Search

Abstract Core body temperature (CBT) regulation is crucial for mammalian wellbeing and survival. Cattle pant to dissipate excess heat to regulate CBT when ambient conditions exceed thermoneutral zones. However, to date, neither the variability in cattle heat response, the lagged response of CBT to thermal indices, nor the diurnal patterns of thermal indices, CBT and panting have been reported in the literature. We decomposed thermal indices, CBT and panting time-series data for 99 feedlot heifers across three discrete heat events into diurnal, trend and residual components. Both raw and decomposed data were analysed to explore the lagged CBT and panting responses and the association between series. We show ambient thermal conditions impact CBT with a 1-h lag despite a lag of between 1.5 to 3 h from raw data. Average individual panting scores were used to identify heat-susceptible and heat-tolerant cattle. Heat-susceptible cattle showed greater CBT (P

Purple blotch of garlic caused by Alternaria porri is recognized as a prominent diseases posing threat to garlic cultivation throughout the world including Bangladesh. The experiments were conducted to determine the prevalence of purple blotch disease on garlic varieties in field condition, to test the pathogenicity of isolated causal organism and to find out the suitable management options of the disease. Eight garlic varieties viz. BAU Rashun-1, BAU Rashun-2, BARI Rashun-1, BARI Rashun-2, BARI Rashun-3, BARI Rashun-4, Local Deshi and Local Indian were explored in prevalence study and nine management option comprising a bio-agent Trichoderma harzianum (T1), five botanicals viz. Lantana camara (T2), Spilanthes paniculata (T3), Ocimum sanctum (T4), Raphanas raphanistrum (T5) and Azadirachta indica (T6), two fungicides Mancozeb 80% WP (T7) and Sulcox 50% WP (T8) and, an untreated control (T9) were explored in the experiments. BARI Rashun-3 showed the highest disease incidence (40.00%) and severity (92.00%) of purple blotch disease. Isolation, identification of pathogen and pathogenicity test was carried out as well. In case of management, all botanicals and bio-agent were tested significantly beneficial in lessening the disease incidence and severity of purple blotch disease. The results revealed that Lantana camara (T2) was found most effective for minimizing the disease incidence (26.67, 26.67 and 33.33%) at 30, 45 and 60 DAS, respectively while maximum disease incidence was recorded in control (T9) (86.67, 96.67 and 100.00%). T2 also reduced disease severity at 30 DAS (11.00%) whereas, at 45 DAS (18.67%) and 60 DAS (19.33%) T1 performed well against the disease.

The growingdisposition of livestock resources as well as the poultry sector with the corroborating weather conditions in Bangladesh encourages an auspicious future of bioenergy. In this paper, existing energy situation of Bangladesh and noteworthy activities associated with renewable energy has been mentioned. After presenting the potential of livestock resources of Bangladesh, the Union based biogas plant model has been explained. The model has been employed to study the potential of generating biogas as well as electricity in Chattogram division of Bangladesh. Under this model, each union can contribute 552 m3 of gas or 0.75 MW of electricity daily and in total 3.2×105 m3 of gas or 435 MW of electricity can be generated in Chattogram division. Union based biogas plants will be beneficial for the rural development but difficult in implementation. Therefore, several issues that required reconciling before installations have been indicated.

The heterogeneous networks (HetNets) are regarded as a promising solution in LTE-Advanced for ubiquitous and cost effective broadband user experience. But there are challenges to support seamless mobility in HetNets, especially, when the user speed is high. In this paper, we investigate these challenges and study the scopes to address them for the improvement of cell edge performance. The study indicates the requirement of enhanced and versatile controllability over adaptation of cell switching parameters that simultaneously depends on variation in user speeds, traffic loads, street patterns, types of cells involved in switching, and so forth. We propose a scheme to scale cell switching parameters that incorporates Doppler spread estimation and adapts smoothly to various changes. Both the eNodeB and the UE participate in a versatile control over the scaling. Limited simulations have been performed to partially reflect the outcome of the proposed scheme.

