Effect of different patterns of food restriction from different ages on growth and efficiency of broilers

1. The effect of restricted feeding on performance and carcass characteristics of broilers was determined in three experiments.

2. In the first experiment, removal of food for 8 h/d from 42 to 56 d of age significantly improved food conversion efficiency of broilers on deep litter. Removal of food for 16 h/d or on alternate days tended to cause slower growth and also improved conversion efficiency.

3. In the second experiment, denial of food for 8 h/d did not significantly affect either growth rate or conversion efficiency of caged broilers. Denial of food on alternate days, from 28 d of age, depressed food intake and growth rate. Food restriction decreased dressing percentage regardless of the age of introduction. With 32, 40 or 48 h food denial each 72 h there was a large depression in growth rate and dressing percentage. Carcass dry matter was also less, indicating less carcass fat, when food was denied for 48 h each 72 h.

4. In the third experiment, growth rate of broilers on deep litter was significantly improved by denying food for 8 h/d from 28 d of age, and was significantly depressed by food denial on alternate days. This depression was significantly more severe if restriction started at 28 d rather than at 42 d of age. Conversion efficiency was not significantly improved by denial for 8 h/d.

5. In the last two experiments conversion efficiency was much worse in severe restriction.     

Rapeseed meal and egg taint: Treatment of rapeseed meal to reduce tainting potential

1. Treatment of rapeseed meal with calcium hydroxide suspension decreased the sinapine content by up to 90%. Smaller decreases were obtained by autolysis, steaming and treatment with ammonia.

2. When this treated meal was fed to susceptible ("tainting") hens the concentration of trimethylamine in the eggs was decreased to much less than that required to cause taint.     

Comparison of maize,wheat and triticale in broiler diets

1. Wheat, triticale 131 or triticale 72‐S could replace up to half the maize in broiler diets without affecting performance. Replacing more of the maize on either an equal nitrogen basis or a weight basis adversely affected performance.

2. Triticale 72‐S appeared to be superior to triticale 131 as a direct replacement for maize, but both grains were inferior to maize as energy sources.     

The effects of meal feeding of calcium,protein and energy on production and calcium status of laying hens

1. Laying birds were allowed free access to a basal diet (treatment 1) or were restricted to either early morning and late afternoon access to the basal diet (treatment 2) or a high‐energy diet in the morning and a high‐protein, high‐calcium diet in the afternoon (treatment 3). The sum of the components fed in treatment 3 was equivalent to the basal diet. These diets were fed for 5 weeks. In the next phase of the experiment, which lasted for 3 weeks, the compositions of the diets for treatments 2 and 3 were altered so that the intakes of dietary components approached those of birds on treatment 1.

2. In both experimental phases birds on treatment 3 produced significantly fewer eggs of smaller mean weight and shell weight. Plasma calcium, inorganic phosphorus concentrations and alkaline phosphatase activity were indicative of decreased calcium status.     

Lymphocyte transformation test in the calf]

Studies into the effects of the environment on health and performance of agricultural animals are of clear-cut relevance to farming practice. The theoretical and practical importance of lymphocyte transformation to any assessment of immunological reactivity under defined environmental conditions, therefore, is reported in this paper. Communicated is methodical experience obtained from isolation of lymphocytes from peripheral blood of calves, lymphocyte culturing, and morphological evaluation of lymphocyte transformation. Views are given on the suitability of the lymphocyte transformation test. The following results have been obtained: Centrifugation of defibrinated blood, using "Visotrast-370", is recommended for lymphocyte isolation. Morphological evaluation will ensure a high degree of precision when 1 x 10(6) cells in one millilitre culturing fluid are to be cultured over three days, the culturing fluid consisting of 20 per cent of autologous serum and 80 per cent of Eagle medium, antibiotics, and a portion of 1-vol.% of phytohaemagglutinin (Wellcome). The lymphocyte transformation test, for its methodical accuracy, is good enough to detect and identify environmental effects on immunological reactivity of calf. It is likely to reflect the immunological response to an antigen application.     

AN OESOPHAGEAL DIVERTICULUM IN A DOG

An 11-month-old male Miniature Poodle was found to regurgitate small volumes of fluid and food particles due to a diverticulum in the thoracic oesophagus. The diverticulum was removed surgically. Histologically the wall contained extensive scar tissue. Longterm recovery was uneventful and 5 months after surgery the dog is in good health