Fecal indices for prediction of forage intake and quality by steers

Six in vivo digestion trials were conducted, in which a total of thirty-nine fecal samples were obtained from Angus steers receiving tall fescue-legume mixtures of varying proportions. The forages were of diverse maturities and digestibilities. The forage and fecal samples were analyzed for dry matter, nitrogen, ether extract, crude fiber, ash, cell wall constituents, acid-detergent fiber, acid-detergent lignin, in vitro dry matter digestibility, and in vitro organic matter digest-ibility, and in addition, the fecal samples were analyzed for acid-insoluble ash, sodium, zinc, and urobilinogen. Nitrogen-free extract, cellulose, hemicellulose, and acid-soluble ash were calculated. Wet matter intake, dry matter intake, wet fecal output, fecal dry matter output, dry matter digestibility, digestible dry matter intake, total digestible nutrients, total digestible nutrient intake, crude protein digestion coefficient, and digestible crude protein intake were determined for each steer. A factor analysis was conducted to aid in explaining how each variable was related to other variables. Several equations were de-veloped in which fecal variables served as indpendent variables for the prediction of digestion trial variables. For each dependent variable, a series of multiple regression equations containing one to eleven variables was formulated which best predicted (maximum R2) that particular variable. These equations included squared and interaction terms of fecal variables when its addition produced greater increase in R2 values than addition of any other variable. Over 91% and 89% of the variation in wet matter intake and dry matter intake, respectively, were accounted for with each best-fit eleven-variable index. The fecal index containing ten independent variables explained almost 65% of the variation in wet fecal output, whereas the eleven-variable model for prediction of fecal dry matter output explained about 63% of its variation. A ten-variable model provided a fecal index which explained approximately 79% of the variation in dry matter digestibility; 81.62% of the variation in digestible dry matter intake was accounted for by the best-fit eleven-variable prediction equation. The eleven-variable indices developed for the prediction of total digestible nutrients and total digestible nutrient intake explained approximately 88% and 85% of the variation, respectively. Digestible crude protein and digestible crude protein intake, when predicted from eleven-variable models, accounted for over 88% of the variation in each of these dependent variables. The R2 values obtained from these fecal indices support the theory that the fecal index technique is a valuable method of evaluation of pasture, and that large amounts of variation can be accounted by using a broad spectrum of forage compositions

Synthesis Paper: Targeted Livestock Grazing: Prescription for Healthy Rangelands

Targeted livestock grazing is a proven tool for manipulating range land vegetation, and current knowledge about targeted livestock grazing is extensive and expanding rapidly. Targeted grazing prescriptions optimize the timing, frequency, intensity, and selectivity of grazing (or browsing) in combinations that purposely exert grazing/ browsing pressure on specific plant species or portions of the landscape. Targeted grazing differs from traditional grazing management in that the goal of targeted grazing is to apply defoliation or trampling to achieve specific vegetation management objectives,whereas the goal of traditional livestock grazing management is generally the production of livestock commodities. A shared aim of targeted livestock grazing and traditional grazing management is to sustain healthy soils, flora, fauna, and water resources that, in turn, can sustain natural ecological processes (e.g., nutrient cycle, water cycle, energy flow). Targeted grazing prescriptions integrate knowledge of plant ecology, livestock nutrition, and livestock foraging behavior. Livestock can be focused on target areas through fencing, herding, or supplement placement. Although practices can be developed to minimize the impact of toxins contained in target plants, the welfare of the animals used in targeted grazing must be a priority. Monitoring is needed to determine if targeted grazing is successful and to refine techniques to improve efficacy and efficiency. Examples of previous research studies and approaches are presented to highlight the ecological benefits that can be achieved when targeted grazing is applied properly. These cases include ways to suppress invasive plants and ways to enhance wildlife habitat and biodiversity. Future research should address the potential to select more adapted and effective livestock for targeted grazing and the associated animal welfare concerns with this practice. Targeted livestock grazing provides land managers a viable alternative to mechanical, chemical, and prescribed fire treatments to manipulate range land vegetation

