Hydroxyl radical concentrations measured in ambient air

Diurnal variations in the hydroxyl radical concentration of ambient air were measured for the first time by the technique of laser-induced fluorescence.     

A quantitative analysis of the literature concerning the restricted feeding of growing pullets

The sexual maturity of growing pullets can be retarded either by restricting calorie intake or by feeding a diet deficient in one or more essential amino acids, Several methods have been proposed for achieving either of these objectives. In this review the methods have been classified as (a) limiting the birds’ time of access to food, (b) quantitative food restriction, (c) the use of low energy diets and (d) dietary protein restriction.

Food restriction by limiting the time of access to food has given inconsistent results and is an unsatisfactory technique. Birds quickly learn to eat normal quantities of food in a very short space of time.

Quantitative food restriction has been widely used in experiments and is usually applied from about 6 to about 20 weeks of age. The available evidence enables relationships to be established between the degree of food restriction and subsequent body weight and sexual maturity. The effect of rearing treatment on mortality and rate of lay is also examined.

The ad libitum feeding of a low‐energy growing diet has always resulted in greater rearing food costs. This is because moderate reductions in energy content of the diet are offset by higher food intake. Diets sufficiently low in energy to cause a reduction in calorie intake will involve the purchase and handling of very large proportions of non‐nutritive material.

The use of protein‐deficient diets during the growing period, or from one day of age, offers a suitable means of delaying sexual maturity. The effects of such a treatment are apparently very similar to those of restricted feeding, but there is a lack of suitable comparisons of the alternative methods.     

Diseases of chelonians: (1) Necropsy survey of tortoises.

The results of necropsies of 144 tortoises of 17 species that died in captivity are presented. Intestinal and nutritional disorders (27.0 and 22.2 per cent respectively) were the most common causes of death. Nematode infestations were found in 43.8 per cent, but with exception of a few species the parasites were seldom pathogenic. Infestations with other helminths appear to be very unusual. Protozoan infections were relatively common (at least 22.9 per cent) but protozoa are probably seldom pathogenic. Bacterial infections occurred in 7.6 per cent and no fungal infections were diagnosed. It was tentatively concluded that infections with Salmonella spp are less important in tortoises than in other reptiles in this country. In 34.7 per cent of cases no diagnosis was made.     

Verminous (Strongylus vulgaris) myelitis in a donkey

A fifth stage Strongylus vulgaris migrated through the spinal cord of a 2-year-old, male donkey resulting in progressive paraparesis and then tetraplegia. A profound neutrophilic pleocytosis was detected on analysis of cerebrospinal fluid. The parasite appeared to have entered the mid-lumbar spinal cord, migrated to the cranial thoracic segments, exited, then re-entered the spinal cord a few segments craniad. It then traveled further cranially and was found in the third cervical spinal cord segment. Some parts of the lesion were remarkably free from tissue necrosis, hemorrhage and inflammation. Severe granulomatous myelitis with hemorrhage and necrosis were seen at other sites. The latter were quite similar to lesions seen in equine protozoal myeloencephalitis.