Phosphorus (P) losses due to overfeeding of the mineral to livestock can contribute to surface water degradation. The objective of this study was to examine the impact to supplementing various levels of mineral P to grazing beef cattle. A producer survey and a research trial were conducted to examine the effects of supplementing mineral phosphorus (P) to grazing cattle. In the first study, mineral tags, producer surveys, and fecal, forage, and soil samples were collected from beef cattle operations in Virginia's Chesapeake Bay watershed. Samples (n=166) were collected from 120 producers in 11 counties. Soil test P results were based on Virginia Cooperative Extension soil test guidelines characterized as low (12 %), medium (37 %), high (35 %), and very high (16 %). Pasture grab samples contained 0.34 ± 0.12% P and forage P concentration increased (P < 0.01) across soil P categories going from low to very high. Fecal total phosphorus (TP) was lowly correlated (R2 = 0.18, P < 0.01) to forage P concentration. Mineral supplements were categorized as nil (<1.0% P), low (1.0-<3.0% P), medium (3.0-<6.0% P), and high (>6.0% P). Fecal TP and inorganic phosphorus (Pi) concentration increased (P < 0.01) with mineral P levels. Fecal TP and Pi were lower (P < 0.01) when nil and low P mineral were supplemented as compared to medium and high P mineral. Soluble P (defined as fecal Pi/fecal TP*100) also increased (P < 0.01) with increasing mineral P content going from nil to high. All farms surveyed required little or no P supplementation in regard to beef cattle P requirements. The majority (82%) of producers were receptive to modifying mineral P supplementation practices based on forage P levels. A 56-d study was also conducted with eight yearling Hereford steers (261±30 kg) grazing cool-season grass fall re-growth to determine the effects of varying levels of P supplementation on fecal P excretion. Treatments consisted of dicalcium phosphate supplemented at 0 (D1), 10.0 (D2), 20.0 (D3), or 30.0 (D4) g/d in a randomized 4x4 replicated Latin square design. These treatments provided an additional 0, 1.9, 3.7, and 5.6 g/d of P respectively. Two esophageally cannulated steers were used to collect forage samples for nutrient analysis. Forage P content was analyzed from hand collected samples. Forage P concentrations averaged 0.49% of dry matter (DM) across all periods. Chromic oxide (Cr2O3) was administered twice daily via gelatin capsule at 0630 and 1830 to serve as an external marker for determination of fecal dry matter excretion (DME). Indigestible NDF (iNDF) was used as an internal marker to determine dry matter intake (DMI). Due to the high forage P content, average P intake was in excess of National Research Council (NRC) requirements for all diets (D1 = 281%; D2 = 297%; D3 = 323%; D4 =348%). Orthogonal contrasts were performed to assess the relationship between treatment and P excretion. A linear response (P < 0.01) in daily inorganic P (Pi) excretion (0.054, 0.052, 0.062 and 0.063 g/kg of BW ± 0.003 for D1, D2, D3 and D4, respectively) was observed across treatments. Daily total P (TP) excretion increased linearly (P < 0.01) across treatments (0.080, 0.079, 0.092 and 0.093 g/kg of BW ± 0.003 for D1, D2, D3 and D4, respectively. When forage P content is sufficient to meet the requirement of grazing cattle, increasing P supplementation results in greater P excretion without additional benefits to growth or nutrient digestibility. / Master of Science

Thesis (MTech (Nature Conservation))--Cape Technikon, 2003. / The study was carried out on two adjacent farms on the plains of the Nama Karoo near Beaufort West. The impacts of three grazing treatments (a) zero grazing (b) non-selective grazing (c) conventional grazing, on plant diversity and certain vegetation parameters were compared. Unpredictable and variable rainfall and major disturbance events such as droughts drive vegetation change in the Nama Karoo. Major recruitment events are rare and can determine Karoo vegetation composition for many years. The diversity of plant species plays an important role in determining vegetation composition during major recruitment events and following drought or disturbance such as grazing. Grazing can influence the composition, abundance and seed production of Karoo plants and in so doing influence the future abundance of desirable and undesirable forage species. These changes may only become evident over long periods, but small changes in vegetation as a response to grazing treatment can accumulate considerably over time.On the farm Elandsfontein, studies have shown that non-selective grazing leads to a higher plant turnover rate, resulting in more vigorous and productive plants, and improved ecosystem functioning. However there is no evidence of this grazing system promoting or reducing plant diversity. The aim of this study was to test whether the non-selective grazing system promoted or reduced plant diversity compared to no grazing and conventional grazing. The hypothesis was that there were no differences between the grazing treatments in terms of plant diversity or any of the vegetation parameters measured. To evaluate this hypothesis, plant data were collected from the three grazing treatments using the Modified-Whittaker vegetation sampling method. The method was further modified for this study to allow for accurate abundance measurements rather than estimates, and an increased area for recording species richness. Using various diversity indices that incorporate species richness and the proportional abundance of species, plant diversity values for each treatment were obtained. No differences in terms of plant diversity were found between the treatments. A significant difference between treatments was found in the density of plants, particularly in perennial grasses and shrubs. Canopy cover percentage did not differ for individual species or as total cover between the treatments.

