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1.
In one study, a comparison was made of the concentrations and ratios of certain blood cations in 2 groups of cows with milk fever, one showing normal consciousness (n = 8) and the other depressed consciousness (n = 24). There were no significant differences in the mean concentrations of serum total calcium, plasma inorganic phosphorus and potassium, erythrocyte sodium and potassium, the serum calcium/serum magnesium ratio or the plasma sodium/erythrocyte sodium ratio. There were significant differences (all P less than 0.05) in the mean (+/- SD) concentrations of serum magnesium and plasma sodium concentrations, and the plasma sodium/serum magnesium ratio of 0.8 +/- 0.28 vs 1.2 +/- 0.37 mmol/l, 155 +/- 3.0 vs 147 +/- 6.4 mmol/l and 180 +/- 40.1 vs 116 +/- 34.1 for normal vs depressed cows, respectively. In a second study, a comparison was made of the concentrations and ratios of the same blood cations in 3 groups of cows in different positions when attended for milk fever, namely standing (n = 6), sternal recumbency (n = 24) and lateral recumbency (n = 31). There were no significant differences between the mean concentrations or ratios of any of the cations.  相似文献   

2.
Metabolic diseases of cows represent the leading internal pathology in Lithuania in terms of incidence and economic impact. This paper summarizes the mineral metabolic state of milk cows, and details the influence of feeding on serum levels of calcium, nonorganic phosphorus, magnesium, potassium, sodium, glucose, total protein, and urea quantity, and correlationd among them, in healthy dry or post-calving cows as well as in cows with osteomalacia and milk fever after calving. There was less pronounced hypocalcaemia and there were only minor changes in phosphorus, magnesium, potassium and sodium in the serum of healthy dry and post-calving cows that had silage and mineral-vitamin supplements, compared to cows that did not have supplements and silage. There was a fall in calcium and phosphorus (to 1.89 +/- 0.12 mmol/L and 0.71 +/- 0.06 mmol/L, respectively) in the blood of cows sick with milk fever after calving, while levels of magnesium and potassium were increased. The correlation between calcium and phosphorus was r = 0.6993, p < 0.001 in the serum of sick cows. There was a fall in calcium, phosphorus and magnesium (to 1.86 +/- 0.46 mmol/L, 0.75 +/- 0.37 mmol/L, and 0.60 +/- 0.19 mmol/L, respectively) and an increase in sodium level (to 158.90 +/- 19.30 mmol/L) in the blood of cows with osteomalacia in comparison with healthy cows.  相似文献   

3.
OBJECTIVE: To determine concentrations of electrolytes, total bilirubin, urea, creatinine, and hemoglobin; activities of some enzymes; and Hct and number of leukocytes and erythrocytes of newborn calves in relation to the degree of acidosis and treatment with a hypertonic sodium bicarbonate (NaHCO(3)) solution. ANIMALS: 20 acidotic newborn calves with a blood pH < 7.2 and 22 newborn control calves with a blood pH > or = 7.2. PROCEDURES: Approximately 10 minutes after birth, acidotic calves were treated by IV administration of 5% NaHCO(3) solution. The amount of hypertonic solution infused was dependent on the severity of the acidosis. RESULTS: Treatment resulted in a significant increase in the mean +/- SEM base excess from -8.4 +/- 1.2 mmol/L immediately after birth to 0.3 +/- 1.1 mmol/L 120 minutes later. During the same period, sodium concentration significantly increased from 145.3 +/- 0.8 mmol/L to 147.8 +/- 0.7 mmol/L. Mean chloride concentration before NaHCO(3) administration was significantly lower in the acidotic calves (99.6 +/- 1.1 mmol/L) than in the control calves (104.1 +/- 0.9 mmol/L). Calcium concentration in acidotic calves decreased significantly from before to after treatment. Concentrations of potassium, magnesium, and inorganic phosphorus were not affected by treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of hypertonic NaHCO(3) solution to acidotic neonatal calves did not have any adverse effects on plasma concentrations of several commonly measured electrolytes or enzyme activities. The treatment volume used was smaller, compared with that for an isotonic solution, which makes it more practical for use in field settings.  相似文献   