The Fractional Frequency Reuse (FFR) is a resource allocation technique that can effectively mitigate inter-cell interference (ICI) in LTE based HetNets and it is a promising solution. Various FFR schemes have been suggested to address the challenge of interference in femtocell systems. In this paper, we study the scopes of interference mitigation and capacity improvement. We propose a resource allocation scheme that gradually varies frequency resource share with distance from the eNodeB for both macrocells and femtocells in order to attain better utilization of the resources. This is performed effectively using three layers in the cell. The proposal also employs high number sectors in a cell, low interference and good frequency reuse. Monte-Carlo simulations are performed, which show that the proposed scheme achieves significantly better throughput compared to the existing FFR schemes.

The aim of this modelling study was to investigate the effect of large herd size (and land areas) on walking distances and milking interval (MI), and their impact on milk yield and economic penalties when 50% of the total diets were provided from home grown feed either as pasture or grazeable complementary forage rotation (CFR) in an automatic milking system (AMS). Twelve scenarios consisting of 3 AMS herds (400, 600, 800 cows), 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as ‘moderate’; optimum pasture utilisation of 19.7 t DM/ha, termed as ‘high’) and 2 rates of incorporation of grazeable complementary forage system (CFS: 0, 30%; CFS = 65% farm is CFR and 35% of farm is pasture) were investigated. Walking distances, energy loss due to walking, MI, reduction in milk yield and income loss were calculated for each treatment based on information available in the literature. With moderate pasture utilisation and 0% CFR, increasing the herd size from 400 to 800 cows resulted in an increase in total walking distances between the parlour and the paddock from 3.5 to 6.3 km. Consequently, MI increased from 15.2 to 16.4 h with increased herd size from 400 to 800 cows. High pasture utilisation (allowing for an increased stocking density) reduced the total walking distances up to 1 km, thus reduced the MI by up to 0.5 h compared to the moderate pasture, 800 cow herd combination. The high pasture utilisation combined with 30% of the farm in CFR in the farm reduced the total walking distances by up to 1.7 km and MI by up to 0.8 h compared to the moderate pasture and 800 cow herd combination. For moderate pasture utilisation, increasing the herd size from 400 to 800 cows resulted in more dramatic milk yield penalty as yield increasing from c.f. 2.6 and 5.1 kg/cow/d respectively, which incurred a loss of up to $AU 1.9/cow/d. Milk yield losses of 0.61 kg and 0.25 kg for every km increase in total walking distance (voluntary return trip from parlour to paddock) and every one hour increase in MI, respectively. The high pasture utilisation combined with 30% of the farm in CFR in the farm increased milk yield by up to 1.5 kg/cow/d, thereby reducing loss by up to $0.5/cow/d (c.f. the moderate pasture and 800 cow herd scenario). Thus, it was concluded that the successful integration of grazeable CFS with pasture has the potential to improve financial performance compared to the pasture only, large herd, AMS.

To maintain a predominantly pasture-based system, the large herd milked by automatic milking rotary would be required to walk significant distances. Walking distances of greater than 1-km are associated with an increased incidence of undesirably long milking intervals and reduced milk yield. Complementary forages can be incorporated into pasture-based systems to lift total home grown feed in a given area, thus potentially ‘concentrating’ feed closer to the dairy. The aim of this modelling study was to investigate the total land area required and associated walking distance for large automatic milking system (AMS) herds when incorporating complementary forage rotations (CFR) into the system. Thirty-six scenarios consisting of 3 AMS herds (400, 600, 800 cows), 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as moderate; optimum pasture utilisation of 19.7 t DM/ha, termed as high) and 6 rates of replacement of each of these pastures by grazeable CFR (0%, 10%, 20%, 30%, 40%, 50%) were investigated. Results showed that AMS cows were required to walk greater than 1-km when the farm area was greater than 86 ha. Insufficient pasture could be produced within a 1 km distance (i.e. 86 ha land) with home-grown feed (HGF) providing 43%, 29%, and 22% of the metabolisable energy (ME) required by 400, 600, and 800 cows, respectively from pastures. Introduction of pasture (moderate): CFR in AMS at a ratio of 80:20 can feed a 400 cow AMS herd, and can supply 42% and 31% of the ME requirements for 600 and 800 cows, respectively with pasture (moderate): CFR at 50:50 levels. In contrast to moderate pasture, 400 cows can be managed on high pasture utilisation (provided 57% of the total ME requirements). However, similar to the scenarios conducted with moderate pasture, there was insufficient feed produced within 1-km distance of the dairy for 600 or 800 cows. An 800 cow herd required 140 and 130 ha on moderate and high pasture-based AMS system, respectively with the introduction of pasture: CFR at a ratio of 50:50. Given the impact of increasing land area past 86 ha on walking distance, cow numbers could be increased by purchasing feed from off the milking platform and/or using the land outside 1-km distance for conserved feed. However, this warrants further investigations into risk analyses of different management options including development of an innovative system to manage large herds in an AMS farming system.