Synthesis Paper: Targeted Livestock Grazing: Prescription for Healthy Rangelands

Targeted livestock grazing is a proven tool for manipulating rangeland vegetation, and current knowledge about targeted livestock grazing is extensive and expanding rapidly. Targeted grazing prescriptions optimize the timing, frequency, intensity, and selectivity of grazing (or browsing) in combinations that purposely exert grazing/browsing pressure on specific plant species or portions of the landscape. Targeted grazing differs from traditional grazing management in that the goal of targeted grazing is to apply defoliation or trampling to achieve specific vegetation management objectives, whereas the goal of traditional livestock grazing management is generally the production of livestock commodities. A shared aim of targeted livestock grazing and traditional grazing management is to sustain healthy soils, flora, fauna, and water resources that, in turn, can sustain natural ecological processes (e.g., nutrient cycle, water cycle, energy flow). Targeted grazing prescriptions integrate knowledge of plant ecology, livestock nutrition, and livestock foraging behavior. Livestock can be focused on target areas through fencing, herding, or supplement placement. Although practices can be developed to minimize the impact of toxins contained in target plants, the welfare of the animals used in targeted grazing must be a priority. Monitoring is needed to determine if targeted grazing is successful and to refine techniques to improve efficacy and efficiency. Examples of previous research studies and approaches are presented to highlight the ecological benefits that can be achieved when targeted grazing is applied properly. These cases include ways to suppress invasive plants and ways to enhance wildlife habitat and biodiversity. Future research should address the potential to select more adapted and effective livestock for targeted grazing and the associated animal welfare concerns with this practice. Targeted livestock grazing provides land managers a viable alternative to mechanical, chemical, and prescribed fire treatments to manipulate rangeland vegetation

Integrating space and time: a case for phenological context in grazing studies and management

In water-limited landscapes, patterns in primary production are highly variable across space and time. Livestock grazing is a common agricultural practice worldwide and a concern is localized overuse of specific pasture resources that can exacerbate grass losses and soil erosion. On a research ranch in New Mexico with average annual rainfall of 217 mm, we demonstrate with a quantitative approach that annual seasons vary greatly and examine foraging patterns in Angus-Hereford (Bos taurus) cows. We define five seasonal stages based on MODIS NDVI: pre-greenup, greenup, peak green, drydown and dormant, and examine livestock movements in 2008. Daily distance traveled by cows was greater and foraging area expanded during periods with higher precipitation. A regression model including minimum NDVI, rainfall and their interaction explained 81% of the seasonal variation in distance traveled by cows (P<0.01). Cows explored about 81 ha·d−1 while foraging, but tended to explore smaller areas as the pasture became greener (greenup and peak green stages). Cows foraged an average of 9.7 h daily and spent more time foraging with more concentrated search patterns as pastures became greener. Our findings suggest that phenological context can expand the capacity to compare and integrate findings, and facilitate meta-analyses of grazing studies conducted at different locations and times of year

The Changing Role of Shrubs in Rangeland-Based Livestock Production Systems: Can Shrubs Increase Our Forage Supply?

On the Ground • Loss of grasslands to shrublands continues. • Demand for livestock products is expected to continue to grow. • Increased demand for red meat may stimulate rangeland livestock production. • Methods for increasing shrub use are needed to meet increasing forage demands.The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202

One-Seed Juniper Sapling Use by Goats in Relation to Stocking Density and Mixed Grazing With Sheep

