Forage Mineral Research Articles

Mineral Concentrations in Grazed Cool-Season Annual Grass Pastures in North Florida

AN224, a 3-page illustrated fact sheet by Bob Myer, G. Chelliah, Lee McDowell, Nancy Wilkinson, Ann Blount, and Cheryl Mackowiak, describes information gained from a mineral study component of a four-year grazing study at NFREC Beef Unit, to measure monthly concentrations of selected minerals in forage during the late fall-winter-spring grazing season in north Florida. Published by the UF Department of Animal Science, August 2009.

Effects of Aluminum from Water‐Treatment‐Residual Applications to Pastures on Mineral Status of Grazing Cattle and Mineral Concentrations of Forages

Aluminum (Al) applied to land in the form of water treatment residuals (Al‐WTR) can reduce soluble soil phosphorus (P). Two experiments (145 and 148 d) using 36 grazing Holstein steers were conducted to determine effects of Al‐WTR applications to pasture on mineral status of cattle and bahiagrass (Paspalum notatum). Four treatments were with and without Al‐WTR and P‐free mineral supplementation. Total pasture application of Al‐WTR over 2 years was 75.8 metric tons dry weight/ha. There were few treatment effects on weight gains and mineral tissue concentrations. Forage mineral concentrations were generally unaffected by treatment but were affected (P < 0.05) by collection dates. Most forage samples were deficient in sodium (Na), copper (Cu), selenium (Se), and cobalt (Co) and at various collections deficient in calcium (Ca), P, iron (Fe), and zinc (Zn). Applications of Al‐WTR are effective in reducing P contamination without affecting forage or cattle mineral concentrations.

Composition of Forage and Grain from Second-Generation Insect-Protected Corn MON 89034 Is Equivalent to That of Conventional Corn (Zea mays L.)

Insect-protected corn hybrids containing Cry insecticidal proteins derived from Bacillus thuringiensis have protection from target pests and provide effective management of insect resistance. MON 89034 hybrids have been developed that produce both the Cry1A.105 and Cry2Ab2 proteins, which provide two independent modes of insecticidal action against the European corn borer ( Ostrinia nubilalis ) and other lepidopteran insect pests of corn. The composition of MON 89034 corn was compared to conventional corn by measuring proximates, fiber, and minerals in forage and by measuring proximates, fiber, amino acids, fatty acids, vitamins, minerals, antinutrients, and secondary metabolites in grain collected from 10 replicated field sites across the United States and Argentina during the 2004-2005 growing seasons. Analyses established that the forage and grain from MON 89034 are compositionally comparable to the control corn hybrid and conventional corn reference hybrids. These findings support the conclusion that MON 89034 is compositionally equivalent to conventional corn hybrids.

The effect of dairy effluent on dry matter yields, nutritive characteristics, and mineral content of summer-active regrowth forage crops in southern Australia