One of the challenges to increase milk production in a large pasture-based herd with an automatic milking system (AMS) is to grow forages within a 1-km radius, as increases in walking distance increases milking interval and reduces yield. The main objective of this study was to explore sustainable forage option technologies that can supply high amount of grazeable forages for AMS herds using the Agricultural Production Systems Simulator (APSIM) model. Three different basic simulation scenarios (with irrigation) were carried out using forage crops (namely maize, soybean and sorghum) for the spring-summer period. Subsequent crops in the three scenarios were forage rape over-sown with ryegrass. Each individual simulation was run using actual climatic records for the period from 1900 to 2010. Simulated highest forage yields in maize, soybean and sorghum- (each followed by forage rape-ryegrass) based rotations were 28.2, 22.9, and 19.3 t dry matter/ha, respectively. The simulations suggested that the irrigation requirement could increase by up to 18%, 16%, and 17% respectively in those rotations in El-Niño years compared to neutral years. On the other hand, irrigation requirement could increase by up to 25%, 23%, and 32% in maize, soybean and sorghum based rotations in El-Nino years compared to La-Nina years. However, irrigation requirement could decrease by up to 8%, 7%, and 13% in maize, soybean and sorghum based rotations in La-Nina years compared to neutral years. The major implication of this study is that APSIM models have potentials in devising preferred forage options to maximise grazeable forage yield which may create the opportunity to grow more forage in small areas around the AMS which in turn will minimise walking distance and milking interval and thus increase milk production. Our analyses also suggest that simulation analysis may provide decision support during climatic uncertainty.

Joining dissimilar metals has recently become very popular in industries because of the advantages associated with the weld joint. This paper focuses on an investigation of mechanical and material properties, and the optimization of mechanical properties in resistance spot welding methods in lap configurations between AISI 301 stainless steel and AISI 1020 carbon steel. The Taguchi method was used to design experiments. Welding was conducted using a spot welder. Tensile and Charpy impact test specimens were prepared from the welded sheets in appropriate dimensions and tensile and Charpy impact tests were performed for each specimen. The depth and width of weld nuggets were investigated. It can be concluded from the investigation that the welding joint in this method can offer moderate strength and moderate Charpy impact energy. From the results of the Taguchi analysis, the combination of optimum parameters for dissimilar stainless steel-carbon steel resistance spot welding is: welding current, 5.0kA; welding squeeze time, 3.0 cycle; and welding pressure, 40 psi. In order to improve significant mechanical and metallurgical properties of the joint, other variable parameters like voltage, electrode tip diameter etc. can also be introduced and investigated so that the most influential parameters and their suitable ranges can be identified.

Pasture-based automatic milking systems (AMS) require cow traffic to enable cows to be milked. The interval between milkings can be manipulated by strategically allocating pasture. The current experiment investigated the effect of replacing an allocation of grazed pasture with grazed soybean (Glycine max) with the hypothesis that incorporating soybean would increase voluntary cow traffic and milk production. One hundred and eighty mixed age, primiparous and multiparous Holstein-Friesian/Illawarra cows were randomly assigned to two treatment groups (n = 90/group) with a 2×2 Latin square design. Each group was either offered treatments of kikuyu grass (Pennisetum clandestinum Hoach ex Chiov.) pasture (pasture) or soybean from 0900 h to 1500 h during the experimental period which consisted of 2 periods of 3 days following 5 days of training and adaptation in each period with groups crossing over treatments after the first period. The number of cows trafficking to each treatment was similar together with milk yield (mean ≈18 L/cow/d) in this experiment. For the cows that arrived at soybean or pasture there were significant differences in their behaviour and consequently the number of cows exiting each treatment paddock. There was greater cow traffic (more cows and sooner) exiting pasture allocations. Cows that arrived at soybean stayed on the allocation for 25% more time and ate more forage (8.5 kg/cow/d/allocation) relative to pasture (4.7 kg/cow/d/allocation). Pasture cows predominantly replaced eating time with rumination. These findings suggest that replacing pasture with alternative grazeable forages provides no additional incentive to increase voluntary cow traffic to an allocation of feed in AMS. This work highlights the opportunity to increase forage intakes in AMS through the incorporation of alternative forages.

