Browsing by Subject "Forage"
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Item Below-ground plant residues as a source of nitrogen in double-crop forage systems(2016-09) Raskin, DanielDouble-cropping with forages can increase yields and N-use efficiency over sole-crop systems, but reductions in primary crop yield can limit economic returns. This study assessed whether the combination of high value, forage, early maturing corn varieties, and reduced N inputs constitutes an economically viable, low N-input double crop system for Minnesota. Biomass yield, N uptake, and residual soil N were measured in two double-crop (DC) and one sole-crop (SC) systems at site-years in MN, from 2014 to 2016. In DC treatments, a pea- (Pisum sativum L.) barley (Hordeum vulgare L.) forage bi-culture was double-cropped with early-maturing hybrid (DC-HC) or semidwarf (DC-SD) corn (Zea mays, L.) varieties. In SC treatments, full-season hybrid corn (SC-HC) was planted with no preceding forage. Corn was supplied with 6 N rates (0 to 224 kg N ha-1 for each yield component. Corn yielded less biomass in DC-HC (8.2 Mg ha-1) and DC-SD (1.8 Mg ha-1) treatments yielded compared to SC-HC (16.3 Mg ha-1). Biomass yield deficits lowered corn N demand in DC-HC treatments so that N rates >166 kg N ha-1 did not limit biomass yield in DC-HC treatments, where SC-HC corn was limited by N rate in three of four site-years. Total biomass accumulation was similar between DC-HC and SC-HC treatments when forage bi-culture yielded >7 Mg ha-1. This suggests that double-cropping with high-quality forages may constitute an economically viable low N-input alternative to sole-crop corn production in Minnesota.Item Effects of source and concentration of NDF from roughage on performance and carcass characteristics in finishing feedlot diets(2021-02) Zellmer, ChrisA meta-analysis was performed to investigate the effects of neutral detergent fiber from various dietary constituents (total, TNDF, forage, FNDF, co-products, CNDF, and grain, GNDF) on performance and carcass characteristics in finishing feedlot cattle. Backward elimination procedures were used on mixed models to determine effect of concentration and source of NDF on feedlot and carcass performance. Significant effect (P < 0.05) covariates representing use of growth technology (implants and ionophores), gender, days on feed and initial BW were permitted in the model. Models containing total, co-product and grain NDF concentration and source were least useful (based on reductions in AIC values) in describing the relationship between NDF and performance than forage NDF. Feeding any forage increased DMI (P < 0.03) compared to feeding no forage, and increasing concentration of FNDF tended to increase DMI quadratically (P =.10). Increasing concentration of FNDF decreased ADG (P = 0.02) and gain-to-feed ratio. (P = 0.01). Concentration of FNDF was quadratically related to quality grade (P < .0001). Yet, feeding a greater FNDF concentration was positively correlated to decreasing liver abscesses (P = 0.001). Fiber constituents associated with forage NDF were more consistently associated with finishing and carcass performance response than those constituents associated with total NDF.Item Expanding agroforestry in Minnesota, USA: assessing the potential for silvopasture as an alternative to passive woodland grazing(2016-08) Ford, Madeline177,791 ha of woodlands in Minnesota, USA are grazed. Often these woodlands are not managed specifically for timber or cattle benefits. This lack of management often leads to decreased timber value and reduced forage yields. Silvopasture is a potential alternative to this lack of land management on Minnesota woodlots. Silvopasture is a type of agroforestry that intentionally combines trees, forage and livestock in an intensively-managed system. However, very limited information exists about silvopasture use in Minnesota. This three-year study (2013-2015) examines the potential for silvopasture success in Minnesota through comparing production of unmanaged woodland grazing, silvopasture and open pasture sites. The study collaborated with three farmers in Central Minnesota to assess these three grazing systems on their land. Silvopasture paddocks were established through thinning and seeding woodland areas. The study assessed forage production, forage quality, species diversity, and livestock performance. Forage production was generally greater in silvopasture systems compared to unmanaged woodland grazing systems, and forage quality was lower in open pasture systems, at least during the first year. Additionally, species diversity was typically lowest in open pasture systems, and comparable between silvopasture and woodland areas. Livestock performance was similar between the grazing systems. Results indicate that silvopasture has potential in Minnesota, but more research is needed to develop specific management guidelines as well as monitor silvopasture for longer periods of time.Item The influence of mid-continent agricultural land use on the health and survival of commercially managed honey bee (Apis mellifera L.) colonies(2015-02) Smart, MatthewCommercial honey bee colonies were assessed in six apiaries that varied in their land use composition, in the Prairie Pothole Region of North Dakota over three years, 2010-2013. All colonies were transported to California to pollinate almonds each fall and were transported back to North Dakota each spring. The goal of the study was to determine the factors that most influenced, and thus predicted, annual survival of colonies in the different apiaries from summer through the following spring. The factors were grouped into three levels of analysis: 1) land use surrounding the North Dakota summer apiaries, including