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Notizen: [Auszug] Fig. 1. Main vessels of the udder of the sheep and goat, indicating the position of the venous valves (left lateral aspect). Arteries black ; veins white At the end of an experiment involving the measurement of blood-flow through the udder of a lactating sheep, it was of great interest to find ...

Notizen: [Auszug] The question to beÅ considered here is whether oxygen consumption varies with age independently of concomitant changes in body-weight. Holub, Jezkova and Forman5 have found oxygen consumption per unit body-weight to be closely correlated both with age and with body-weight. Because of the high ...

Notizen: [Auszug] Observations were made on male and female Large White piglets. The animals used were 1-23 days old and had body weights of 1.16-4.45 kg. The rate of oxygen consumption was measured on conscious animals resting individually in a chamber of about 45 1. capacity. The chamber was situated in a ...

Notizen: [Auszug] A simple form of thermocline was constructed. This was a hardboard enclosure 2.5 m long, 0.65 m high and 0.65 m deep, divided into four compartments, each approximately 0.6 m wide and provided with a 1-cm mesh wire floor. Each compartment had a door at the front, and each connected with the next ...

Notizen: [Auszug] The piglets used in these experiments (Landrace X Large White or Large White X Large White) were installed at about two weeks of age in funnel type metabolism cages, equipped for the measurement of food and water intakes and the 24-hourly collection of urine under toluene. The pellet diet used ...

Notizen: [Auszug] 18 Large White pigs, of both sexes and taken from six litters, were used in these experiments ; six were less than 1 day old, including two which had not been suckled by the sow (weight range : 1 .07-1 .40 kgm.), six were 2-4 days old (weight range : 1.15-1.72 kgm.) and six were 5-6 days old ...

Notizen: Abstract Standard meteorological measurements of dry bulb temperature, wind speed, sunshine, cloud cover and rainfall are used to calculate the clothing insulation required by man for thermal comfort under given weather conditions. The calculation is based on earlier work on the effect of weather on sensible (non-evaporative) heat loss from sheep, which used the relation between heat flow, thermal insulation and the difference between body and environmental temperatures. Clothing insulation for man is estimated in two ways: as clothing (Ic) that is impervious to the effects of wind and rain; and as the equivalent depth of sheep fleece (fm), which is not impervious. This allows the assessment of wind chill for a range of clothing of varied penetration by wind instead of for only one type of garment. Results are given as daily means calculated from hourly measurements throughout 1973 for Plymouth (on the south coast of Britain) and Aberdeen (on the far northeast coast of Britain). Wind chill is estimated both by its effect on fm requirement and by the fall in air temperature that would be needed to produce under still-air conditions the same demand for fm that occurs in the actual environment. The monthly mean fm requirement is reduced by about 40% when the effect of wind is removed. When wind chill is estimated as an equivalent fall in air temperature it approximates to 1 K per knot wind speed measured at the standard meteorological height of 10 m.

Notizen: Abstract Wind chill is defined as the excess of sensible heat loss over what would occur at zero wind speed with other conditions unchanged. Wind chill can be broken down into a part that is determined by air temperature and a radiative part that comprises wind-dependent effects on additional long-wave radiative exchange and on solar radiation (by reducing solar warming). Radiative exchange and gain from solar radiation are affected by changes that are produced by wind in both surface and fleece insulations. Coefficients are derived for (a) converting the components of sensible heat exchange (air-temperature-dependent including both convective and associated long-wave radiative, additional long-wave radiative and solar) into the components of the total heat loss that are associated with wind and (b) for calculating equivalent air temperature changes. The coefficients contain terms only in wind speed, wetting of the fleece and fleece depth; these determine the external insulation. Calculation from standard meteorological records, using Plymouth and Aberdeen in 1973 as examples, indicate that in April–September 1973 at Plymouth reduction in effective solar warming constituted 28% of the 24-h total wind chill, and 7% in the other months of the year combined; at Aberdeen the corresponding percentages were 25% and 6%. Mean hour-of-day estimates for the months of April and October showed that at midday reduction in solar warming due to wind rose to the order of half the air-temperature-dependent component of wind chill, with a much smaller effect in January. For about six hours at midday in July reduction in solar warming due to wind was similar in magnitude to the air-temperature-dependent component. It is concluded that realistic estimates of wind chill cannot be obtained unless the effect of solar radiation is taken into account. Failure to include solar radiation results not only in omitting solar warming but also in omitting the effects of wind in reducing that warming. The exchange of sensible (non-evaporative) heat loss between a homeothermic animal and its environment can be divided into two parts: one part is due to the temperature difference between the animal and the surrounding air, and the other part is due to additional long-wave radiative exchange between animal and environment and to solar radiation. Both parts of the heat exchange are determined in magnitude by the animal's thermal insulation, which is itself affected by windspeed and wetting. Wind diminishes as animal's external insulation, so increasing heat loss under all conditions when the air temperature is lower than the animal's surface temperature: this effect is termed wind chill. Wind chill has previously been investigated more commonly in relation to man (Burton an Edholm, 1955; Smithson and Baldwin, 1978; Mumford, 1979; Baldwin and Smithson, 1979). This paper is concerned with the separate contributions to wind chill calculated for sheep that can be associated with convective and radiative heat exchanges.

Notizen: Résumé Deux augmentations, l'une immédiate et l'autre latente, s'observent dans la consommation d'oxygène après injection sous-cutanée de thyroxine au porcelet nouveau-né. L'augmentation immédiate présente un maximum environ 4 h après l'injection. Elle a été la plus forte chez les porcelets de l'âge 1 à 4 journées.

Notizen: Summary The temperature at the surface of the carotid artery was measured by radiotelemetry over several successive 24 h periods in seven young pigs. The animals were housed solitarily in a temperature-controlled but not sound-proofed room under conditions of constant lighting. In animals fed once in the 24 h there was a rapid rise in the temperature of the carotid artery at the time of feeding followed by a slow decline. Feedingad libitum for 6 days was not accompanied by any definite rhythm in body temperature. During periods of fasting for up to 5 days, the mean body temperature tended to fall and a 24-hourly rhythm was apparent with the maximum in the afternoon and evening. Increases in body temperature were associated with increased activity in all experiments.