Este estudo teve por hipótese que o manejo de pastos de Tifton 85 baseado em parâmetros ingestivos dos animais (pastoreio Rotatínuo – RN), resulta em colheita do pasto mais eficiente que no manejo tradicional. Foram estudadas três estratégias de manejo de pastoreio rotativo em pastos de Tifton 85 pastejados por novilhas leiteiras no Sul do Brasil. Os tratamentos consistiam em variações de critério de altura de pasto para entrada e retirada dos animais. O primeiro tratamento foi o método de pastoreio rotativo “clássico” (máximo aproveitamento do pasto) com metas de altura de manejo pré-pastejo de 30 cm e pós-pastejo de 5 cm (30-05). O segundo tratamento foi o Rotatínuo (RN) que permite a máxima taxa de ingestão de forragem, com altura pré-pastejo de 19,2 cm e pós-pastejo de 11,5 cm. No terceiro tratamento foi utilizada uma proposição de rebaixamento de apenas 40% da altura pré-pastejo tradicionalmente recomendada no país, 30 cm de altura pré-pastejo e 18 cm de altura pós-pastejo (30-18). Foram utilizados animais da raça Holandês, com idade de 20±2 meses e peso médio de 496±22 kg. O delineamento experimental foi em blocos completos casualizados com três repetições. O período experimental foi de 67 dias, entre 14 de janeiro a 22 de março de 2014. Os número de pastejos chegaram a 7 para o RN, 2 para o RT e 5 para o 30-18. A taxa de ingestão de forragem foi semelhante entre os tratamentos. Para manter a taxa de ingestão constante os animais utilizaram diferentes componentes do comportamento. No tratamento 30-05 os animais apresentaram maior massa do bocado, e no RN maior taxa de bocado (P<0,05). O RN obteve maior taxa de acúmulo diária de forragem frente aos demais tratamentos, maior massa de forragem colhida e maior eficiência de colheita do pasto (P<0,05). A adoção de metas de manejo do pasto via alturas pré e pós-pastejo definidas por parâmetros ingestivos, conforme previsto no Rotatínuo, possibilitou obter adequada eficiência de colheita de pasto, sem comprometer o potencial de regeneração dos pastos. / This study hypothesized that the grazing management of Tifton 85 based on animal ingestive behavior parameters (Rotatinuous grazing - RN), results in higher harvesting efficiency than traditional management. Three rotational grazing management strategies were tested on Tifton 85 pastures grazed by dairy heifers in southern Brazil. The treatments were different sward height targets to put and take the animals from the strip. The first treatment was the traditional rotational grazing method named "Classic" (maximum pasture harvest) with pre-grazing height of 30 cm and post-grazing of 5 cm (30-05). The second treatment was named Rotatinuous (RN), aimed to maximize the animal herbage intake rate, where the pre-grazing height was 19.2 cm and post-grazing of 11.5 cm. In the third treatment it was proposed the grazing down of 40% of pre-grazing height traditionally recommended in Brazil (30 cm), resulting in 30 cm and 18 cm of pre and post-grazing height, respectively (30-18). Holstein animals, aged 20 ± 2 months, were used with an average weight of 496 ± 22 kg. The experimental design was a randomized complete block design with three replicates. The experimental period was 67 days, from 14 January to 22 March 2014. The numbers of grazing cycles were 7 on RN, 2 on 30-05 and 5 on 30-18 treatments. Herbage intake rate did not differ among treatments (P>0.05). The animals behaved differently using distinct grazing behavior strategies during the grazing down in order to reach the same level of intake rate. In the treatment 30-05 animals presented higher bite mass, whist RN higher bite rate (P <0.05). The RN had higher daily herbage accumulation rate, amount of forage harvested and pasture harvest efficiency (P <0.05). The grazing management goals defined by ingestive parameters (Rotatínuous) provided adequate pasture harvest efficiency without compromising pasture regrowth potential.