In southern Australia, the majority of dry land dairy farms use a 2-pond system to treat and contain dairy effluent collected at the milking platform. This effluent contains a range of nutrients that have the potential to affect forage dry matter (DM) yields, nutritive characteristics, and mineral content of forages. The effect of applying second-pond dairy effluent to the summer-active forages chicory (Chichorium intybus L. cv. Grouse), Hunter (Brassica campestris L. × Brassica napus L.), Winfred (Brassica napus L.), and Sweet Jumbo (Sorghum bicolor (L.) Moench × Sorghum sudanese (Piper) Stapf.) over two summer periods was measured. Effluent was applied at rates of 0, 40, 80, and 100 mm with application split into two equal application times. The first occurred 6–10 weeks after sowing and the second immediately after the first grazing. Forages were assessed for DM yield, nutritive characteristics, and mineral content over the two growth periods in each year. Analysis of effluent showed that on average over the 2 years, the effluent contained 146, 34, 439, and 18 kg/ML of nitrogen (N), phosphorus (P), potassium (K), and sulfur (S), respectively. Furthermore, the effluent also contained 161 kg/ML of calcium (Ca) and 222 kg/ML of magnesium (Mg). For the total growth period in Year 1, all crops showed a linear increase (P &lt; 0.05) in DM yield to applied effluent, with response values varying for each crop. Responses were 49, 52, 29, and 51 kg DM/ha.mm applied effluent for chicory, Hunter, Sweet Jumbo, and Winfred, respectively. For Year 2, all crops also showed a linear increase (P &lt; 0.05) in DM yield (15 kg DM/ha.mm applied effluent) with applied effluent. In Year 1, crude protein (CP) content of all crops increased (P &lt; 0.05) in a linear manner at rates of 0.073 and 0.047% per mm applied effluent for growth periods 1 and 2. There were also linear responses (P &lt; 0.05) in Year 2, with responses varying for each crop for each growth period. For chicory there was no effect of effluent application on CP content in either growth period, while other crops generally exhibited a linear increase with responses of up to 0.08% per mm applied effluent. The greatest changes in mineral content of herbage were those of K, Ca, and Mg. There was a linear increase (P &lt; 0.05) in K content for all growth periods in Years 1 and 2. Magnesium content of chicory (periods 1 and 2) and Winfred (period 2) showed a linear decrease (P &lt; 0.05) in response to effluent application in Year 1, whereas there was no effect in Year 2 for any crops. The results from this study highlight the potential of second-pond dairy effluent to increase DM yields of a range of summer-active forage crops. The data also suggest that while effluent can improve DM yields when soil moisture is limiting, when additional moisture as rainfall occurs, responses from effluent are even more pronounced. In addition, the CP content of forages can be improved when effluent is applied. The combination of increased DM yield with higher CP content provides greater flexibility in dairy cattle feeding options through the dry summer period.

Forage Nutritive Value in an Emulated Silvopasture

Incorporating trees into pastures may alter forage nutritive value. The objective of this study was to determine nutritive value in response to trees and slope position in an emulated (no animals) silvopasture. In 1995, black walnut (Juglans nigra L.) and honey locust (Gleditsia triacanthos L.) trees were planted within three block plots of predominantly tall fescue (Lolium arundinaceum (Schreb.) Darbysh.) pasture. Soils on the site, (Unison and Braddock) are fine, mixed mesic Typic Hapludults, well drained, with moderately steep slopes (10–25%). Trees were planted down slopes in rows to create low‐, medium‐, and high‐tree densities at shoulder‐, mid‐, and toe‐slope positions. Forage from sampling sites (n = 54) under field treatment combinations was harvested May, June, and July in 2002 and 2003. Concentrations of neutral and acid detergent fiber (NDF, ADF), acid detergent lignin (ADL), crude protein (CP), total nonstructural carbohydrate (TNC) and Ca, P, Mg, and K were determined. Few differences due to treatment were observed for NDF and ADF concentrations. Concentrations of TNC decreased with greater tree density and appeared to follow tree leaf growth. Crude protein concentrations were typically greater under honey locust trees. Forage mineral concentrations frequently were greater with increased tree density. Trees appear to have both positive and negative effects on forage nutritive value, and their effects on animal performance warrants further research.

Seasonal Variation of Trace Elements in a Semiarid Veld Pasture

A two‐seasonal study was conducted to determine the trace mineral status of goats' grazing forages and soils in southern Punjab, Pakistan. Soil and forage samples were collected fortnightly for two seasons. Sampling period effects were found in soil copper, zinc, and selenium, and all forage minerals except selenium were affected by sampling times. Seasonal effects were observed in iron, manganese, and selenium for soils and in copper, iron, zinc, manganese, and selenium for forages. All soil mineral levels except cobalt and selenium were found to be above critical levels and likely to be adequate for normal growth of plants growing therein, whereas soil cobalt and selenium were severely deficient during both seasons. The levels of iron, zinc, cobalt, and selenium in soil were higher and copper and manganese were lower during winter than during summer. Forages contained marginal to deficient levels of cobalt during the winter, copper and selenium during the summer, and moderately deficient levels of iron and severely deficient levels of zinc, manganese, and cobalt during the summer. Forage copper, iron, zinc, manganese, and selenium during winter were found to be adequate for the requirements of ruminants. Consequently grazing animals at this location need continued mineral supplementation of these elements to prevent deficiency diseases and to support optimum animal productivity. Florida Agricultural Experiment Station Journal Series No. R‐10513.