Suppression of one-seed juniper (Juniper monosperma [Englem.] Sarg.) reinvasion with goats requires achieving levels of defoliation of newly established saplings that eventually kill or suppress plant growth. We tested the effects of stocking density and mixed grazing with sheep on the level of use of one-seed juniper saplings by goats. In summer and spring, groups of 10 does (goats alone, GA) or 5 does and 4 ewes (mixed grazing, MG), grazed 20 X 30 m cells infested with saplings (500-533 ha-1; mean: 0.8 m tall), either continuously for 6 d (low stocking density, LD) or with daily rotation through 10 X 10 m cells during the 6-d period (high stocking density, HD) in a block design. Feeding activity; juniper in feces; utilization of herbaceous vegetation; frequency of saplings with light, moderate, and heavy foliage and bark use; and branch utilization were determined. Goats in HD spent more time feeding on saplings, less time feeding on herbaceous forages, and tended to consume more juniper than goats in LD. Utilization of herbaceous vegetation ranged from 52% to 73% and was higher for MG than GA and for LD than HD. The MG-HD treatment resulted in the highest frequency of short saplings ( 1 m) saplings. Sapling mortality was not affected by treatments (P > 0.05) and averaged 5% across treatments. Branch debarking was greater in spring (P = 0.02) and explained approximately 80% of branch mortality and 62% and 52% of the reduction in sapling live crown height and volume. Branch utilization (percent length) was not affected by grazing treatments (range: 45-48%), but was influenced by the length and diameter of branches. This study suggests that high stocking density and mixed grazing stimulate feeding behaviors that increase utilization of juniper saplings by goats. Susceptibility of saplings to defoliation and debarking varies with sapling size, branch structure, and season. Targeted grazing in spring appears to have a greater impact on sapling suppression and branch mortality due to higher debarking frequency. The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Synthesis Paper: Targeted Livestock Grazing: Prescription for Healthy Rangelands

Targeted livestock grazing is a proven tool for manipulating range land vegetation, and current knowledge about targeted livestock grazing is extensive and expanding rapidly. Targeted grazing prescriptions optimize the timing, frequency, intensity, and selectivity of grazing (or browsing) in combinations that purposely exert grazing/ browsing pressure on specific plant species or portions of the landscape. Targeted grazing differs from traditional grazing management in that the goal of targeted grazing is to apply defoliation or trampling to achieve specific vegetation management objectives,whereas the goal of traditional livestock grazing management is generally the production of livestock commodities. A shared aim of targeted livestock grazing and traditional grazing management is to sustain healthy soils, flora, fauna, and water resources that, in turn, can sustain natural ecological processes (e.g., nutrient cycle, water cycle, energy flow). Targeted grazing prescriptions integrate knowledge of plant ecology, livestock nutrition, and livestock foraging behavior. Livestock can be focused on target areas through fencing, herding, or supplement placement. Although practices can be developed to minimize the impact of toxins contained in target plants, the welfare of the animals used in targeted grazing must be a priority. Monitoring is needed to determine if targeted grazing is successful and to refine techniques to improve efficacy and efficiency. Examples of previous research studies and approaches are presented to highlight the ecological benefits that can be achieved when targeted grazing is applied properly. These cases include ways to suppress invasive plants and ways to enhance wildlife habitat and biodiversity. Future research should address the potential to select more adapted and effective livestock for targeted grazing and the associated animal welfare concerns with this practice. Targeted livestock grazing provides land managers a viable alternative to mechanical, chemical, and prescribed fire treatments to manipulate range land vegetation

Foraging Behavior of Heritage versus Desert-Adapted Commercial Rangeland Beef Cows in Relation to Dam-Offspring Contact Patterns