Higher stocking density under seasonal-rotation grazing is expected to increase plant abundance because expanded animal distribution and reduced selective grazing on forage species will reduce the spatial variation and competitive advantage of non-forage species compared to yearlong grazing. Rangeland scientists struggle with how long rangeland experiments must continue in order to detect grazing treatment effects, particularly in semi-arid ecosystems with slow responses and high spatio-temporal variability. My first study investigated grazing system effects on plant abundance (cover and density) over the short-term (12yrs) or long-term (22 or 34yrs) after accounting for covariates (mesquite and precipitation gradients). My second study assessed how grazing systems affected spatial variation in grass abundance over 22 or 34 years after accounting for precipitation gradient. The first study was a course resolution approach, looking at grazing impacts on plant abundance. The second study was a finer resolution assessment of the underlying assumption that rotational grazing systems reduce selective grazing. Using split-plot analysis of variance, with year as the split, changes in mean plant abundance and variance in grass abundance were compared between two grazing systems (yearlong vs. seasonal rotation), after accounting for covariate(s). Variance of grass abundance among sample locations within an experimental pasture was the measure of spatial variability and was expected to increase with selective grazing. Grazing systems did not influence plant abundance or spatial variation of grasses. The absence of grazing effect may be due to overriding influences of grazing intensity, large pasture sizes, temporal variation in precipitation, and few replicates. Specific to spatial variation, the absence of grazing system effect may be due to discrepancies in transect representation across ecological sites and spatial variation of grasses occurring at scales different than the 30-m transect size. Like earlier research, my studies failed to substantiate the fundamental premise for implementing rotational grazing systems. This exposes challenges that confront rangeland scientists when implementing grazing studies in spatio-temporally heterogeneous ecosystems. I recommend that research shift from comparing rigid schedule-driven grazing systems to more adaptive management approach where there are comparisons between different levels or different designs of flexible systems.

Este estudo teve por hipótese que o manejo de pastos de Tifton 85 baseado em parâmetros ingestivos dos animais (pastoreio Rotatínuo – RN), resulta em colheita do pasto mais eficiente que no manejo tradicional. Foram estudadas três estratégias de manejo de pastoreio rotativo em pastos de Tifton 85 pastejados por novilhas leiteiras no Sul do Brasil. Os tratamentos consistiam em variações de critério de altura de pasto para entrada e retirada dos animais. O primeiro tratamento foi o método de pastoreio rotativo “clássico” (máximo aproveitamento do pasto) com metas de altura de manejo pré-pastejo de 30 cm e pós-pastejo de 5 cm (30-05). O segundo tratamento foi o Rotatínuo (RN) que permite a máxima taxa de ingestão de forragem, com altura pré-pastejo de 19,2 cm e pós-pastejo de 11,5 cm. No terceiro tratamento foi utilizada uma proposição de rebaixamento de apenas 40% da altura pré-pastejo tradicionalmente recomendada no país, 30 cm de altura pré-pastejo e 18 cm de altura pós-pastejo (30-18). Foram utilizados animais da raça Holandês, com idade de 20±2 meses e peso médio de 496±22 kg. O delineamento experimental foi em blocos completos casualizados com três repetições. O período experimental foi de 67 dias, entre 14 de janeiro a 22 de março de 2014. Os número de pastejos chegaram a 7 para o RN, 2 para o RT e 5 para o 30-18. A taxa de ingestão de forragem foi semelhante entre os tratamentos. Para manter a taxa de ingestão constante os animais utilizaram diferentes componentes do comportamento. No tratamento 30-05 os animais apresentaram maior massa do bocado, e no RN maior taxa de bocado (P<0,05). O RN obteve maior taxa de acúmulo diária de forragem