Dietary Cation Anion Difference of Five Cool‐Season Grasses

Forage‐based rations with a low dietary cation anion difference (DCAD) should be fed to dairy cows 2 to 4 wk prepartum to prevent hypocalcaemia or milk fever. We evaluated the DCAD of two to four cultivars of five grass species at three locations in Québec, Canada. Orchardgrass (Dactylis glomerata L.), meadow bromegrass (Bromus riparius Rehmann), tall fescue (Festuca arundinacea Schreb.), smooth bromegrass (Bromus inermis Leyss.), and timothy (Phleum pratense L.) were harvested twice a year during two production years. Forage mineral concentrations were measured and the DCAD was calculated with a short equation [DCADS = (Na+ + K+) − (Cl− + S2−)], and a long equation [DCADL = (Na+ + K+ + 0.15Ca2+ + 0.15Mg2+) − (Cl− + 0.6S2− + 0.5P3−). The five species had, respectively, DCADS of 656, 540, 510, 490, and 384 mmolc kg−1 DM (dry matter) in spring growth, and 633, 569, 496, 447, and 332 mmolc kg−1 DM in summer regrowth. Orchardgrass had the highest DCAD and timothy the lowest while the three other species were intermediate in both spring growth and summer regrowth. Species differences in DCAD were primarily related to differences in K concentration. Timothy was the only species that decreased significantly in DCADS (by 52 mmolc kg−1 DM) and DCADL (by 35 mmolc kg−1 DM) from spring growth to summer regrowth. Cultivars did not differ in DCADS and DCADL except for tall fescue. Locations did not differ in DCAD. Among the grass species in this study, and because of its low DCAD, timothy is the best suited for producing forages fed to dairy cows in the weeks preceding calving.

Fertilização com N e S na recuperação de pastagem de Brachiaria brizantha cv. Marandu em neossolo quartzarênico

Com o objetivo de avaliar a resposta de pastagens degradadas de Brachiaria brizantha cv. Marandu ao uso de diferentes doses de fertilização com N e S, foi desenvolvido um experimento em campo durante dois anos, em área de cerrado em blocos ao acaso. Foram avaliados sete tratamentos, seis com diferentes combinações de doses de N e S e uma testemunha (pastagem degradada). As combinações foram: 70 kg ha-1 N sem enxofre, 140 kg ha-1 N sem enxofre, 210 kg ha-1 N sem enxofre, 70 kg ha-1 N e 77 kg ha-1 S, 140 kg ha-1 N e 153 kg ha-1 S, 210 kg ha-1 N e 230 kg ha-1 S. A reposta em produção de forragem ao uso de fertilização nitrogenada foi linear, com maior eficiência de uso do nitrogênio no segundo ano de manejo. A maior produção de forragem foi acompanhada por maior extração de N e queda nos teores de matéria orgânica no solo. A extração de enxofre foi menor que as doses de S empregadas. O critério da relação N:S na forragem na nutrição mineral da forrageira foi recomendado apenas na época das águas. Houve acúmulo de enxofre nas camadas subsuperficiais do solo.

