The effect of feed preparation on the pharmacokinetics of peroral administration of chlortetracycline in weaned piglets

The influence of different modes of feeding on the bioavailability of orally administered chlortetracycline was studied in weaned pigs. The animals were divided into three groups receiving a dry, a moist or a soup diet, respectively. CTC was applied at a concentration of 6000 ppm and 2500 ppm to each diet and the oral dosage of CTC was 40 mg chlortetracycline/kg bodyweight. The results of the experiments show that the pharmacokinetics of orally applied chlortetracycline are significantly influenced by the mode of feeding. A significantly higher bioavailability was observed with soup feeding compared with moist or dry food. To achieve a therapeutic blood level of 0.5-1.5 micrograms chlortetracycline/ml blood, 20-30 mg chlortetracycline/kg bodyweight/12 h and 30-40 mg chlortetracycline/kg bodyweight/12 h should be applied to soup and dry or moist feed, respectively.     

Influence of different dietary calcium levels on the digestibility of Ca, Mg and P in Hermann's tortoises (Testudo hermanni)

Calcium and phosphorus are very important minerals in reptile nutrition, but many diets are still not balanced. To achieve optimal growth, including a healthy skeleton and a strong shell, a well-balanced supply with these minerals is prerequisite. The purpose of this study was to evaluate the apparent digestibility in Hermann's tortoises of diets with different calcium levels with special emphasis on the digestibility of minerals. Eight adult Hermann's tortoises of the veterinary faculty in Zurich were used. The animals were housed indoors at a mean temperature between 23 degrees C and 26 degrees C. The animals were fed a diet, which consisted of vegetables, herbs and different supplementation of calcium carbonate. Daily faecal samples of all tortoises were collected from day 8 to day 12. A proximate analysis was performed and the HCl-insoluble ash was used as an indigestible natural indicator (marker) for the determination of the apparent digestibility of minerals. The calcium content of the mixed feedstuffs of diet I was 0.64% on a dry matter basis, and the Ca:P ratio in the food was 3:1. In diet II the Ca content was 1.29% on a dry matter basis, and the Ca:P ratio in the food was 6:1. The digestibility of Ca in diet I was 57%. The other examined minerals, Mg and P, had a digestibility of 46% and 58% respectively. In diet II the digestibility of Ca was 79%, of Mg 52% and of P 52%. The results of this study indicated, that higher Ca concentrations in the diet led to an increased apparent digestibility of Ca and Mg.     

Evaluation of the influences of exercise, birth date, and osteochondrosis on plasma bone marker concentrations in Hanoverian Warmblood foals

OBJECTIVE: To determine whether plasma concentrations of bone turnover markers in growing Hanoverian foals are influenced by age, housing conditions, or osteochondrosis. ANIMALS: 165 healthy foals and 119 foals with osteochondrosis. PROCEDURES: Foals were allocated according to birth date and housing management into groups of early-born (born before March 31, 2001; n = 154 foals, 88 of which were healthy and 66 of which had osteochondrosis) and late-born (born after March 31, 2001; 130 foals, 77 of which were healthy and 53 of which had osteochondrosis) foals. Plasma osteocalcin and carboxyterminal propeptide of type I collagen concentrations were analyzed as markers of bone formation, and carboxyterminal telopeptide of type I collagen concentration was analyzed as a marker of bone resorption. Foals underwent radiographic evaluation to screen for osteochondrosis. RESULTS: Plasma concentrations of osteocalcin, carboxyterminal propeptide of type I collagen, and carboxyterminal telopeptide of type I collagen decreased with age, but these changes were more distinct in late-born foals than in early-born foals. Neither sex nor predisposition to develop osteochondrosis affected the pattern of bone marker changes in either group. CONCLUSIONS AND CLINICAL RELEVANCE: An age-related decrease in concentrations of bone markers was seen during the first 200 days of life. Changes in bone marker concentrations were similar for foals with osteochondrosis and healthy foals. The correlation between the decrease in bone marker concentration and date of birth indicates that there are differences in skeletal development between early- and late-born foals.     

In-vitro susceptibility testing of Leptospira by a modified broth microdilution methods

In Germany, the application of antimicrobial agents represents the method of choice to control infections of food-producing animals by bacteria of the genus Leptospira. However, only few data are available on the susceptibility of Leptospira spp. against antimicrobial agents and the in vivo efficacy of antimicrobial agents. Based on a modified broth microdilution method, a standardised in-vitro susceptibility testing system for Leptospira spp. was established which also included quality control aspects. Considering the minimum inhibitory concentrations determined in this study in-vivo efficacy is expected for the following classes of antimicrobial agents: penicillins, cephalosporins, macrolides, lincosamides, fluoroquinolones, phenicols, and in part also for aminoglycosides and tetracyclines. Clinical aspects and bioavailability of the drugs in the target tissues have to be taken into account. Penicillins and aminoglycosides as commonly used inhibitory supplements in semen extender seem to be effective against leptospires.     

Ultrasonographic imaging of abomasal milk clotting and abomasal diameter in healthy and diarrheic calves

In case of diarrhea calves are treated with oral rehydration solutions (ORS), which are known to increase abomasal pH and inhibit milk clotting in vitro. Nevertheless, recent studies have shown that ORS with HCO₃^‐ ≤ 62 mmol/L do not interfere with abomasal milk clotting in healthy calves. However, in diarrheic calves, feeding ORS and milk simultaneously may disturb abomasal curd formation and exacerbate diarrhea due to faster abomasal passage of ingesta. Therefore, the aim of the present study was to ultrasonographically examine abomasal milk clotting and diameter after feeding milk and milk replacer (MR) with and without ORS to healthy and diarrheic calves. Abomasal curd formation and diameter in healthy and diarrheic calves were ultrasonographically imaged before and after feeding milk, MR and ORS prepared in milk or MR. Feeding mixtures of milk or MR with ORS did not cause any remarkable differences in the ultrasonographic images of abomasal content. Moreover, abomasal milk clotting was not disturbed due to diarrhea. Statistically significant differences of abomasal diameter after feeding between healthy and diarrheic calves indicated that abomasal emptying is delayed in diarrheic calves. Hence, further studies are needed to determine reasons for decelerated abomasal passage in calves suffering from diarrhea.     

Characterization of cation exchange capacity (CEC) for agricultural land-use areas

Spatial assessment of soil properties needs conversion of point data to an area-oriented model. Methods are required that create a reproducible map. The development of a map is shown by the example of cation exchange capacity. Twenty sorption types are formed and derived from the vertical sequence of values for substrate types and are aggregated to six main types. A qualitative assessment of the main CEC sorption types is carried out with comparative ranking. The association of different substrate types on an areal soil pattern requires the identification of sorption association types. These are shown by the areal share of the main sorption types for the substrate types involved in each case. For interpreting the site parameters from the MMK (Mittelmaßstäbige Landwirtschaftliche Standortkartierung), the procedure is presented in detail. An example of the results is shown with CEC maps. Tables complement the visualization for different areas, defined by administrative or natural landscape boundaries. The application of this method for relative evaluation of CEC is demonstrated using KA5-rules. The CEC characterization of agricultural areas can be reproduced on the basis of the mapping units of soil maps with different scales (BÜK 200). The areal-specific labeling of CEC constitutes soil-related decision guideline.