floral availability and pesticide exposure; 2) colony-level measures of population size, pollen and honey stores, queen status, and presence and prevalence of parasites and diseases; and 3) individual bee-level measures of nutritional physiology and immunity in 7-day old nurse bees collected from healthy colonies within each apiary. Results indicated that the area of uncultivated land (including CRP lands, pasture, grassland, flowering trees and shrubs, fallow land, hayland, and ditches) exerted a significant positive influence on the annual proportion of colonies surviving among apiaries. At the colony level, the amount of brood (pupae) in September and the mean pollen (g) collected per day over the summer correlated with higher annual survival. Higher Varroa destructor mite infestation levels in September were associated with reduced overwinter survival. Individual bee measures positively influencing survival included the expression level of vitellogenin in September and abdominal lipid stores in August. The expression level of lysozyme-2 in September was related to decreased apiary survival. A final, integrated model, incorporating all of the significant factors across the three levels, revealed that all, except Varroa levels, remained significant as predictors of annual colony survival within apiaries. Varroa was actively and effectively controlled by the collaborating beekeeper; thus in this study was not an overall contributor to colony mortality. This is the first study to quantify the impact and importance of pollen nutrition; i.e., "pollen flow" from the level of landscape to the individual-bee, to the health and survivorship of colonies. The most significant predictors of health and survivorship across all three levels of analysis were all related to nutrition - beginning with abundant flowers located overwhelmingly in uncultivated lands. More and/or better forage led to greater honey production and pollen collection which in turn led to greater nutritional stores in individual bees, and an overall decreased immune response. The presence of quality and abundant forage surrounding summering locations support healthy, robust, and most importantly, surviving, colonies of honey bees.Item Methods of restricting forage intake in horses(2014-05) Glunk, Emily ClareHorses have evolved to be hindgut fermenters, requiring small amounts of forage to be consumed throughout the day [1]. However, due to the recent increase in equine obesity [2-4], it has become necessary to restrict the amount of feedstuffs a horse consumes, often resulting in a restriction of forage intakes. In order to maintain a healthy gastrointestinal system, management strategies should attempt to replicate a horse's natural foraging habits. The objectives of the following studies were: 1) to investigate the effectiveness of decreasing pasture forage intakes via use of a grazing muzzle, and whether the effectiveness could be altered by grass morphology and palatability, 2) to investigate the effectiveness of "slow-feed hay nets" at increasing time to consumption of a preserved forage meal in stalled horses and 3) to observe the effects of increased time to consumption of daily rations on the post-prandial metabolic response. To determine objective 1, a two-year study was designed where four horses were used in a Latin square design in Year 1, while 3 horses were used in a completely randomized design in Year 2. Horses were grazed for 4 hours on monoculture plots four days per month for four months. Initial herbage mass and residual herbage mass measurements were taken to determine forage intakes. For objective 2, 8 horses were used in a replicated Latin square design, with 2 horses assigned to a treatment at a time. There was a control (C) of feeding hay on the ground, as well as three treatments: small-opening net (SN), medium-opening net (MN) and large-opening net (LN). Horses were allowed 4 h to consume their hay meal. Time to consumption and dry matter intake rate were measured using a stopwatch and any orts remaining after the 4 h were collected and weighed. To estimate objective 3, 8 overweight horses were enrolled in a randomized complete block design. Horses were blocked by bodyweight, BCS, and gender. Horses were fed a control diet of hay at 2% BW for a period of 10 days, and were then switched to a restricted diet of hay fed at 1.08% and ration balancer fed once daily at a rate of 0.001% BW. Horses were assigned to one of two treatments: hay fed off the floor (FLOOR) and hay fed in a small-opening hay net (HN). Serial 24 h blood samples were taken on day 0, when horses were still on baseline diet, as well as days 14 and 28. Plasma glucose, insulin, cortisol, and leptin values were estimated.Results of objective 1 found that grazing muzzles were effective at decreasing pasture intakes by 30% (P < 0.0001). Species had no effect on intakes in Year 1 (P = 0.27), but did impact intakes in Year 2 (P = 0.042). Results of objective 2 found that SN and MN were effective at increasing total time to consumption (P < 0.0001) compared to horses on the control and LN, more closely mimicking a horses' natural foraging behavior. Results of objective 3 found that hay nets decreased overall stress of horses on a restricted diet (P < 0.05), however length of sampling and weight loss had a larger impact on post-prandial metabolite. Horses on day 28 of the trial had higher average glucose, insulin and cortisol values, as well as lower AUC cortisol. Increasing time to consumption of forages is a healthy method of decreasing body weight while maintaining healthy post-prandial metabolite values.Item Varietal Trials of Selected Farm Crops(Minnesota Agricultural Experiment Station, 1996) University of Minnesota. Agricultural Experiment Station