Morphologic changes in the ovary and histologic changes in the tertiary ovarian follicles in ewes after prolonged irradiation during anestrus

The changes in volume, weight and the histomorphological changes of the tertiary follicles of ewes were studied after protracted irradiation with 4.8 Gy in the anoestrous period by the morphometric and qualitative histological methods. The trial was performed in May with 21 ewes of the Slovak Merino breed, divided into three groups. The first group (five ewes) was control. The second and third groups (each containing eight ewes) were exposed to gamma-rays for five days, the total dose being 4.8 Gy. Within ten days after the treatment, all the irradiated and control ewes were given Ampicillin Spofa per os at a dose of 250 mg per head/day and Roboran Spofa at a dose of 10 g per head/day. The animals were killed by bleeding on the fifth day of irradiation and on the tenth day after the end of the treatment. After killing, the volume and weight of the ovaries were determined and a common histological method was used to cut these ovaries into 7 microns slices in series 70 microns apart. The slices were stained with haematoxylin-eosine and were evaluated by means of light microscopy. After irradiation the weight of the ovaries was found to decrease significantly; however, ovary volume remained unchanged. The atretic and non-atretic tertiary follicles were subjected to qualitative histological differentiation after Marion et al. (1968) and the number of non-atretic follicles was found to have decreased significantly in the irradiated ewes. The late type of atresia contributes most significantly to an increase in the proportion of atretic tertiary follicles. The administration of vitamins after irradiation reduced the occurrence of atretic changes.     

The effect of milk cultures on the survival of salmonellae in milk

The influence was investigated of yoghurt and cream cultures on salmonella survival in milk. Salmonella-contaminated milk was blended with yoghurt culture and kept for three hours at the temperature of 43 degrees C; the mixture with cream culture was kept for 20 hours at the temperature of 22 degrees C. The samples were then stored at a room temperature and at the temperature of 4 degrees C. The two milk cultures exerted inhibitory effects on salmonellae within the range of 92.5 to 99.8%. The inhibitory effects depended on the activity of the culture (expressed by titration acidity), storage time and temperature and on the starting concentration of salmonellae.     

Detection of staphylococcal enterotoxins in milk and milk products

For food evaluation the determination of the number of Staphylococcus aureus (hereinafter S. aureus) colonies is insufficient in view of present scientific knowledge. The results, advantages and shortcomings of diagnostic methods are demonstrated on an example of three methods of detection of staphylococcal enterotoxins in milk and milk products. 133 strains were investigated by the method of biotyping of S. aureus strains. Four strains of S. aureus were included in biotype A, seven xin-producing strains were isolated seventeen times by detection of 96 S. aureus strains were not included in any biotype, the other strains belonged to biotypes C and E. This method can be used as an auxiliary method of evaluation of foods containing S. aureus bacteria. The agar-gel precipitation method of enterotoxin detection in isolated strains of S. aureus has just restricted validity. The enteroto-strains. The main shortcoming of this method is a fact that the result concerning the isolated strains need not be identical with the result of enterotoxin detection in food. Direct assays of staphylococcal enterotoxins in milk and milk products using an enzymoimmunological method seem to be the most promising, mainly due to their high sensitivity (0.0001-0.001 micrograms.ml1-) and other advantages. Positive and negative results are presented on an example of two model trials with winter sheep milk cheese.     

Pharmacokinetics of a single intravenous dose of marbofloxacin in adult donkeys

Six donkeys each received 2 mg/kg marbofloxacin as a 10 per cent aqueous solution administered intravenously. Principal pharmacokinetic parameters were determined and two efficacy indices were computed by using pharmacokinetic parameters and selected mic90 values of marbofloxacin against pathogenic equine strains to predict the efficacy of the drug at this dose. The pharmacokinetics of marbofloxacin in donkeys was characterised by a large mean volume of distribution at a steady state (1.15 [0.09] l/kg) and a long mean (sd) elimination half-life of 9.24 (1.96) hours. It was also characterised by a relatively slow total body clearance of 0.10 (0.02) l/kg/hour, slower than in horses. Using mic90 values of marbofloxacin against pathogenic equine strains with a daily dose of 2 mg/kg, appropriate values of efficacy indicators were obtained only for Enterobacteriaceae. Daily intravenous doses of 0.33, 2.62 and 20 mg/kg were calculated for evaluation in clinical trials of infections due to Enterobacteriaceae, Staphylococcus aureus and Streptococci, respectively.     

Effect of carazolol on the oestrous behaviour and concentrations of luteinising hormone and steroids in lactating cows during the periovulatory period

Twelve multiparous, cycling, lactating Holstein-Friesian cows were synchronised with prostaglandin F(2alpha) and treated with either 2.5 mg carazolol or saline. There were no differences between the peripheral blood concentrations of oestradiol or progesterone, but in the cows treated with carazolol the periovulatory surge of luteinising hormone was delayed, and oestrous behaviour was expressed later than in the control cows.