[Methodical investigation of mineral and trace element concentrations in equine feces with special consideration of the sampling location]. / Methodische Untersuchung zu Mengen- und Spurenelementkonzentrationen in Pferdekotproben unter besonderer Berücksichtigung des Probenentnahmeortes.

OBJECTIVE: Objective measurements of the mineral supply in horses are rarely performed. As a result, incorrect elements or an improper amount of elements are provided. The analysis of feces could represent a novel method to evaluate the nutritive supply. The prerequisite is a knowledge of methodological factors influencing the mineral concentration in the fecal samples. Within the scope of this investigation, the effects of different kinds of mineral supply and the influence of the sampling location on the concentration of minerals in equine feces samples were analyzed. Additionally, the methodical error of the measurement procedure was estimated. MATERIAL AND METHOD: Six minerals and 22 trace elements in 30 fecal samples of 5 warmbloods, 3 haflinger horses and 2 ponies with differing mineral supplementation (none, calculated amount, mineral lick mass for free intake) were investigated. The samples derived from 3 locations (cranial rectum, ampulla recti and dung heaps) were dried and analyzed using ICP-OES and ICP-MS. Besides a descriptive data analysis, the effects of the fixed factors sampling location and mineral supplementation as well as repeatability and the relative error of the method were assessed. RESULTS: The element concentrations were not influenced by the sampling location, while they varied significantly depending on the type of mineral supplementation. The repeatability of analysis was high with an average measure of certainty of 0.949 (0.894-0.978) and an average median relative error of 0.18 (0.01-0.86). CONCLUSION AND CLINICAL RELEVANCE: The study outlines a methodological framework for the determination of mineral and trace element concentrations in equine feces. The location of fecal sampling did not affect the results, therefore, preference may be given to noninvasive sample collection from a fecal pile. Furthermore, as the types of mineral supplementation result in significantly differing fecal element concentrations, varying concentrations in feces allow for conclusions concerning the amount of mineral intake of the individual horse.

[Bovine trace mineral concentrations in different sample media with emphasis on fecal analysis]. / Konzentration von Spurenelementen beim Rind in verschiedenen Probenmedien unter besonderer Berücksichtigung von Kotproben.

OBJECTIVE: The objective of this study was to evaluate the suitability of feces as sample material for the evaluation of trace mineral supply in cattle. Fecal trace element concentrations of iron, copper, zinc, selenium, manganese and molybdenum were compared with those in feed. Furthermore, fecal trace element-concentrations were compared with those in various additional sample media (serum, plasma, whole blood, urine and hair). MATERIALS AND METHODS: Samples (feces, blood, urine, hair) from up to 10 cows in the close-up (3-0 weeks a. p.) and high-yielding (6-20 weeks p. p.) group each were collected during 73 farm visits on 63 dairy farms. Pooled samples of each lactation group were formed and the concentrations of trace elements were determined with ICP-OES or ICP-MS. Furthermore, TMR was analyzed. Additionally, feces from cattle in cow-calf herds during grazing and housing period were evaluated. RESULTS: Nutritional trace mineral requirements were exceeded by the majority of feeds. Trace mineral concentrations were 2- to 3-fold higher in feces than in feed. In this study, the strongest significant correlation existed between feed and fecal concentrations for all elements. Seasonal variations were detected for iron, copper and manganese. Furthermore, iron concentration differed depending on lactation stage. CONCLUSION AND CLINICAL RELEVANCE: Feed intake of the trace minerals analyzed is most optimally reflected by the fecal concentration in comparison to other substrates. Fecal analysis of these minerals may therefore be employed as an alternative to feed analysis with regards to the evaluation of nutritional trace mineral supply. Analyzing fecal trace mineral concentrations possesses practical significance wherever feed or TMR cannot be analyzed. In particular, this concerns grazing animals, heifers, mother cows and cattle in barns without TMR. Assessment of the complete metabolic status only on the basis of fecal contents is insufficient. However, subnormal fecal copper-, zinc- and manganese concentrations may be suggestive of an inadequate metabolic situation and represent an indication for further diagnostics.

Comparative study on 3 oral potassium formulations for treatment of hypokalemia in dairy cows.