An improved method for predicting slant path attenuation in tropical climates is presented in this paper. The proposed approach is based on rain intensity data R_0.01 (mm/h) from 37 tropical and equatorial stations; and is validated by using the measurement data from a few localities in tropical climates. The new method seems to accurately predict the slant path attenuation in tropical localities, and the comparative tests seem to show significant improvement in terms of the RMS of the relative error variable compared to the RMS obtained with the SAM, Crane, and ITU-R prediction models.

A boundary value of velocity of data gathering node (DGN) and a critical value for training overhead beyond which the cooperative communication in wireless sensor network will not be feasible is proposed in this paper. Multiple Input Multiple Outputs (MIMO) cooperative communication is taken as an application. The performance in terms of energy efficiency and delay for a combination of two transmitting and two receiving antennas is analyzed. The results show that a set of critical value of velocity and training overhead pair is present for the long haul communication from the sensors to the data gathering node. Later a graphical relation between boundary value of training overhead and velocity is simulated. A mathematical relation between velocity and training overhead is also developed. The effects of several parameters on training overhead and velocity are analyzed.

An improved Quasi Cyclic Low Density Parity Check code (QC-LDPC) is proposed to reduce the complexity of the Low Density Parity Check code (LDPC) while obtaining the similar performance. The proposed QC-LDPC presents an improved construction at high SNR with circulant sub-matrices. The proposed construction yields a performance gain of about 1 dB at a 0.0003 bit error rate (BER) and it is tested on 4 different decoding algorithms. Proposed QC-LDPC is compared with the existing QC-LDPC and the simulation results show that the proposed approach outperforms the existing one at high SNR. Simulations are also performed varying the number of horizontal sub matrices and the results show that the parity check matrix with smaller horizontal concatenation shows better performance.

In linear approximation by wavelet, we approximate a given function by a finite term from the wavelet series. The approximation order is improved if the order of smoothness of the given function is improved, discussed by Cohen (2003), DeVore (1998), and Siddiqi (2004). But in the case of nonlinear approximation, the approximation order is improved quicker than that in linear case. In this study we proved this assumption only for the Haar wavelet. Haar function is an example of wavelet and this fundamental example gives major feature of the general wavelet. A nonlinear space comes from arbitrary selection of wavelet coefficients, which represent the target function almost equally. In this case our computational work will be reduced tremendously in the sense that approximation error decays more quickly than that in linear case.

The aim of this study was to determine the prevalence of diseases and its associated risk factors in crossbred Friesian calves in a dairy farm in Bangladesh. Date of birth, birth weight, age and sex of 194 calves up to three months old, season of disease occurrence, date of illness and the percentage of IgG in colostrum were recorded. The prevalence of calf diseases was 33.5%, of which 30.1% were suffering from medical conditions, 19.6% having enteritis: only 5% had surgical disorders. Calves up to 21 days old had significantly higher disease prevalence (22.2%) than calves aged 22-90 days (11.3%). The prevalence of diseases was significantly higher (43.1%) in calves with birth weight up to 29 kg than calves with birth weight 30 kg or more (28.7%). The prevalence of diseases was higher in male calves (38.0%) than female (28.7%). The prevalence of diseases was significantly higher (72.4%) in calves consumed colostrum containing 22-24% IgG compared to calves given colostrum containing 28-30% IgG. The prevalence of diseases was significantly higher in rainy season (64.2%) than in summer (29.5%) and in winter (6.1%). [ABSTRACT FROM AUTHOR]