Economic costs of recorded reasons for cow mortality and culling in a pasture-based dairy industry

The objective of this study was to determine the economic costs associated with different reasons for cow culling or on-farm mortality in a pasture-based seasonal system. A bioeconomic model was developed to quantify costs associated with the different farmer-recorded reasons and timing of cow wastage. The model accounted for the parity and stage of lactation at which the cows were removed as well as the consequent effect on the replacement rate and average age structure of the herd. The costs and benefits associated with the change were quantified, including animal replacement cost, cull salvage value, milk production loss, and the profitability of altered genetic merit based on industry genetic trends for each parity. The total cost of cow wastage was estimated to be NZ$23,628/100 cows per year (NZ$1 = US$0.69) in a pasture-based system. Of this total cost, NZ$14,300/100 cows worth of removals were for nonpregnancy and unknown reasons, and another NZ$3,631/100 cows was attributed to low milk production, mastitis, and udder problems. The total cost for cow removals due to farmer-recorded biological reasons (excluding unknown, production, and management-related causes) was estimated to be NZ$13,632/100 cows per year. Of this cost, an estimated NZ$10,286/100 cows was attributed to nonpregnancy, mastitis, udder problems, calving trouble, and injury or accident. There is a strong economic case for the pasture-based dairy industries to invest in genetic, herd health, and production management research focused on reducing animal wastage due to reproductive failure, mastitis, udder problems, injuries or accidents, and calving difficulties.     

Heterogeneity of genetic parameters for calving difficulty in Holstein heifers in Ireland

Calving difficulty is a trait that greatly affects animal welfare, herd profitability, and the amount of labor required by cattle farmers. It is influenced by direct and maternal genetic components. Selection and breeding strategies can optimize the accuracy of genetic evaluations and correctly emphasize calving difficulty in multiple-trait indices provided there are accurate estimates of genetic parameters. In Ireland, large differences exist in the age at which heifers first give birth to calves. The objective of this study was to estimate genetic parameters for calving difficulty in first-parity Holsteins and to determine whether these differed with age of the heifer at calving. Transformed calving difficulty records for 18,798 Holstein heifers, which calved between January 2002 and May 2006, were analyzed using univariate, multitrait, and random regression linear sire-maternal grandsire models. The model that 1) fitted a second-order random regression of dam age at first parity for the direct component, 2) treated the maternal component as a single trait regardless of dam age, and 3) fitted a single residual variance component was optimal. Heritabilities for direct (0.13) and maternal (0.04) calving difficulty were significantly different from zero. These 2 components were moderately negatively correlated (−0.47). Estimates of direct genetic variance and heritability were heterogeneous along the dam age trajectory, decreasing initially with dam age before subsequently increasing. Heritability estimates ranged between 0.11 and 0.37 and were higher for records with younger and older dams at parturition. Genetic correlations between the direct components of calving difficulty decreased from unity to 0.5 with increasing distance between dam ages at parturition. The results of this study indicated that heterogeneity of direct genetic variance existed for calving difficulty, depending on dam age at first parturition.     

A design for hydrogen production and dispensing for northeastern United States,along with its infrastructural development timeline

Countries are trying to reduce their energy consumption, fossil fuel usage, and greenhouse gas emissions. Recent guidelines generated by various government agencies indicate an increase in the fuel economy, with a reduction in green house gases. The use of both alternative fuel vehicles and renewable energy sources is thus necessary toward achieving this goal. This paper proposes a hydrogen fueling infrastructure design for the Northeastern United States. The design provides an implementation plan for a period of 13 years (from 2013 to 2025). This design gives priority to customer convenience with minimum additional investments for its implementation. Extensive research has been conducted on generating a hydrogen supply from factories and other potential sources that can satisfy demand in the region. Markers (e.g. population density, traffic density, legislation, and growth pattern) have driven the process of demand estimation.     

An investigation of a nonthermally insulated mixing ventilated office room for partitioning in hot and dry climate by simulation approach

Due to the recent situation, especially since the beginning of the spread of COVID-19, work in administrative or service offices under conditions of social divergence and the working environment has become conditional on the ventilation system; thus, enhancing ventilation's function to minimize the spread of infections, and impurities to larger areas or limiting its transition from one employee to another who work in the same place for long hours. A nonisothermal office room, designed with a mixing ventilation system has been simulated by using AIRPAK3.0.16 software, and RNG k–$\epsilon$ as a turbulence model, where the adoption of partitions in such rooms was studied and its effect on thermal employee's comfort and quality of fresh air, by monitoring the air diffusion performance index, prediction of the mean vote, and percentage of predicted dissatisfied. The main findings were that partitions are seen as a technique of preventing and protecting against the spread of pollutants and illnesses since they prevent contaminants from reaching the breathing zones of the office's inhabitants. It was noted that the change in the height of the partition with an increase of 10% of the room's height as a gap, gives a more acceptance value of the heat removal efficiency and ventilation rate.