4.
To study the effect of short term high intensity exercise on plasma lactate, potassium, sodium and chloride concentrations, five Thoroughbred horses were galloped on a treadmill at a 5 degree incline. Following a standardised warm-up period, they were galloped at 8, 10, or 12 metres/sec for 2 mins. One horse also galloped at 14 metres/sec for 1.5 mins. Sequential arterial and/or venous blood samples were collected during exercise and recovery. At 12 metres/sec, the effect of different recovery modes, ie, standing, walking or trotting, on the electrolytes was also examined. There was a progressive rise in plasma potassium concentration during galloping, with peak values occurring at the end of the exercise bout. In some cases, values above 10 mmol/litre were recorded at the highest workloads. Plasma lactate concentrations peaked during early recovery, with values up to 32 mmol/litre. A high correlation existed between peak potassium and lactate concentrations (venous r = 0.923, and arterial r = 0.989). Following exercise there was a rapid return to baseline plasma potassium concentrations, but by 12 mins recovery there was still an elevated lactate concentration, the extent depending on the intensity of the exercise bout and the recovery mode. There was a small rise in plasma sodium but no significant change in plasma chloride concentrations during exercise. However, when adjusted for the decrease in plasma volume, as determined from total plasma protein concentration, there was a decrease in circulating amounts of both electrolytes.  相似文献   

5.
The association between the concentrations of various blood constituents and the responses of cows with milk fever following calcium borogluconate therapy was determined using analysis of variance. In cows which had not received herdsman treatment prior to sampling (n = 63), plasma potassium was the only constituent with a significant effect (p less than 0.01), the mean concentrations for cows classified as unassisted, assisted, or delayed, recoveries, and deaths ranging down from 4.3 to 2.8 mmol/l, respectively. In cows which had received treatment prior to sampling (n = 55) those making unassisted recoveries had significantly lower mean concentrations of serum total calcium than those making assisted recoveries (1.3 v 1.9 mmol/l, respectively, p less than 0.05), and cows making delayed recoveries had significantly lower mean plasma inorganic phosphate concentrations (0.3 mmol/l) than those making unassisted and assisted recoveries (both 0.7 mmol/l, p less than 0.05) and those subsequently dying (1.2 mmol/l, p less than 0.01). Response was not dependent on plasma potassium concentrations in the treated group of cows, and plasma sodium, serum magnesium, and erythrocyte sodium concentrations were not significant in either group of cows.  相似文献   

6.
The article describes the dynamics of changes in blood concentrations of the active substances present in the solution after its infusion to healthy cows in comparison to NaCI solution as well as the response of paretic cows to treatment with the new complex solution. Cows received a dose of 400 ml of A1 solution (containing 8.4 g of Ca2+) intravenously. In healthy cows the average calcium concentration in blood serum prior to the test was 2.52 +/- 0.08 mmol/l while 15 min. after the infusion the concentration rose to 3.10 +/- 0.08 mmol/l (p < 0.05) and magnesium concentration rose from 0.61 +/- 0.05 to 1.39 +/- 0.08 mmol/l (p < 0.05). This experiment showed that elevated concentration of non-organic phosphates persisted 1 hour after infusion (p < 0.05). In the second phase of efficacy evaluation of the novel preparation A1 on paretic cows the intravenous injection of 1 ml/kg of body weight of A1 solution increased calcium concentration up to almost normal level (p < 0.05). The level of magnesium in serum 1 h after injection was statistically significantly higher by 63% (p < 0.05) and reached the physiologically normal concentration. 1 h after the infusion of test solution the level of phosphate was higher by 13% (p > 0.05). The rise was statistically not significant. Even though A1 solution undoubtedly produced an increase in glucose concentration in the blood serum, due to wide dispersion of individual measurements and high standard deviation the increase (p > 0.05) in glucose concentration was found insignificant. Most of the treated paretic cows rose within 1-6 h after infusion of 400 ml of solution A1. No relapses were observed. A combination of different salts of calcium and magnesium, non-organic phosphates and glucose with analeptic substance mixed in one solution (A1 solution) administered at a dose of 1 ml/kg of body weight raises concentrations of essential macroelements in blood serum of cattle and promotes improvement of paretic cows condition.  相似文献   

