Anti-Predator Vigilance as an Indicator of the Costs and Benefits of Supplemental Feeding in Newly Released ‘Alalā (Corvus hawaiiensis)

Although supplemental feeding is commonly used as a conservation strategy during animal translocations, it comes with a number of pros and cons which can be hard to quantify. Providing additional food resources may lead to improved physical health, survivorship, and reproduction. However, offering predictable food sources could make individuals more conspicuous to predators and less aware of their surroundings, disrupting their natural predator-prey dynamic. Decisions such as release cohort size and supplemental feeder design could influence the balance of these costs and benefits, depending on how animals behave in the face of predation risk and static food sources. Additionally, animals released to the wild from long term human care must balance foraging and predation risk while adjusting to a novel environment. To help conservation managers make informed decisions in light of these potential costs, we studied the behavior of a cohort of 11 conservation-bred ‘alalā (Corvus hawaiiensis) at supplemental feeding stations after release into the wild. Vigilance, foraging behavior and social group size was quantified via 1,320 trail camera videos of ‘alalā over the span of 12 months. We found that vigilance increased over time since release, suggesting that ‘alalā learn and adjust to their novel surroundings. Both vigilance and eating decreased with group size, indicating that although conspecifics may share the burden of scanning for threats, they also increase competition for food. We also found that the design of the feeder may have limited birds' abilities to express anti-predator behavior since less vigilance was observed in individuals that manipulated the feeder. Yet, birds may have been able to offset these costs since they increasingly scrounged for food scraps next to the feeder as time progressed. We discuss how changes to behavior over time, social interactions, and feeder design should all be considered when planning supplemental feeding as part of wildlife translocations.

Effects of bale feeder design on hay waste, intake, and apparent diet digestibility in gestating beef cows

Two experiments were conducted to determine the effects of feeder design on hay intake, apparent diet digestibility, and hay waste in gestating beef cows. Native tallgrass prairie hay and a protein supplement was fed throughout both experiments. In Exp. 1, 56 crossbred cows were used in a Latin square arrangement. Feeder design treatments included a conventional open bottom steel ring (OBSR), an open bottom polyethylene pipe ring (POLY); a sheeted bottom steel ring (RING), and a sheeted bottom steel ring with a basket (BASK). Cows were weighed and allotted based on BW to one of four previously grazed 2.0 ha paddocks equipped with a concrete feeding pad. Fourteen cows were assigned to each paddock and three round bales were fed consecutively within each treatment period. The cows acclimated to the feeders while the first bale was being consumed. Subsequently, hay waste data was collected while the 2 nd and 3 rd bale within each period were being consumed. Waste was measured for each bale at 24, 48, 72, and 96 h after each bale was introduced into the pen. Hay waste was significantly affected by hay feeder design with 19.7, 21.1, 12.4, and 5.5% of original bale weight wasted for OBSR, POLY, RING and BASK, respectively (P < 0.01). There was a feeder design x day interaction (P < 0.01) with greater waste when the bale was first introduced into the pen in OBSR, POLY, and RING feeders and gradually declining thereafter, while waste from the BASK feeder was consistently low. There was a tendency (P = 0.06) for cows eating from OBSR feeders to consume less hay than cows eating from RING feeders. Feeder design did not influence apparent diet digestibility (P = 0.46). In Exp. 2, sixty-four crossbred cows (BW = 590 ± 59 kg) were used to determine waste, forage intake and apparent diet digestibility when hay was fed from a sheeted bottom steel ring (RING) or a RING feeder with a cone insert (CONE). More hay was wasted when cows were fed from RING feeders compared to CONE feeders (11.9% vs. 4.8%, P < 0.01). Feeder design had no effect on DMI or apparent digestibility (P > 0.45). Hay savings from adopting a more conservative feeder design can have a dramatic influence on hay utilization by beef cows and thus on cost of production.