We compared cow-calf contacts, as well as movement, activity, and pasture use patterns of heritage Raramuri Criollo (RC) and desert-adapted commercial Angus Hereford crossbred (AH) beef cattle grazing Chihuahuan Desert pastures during 4 wk in the summers of 2016 and 2017. Within each herd of 11 cow-calf pairs, a group of 7−9 randomly selected cows were fitted with Global Positioning System collars that recorded animal position at 10-min intervals. Proximity loggers configured to record contact events (< 1-m radius) were fitted on a subset of five cow-calf pairs of each breed. The effect of breed on cow-calf contacts, as well as the dams’ movement, activity, and pasture use patterns were analyzed via mixed analysis of variance models. A higher number of RC cow-calf contacts occurred while the dam was grazing and traveling compared with AH counterparts (P ≤ 0.05). No breed-related differences were observed in the overall number and duration of cow-calf contact events. Compared with AH dams, RC cows traveled farther each day (RC: 7.51 vs. AH: 4.85 km, P < 0.01) at higher movement velocities (5.46 vs. 3.53 m. min−1, P < 0.01) and spent more time traveling (1.05 vs. 0.48 h, P < 0.01), more time grazing (9.37 vs. 7.45 h, P < 0.01), and less time resting (13.07 vs. 15.68 h, P < 0.01). RC cows explored almost three times more daily area than AH (152.30 vs. 57.69 ha, P = 0.01) but spent similar amounts of time within 200 m and 100 m of a drinker. RC calves explored larger daily areas than their AH counterparts (83.0 vs. 20.8 ha, P = 0.05), but no breed differences were detected in the number of contact events near drinkers. RC calves possibly impose fewer constraints on their dams’ movement and activity patterns compared with commonly used British crossbreds when grazing the Chihuahuan Desert during summer.EEA BalcarceFil: Nyamuryekung’e, Shelemia. New Mexico State University. Department of Animal and Range Sciences; Estados Unidos.Fil: Cibils, Andres F. New Mexico State University. Department of Animal and Range Sciences; Estados Unidos.Fil: Estell, Richard E. US Department of Agriculture-Agricultural Research Service; Estados Unidos.Fil: McIntosh, Matthew. New Mexico State University. Department of Animal and Range Sciences; Estados Unidos.Fil: VanLeeuwen, Dawn. New Mexico State University. Department of Agricultural Extension Education; Estados Unidos.Fil: Steele, Caitriana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: González, Alfredo. New Mexico State University. Department of Agricultural Extension Education; Estados Unidos.Fil: Spiegal, Sheri. Agricultural Research Service, Department of Agriculture; Estados Unidos.Fil: Continanza, Fátima Guadalupe. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina

Genetic and productive background of Criollo cattle in Argentina, Mexico, Uruguay and the United States

Cattle were first introduced to the Western Hemisphere in 1493 and by subsequent introductions from the Iberian Peninsula, providing the genetic background of the American Criollo cattle, with influences from Spanish, Portuguese and African breeds. Criollo's high adaptive capacity enabled them to spread and colonize a wide variety of environments. Their ancestry combined with local adaptations created the wide spectrum of American Criollo breeds that we see today, many currently at risk of extinction. We review the existing genetic and production data on the Argentinian, Mexican, Uruguayan and US Creole cattle that form the basis of the current and future research described in this special issue. In these countries, Criollo cattle became the basis of the livestock industry for the supply of meat, hides and animal work, until they were displaced by more specialized European and cebuine type cattle breeds at the end of the 19th century. Since then, Criollo herds remained mostly in marginal regions unsuitable for commercial breeds. Efforts by local producers and research institutions helped to preserve Criollo populations. Several studies have demonstrated that these animals can produce high quality meat and are more resistant to diseases, and emphasize their high fertility, calving ease, longevity and ability to adapt to harsh environments. Mexican Criollos have high genetic diversity but lack strong conservation programs. More detailed genetic characterization within each regional Criollo population is needed to establish appropriate conservation strategies. In US, Texas Longhorn cattle are closely related to Mexican Criollos, while Pineywoods show a stronger relationship with Iberian breeds. Variable levels of genetic diversity were found among all North American Criollos, probably due to crossbreeding. Criollos from Argentina and Uruguay showed clear divergence due to genetic isolation but clustered together, representing the southernmost expansion of bovine cattle in the Americas.Instituto de GenéticaFil: Armstrong, Eileen. Universidad de la República. Facultad de Veterinaria. Unidad Académica Genética y Mejora Animal. Departamento de Producción Animal; UruguayFil: Rodriguez Almeida, Felipe A. Universidad Autónoma de Chihuahua. Facultad de Zootecnia y Ecología; MéxicoFil: McIntosh, Matthew. New Mexico State University. Department of Animal and Range Sciences; Estados UnidosFil: Poli, Mario Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Cibils, Andrés Francisco. New Mexico State University. Department of Animal and Range Sciences; Estados UnidosFil: Martínez-Quintana, José Alfredo. Universidad Autónoma de Chihuahua. Facultad de Zootecnia y Ecología; MéxicoFil: Félix-Portillo, Monserrath. Universidad Autónoma de Chihuahua. Facultad de Zootecnia y Ecología; MéxicoFil: Estell, Richard E. United States Department of Agriculture. Agricultural Research Service. Jornada Experimental Range; Estados Unido