7.
Blood and urine chemical values at parturition in clinically normal Holstein cows (n = 12) were compared with the same values in Holstein cows developing udder edema (n = 12). There was no statistically significant mean difference between the 2 groups for the serum and urine chemical data. Furosemide (500 mg) given IV caused a significant increase in serum calcium and sodium, urine chloride, potassium, and sodium, and fractional excretional ratio of chloride, potassium, and sodium. There was a significant mean decrease in the serum potassium, urine creatinine, osmolality, pH, and specific gravity. Hydrochlorothiazide (250 mg) given IV caused a significant mean increase in serum chloride, urine chloride, potassium, and sodium, and fractional excretion ratio of chloride, potassium, and sodium. There was a significant mean decrease in serum potassium and sodium, urine osmolality, pH, and specific gravity. Acetazolamide (500 mg) given IV caused a significant mean increase in blood urea nitrogen, serum chloride and glucose, urine sodium, and fractional excretion ratio of sodium, while causing a significant mean decrease in serum potassium, sodium, and phosphorus, and urine creatinine. Dextrose (500 g) given IV as a 50% solution caused a statistical mean increase in serum glucose, urine chloride, potassium, and sodium, and fractional excretion ratio of chloride and potassium. A statistical mean decrease occurred in the packed cell volume, blood urea nitrogen, serum calcium, potassium, sodium, and phosphorus, urine creatinine, osmolality, and pH.  相似文献   

8.
Serum and urine were taken from healthy dairy cattle from 22 different farms. 214 animals belonged to the Swiss Brown breed and 210 were crossbreds of Simmental-Red Holstein. The animals were given at least 70 g of sodium chloride with their daily feed ration. On 6 farms sodium chloride was offered ad libitum in form of licks, which was presumed to be sufficient for covering their needs. Concentrations of sodium (UR Na), potassium (UR K) and creatinine were analyzed from serum and urine and fractional excretion of Na and K was calculated. Concentrations of sodium and potassium in urine from all cows (mean +/- sd) was 60.9 +/- 44.7 mmol/l and 370.7 +/- 66.9 mmol/l respectively. The FE values were 0.954 +/- 0.939% for sodium and 173.1 +/- 54% for potassium. In 5.5% of the animals values for UR Na < 10 mmol/l were found. There were no significant differences, however, were found in sodium and potassium excretion among farms. Urine samples of at least 10 animals should be analyzed in order to have a reliable estimation of the supply with sodium chloride within a herd. Our results do not support the hypothesis that low sodium excretion would be a predisposing factor for Bovine Dilative Cardiomyopathy in Simmental-Red Holstein cattle.  相似文献   

9.
Samples of blood, urine and milk were examined in 94 clinically healthy cows of 10 herds. The average milk samples and the feed ration used in these herds were also examined. The determination of urea concentration and milk acidity was evaluated as to its suitability for the assessment of the protein-glycide ratio and acid-base activity of feed ration. The determination of urea content in an average milk sample was found to be an expeditious procedure. The results of this examination can be used for the evaluation of the protein supply to cows with the same reliability as the determination of serum urea. The passage of urea from serum to milk was proportional. The correlation coefficient for the relation of both parameters was statistically highly significant (r = 0.940). According to the calculated equation of regression line (f2 = 0.734 + 0.669 X f1), the values from 2.94 to 4.10 mmol/l are approximately adequate to the reference range of serum urea from 3.30 to 5.00 mmol/l in milk used in Czechoslovakia. The acidity of milk was found to have a low sensitivity for being used with success for the determination of the acid-base activity of feed ration. The examination of the net acid-base urinary output cannot be replaced by the determination of milk acidity.  相似文献   

10.
Sodium propionate (3 mmol/kg) was injected IV into 8 nonlactating dairy cows before and after 6 days (144 hours) of fasting. During fasting, long-chain fatty acids in plasma increased from 0.30 +/- 0.05 (SE) mM to 1.09 +/- 0.15 mM (P less than 0.05). Liver fat increased from 0.5 +/- 0.3% to 9.3 +/- 1.7% (P less than 0.05). Half-life of injected sodium propionate increased significantly (P less than 0.05) from 7.6 +/- 0.5 minutes to 10.1 +/- 1.0 minutes during fasting. Sulfobromophthalein half-life did not change significantly (3.8 +/- 0.79 minutes to 5.3 +/- 1.3 minutes). Increases in plasma glucose concentrations after propionate loading were significantly less during fasting than during feeding. Thus, the change in glucose concentration served as an indicator of hepatic conversion of propionate to glucose. Increases in glucose concentration of less than 2 mM at 30 minutes after propionate loading indicated that liver function was altered in nonlactating dairy cows.  相似文献   