The Status of Selected Minerals in Soil, Forage and Beef Cattle Tissues in a Semi-arid Region of Zimbabwe

Five districts in the Matabeleland region, an arid western area of Zimbabwe, were investigated for the status of Ca, P, Na, Cu and Zn in soil, forage and cattle during the wet and dry seasons over a period of one year. The cattle came from the natural grazing lands and were not supplemented at the time of sampling. Some deficiencies in soil Zn and P were found in the districts of Lupane and Bulilimamangwe, respectively. Dry season soil Ca, Cu and P concentrations were significantly higher (p < 0.05) than rainy season values owing to leaching in all five districts. Most forage samples had mineral concentrations below the critical levels known to be adequate for animal requirements. Forage levels of Ca, Na. Cu and Zn significantly increased (p < 0.05) with advancing maturity, while P significantly decreased (p < 0.05) in almost all the districts. Marked deficiencies of minerals were found in cattle tissues and these levels followed the seasonal trend seen in the forage. These results indicate that cattle in Matebeleland are deficient in P, Ca, Cu and Zn and that grazing areas in the region cannot provide adequate levels of the five minerals studied.

Alfalfa Yield and Nutrient Uptake as Affected by pH and Applied K

Approximately 30% of the cultivated cropland in the state of Wisconsin is devoted to alfalfa (Medicago sativa) production. Much of the alfalfa forage produced is used to feed the approximately 1,350,000 dairy cattle found in the state. A key concern of dairy producers is the cation to anion balance in rations for dry and early lactation cows, which is greatly influenced by soil K levels. This study was designed to examine the interactive effects that varying soil pH levels and annual potassium applications would have on forage mineral balance, yield, and quality. Three locations with varying soil textures were used for this 4‐yr study. Results indicate that soil pH and applied K can both significantly influence forage yield, quality, and cation levels. At soil pH levels that are near optimum for alfalfa production and yield levels in the 8–10 Mg ha−1 range, it appears that approximately 224 kg K2O ha−1 is required annually to optimize yield and stand quality and to maintain soil test in the optimum category. At all locations, as soil K increased, tissue K increased, and to a much smaller extent, tissue Ca and Mg decreased. Annual K application resulted in a buildup of soil test K and a decrease in soil test Ca and Mg. Increasing soil pH, and consequently soil test Ca, did not consistently result in reduced tissue K levels. However, liming these acid soils was essential to optimize alfalfa yield. Keeping soil test K levels in the optimum range appears to be the best strategy for keeping forage tissue K levels in acceptable ranges for use as dry cow and early lactation dairy feed.

Minerals in Soils and Forages Irrigated with Secondary Treated Sewage Water in Sebele, Botswana

Production of forage using treated sewage water is a viable practice internationally. However, there is not much information on the heavy metal content of such forages. This study was conducted to determine the effect of sewage water on soils and forages irrigated with treated sewage water at Botswana College of Agriculture 's farm. The study was conducted for a period of 120 days using established forage pastures of rye grass (Lolium multiflorum) and lucerne (Medicago sativa). Heavy metals determined were Fe, Mn, Cu, Zn, Ni, Pb and Cd. Generally the treated sewage water contained relatively low levels of heavy metals. Zn, Ni and Mn concentration were below the detectable levels. In the sewage water while soils and plants had low levels of heavy metals. Comparatively the soil and plants heavy metal levels were much higher than those in the water and the difference was significant (p<0.05). There was some low correlation between trace element contents in the water and soil. In addition there was some significant difference (p<0.05) in heavy metal concentration in sewage water between the months during which the analyses were done. However, the sewage water, soils and forage mineral concentrations were within the internationally allowable heavy metal concentration with respect to irrigation, soil loadings and animal feeds. poor performance is largely attributed to low and variable effluent is generated per annum and discarded in rainfall as well as the occurrence of successive droughts. Gaborone alone as sewage . The use of sewage water for This calls for exploitation of other means of water sources irrigation is a positive way to dispose off sewage. Such to sustain the sector as underground water from huge volumes of water in a country with persistent boreholes, damming of rivers and sewage water. The latter droughts and unreliable rainfall can be of great agronomic being the most sustainable as it minimizes the cost of and economic importance. Irrigation with sewage water procuring portable or fresh water for agricultural use. can increase available water supply or release water for Concern for water quality denotes it's suitability and is alternative use. The utilization of sewage water also related to it's effect on the soil and plants and the contributes to cleaning of the environment, as the water management that may be necessary to control or is not discharged into water bodies that could otherwise compensate for a water quality related problem is the most get polluted. In addition to these direct economic benefits limiting factor in the use of sewage water for agricultural that conserve natural resources, this water contains a lot purposes. The principle for evaluating the quality of of nutrients and can serve as an alternative source to irrigation water deals with the total concentration and expensive chemical fertilizers. FAO estimated that typical composition of soluble salts in water . Soluble salts wastewater from domestic sources could supply all of the (2)

