Influence of dietary osteolathyrogenson the eggshell quality of laying hens

1. Laying hens were fed osteolathyrogens, either semicarbazide hydrochloride at 0.3 or 0.4 g/kg or β-aminopropionitrile fumarate at 0.5 or 0.6 g/kg diet to examine their effects on eggshell quality. 2. Shell quality characteristics considered for evaluation were shell surface area, shell thickness, shell weight, percentage shell, shape index and the specific gravity of eggs. Measurement of shell quality traits revealed that the hens fed osteolathyrogens laid eggs with significantly lower specific gravities and proportion of shell by weight. These differences were not explained by differences in shell thickness or weight or the shape index of eggs. 3. It was concluded that osteolathyrogens cause hens to lay eggs with poor shell quality and such eggs are weak and fragile.     

Organic matrix morphology and distribution in the palisade layer of eggshells sampled at selected periods during lay

1. 1 cm2 pieces of eggshells from a commercial battery flock were plasma etched to remove the outer shell membranes. 2. They were decalcified using EDTA (200 g/l, pH 6.9 to 7.0) in paraformaldehyde (20 g/l) and 25% gluteraldehyde (20 ml in 0.98 l) in phosphate buffer, then prepared for light and transmission electron microscopy. 3. Light microscopy revealed a differential distribution of matrix material within all 3 regions of the palisade layer at the beginning of lay. 4. Transmission electron microscopy revealed a more even distribution of matrix at the beginning of lay, although morphological differences were observed. At the end of lay all 3 regions showed an increase in % matrix and vesicles/10 cm2 of micrograph compared to the middle and beginning of lay periods. 5. It is hypothesised that matrix vesicles are involved in the regulation of the physiochemical environment within the forming eggshell and that the decline in shell quality associated with the end of lay is related to a concomitant change in matrix quality.     

Combined effects of clenbuterol and various concentrations of protein on performance of broiler chickens

1. The effects of the beta-adrenergic agonist, clenbuterol (1 mg/kg diet) on the growth and muscle composition in female broiler chickens (14 to 32 d of age) fed on diets containing various concentrations of protein (220, 240 or 260 g protein/kg) were examined. 2. Body weight gain over the 18 d period increased linearly with increasing protein intake. The rate of gain was significantly higher in clenbuterol-treated chickens than in control birds. 3. Dietary clenbuterol increased thigh muscle weight and protein concentration of breast and thigh muscle, regardless of dietary protein content. Protein/DNA ratio in thigh muscle was enhanced by clenbuterol feeding, and the magnitude of difference of the ratio was higher in chickens fed on the 240 and 260 g CP/kg diets than in those fed the 220 g CP/kg diet. 4. It was concluded that clenbuterol-treated chickens require increased dietary protein to maintain maximal growth, and that increased protein consumption is an important factor in improving growth in clenbuterolfed broilers.     

The control of Fannia canicularis in a poultry house using a black-light technique

The lesser house fly Fannia canicularis and other species of fly of animal health and public health importance, were shown to be attracted to “ black‐light “ traps in semi‐open poultry houses permitting free access and strong daylight competition. The fly populations were reduced and the number of ovipositions in the droppings pit apparently decreased. It is shown that the use of these traps, normally reserved for indoor insect control, can be extended to include certain farm situations.     

A Histological Study of the Effects of Enzootic Abortion of Ewes Virus in the Lactating Bovine Mammary Gland

Inoculation of the udders of cows with the virus of enzootic abortion of ewes resulted in a severe acute mastitis. The mastitis was characterized clinically by pyrexia, anorexia, decreased milk production, swelling and marked alteration in the physical quality of the milk. The basic lesion was necrosis of alveolar and duct epithelial cells. Virus particles were demonstrated in all levels of the mammary gland three days after inoculation illustrating the rapid spread of the agent. Cells resembling Reed-Sternberg cells and similar to those seen in experimental mastitis produced by the virus of infectious bovine rhinotracheitis were seen in tissues collected six and nine days after inoculation.