11.
The concentrations of sodium, potassium, reduced glutathione (GSH) and free amino acids and Na-K-ATPase activity in erythrocytes were examined in 35 purebred Jindo dogs in Korea. The incidence of Jindo dogs with a high potassium concentration and high activity of Na-K-ATPase in erythrocytes (HK phenotype) was 25.7%. The erythrocyte GSH concentration in HK Jindo dogs varied widely, from 2.45 to 12.38 mmol/l of RBCs, and was positively correlated with the erythrocyte glutamate concentration. These results indicate that HK Jindo dogs have normal to very high levels of erythrocyte GSH, which might result from the varying quantity of Na-dependent glutamate influx in the erythrocytes.  相似文献   

12.
The effects of whole-body potassium depletion induced by food deprivation on plasma, erythrocyte, and middle gluteal muscle K concentrations was quantified in 16 healthy, adult horses before, during, and at the end of a 7-day period of food deprivation during which water and sodium chloride were available ad libitum. Potassium concentrations were determined by atomic absorption spectroscopy. Plasma K concentration remained constant (3.49 +/- 0.09 mM K/L of plasma; mean +/- SEM) throughout the study. Erythrocyte potassium concentration decreased from 93.10 +/- 1.94 mM K/L of erythrocytes on day 0 to 88.63 +/- 2.39 mM K/L of erythrocytes on day 2 (decrease of 4.8%; P less than 0.05) and thereafter did not change. The K concentration of the middle gluteal muscle decreased from 91.06 +/- 2.96 microM K/g of muscle (wet weight) to 79.61 +/- 2.09 microM K/g of muscle (decrease of 12.6%; P less than 0.05) on day 4 and decreased further on day 7 to 73.62 +/- 1.85 microM K/g of muscle (decrease of 19.2%; P less than 0.05). There was no correlation between the plasma and erythrocyte K concentrations (r = -0.066), the erythrocyte and middle gluteal muscle K concentrations (r = 0.167), or the plasma and middle gluteal muscle potassium concentrations (r = -0.018). The water content of the middle gluteal muscle remained constant (73.23 +/- 0.36%) throughout the study. Erythrocyte membrane potential did not change (-99.26 +/- 0.87 mV) during the study, whereas the magnitude of the membrane potential of the middle gluteal muscle decreased from -105.84 +/- 1.67 mV on day 0 to -100.93 +/- 2.10 mV on day 7 (P less than 0.05).  相似文献   

13.
采用火焰光度计法测定了湟源县日月乡黄牛４０份血样的血钾浓度。测定结果为：全血钾浓度９．１６ｍｍｏｌ／Ｌ；红细胞钾浓度１９．７９ｍｍｏｌ／Ｌ；血清钾浓度４．３５ｍｍｏｌ／Ｌ。全血钾浓度和红细胞钾浓度呈显著的正相关关系（ｒ＝０．９４４１Ｐ＜０．００１）  相似文献   

14.
A total of 2102 urine samples of 49 sows from three farms was collected. The relationship between creatinine or the urinary colour respectively and the urinary mineral concentration was investigated. A highly significant, negative correlation between the flow of urine (3.2 to 61.1 ml/min) and the creatinine concentration could be established (n = 330, r2 = 0.84). The correlation between the urinary colour and the flow of urine showed to be comparably close (r2 = 0.80). The urinary sodium, potassium, calcium, and phosphorus content was closely correlated with the creatinine concentration or the urinary colour respectively. The corrected mineral concentration (mmol/l:creatinine and/or mmol/l:urinary colour, E 405 nm) proved to be a useful parameter of the renal mineral excretion (mmol/min). It can be expected that the additional measurement of the two parameters creatinine and/or urinary colour may increase the indicative value of urine examination. In the three sow herds investigated the correlations between urinary colour and creatinine were higher than r2 = 0.85 in all cases. The relevance of the results with respect to urine examinations is discussed.  相似文献   

15.
To obtain a basal concentration of serum Haptoglobin (Hp) in cattle in Taiwan, Hp concentrations were measured from serum samples collected from 10 healthy heifers, every week for one year. The values were also compared with those collected from 15 cows diagnosed with postpartum metritis. The heifers were successfully impregnated by artificial insemination six months after the tests. Hp concentrations were also measured in the serum collected from 11 other cows within 3 weeks after parturition. The Hp assay developed in this study gave a good correlation (r=0.893)with Western blotting. The Hp concentration of 454 serum samples from the 10 heifers had a mean value of 83.6 +/- 34.1 mg/l, and there was no significant difference among individual heifers. The basal value of Hp in heifers was calculated as less than 73.6 mg/l. No significant difference in Hp concentration was observed among the 10 heifers during cold and warm seasons (19.8 +/- 2.2 degrees C vs 27.3 +/- 1.4 degrees C), or before and after pregnancy. The mean serum Hp concentration from cows suffering from postpartum reproductive disorders was 1133.5 +/- 627.1 mg/l, which was significantly greater than the serum of healthy heifers and postpartum cows (104.6 +/- 61.0 mg/l) (P<0.05). These results demonstrate that Hp concentration may be a useful indicator for cows with postpartum reproductive disorders.  相似文献   