Fertilization with nitrogen and potassium on pastures in temperate areas

Fertilizer application enable producers to influence pasture production. The effect of N fertilization on grass production and leguminous plant content of pasture and strategic N application has received much attention. Changing agricultural policies suggest that chemical fertilizer inputs may be diminished and that alternative sources of nutrients are desired. The aim of this study was to evaluate the effect of N and K fertilization on production, botanical composition, and forage mineral composition to gain some insight into what influence changing fertilization practices would have on pasture productivity. Three K and 3 N application rates were applied in a factorial design on a white clover (Trifolium repens L.)—perennial ryegrass (Lolium perenne L.) sward. Potassium and nitrogen application increased herbage production and had differential influences on botanical composition. Nitrogen decreased clover content in the pasture, whereas K increased the proportion and production of white clover. The effects of K application appeared later in the experiment than those associated with N. We concluded that K is very important for development and maintenance of white clover in pasture, which increases herbage and protein production. Nitrogen was associated with lesser amounts of N, P, K, and Mg in pasture, because of lesser amounts of clover in the sward. Changing fertilization practices will have definite influences on sward composition and pasture productivity. Any interpretation of pasture mineral content should take botanical composition changes into account.

Mineral Content of Forages Grown on Poultry Litter-Amended Soils

Large quantities of poultry litter are applied each year to pastures in Arkansas and Oklahoma. Our objective was to monitor mineral concentrations in forages grown on poultry litter-amended soils and compare them with mineral requirements for gestating and early lactating beef cows. A total of 65 forage samples were gathered from four farms in northwest Arkansas and northeast Oklahoma from April 2000 to March 2002. Mean forage mineral concentrations were compared with beef cattle requirements using a two-tailed t test. Two-year average forage Ca, P, K, S, and Fe concentrations from each farm exceeded (P<0.05) gestation and lactation requirements, but forage Zn concentrations from one farm did not differ (P>0.05) from gestation and lactation requirements. On individual sampling dates, concentrations of Ca, P, K, and Zn rarely fell below lactation requirements. Mean forage Mg concentrations from one farm exceeded (P<0.05) lactation requirements, but those from the other three farms exceeded (P<0.05) gestation but not (P>0.05) lactation requirements. Mean tetany ratios from all farms were below (P<0.05) the tetany threshold of 2.2, but forage from two farms surpassed the tetany threshold during Spring 2000, and one sur-passed it during Spring 2001. Average forage Cu concentrations were below (P<0.05) requirements on one farm and did not differ (P>0.05) from the requirements on three farms. Forages from pastures fertilized with broiler litter may meet most but not all mineral requirements of beef cattle, and supplementation of specific minerals, particularly Mg and Cu, may be necessary.

Effects of concentrate supplementation on blood mineral concentration of growing upgraded Philippine goats

ABSTRACTA total of 32 4‐month‐old‐upgraded Philippine goats with mean bodyweight of 13.5 kg were used to study the effects of concentrate supplementation on mineral status of growing goats. All animals received a basal diet comprised of different forage species. Twenty of the animals were supplemented with concentrate at a rate of 150–200 g dry matter/day while the remaining 12 animals were not supplemented. Blood sampling and bodyweight measurement were done every 2 weeks during the 5 months of experiment. Forage, concentrate and blood sulfur, calcium, phosphorus, magnesium, copper, zinc and selenium concentration were analyzed after wet digestion. Forage mineral contents, except for zinc and selenium, were sufficient for requirements of ruminants. Concentrate mineral contents were much higher than the requirements, but did not exceed the toxic levels. The concentrate supplementation resulted in high (P &lt; 0.05) plasma phosphorus, copper, zinc, whole blood selenium concentrations and bodyweight of growing goats, although some supplemented animals showed plasma zinc concentration below the lower critical level. It was recommended that pellets, glass bolus or capsules that contain deficient minerals, such as zinc and selenium, should be used in the study area.