frente aos demais tratamentos, maior massa de forragem colhida e maior eficiência de colheita do pasto (P<0,05). A adoção de metas de manejo do pasto via alturas pré e pós-pastejo definidas por parâmetros ingestivos, conforme previsto no Rotatínuo, possibilitou obter adequada eficiência de colheita de pasto, sem comprometer o potencial de regeneração dos pastos. / This study hypothesized that the grazing management of Tifton 85 based on animal ingestive behavior parameters (Rotatinuous grazing - RN), results in higher harvesting efficiency than traditional management. Three rotational grazing management strategies were tested on Tifton 85 pastures grazed by dairy heifers in southern Brazil. The treatments were different sward height targets to put and take the animals from the strip. The first treatment was the traditional rotational grazing method named "Classic" (maximum pasture harvest) with pre-grazing height of 30 cm and post-grazing of 5 cm (30-05). The second treatment was named Rotatinuous (RN), aimed to maximize the animal herbage intake rate, where the pre-grazing height was 19.2 cm and post-grazing of 11.5 cm. In the third treatment it was proposed the grazing down of 40% of pre-grazing height traditionally recommended in Brazil (30 cm), resulting in 30 cm and 18 cm of pre and post-grazing height, respectively (30-18). Holstein animals, aged 20 ± 2 months, were used with an average weight of 496 ± 22 kg. The experimental design was a randomized complete block design with three replicates. The experimental period was 67 days, from 14 January to 22 March 2014. The numbers of grazing cycles were 7 on RN, 2 on 30-05 and 5 on 30-18 treatments. Herbage intake rate did not differ among treatments (P>0.05). The animals behaved differently using distinct grazing behavior strategies during the grazing down in order to reach the same level of intake rate. In the treatment 30-05 animals presented higher bite mass, whist RN higher bite rate (P <0.05). The RN had higher daily herbage accumulation rate, amount of forage harvested and pasture harvest efficiency (P <0.05). The grazing management goals defined by ingestive parameters (Rotatínuous) provided adequate pasture harvest efficiency without compromising pasture regrowth potential.

Este estudo teve por hipótese que o manejo de pastos de Tifton 85 baseado em parâmetros ingestivos dos animais (pastoreio Rotatínuo – RN), resulta em colheita do pasto mais eficiente que no manejo tradicional. Foram estudadas três estratégias de manejo de pastoreio rotativo em pastos de Tifton 85 pastejados por novilhas leiteiras no Sul do Brasil. Os tratamentos consistiam em variações de critério de altura de pasto para entrada e retirada dos animais. O primeiro tratamento foi o método de pastoreio rotativo “clássico” (máximo aproveitamento do pasto) com metas de altura de manejo pré-pastejo de 30 cm e pós-pastejo de 5 cm (30-05). O segundo tratamento foi o Rotatínuo (RN) que permite a máxima taxa de ingestão de forragem, com altura pré-pastejo de 19,2 cm e pós-pastejo de 11,5 cm. No terceiro tratamento foi utilizada uma proposição de rebaixamento de apenas 40% da altura pré-pastejo tradicionalmente recomendada no país, 30 cm de altura pré-pastejo e 18 cm de altura pós-pastejo (30-18). Foram utilizados animais da raça Holandês, com idade de 20±2 meses e peso médio de 496±22 kg. O delineamento experimental foi em blocos completos casualizados com três repetições. O período experimental foi de 67 dias, entre 14 de janeiro a 22 de março de 2014. Os número de pastejos chegaram a 7 para o RN, 2 para o RT e 5 para o 30-18. A taxa de ingestão de forragem foi semelhante entre os tratamentos. Para manter a taxa de ingestão constante os animais utilizaram diferentes componentes do comportamento. No tratamento 30-05 os animais apresentaram maior massa do bocado, e no RN maior taxa de bocado (P<0,05). O RN obteve maior taxa de acúmulo diária de forragem frente aos demais tratamentos, maior massa de forragem colhida e maior eficiência de colheita do pasto (P<0,05). A adoção de metas de manejo do pasto via alturas pré e pós-pastejo definidas por parâmetros ingestivos, conforme previsto