Adapting to climate change on desert rangelands: A multi-site comparison of grazing behavior plasticity of heritage and improved beef cattle

Climate change is amplifying the spatiotemporal heterogeneity of desert rangeland forages through its impact on precipitation variability. Foraging behavior plasticity (an animal's ability to alter its behavior to cope with environmental variation) could be a key trait for climate adaptation of beef cattle in arid environments. We analyzed GPS-derived movement and activity data of Criollo and commercial beef cattle from eight studies conducted at sites in North and South America to determine whether seasonal and year-to-year behavior plasticity varied significantly between breeds. We calculated dormant/brown season or driest year percent change in foraging behavior relative to growing/green season or wettest year. Compared to commercial beef breeds, Criollo cattle exhibited significantly greater seasonal adjustment in daily distance traveled (20% increase vs. 2% decrease, P ≤ 0.02) and daily grazing effort (25% vs. 1.5% increase, P = 0.01) during the dormant/brown vs. growing/green season. Increase in daily area explored during the dormant/brown season was almost three times greater in Criollo vs. commercial beef cattle (P = 0.09). Seasonal adjustment in daily time spent grazing was similar for Criollo and commercial beef breeds. Increase in daily area explored during the dormant/brown season of dry vs. wet years was three times greater for Criollo vs. commercial beef breeds (P = 0.03). Criollo cattle tended (P = 0.09) to exhibit greater behavior adjustment than commercial beef counterparts in daily distance traveled during the dormant/brown season of dry vs. wet years (22% vs. 4% increase, respectively). No breed differences in adjustment of time spent grazing (P = 0.36) or grazing effort (P = 0.20) during dormant/brown season of dry vs. wet years were observed. Dry vs. wet year grazing behavior adjustments during the growing/green season were similar for both breeds. Grazing behavior plasticity observed in Criollo cows could be a critical trait for desert beef herds in the face of increasingly variable rainfall patterns occurring as a result of climate change.EEA CatamarcaFil: Cibils, Andrés Francisco. USDA ARS Oklahoma and Central Plains Agricultural Research Center. USDA Southern Plains Climate Hub; Estados UnidosFil: Estell, Richard E. United States Department of Agriculture. Agricultural Research Service. Jornada Experimental Range; Estados UnidosFil: Spiegal, Sheri. United States Department of Agriculture. Agricultural Research Service. Jornada Experimental Range; Estados UnidosFil: Nyamuryekung'e, Shelemia. New Mexico State University. Department of Animal and Range Sciences; Estados UnidosFil: McIntosh, Matthew. United States Department of Agriculture. Agricultural Research Service. Jornada Experimental Range; Estados UnidosFil: Duni, Danielle M. New Mexico State University. Department of Animal and Range Sciences; Estados UnidosFil: Herrera Conegliano, Oscar Ariel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Catamarca; ArgentinaFil: Rodriguez Almeida, Felipe A. Universidad Autónoma de Chihuahua. Facultad de Zootecnia y Ecología; MéxicoFil: Roacho Estrada, Octavio. Universidad Autónoma de Chihuahua. Facultad de Zootecnia y Ecología; MéxicoFil: Blanco, Lisandro Javier. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria La Rioja; ArgentinaFil: Duniway, Michael C. Southwest Biological Science Center. US Geological Survey; Estados UnidosFil: Utsumi, Santiago A. New Mexico State University. Department of Animal and Range Sciences; Estados UnidosFil: Gonzalez, Alfredo L. United States Department of Agriculture. Agricultural Research Service. Jornada Experimental Range; Estados Unido