Spatial dynamics of lions and their prey along an environmental gradient

AbstractEstablishing the ecological determinants of the spatial dynamics of large African savanna mammals is necessary for understanding the cumulative impacts on the suitability and resilience of their natural habitats, of progressive habitat fragmentation and temporal shifts in climate, fire regimes and elephant browsing. Systematic directional gradients and small‐scale spatial dependence were evident in rainfall, herbivore biomass and lion density in the Masai Mara National Reserve during September 1990 to July 1992. Lion density, the biomass of resident and all herbivore species were autocorrelated within 4.3, 4.1 and 3.3 km, respectively, and peaked in areas of relatively low rainfall but higher microtopographic and vegetation heterogeneity and complexity and more diverse drainage systems. Rainfall influenced herbivore biomass and hence lion density non‐linearly and that influence was apparently modified by forage mineral nutrients, structural habitat complexity, degree of drainage and distance to waterpoints. Lion density was related to the biomass of resident herbivores, even after controlling for rainfall and spatial trends. Persistence of the recent decline in Mara woodlands and increasing human population along the reserve–ranch boundary would likely reduce the reserve's lion population because most lions spent the daytime within the vegetation mosaic fringing drainage lines, away from humans and domestic livestock.

Fertilization with nitrogen and potassium on pastures in temperate areas

Fertilizer application enable producers to influence pasture production. The effect of N fertilization on grass production and leguminous plant content of pasture and strategic N application has received much attention. Changing agricultural policies suggest that chemical fertilizer inputs may be diminished and that alternative sources of nutrients are desired. The aim of this study was to evaluate the effect of N and K fertilization on production, botanical composition, and forage mineral composition to gain some insight into what influence changing fertilization practices would have on pasture productivity. Three K and 3 N application rates were applied in a factorial design on a white clover (Trifolium repens L.)—perennial ryegrass (Lolium perenne L.) sward. Potassium and nitrogen application increased herbage production and had differential influences on botanical composition. Nitrogen decreased clover content in the pasture, whereas K increased the proportion and production of white clover. The effects of K application appeared later in the experiment than those associated with N. We concluded that K is very important for development and maintenance of white clover in pasture, which increases herbage and protein production. Nitrogen was associated with lesser amounts of N, P, K, and Mg in pasture, because of lesser amounts of clover in the sward. Changing fertilization practices will have definite influences on sward composition and pasture productivity. Any interpretation of pasture mineral content should take botanical composition changes into account.

In situ solubility of selected macrominerals from common bermudagrass fertilized with different nitrogen rates and harvested on two dates