no Rotatínuo, possibilitou obter adequada eficiência de colheita de pasto, sem comprometer o potencial de regeneração dos pastos. / This study hypothesized that the grazing management of Tifton 85 based on animal ingestive behavior parameters (Rotatinuous grazing - RN), results in higher harvesting efficiency than traditional management. Three rotational grazing management strategies were tested on Tifton 85 pastures grazed by dairy heifers in southern Brazil. The treatments were different sward height targets to put and take the animals from the strip. The first treatment was the traditional rotational grazing method named "Classic" (maximum pasture harvest) with pre-grazing height of 30 cm and post-grazing of 5 cm (30-05). The second treatment was named Rotatinuous (RN), aimed to maximize the animal herbage intake rate, where the pre-grazing height was 19.2 cm and post-grazing of 11.5 cm. In the third treatment it was proposed the grazing down of 40% of pre-grazing height traditionally recommended in Brazil (30 cm), resulting in 30 cm and 18 cm of pre and post-grazing height, respectively (30-18). Holstein animals, aged 20 ± 2 months, were used with an average weight of 496 ± 22 kg. The experimental design was a randomized complete block design with three replicates. The experimental period was 67 days, from 14 January to 22 March 2014. The numbers of grazing cycles were 7 on RN, 2 on 30-05 and 5 on 30-18 treatments. Herbage intake rate did not differ among treatments (P>0.05). The animals behaved differently using distinct grazing behavior strategies during the grazing down in order to reach the same level of intake rate. In the treatment 30-05 animals presented higher bite mass, whist RN higher bite rate (P <0.05). The RN had higher daily herbage accumulation rate, amount of forage harvested and pasture harvest efficiency (P <0.05). The grazing management goals defined by ingestive parameters (Rotatínuous) provided adequate pasture harvest efficiency without compromising pasture regrowth potential.

Forest Service grazing permits for cattle and sheep were analyzed. A livestock and land resource summary was completed for each non-temporary permit reported on the 98 forests in the twelve western states. The economic feasibility of private rangeland improvements to offset public land grazing in Rich County, Utah, was analyzed in the second section of this thesis. The internal rate of return for various projects was computed. The internal rate of return was used as an indicator of the economic feasibility to ranchers. These estimates were made on a county basis and do not apply to any particular ranch situation.

Service-grazing is a novel term for grazing done on land not owned or rented by a livestock producer or manager, for the purpose of land management, and for which the owner or land manager receiving grazing services pays compensation to the service provider. This research project seeks to gather detailed information about producers in the Western United States, providing grazing services under this project’s definition of “service-grazing”, with a focus on those operating in California, in order to discover the business models or practices necessary to be successful within a service-based grazing operation. To this end, an online survey consisting of 59 questions was designed and administered to 25 service-grazers operating with the Western United States. Demographic data collected suggested that service-grazers tend to be younger than most sheep producers. They are also highly educated and generally not generational farmers. The majority of service grazers graze mostly goats and are highly dependent on off-farm income. Due to the limited number of responses received to the survey, it is recommended that future work be split into two parts: 1) compiling an accurate and up-to-date list of producers providing grazing services, with detailed demographic information and specific characteristics of each operation; 2) a further survey to question those producers as to the feasibility of transitioning, in whole or in part, from a production-based livestock operation to one providing grazing services.