Effect of Pocket Height on Aluminum flow through zero-bearing extrusion dies to produce single solid profile using FEM Simulation: تأثير ارتفاع المغذي على تدفق الألمنيوم عبر قوالب البثق ذات سطح الضبط الصفري لإنتاج مقطع مصمت مفرد بطريقة العناصر المنتهية

Extrusion is known as an industrial forming process for producing long sections with a fixed cross-sectional area and is often used to extrude colored metals, especially aluminum. The aluminum rods (Billets) are heated and pressed through a die to obtain the required profile. The research aims to study the effect of Pocket height when using zero bearing dies by modeling using the INSPIRE EXTRUDE METAL program package for a single rectangular section of 65 mm in length and 1.5 mm in width, and then to conduct experimental verification of the results by designing, manufacturing and testing a real mold in an aluminum extrusion factory that matches one of the molds Studied. As we studied a group of molds that have a Pocket so that the height of the pocket in them changes from zero (a reference flat die) to a height of 20 mm. The feeder design takes into account the homogenization of the flow across the studied section, which narrows in the center and widens at the edges. The measurement of the relative flow velocity at the front of the section was used as an indicator to analyze the results of the analytical experiment. The study showed that a certain height of the feeder of 10 mm must be maintained for the studied section. The FEM results and the practical experience were identical. This shows the importance of the FEM and its effectiveness in shortening the experimental work and that it can, to a large extent, save time and effort to manufacture, test and correct dies.

PSVII-13 Mineral feeder design impacts frequency of use in grazing beef cattle

Trace minerals are essential for many biological and metabolic processes and often supplemented ad libitum to grazing beef cattle. However, research has shown large variations in individual intakes. The objective of this study was to examine the impact of mineral feeder design on visitations and intake. In a crossover experimental design, beef cattle operations (n = 5) were randomly assigned to treatment sequence (lid status) and each evaluation period occurred for 5 – 7 days. Browning game trail cameras (Prometheus Group LLC, Birmingham, AL) were used to record time lapse pictures at 2-minute intervals from sunrise to sunset. Time was categorized as morning (≤10:00), mid-day (10:01 – 14:00), afternoon (14:01 – 18:00) and evening (>18:00). Activity was categorized as eating mineral, standing, lying or other within 0.5 m of feeder. Effects of farm, treatment, and time were analyzed using the GENMOD procedures of SAS 9.4 and mineral intake data were analyzed using PROC GLM. There were significant effects of farm (P < 0.001), treatment (P < 0.007), time (P < 0.001), and the treatment by time interaction (P < 0.001) for the numbers of cows and calves eating. Different herd sizes likely contributed to the significance of farm. Data were further analyzed using PROC FREQ. Of the animals eating, more cows and calves were observed eating with the lid removed (59.1% and 61.7%, respectively). However, average mineral disappearance did not differ (P = 0.57) by treatment (50.4 kg vs. 42.0 kg). Regardless of treatment, more cows were observed eating during the morning and afternoon (35% and 34.8%, respectively) than in the evening (10.3%). Similarly, more calves were categorized as eating in the morning and afternoon (29.3% and 41.3%, respectively) than in the evening (14.1%). These preliminary results indicate that feeder design may impact visitation of cows and calves but not average mineral disappearance.

Radial Line Slot Array Antenna Feeder Design Using Optimization Algorithm

High Bandwidth is required today to meet the demands for high data rates needed for future Direct-to Home (DTH) services in Ka-Band. In this work, the Brainstorm Optimization (BSO) method for the feeder architecture design is utilized to meet this need at 28GHz. The BSO is used as tool for the optimization of the beam squinted antenna feeder parameters in terms of air gaps, radial cavity dimensions and dielectric thickness needed for the optimal customization of the conventional Sub-Miniature A (SMA) connector for enhanced bandwidth realization in Ka Band at 28 GHz required for Direct to Home Services (DTH). Solutions values realized from the BSO algorithm using MATLAB computations were included in a visual BASIC program in the macros of CST 2017 microwave suites for pattern generation and antenna radiation characteristics computations A radiation efficiency value of 95.97% was achieved, an Impedance Bandwidth of 99.61% and Gain of 23.09dBi were achieved. Results were compared with earlier studies on Ka Band at 28GHz and the results shows an improvement in the bandwidth and directivity values.