Minerals are essential nutrients for animals as primordial elements for structural tissues and metabolic reactions. Forages are considered an important source of minerals for ruminants, but forage mineral concentrations may vary across the growing season due to several factors such as forage species and fertilization levels. Common bermudagrass [ Cynodon dactylon (L.) Pers.] growing on a poultry layer manure-amended site was fertilized with ammonium nitrate at four rates (0, 56, 112, and 168 kg N/ha) approximately 1 month before the first and third harvests (30 May and 18 August 2000, respectively) to evaluate those effects on forage concentration and ruminal disappearance of Ca, P, Mg, and K. Five crossbred ruminally cannulated steers (422±21.0 kg BW) were used to evaluate these forages in situ in a randomized complete block design with a 2×4 ( harvest date × N fertilizationrate ) factorial arrangement of treatments. Forage P content decreased ( P<0.01) with increasing N fertilization on 18 August, while forage Mg increased ( P<0.01) and forage Ca content tended ( P=0.08) to increase with increasing N fertilization on both harvest dates. Approximately, 992 g/kg of the K disappeared immediately (fraction A) from the bags compared with approximately 821, 718, and 476 g/kg of Mg, P, and Ca, respectively. Fraction A, fraction B (the fraction disappearing at a measurable rate), and effective ruminal disappearance of Ca, P, Mg, and K were affected by linear or quadratic interactions between N fertilization and harvest date. Effective P disappearance increased linearly ( P<0.05) on 30 May and decreased quadratically ( P<0.01) on 18 August, and effective Mg disappearance increased linearly ( P<0.01) on both dates with N fertilization rate. The intercepts of the regression of effective P, Mg, and K disappearance on N rate were greater ( P<0.05) on 30 May than 18 August, but the mean values for each date were >830 g/kg. Rate of Mg disappearance responded quadratically ( P<0.01) to N fertilization rate and was greater ( P<0.05) on 18 August compared with 30 May. Therefore, N fertilization rates affected the concentration and ruminal liberation of macrominerals from bermudagrass, and effective mineral disappearance was greater than 700 g/kg in all instances.

Adequate Soil Phosphorus Decreases the Grass Tetany Potential of Tall Fescue Pasture

Adequate Soil Phosphorus Decreases the Grass Tetany Potential of Tall Fescue Pasture

Botanical composition, soil and forage quality under different management regimes in Russian grasslands

Little is known on how management of Russian native grasslands affects botanical composition, soil and forage properties. Three fields were sampled in the V.V. Alekhin Central-Chernozem Biosphere State Reserve in the Kursk region of Russia: a native grassland (not cultivated for at least 300 years), a grazed/hay field with 4 years of annual harvest followed by 1 year of rest (periodically-cut grazed/hay field), and a yearly-cut grazed/hay field. Soil samples were collected from the top 10 cm and analyzed. Plant species were identified at the sampling sites and this plant material was used to determine total elemental analysis of forage, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), in vitro true digestibility (IVTD) and lignin concentrations. Above-ground live and dead plant material and roots were analyzed for C, N and lignin. Soil sample analysis showed that fields were comparable in terms of soil chemical and physical properties. SOC and N contents were not statistically different in the native and yearly grazed/hay fields. Soil bulk density significantly increased as a result of utilization, from 0.80±0.09 Mg m −3 for the native grassland to 0.97±0.06 Mg m −3 for the yearly grazed/hay field. A total of 107 different plant species were recorded at the three fields. There were changes in plant composition among the fields. The native grassland field had the least number of plant species (41) followed by the yearly-cut grazed/hay field (68), and the periodically-cut grazed/hay field (87). There was a greater proportion of grass species (20%) in the native grassland field. Dead plant biomass and roots from the grazed/hay fields were higher in N and lignin concentrations. Forage mineral concentration was highest in the periodically-cut hay field. No significant differences were observed in terms of forage properties.

Can cow adaptability and carcass acceptability both be achieved?

Mineral supplementation programs in the cow-calf/stocker industry range from plain salt/sulfur blocks to highly formulated free-choice mineral supplements containing organic and inorganic sources of minerals. Choice of a mineral supplementation program that provides the greatest return on investment is important in a competitive marketplace. Many variables must be considered when designing the mineral supplement. Environmental condition, management practices, forage type, animal genetics, and physiological state of production make every production system different with respect to needs for mineral supplementation. However, to prevent tremendous complexity in managing mineral supplementation programs, average environments, forage mineral supplies, animal characteristics, and production levels are generally used as a starting point. In unique situations, formulations can be altered to account for variances from the norm. However, care must be taken to avoid critical negative mineral-to-mineral interactions that are known to exist. It is not uncommon to create a completely new problem when changing a mineral supplement program to fix an old problem. Choice of supplement ingredients is also critical to ensure adequate mineral absorbability. In addition, the mineral supplement providing the best mixture of mineral salts to meet production needs is of little value if consumption is not adequate. These issues are discussed with respect to forage supply of minerals meeting animal requirements.