16.
Milk urea determination is being used as a broad indicator of protein/energy imbalance in dairy herds. The main purpose of this study was to compare blood and bulk milk urea values in grazing herds, to evaluate their seasonal variation under South Chilean conditions, and to examine their potential relationships with herd fertility. The association between herd blood urea concentration (mean of seven lactating cows) and bulk milk urea concentration (tank containing milk from the previous 24 h) was determined in 21 diary herds. Reference values, seasonal and herd variance, and the frequency of herds with values outside a range of 2.5 to 7.3 mmol/l were determined in bulk milk samples obtained monthly for a period of one year from 82 suppliers at two creameries located in southern Chile. Finally, bulk milk urea was measured every two weeks in samples from 24 herds, and the first service conception rate (FSCR) from 2153 dairy cows was determined. Mean bulk urea concentration was highly correlated with mean herd blood urea concentration (r = 0.95; p < 0.01). Mean urea concentration in the bulk milk samples obtained during one year from 82 herds was 4.9 +/- 1.2 mmol/l, with a range of 1.5 to 11.6 mmol/l. The highest values were found during spring and the lowest values during the summer. There was a high seasonal variation (CV = 13-47%) and between-herd variation (CV = 20-31%). Out of a total of 984 samples, 5.4% had urea values > 7.3 mmol/l and 3.8% had values < 2.5 mmol/l. Of the 82 herds, 27% had values outside the reference interval (2.5-7.3 mmol/l) on two or more occasions. FSCR was lower in herds when the bulk milk urea was > 7.3 mmol/l (50.7%) than in cows, where the urea concentration was < 5.0 mmol/l (73.8%) at the time of insemination. The study concluded that bulk milk urea concentrations provided information similar to herd blood urea concentrations in local grazing dairy herds. There was a high frequency of herds with abnormal values, with large variations between herds and between seasons. Increased milk urea concentrations during spring were associated with lower conception rates.  相似文献   

17.
OBJECTIVE: To determine effects of experimentally induced hypercalcemia on serum concentrations and urinary excretion of electrolytes, especially ionized magnesium (iMg), in healthy horses. ANIMALS: 21 clinically normal mares. PROCEDURES: Horses were assigned to 5 experimental protocols (1, hypercalcemia induced with calcium gluconate; 2, hypercalcemia induced with calcium chloride; 3, infusion with dextrose solution; 4, infusion with sodium gluconate; and 5, infusion with saline [0.9% NaCl] solution). Hypercalcemia was induced for 2 hours. Dextrose, sodium gluconate, and saline solution were infused for 2 hours. Blood samples were collected to measure serum concentrations of electrolytes, creatinine, parathyroid hormone, and insulin. Urine samples were collected to determine the fractional excretion of ionized calcium (iCa), iMg, sodium, phosphate, potassium, and chloride. RESULTS: Hypercalcemia induced by administration of calcium gluconate or calcium chloride decreased serum iMg, potassium, and parathyroid hormone concentrations; increased phosphate concentration; and had no effect on sodium, chloride, and insulin concentrations. Hypercalcemia increased urinary excretion of iCa, iMg, sodium, phosphate, potassium, and chloride; increased urine output; and decreased urine osmolality and specific gravity. Dextrose administration increased serum insulin; decreased iMg, potassium, and phosphate concentrations; and decreased urinary excretion of iMg. Sodium gluconate increased the excretion of iCa, sodium, and potassium. CONCLUSIONS AND CLINICAL RELEVANCE: Hypercalcemia resulted in hypomagnesemia, hypokalemia, and hyperphosphatemia; increased urinary excretion of calcium, magnesium, potassium, sodium, phosphate, and chloride; and induced diuresis. This study has clinical implications because hypercalcemia and excessive administration of calcium have the potential to increase urinary excretion of electrolytes, especially iMg, and induce volume depletion.  相似文献   

