Increased knowledge following genetic counselling was not accompanied by an increase in anxiety or depression. Further assessment will be required in the long term to determine the psychological impact of receiving a genetic test result.

Most livestock are transported at least once during their lifetime. Environmental conditions inside the transporter are critically dependent on many factors which can be controlled by well designed and carefully operated ventilation systems. Heat, moisture and carbon dioxide production of cattle, pigs and sheep are fitted to simple models as bases for ventilation design criteria. These assume that the animals are not well fed immediately before or during transport and that maintenance metabolic heat production applies. Interactions between temperature and humidity during transport are important at temperatures above 24°C.Ventilation slots along the sides of transporters can be occluded by the bodies of the stock themselves. Relevant dimensions of pigs, cattle and sheep related to body weight are provided as additional design parameters. Stocking density interacts critically with other aspects of transport and normally recommended values are shown to be inconsistent. Space requirements should be based on species and body weight, provided that the ventilation capacity is satisfactory.Proposed European regulations on the transport of livestock provide general guidelines for the provision of ventilation, but no means of achieving these requirements. This paper draws together detailed criteria for establishing acceptable space, thermal, psychrometric and gaseous conditions on transporters for pigs, cattle and sheep. Application of these quantitative criteria will assist shippers and regulating authorities in providing more suitable environmental conditions than are frequently achieved at present.

No abstract

Leakage and ventilation rates were measured in a four span glasshouse at Silsoe Research Institute. Two tracer gas techniques were used, a decay rate method with different positions of the leeward ventilator (0, 10 and 20% of the maximum opening) and a continuous injection method with the leeward ventilators open 10%. The influences of wind speed, wind direction and temperature difference between inside and outside were analysed for each ventilator position. It was found that wind speed had a strong influence on leakage and ventilation rates. Some influence of wind direction occurred with northeast and southeast winds but no significant conclusions can be drawn because of insufficient data. Temperature difference affected ventilation rates under low wind speeds. For each ventilator position, the air exchange rate was linearly related to wind speed. A dimensionless function was calculated to express the ventilation flux per unit ventilator area and unit wind speed as a function of the angle of ventilator opening. With a 10% opening, the results obtained with the decay and continuous methods were compared and showed good agreement for wind speeds greater than 1 m/s.The results for 10 and 20% ventilator openings obtained by using the decay method were compared with those obtained by applying the theory of convection, using pressure differences generated by wind forces and temperature differences. It was found that the combined effect of wind and temperature difference gave satisfactory predictions of ventilation rates. Also, the values obtained by measurement and prediction based on pressure difference were in close agreement, with a global wind effect coefficient similar to that found in the literature.