Calcium Requirement in Relation to Milk Fever and its Economic Impact in Dairy Cattle

The goal of this research was to compile and consolidate the disparate data on calcium requirements in connection to milk fever and its economic impact in dairy cattle. The most frequent mineral-related metabolic condition affecting dairy cows at parturition is milk fever, which occurs most commonly in adult dairy cows two to three days following parturition .It is caused by a severe lack of metabolizable calcium ions in the circulation (hypocalcaemia), and its primarily affects high-producing and high-performing dairy cows that are nearing their maximal output capability. Milk yield, parity, cow breed, and a lack of awareness of basic dairy management and ration formulation are all variables that contribute to milk fever. It reduces milk yield and fertility, which leads to the culling of high-producing dairy cows from a herd. It also raises the expense of animal treatment and the danger of additional parturient disorders such retained placenta, ketosis, displaced abomasum, and environmental mastitis. Intravenous calcium salts, such as borogluconate, at a rate of 2g/100kg body weight, as well as oral calcium solutions, are two methods for treating milk fever in dairy cows. Cases of milk fever, on the other hand, can be minimized with good management, notably through the use of proper feeds and feeding systems .To summarize, management of milk fever is very important because it should be considered as a gateway disease that greatly reduce the chance for full productivity and reproduction of dairy cows. The key to prevention of milk fever is management of a close-up dry cow or management during late pregnancy .Therefore, milk fever management is economically most important, as a result, raising dairy farmers’ awareness of milk fever and optimal ration compositions for their dairy cows is a critical instrument in the fight against milk fever.

Investigation of a shape memory alloy releasable mechanism applied in space environment

Though the conventional pyrotechnic fastener mechanisms are widely used in spacecraft for their reliable releasable-fastening function, they still have several unavoidable problems: physical shock, high maintenance cost, to name a few. This paper introduces a new type of smart releasable mechanism based on a Shape Memory Alloy (SMA) spring and its corresponding heating apparatus. To obtain the high heating efficiency and increase the response speed, the SMA spring is transitionally fit with the heating apparatus shell instead of directly heating by electric current. As soon as the heating apparatus begins to work, the SMA spring will provide an un-locking force to release the fastening device within the standard time, which also realizes the similar releasable-fastening function comparing with the conventional pyrotechnic fastener mechanisms. In order to ensure the reliability of space products, the heating apparatus is composed of two identical ceramic heating elements which can be controlled independently or synchronously. Finally, the experimental results clearly show that, under the satellite power supply at the constant value of 28 V, the SMA spring can reach the desired 30 N unlocking force within 93 s and 51 s by single or dual heating elements, respectively. The maximal output force can even be increased as large as 40 N under the limited volume of the releasable mechanism.

271 Beta-adrenergic agonists increase maximal output of oxidative phosphorylation in bovine satellite cells

Beta-adrenergic agonists (βAA) are widely used supplements in beef production to improve feed efficiency and increase lean muscle mass, yet little is known about the molecular mechanism by which βAA achieve this outcome. Our objective was to identify the influence of Ractopamine HCl (RH) and Zilpaterol HCl (ZH) on mitochondrial function in muscle stem cells. Satellite cells were isolated from skeletal muscle of cattle (n = 4) and yak (n = 1) at harvest. Cells were exposed to ZH, RH, or no βAA in replicates of four. Real-time measurements of oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) were recorded using intracellular flux analysis. Incubation of bovine (n = 4) cells with either ZH or RH increased maximal respiration (P = 0.004) and spare respiratory capacity (P = 0.013). When yak cells were included, the response to treatment was similar (P = 0.006 and P = 0.006), but an animal effect was also observed (P < 0.02), presumably due to differences in genetic background. These findings indicate that βAA-treated cells have the capacity to respond more efficiently to increased energy demands than non-supplemented cells. Beta-adrenergic agonists improve the efficiency of muscle stem cells in part by modifying mitochondrial function.

Reference Governors Based on Online Learning of Maximal Output Admissible Set

Reference governors are add-on control schemes that modify the reference commands, if it becomes necessary, in order to avoid constraint violations. To implement a reference governor, explicit knowledge of a model of the system and its constraints is typically required. In this paper, a reference governor which does not require an explicit model of the system or constraints is presented. It constructs an approximation of the maximal output admissible set, as the system operates, using online neural network learning. This approximation is used to modify the reference command in order to satisfy the constraints. The potential of the algorithm is demonstrated through simulations for an electric vehicle and an agile positioning system.