151 research outputs found

    Evaluation of Beef Cattle Operations Utilizing Different Seasons of Calving, Weaning Strategies, Postweaning Management, and Retained Ownership

    Get PDF
    Data from a 3-yr study in Montana were utilized to evaluate impacts of season of calving, weaning strategy, and retained ownership of steer calves on enterprise profitability. Calving seasons were late winter (LW), early spring (ES), or late spring (LS). Each season had 2 weaning times: 190 (LW190, ES190) or 240 (LW240, ES240) d for LW and ES, and 140 (LS140) or 190 (LS190) d for LS. Backgrounding options included shipping steers to Oklahoma (OK1), or backgrounding in Montana to a constant age (MT2) or weight (MT3). Steers from OK1 and MT2 were finished in Oklahoma in confinement or via self-feeders on pasture and harvested in Texas. Steers in MT3 were finished in Montana in confinement and harvested in Colorado. Performance of each system was modeled based on actual animal performance, market prices, and variable input costs. When calves were sold at weaning, gross margins per cow were greatest for LS190 (P \u3c 0.05) and lowest for LW240. During backgrounding, costs of gain were similar among cow-calf systems, and gross margins per steer were greatest for LS140 (P \u3c 0.05), but not different among backgrounding systems. During finishing, costs of gain were greatest for steers from MT2 due to transportation costs to Oklahoma (P \u3c 0.05), and gross margin per steer favored MT3 (P \u3c 0.05). Gross margin for a ranch with a fixed land base did not differ among systems if calves were sold at weaning, but was greatest for LS systems after backgrounding or finishing (P \u3c 0.05)

    Cowpea in evolving livestock systems

    Get PDF
    Demand for livestock products has been increasing through much of the semi-arid tropics and will likely continue to increase along with the use of purchased feedstuffs. As smallholder livestock systems evolve and become more market oriented, the type of diets fed to livestock may change and the importance of feed marketing may increase. Mixed crop–livestock systems are key to meeting this increasing livestock product demand and cowpea (Vigna unguiculata [L.] Walp.) fodder (haulms) is an important component of these systems in semi-arid regions of the tropics where its high nutritional quality allows it to be used as a supplement to livestock diets based on cereal stovers and other low-quality forages. Improving the nutritional quality of cowpea fodder for use by livestock is important to improving the productivity and profitability of these mixed farming systems. Legume fodders will remain an important part of changing livestock diets and the development of cowpea varieties that better feed both people and their farm animals will give farmers new and better choices for improving levels and efficiency of livestock production. Cowpea breeding programs have worked toward producing dual-purpose varieties that emphasize the production of grain and fodder since the late 1980s and have produced several that have become well accepted when tested on-farm. Systematic screening of cowpea genetic resources is important for advancing development of dual-purpose varieties. Involvement of cultivar release agencies and seed production programs are also important to advance the use of improved dual-purpose crop varieties

    Cowpea and groundnut haulms fodder trading and its lessons for multidimensional cowpea improvement for mixed crop livestock systems in West Africa

    Get PDF
    Cowpea is an important legume crop in Africa, valued highly for its grain and also haulms, which are a tradable commodity in fodder markets. Fodder market surveys in Northern Nigeria showed that groundnut haulms were priced higher than cowpea haulms, probably because of their superior nutritive value. The economic value of haulms has prompted cowpea breeders and livestock nutritionists to explore haulm fodder traits as additional selection and breeding criteria. Fifty cowpea genotypes cultivated across five locations in Nigeria in 2013 and 2014 were evaluated for food fodder traits. Significant (P < 0.05) genotypic dependent variations were observed in yields (kg/ha) of grains (537–1082) and haulms (1173–3368), though significant (P < 0.05) effects of location and year were observed. Grain and fodder yield had a tendency to be positively correlated (r = 0.26, P = 0.07). Haulms were analyzed for nitrogen (N), fiber fractions, in vitro digestibility, and metabolizable energy content. Highly significant variations were observed in all genotypic and livestock nutrition traits, although location and year had significant effects. Trade-offs between grain yield and haulm fodder quality traits were largely absent and haulm acid detergent lignin and grain yield were even inversely correlated (r = -0.28, P = 0.05), that is high grain yielders had decreased haulm lignin. However, haulm N and grain yield also tended to be negatively associated (r = -0.26, P = 0.07). Haulm fodder quality traits and haulm yield were mostly positively correlated (P < 0.05). Broad sense heritabilities for grain and fodder yield were 0.50 and 0.29, respectively, while heritability for haulm fodder quality traits ranged from 0.61 to 0.67, providing opportunities for concomitant increase in grain yield and haulm fodder quality traits. Selection of the 10 highest ranking genotypes for grain yield, haulm yield, haulm N, and haulm in vitro organic matter digestibility showed selection groups overlapping, suggesting that multi-trait selection is feasible. Economical evaluation showed that choice of primary traits is context specific, highlighting the need for identifying and targeting appropriate genotypes to fit different production systems. Considering haulm quantity and quality as traits of economic value can increase overall plant value in mixed crop-livestock systems

    Behavior of multitemporal and multisensor passive microwave indices in Southern Hemisphere ecosystems

    Get PDF
    ©2014. American Geophysical Union. All Rights Reserved. This study focused on the time series analysis of passive microwave and optical satellite data collected from six Southern Hemisphere ecosystems in Australia and Argentina. The selected ecosystems represent a wide range of land cover types, including deciduous open forest, temperate forest, tropical and semiarid savannas, and grasslands. We used two microwave indices, the frequency index (FI) and polarization index (PI), to assess the relative contributions of soil and vegetation properties (moisture and structure) to the observations. Optical-based satellite vegetation products from the Moderate Resolution Imaging Spectroradiometer were also included to aid in the analysis. We studied the X and Ka bands of the Advanced Microwave Scanning Radiometer-EOS and Wind Satellite, resulting in up to four observations per day (1:30, 6:00, 13:30, and 18:00-h). Both the seasonal and hourly variations of each of the indices were examined. Environmental drivers (precipitation and temperature) and eddy covariance measurements (gross ecosystem productivity and latent energy) were also analyzed. It was found that in moderately dense forests, FI was dependent on canopy properties (leaf area index and vegetation moisture). In tropical woody savannas, a significant regression (R2) was found between FI and PI with precipitation (R2->-0.5) and soil moisture (R2->-0.6). In the areas of semiarid savanna and grassland ecosystems, FI variations found to be significantly related to soil moisture (R2->-0.7) and evapotranspiration (R2->-0.5), while PI varied with vegetation phenology. Significant differences (p-<-0.01) were found among FI values calculated at the four local times. Key Points Passive microwave indices can be used to estimate vegetation moisture Microwave observations were supported by flux data Passive microwave indices could be used to estimate evapotranspiratio
    • 

    corecore