BACKGROUND: Hypokalemia is of clinical relevance in cattle. Different mostly empirical treatment options are suggested. HYPOTHESIS/OBJECTIVES: To evaluate if oral administration of potassium influences the plasma concentration, the intracellular concentration in erythrocytes and in muscle, renal excretion of potassium, and to assess if there are differences in the efficacy of the potassium formulations. ANIMALS: Thirty cows with hypokalemia (plasma concentration <3.5 mmol/L) were systematically allocated to 3 treatment groups (10 cows/group). METHODS: The cows received 52 g of potassium in different formulations: group B-potassium chloride bolus (release over 12 hours); group G-potassium propionate gel (release over 2 hours); and group S-potassium chloride solution (immediately available). Potassium concentrations were repeatedly measured in plasma, erythrocytes, muscle, and urine using ICP-OES. RESULTS: Plasma potassium concentrations for all preparations increased within 30 minutes and the increase lasted for 12 hours. The concentrations of potassium in the erythrocytes and in the muscle, renal potassium excretion, and total urine volume were not affected by administration of any product. There were no differences between the treatments groups. The feed intake increased in 50% of cows within 2 hours after potassium application, which may contribute to the increase of plasma potassium concentration. CONCLUSIONS AND CLINICAL IMPORTANCE: All the studied potassium formulations are equally effective to treat hypokalemia in dairy cows for over 12 hours but do not influence intracellular concentration or renal excretion of potassium. The plasma potassium concentration should be reevaluated after 12 hours.

[Mineral concentrations in cattle in different sample media with emphasis on fecal analysis]. / Konzentrationen an Mengenelementen beim Rind in verschiedenen Probenmedien unter besonderer Berücksichtigung von Kotproben.

OBJECTIVE: The objective of this study was to evaluate whether the concentrations of calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), sodium (Na) and sulfur (S) in the feces reflect the content in feeds and whether analysis of the feces provides information on the nutritional supply of the body with these elements. MATERIALS AND METHODS: For this purpose, element concentrations in feed and in serum, plasma, whole blood, urine and hair were compared. During 73 farm visits on 63 dairy farms, samples were collected from up to 10 cows in both the close-up (3-0 weeks a. p.) and high-yielding (6th-20th week p. p.) groups. Concentrations of Ca, P, Mg, K, Na and S were determined in pooled samples of each lactation group and in a sample of the total mixed ration (TMR) by ICP-OES. Additionally, feces from beef cows during the grazing and housing periods were analyzed. RESULTS: Mineral concentrations in feed samples were sufficiently high to meet the nutritional requirements. Mineral concentrations were higher in feces than in feed, with the exception of Na and K. There were significant correlations between feed and fecal concentrations for all elements, whereby the correlations between the TMR and urine concentrations were higher for K, Na and S. Seasonal variations were detected in all elements, with the exception of Ca. Furthermore, Ca, P, Mg and S concentrations differed depending on the stage of lactation. CONCLUSION: The fecal concentration of Ca, P and Mg best reflect the intake with the feed in comparison to other substrates. Fecal analysis of these elements can, therefore, be applied as an alternative to feed analysis regarding the evaluation of the nutritional mineral supply. Assessment of the metabolic status only on the basis of the fecal contents is insufficient. The urine Mg concentration provides information regarding Mg metabolic status. Furthermore, urine is the substrate of choice for the evaluation of the K and Na metabolic status. The most useful information about S nutritional and metabolic status is provided by combining the results of fecal and urinary examinations.

[Zinc concentrations in different sample media from dairy cows and establishment of reference values]. / Untersuchungen zur Zinkkonzentration in unterschiedlichen Probenmedien von Milchkühen und Ableitung von Referenzwerten.

OBJECTIVE: Zinc plays an important role in many body functions, including health and fertility. The assessment of the zinc supply can be performed using blood, urine and hair. The objective of this study was to establish reference values for herd analysis for the different sample media and stages of lactation in German dairy herds. MATERIALS AND METHODS: The data of 1515 herds, which had been visited by the Clinic for Ruminant and Swine, Free University of Berlin, Germany, between 1995 and 2012 were analyzed. Serum, plasma, whole-blood, hair and urine zinc concentrations of pooled samples with 7 to 10 cows per group were determined. In herds with more than 200 cows, five groups were sampled (8-3 weeks ante partum [a. p.], 3-0 weeks a. p., 0-1 week post partum [p. p.], 3-5 weeks p. p. and 15-18 weeks p. p.). In herds with fewer than 200 cows, only four groups were sampled (8-3 weeks a. p., 3-0 weeks a. p., 0-5 weeks p. p. and 6-20 weeks p. p.). RESULTS: Correlations among zinc concentrations in different sample media varied between r = 0.001 (whole blood and urine) and r = 0.75 (serum and plasma). Serum and plasma zinc concentrations changed rapidly and followed a lactation dynamic, with the lowest values around parturition. Whole-blood and hair zinc concentrations changed slowly but displayed a similar decrease a few weeks after parturition. Reference values for pooled samples for the different sample media and stages of lactation are proposed. CONCLUSION AND CLINICAL RELEVANCE: When assessing the zinc supply, different reference values have to be applied for the different sample media and stages of lactation. For repeated analysis to evaluate changes in zinc nutritional status, the same sample medium and stage of lactation should be used.