Plasma Calcium, Inorganic Phosphate and Magnesium During Hypocalcaemia Induced by a Standardized EDTA Infusion in Cows

The intravenous Na2EDTA infusion technique allows effective specific chelation of circulating Ca2+ leading to a progressive hypocalcaemia. Methods previously used were not described in detail and results obtained by monitoring total and free ionic calcium were not comparable due to differences in sampling and analysis. This paper describes a standardized EDTA infusion technique that allowed comparison of the response of calcium, phosphorus and magnesium between 2 groups of experimental cows. The concentration of the Na2EDTA solution was 0.134 mol/l and the flow rate was standardized at 1.2 ml/kg per hour. Involuntary recumbency occurred when ionised calcium dropped to 0.39 – 0.52 mmol/l due to chelation. An initial fast drop of ionized calcium was observed during the first 20 min of infusion followed by a fluctuation leading to a further drop until recumbency. Pre-infusion [Ca2+] between tests does not correlate with the amount of EDTA required to induce involuntary recumbence. Total calcium concentration measured by atomic absorption remained almost constant during the first 100 min of infusion but declined gradually when the infusion was prolonged. The concentration of inorganic phosphate declined gradually in a fluctuating manner until recumbency. Magnesium concentration remained constant during infusion. Such electrolyte responses during infusion were comparable to those in spontaneous milk fever. The standardized infusion technique might be useful in future experimental studies

Effect of Anionic Salt and Highly Fermentable Carbohydrate Supplementations on Urine pH and on Experimentally Induced Hypocalcaemia in Cows

The objective of this experiment was to determine the effect of dietary grain on calcium homeostasis. Six rumen-fistulated dairy cows with 3 or more previous lactations and no history of parturient paresis were randomly assigned to a sequence of diets in a crossover study with 4 periods of 10 days each. Dietary treatments were: A control ration consisting of wrap grass silage alone (1), the control ration supplemented with ammonium chloride and ammonium sulphate salt solution (2), control ration following a period with supplementation (3) and control ration supplemented with increasing amounts of barley from 4 to 10 kg/cow per day, expected to produce subclinical rumen acidosis (4). Daily intake of the diets was adjusted to 14 kg DM/cow per day. On day 11, the calcium-regulating mechanisms in cows were challenged until recumbency by a standardized intravenous EDTA infusion and cows were left to recover spontaneously. Anion supplementation and the feeding of highly fermentable carbohydrate lowered urine pH below 7.0 due to subclinical acidosis. During spontaneous recovery from EDTA induced hypocalcaemia, the cows more quickly regained a whole blood free calcium concentration of 1.00 mmol/L if they had most recently been supplemented with either anionic salts or with increasing amounts of barley, as compared to the basic ration. It is concluded that so-called slug-feeding or 'steaming up' with highly fermentable carbohydrates before parturition in milk fever susceptible cows enhanced calcium homeostasis similar to the effect seen in cows on anionic diets

Plasma magnesium in cows infused intravenously with EDTA from time zero onwards

<p><b>Copyright information:</b></p><p>Taken from "Plasma Calcium, Inorganic Phosphate and Magnesium During Hypocalcaemia Induced by a Standardized EDTA Infusion in Cows"</p><p>http://www.actavetscand.com/content/42/2/251</p><p>Acta Veterinaria Scandinavica 2001;42(2):251-260.</p><p>Published online 30 Jun 2001</p><p>PMCID:PMC2202322.</p><p></p> The last blood sample was taken at recumbency. Cows were supplemented with anions in their ration for 10 days before EDTA infusion

Plasma ionised calcium in cows supplemented with anions then infused intravenously with EDTA from time zero onwards

<p><b>Copyright information:</b></p><p>Taken from "Plasma Calcium, Inorganic Phosphate and Magnesium During Hypocalcaemia Induced by a Standardized EDTA Infusion in Cows"</p><p>http://www.actavetscand.com/content/42/2/251</p><p>Acta Veterinaria Scandinavica 2001;42(2):251-260.</p><p>Published online 30 Jun 2001</p><p>PMCID:PMC2202322.</p><p></p> The last blood sample was taken at recumbency

Plasma total calcium in cows infused intravenously with EDTA from time zero onwards

<p><b>Copyright information:</b></p><p>Taken from "Plasma Calcium, Inorganic Phosphate and Magnesium During Hypocalcaemia Induced by a Standardized EDTA Infusion in Cows"</p><p>http://www.actavetscand.com/content/42/2/251</p><p>Acta Veterinaria Scandinavica 2001;42(2):251-260.</p><p>Published online 30 Jun 2001</p><p>PMCID:PMC2202322.</p><p></p> The last blood sample was taken at recumbency. Cows were supplemented with anions in their ration for 10 days before EDTA infusion

Application of microagglutination test for detection of antibodies to Salmonella gallinarum in commercial layer chickensApplication du test de microagglutination pour la detection des anticorps a Salmonella gallinarum chez les pondeuses commerciales

In this study a microagglutination test (MAT) was developed, evaluated and compared with a rapid whole-blood agglutination test (RWBAT) for detection of Salmonella gallinarum antibodies in commercial layer chickens in Morogoro, Tanzania. The results showed that at Kigurunyembe farm, 16 (32%) of chicken tested were RWBAT positive while 30 (60%) were MAT positive among the 50 sera tested. Results from Kilakala farm revealed 10 (20%) sera that were RWBAT positive whereas 5 (10%) were positive for MAT among the 50 sera tested. On both farms, S. gallinarum was isolated from 21 chickens. The sensitivities, specificities, positive and negative predictive values for MAT were 57, 71, 34 and 86%, respectively, and 67, 85, 54 and 82 %, respectively for RWBAT. Although MAT was slightly less sensitive and less specific than RWBAT, it revealed a higher true seroprevalence (35%) of fowl typhoid than RWBAT (26%). When the test is optimized it may be preferred because it uses less time, space and antigen while permitting more objective evaluation of antibody titers. Higher growth and seroprevalence of S. gallinarum was observed in Rhode Island Red than Black Australop chickens. Keywords: chickens, microagglutination test, Salmonella gallinarum, seroprevalence, whole blood agglutination test Bulletin of Animal Health and Production in Africa Vol. 54(2) 2006: 124-13

Plasma ionised calcium in cows fed basic ration then infused intravenously with EDTA from time zero onwards

<p><b>Copyright information:</b></p><p>Taken from "Plasma Calcium, Inorganic Phosphate and Magnesium During Hypocalcaemia Induced by a Standardized EDTA Infusion in Cows"</p><p>http://www.actavetscand.com/content/42/2/251</p><p>Acta Veterinaria Scandinavica 2001;42(2):251-260.</p><p>Published online 30 Jun 2001</p><p>PMCID:PMC2202322.</p><p></p> The last blood sample was taken at recumbency