 mg/kg. Drought‐stressed plants contained 3% nitrate and non‐drought stressed plants contained 1% nitrate. Under extreme drought stress conditions, there appeared to be a negative relationship between both total alkaloids and % NO3, and palatability and total consumption.