Beef cattle follow a daily, cyclical pattern of grazing, rumination, and digestion that coincides with their environment and season. Traditionally backgrounding operations hand feed any supplement in the morning. However, this practice may interrupt typical grazing patterns during early morning and subsequent rumination during the heat of the day. Self-fed concentrate feeds containing intake limiters are used to minimize the labor associated with hand feeding and allow cattle to eat throughout the day. The objectives of this experiment were to investigate the effect of supplement feeding time on performance and grazing behavior of backgrounded beef steers. Crossbred beef steers (n = 54; 7 ± 1 m of age; body weight, BW = 243 ± 2 kg) were sourced from a regional cattleman's association and grazed on tall fescue pasture (Festuca arundinacea) at the Southwest Virginia Agricultural Research and Extension Center in Glade Spring, VA from October 1 to November 7, 2019. Cattle were stratified by BW and source and allotted to 9 pasture groups (6 steers per pasture) in a randomized design. Pasture groups were randomly assigned to 1 of 3 treatments (3 pastures per treatment): 1) steers hand-fed supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a self-feeder supplement with an intake limiter (SELF). Hand-fed groups were fed a commercial commodity blend (38% corn gluten feed pellets, 30% cracked corn, 22% soy hull pellets, and 10% dried distillers grains) daily at 1.5% BW on an as fed basis. The SELF supplement was a blend of 70% cracked corn and 30% of an intake limiter-containing pellet that was formulated to maintain voluntary supplement intake at 1.5% BW on an as fed basis. Cattle were weighed on 2 consecutive days at the start and end of the experiment, and feed adjustments were made following three interim weigh-ins. Motion-sensing cameras were used to monitor cattle visits to the feeder and waterer portions of the pasture. Treatment did not impact (P = 0.13) BW, flesh condition score (FCS), dry matter intake (DMI), average daily gain (ADG), and backfat thickness. SELF steers were significantly more feed efficient than the AM supplemented groups (P = 0.03) and tended to be a greater G:F ratio (P = 0.08) for the PM supplemented groups vs. AM supplemented steers. Steers with access to a self-feeder showed behavioral differences to hand supplemented cattle, with more feeder visits in a 24 h period (P = 0.01) compared to AM and PM steers. Despite these behavioral observations, any disruption in natural grazing behavior was not dramatic enough to negatively influence backgrounded cattle growth performance. / Master of Science / Grazing beef cattle tend to follow a general pattern of grazing, rumination, and digestion that coincides with their environment and the time of year. Backgrounded cattle managed in pasture-based systems are traditionally offered supplemental feedings in the morning. However, this practice could be decreasing how efficiently cattle utilize forage resources. Natural grazing behaviors are more intense preceding the heat of the day and interruption of morning grazing bouts could decrease forage intake by causing cattle to come to the feeder to consume supplement feedings. To examine how feeding time potentially influences performance and grazing behavior of backgrounded beef cattle, 52 crossbred beef steers 7 to 8 months of age and weighing 243 kg were grazed on tall fescue pastures at the Southwest Virginia Agricultural Research and Extension Center from October 1 to November 8, 2019. Cattle were supplemented with either a commodity blend or cracked corn mixed with an intake limiter. Cattle were sourced from 4 local producers and allotted to 9 pastures by body weight (BW) and source. Pasture groups were randomly assigned to 1 of 3 treatments (3 pastures per treatment): 1) steers hand-fed supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a self-feeder supplement with an intake limiter (SELF). Hand-fed groups were fed a commercial commodity blend (38% corn gluten feed pellets, 30% cracked corn, 22% soy hull pellets, and 10% dried distillers grains) daily at 1.5% BW on an as fed basis. The SELF supplement was a blend of 70% cracked corn and 30% of an intake limiter-containing pellet that was formulated to maintain voluntary supplement intake at 1.5% BW on an as fed basis. Adjustments were made to the average BW of pasture groups, following three interim weigh dates at d 11, d 21, and d 30, to keep intake levels accurately at 1.5% BW. Flesh condition scores (FCS) were assigned on a scal of 1 to 9, with 1 considered emaciated and 9 excessively fat. 12th rib fat thickness (FT) was measured using an Aloka 500SC ultrasound. Both measurements were taken on the first and final day of the experiment. Motion-sensing cameras were installed in each pasture to capture pictures every one-minute following motion detection. Subsequent pictures were used to analysis the number of feed and water visits, along with time of day, in an attempt to characterize intake behavior. There were no major differences seen by treatment groups for BW, flesh condition score, DMI, ADG, and backfat thickness. Cattle on the SELF treatment had greater G:F than AM, with PM cattle being intermediate and not different than either. Steers with access to a self-feeder visited the feeder more than double the number of times in a 24 h period than either of the hand supplemented group. Despite differences in observed cattle behavior, any disruption in natural grazing behavior did not negatively influence performance of backgrounded steers.

No description available.