18.
The aim of this study was to monitor renal function in diarrhoeic calves and to determine the effectiveness of an applied fluid therapy. A total of 28 diarrhoeic (n = 18) and healthy (n = 10) Holstein-Friesian calves of different sexes, between 1 and 30 days of age, were used. Blood and urine samples were obtained from diarrhoeic calves before the treatment and then three more times at 24-h intervals during the treatment. From healthy calves, samples were taken only once. Therapy was started by the intravenous administration of 8.4% sodium bicarbonate and 0.9% sodium chloride solutions for the first 24 h, followed by the oral application of a commercial electrolyte solution (sodium chloride 3.5 g, trisodium citrate 2.9 g, potassium chloride 1.5 g and glucose anhydrous 20 g in 1 litre H2O) up to the 48th h of therapy. Before the therapy, the average levels of pH (7.10 +/- 0.12), bicarbonate (HCO3-) (16.48 +/- 3.80 mmol/l), base deficit (-12.65 +/- 5.97 mmo/l) and fractional excretion (FE) of sodium (0.16 +/- 0.11%) and potassium (15.07 +/- 8.56%) were significantly lower while serum urea (17.48 +/- 10.32 mmol/l) and creatinine (Cr) concentrations (169.72 +/- 98.12 micromol/l), haematocrit levels (45.13 +/- 13.60%) and urinary gamma glutamyl transferase (GGT)/Cr ratio (8.6 +/- 4.3 x 1/10(3) U/micromol) were significantly higher in diarrhoeic calves than in healthy calves. Alterations in parameters indicating the presence of renal dysfunction were normalised in the diarrhoeic calves that survived (83.3%). Three calves with severe metabolic acidosis and azotaemia died at the beginning of therapy. It was concluded that the FE of Na and K (FENa, FEK) and urine GGT/Cr ratio may have an important role in assessing renal function in diarrhoeic calves and in evaluating the effectiveness of an applied fluid therapy.  相似文献   

19.
Propionate utilisation by the liver in spontaneously ketotic dairy cows was investigated by determining blood glucose levels after an intravenous sodium propionate load (2.5 mmol kg-1). In addition, blood ketone body concentrations were measured after propionate loading. Cows were divided into three groups (control, mildly ketotic and severely ketotic) by their blood acetoacetate concentrations. Plasma glucose concentrations increased significantly after sodium propionate injection in all three groups (P less than 0.05). The maximum glucose concentration occurred earlier in the control group than in the ketotic groups. Changes in glucose concentrations following propionate loading of control and ketotic cows differed significantly at 20 minutes and beyond. Differences in the change in glucose concentration between mildly ketotic and severely ketotic cows were not significant. Acetoacetate concentration was significantly decreased at five minutes and beyond after the injection in ketotic cows, whereas beta-hydroxybutyrate concentration decreased more slowly. A decrease in beta-hydroxybutyrate concentration was significant at 40 minutes and beyond in the severely ketotic group and at 10 minutes and beyond in the mildly ketotic group after loading.  相似文献   

20.
Propionate was recently shown to increase leptin synthesis in rodents. To determine if a similar effect occurs in ruminants, propionate was administered to lactating dairy cows. In experiment 1, 31 cows were given an intrajugular Na propionate bolus (1,040 micromol/kg body weight), increasing plasma propionate from 160 to 5,680 microM and plasma insulin from 6.8 to 77.8 microIU/mL. Plasma leptin concentration decreased from 2.11 ng/mL before bolus to 1.99 ng/mL after dosing (P<0.05) with no differences in leptin concentrations at 20, 50, and 100 min post-bolus (P>0.10). In experiment 2, 12 cows were used in a duplicated 6 x 6 Latin square experiment to assess the dose-response effect of ruminal propionate infusion on plasma leptin concentration. Sodium propionate was infused at rates of 0, 260, 520, 780, 1040, or 1,300 mmol/h, while total short-chain fatty acid infusion rate was held constant at 1,300 mmol/h by addition of Na acetate to the infusate. Coccygeal blood was sampled following 18 h of infusion. Increasing the rate of propionate infusion linearly increased plasma propionate concentration from 180 to 330 microM (P<0.001) and plasma insulin concentration from 6.7 to 9.1 microIU/mL (P<0.05). There was a quadratic response in plasma leptin concentration (P=0.04) with a maximum at 780 mmol/h propionate, but leptin concentrations increased by no more than 8% relative to the 0 mmol/h propionate infusion. Leptin concentrations were correlated with insulin concentrations but not with propionate concentrations in plasma. Propionate is not a physiological regulator of leptin secretion in lactating dairy cows.  相似文献   

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