References of "Lebreton, Pascal"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailInvestigation of the death of calves after epileptiform seizures associated with metabolic disorders
Chevalier, Marine; Lebreton, Pascal; Garnier, Catherine et al

in Cattle Practice (2014), 22(1), 10-16

Death of calves after epileptiform seizures can be caused by metabolic disorders including hypomagnesaemia, although a range of other conditions may also be implicated and therefore also warrant ... [more ▼]

Death of calves after epileptiform seizures can be caused by metabolic disorders including hypomagnesaemia, although a range of other conditions may also be implicated and therefore also warrant investigation. Hypomagnesaemia is primarily observed in herds where calves are fed exclusively with either milk or milk substitute products. Hyperparathyroidism is associated with congestion and hypertrophy of the parathyroid gland and causes both hypercalcaemia and hypophosphataemia. However, its exact aetiology currently remains unclear. The purpose of this study was to explain epileptiform seizures in calves from a cattle herd presenting both deaths and decreased average daily gain (ADG). A Montbeliard herd with calves presenting epileptiform seizures from the age of five weeks was studied. The herd consisted of 39 cows and 46 calves. Tachycardia, nervousness and trampling, violent seizures of tetany lasting approximately 15 minutes were all observed, while opisthotonos was observed in 5 calves. Three of the latter calves died. The remaining calves presented a decreased ADG. Blood and urine biochemical assays were performed on 8 sick calves to determine the aetiology of the clinical signs. The assays revealed normo/hyper-calcaemia, hypophosphataemia and hypomagnesaemia, as well as hypocalciuria, hyperphosphaturia and hypomagnesuria. Deficiencies in iodine, iron and vitamins A, D3 and E were also reported in the herd. These calves could potentially be suffering from hyperparathyroidism. Hyperparathyroidism results in hypomagnesaemia, hypovitaminosis-A and, on occassion, hypercalcaemia and hypophosphataemia. This condition can lead to seizures, muscular problems, heart attacks and anorexia. The simultaneous occurrence of hypomagnesaemia, hyperparathyroidism and hypovitaminosis-A has been never described in related research literature. This is, therefore, in all likelihood a new metabolic disorder facing young cattle. Blood and urine biochemical assays are important tools for the detection of this pathological entity in calves. A dosage of parathyroid hormone (PTH) by the enzyme-linked immunosorbent assay (EIA) method using a kit suitable for cattle can be used to detect hyperparathyroidism. [less ▲]

Detailed reference viewed: 16 (1 ULg)
Full Text
Peer Reviewed
See detailInvestigation of body condition score and insulin sensitivity (RQUICKY) in downer cow syndrome
Bonvoisin, Marie ULg; Rollin, Frédéric ULg; Lebreton, Pascal et al

in Revista Portuguesa de Buiatria (2012, June), (Special Edition),

Detailed reference viewed: 43 (10 ULg)
Full Text
Peer Reviewed
See detailInvestigation of sudden death of calves after epileptic seizures due to hypomagnesaemia and hyperparathyroidism
Chevalier, Marine ULg; Lebreton, Pascal; Garnier, Catherine et al

in Revista Portuguesa de Buiatria (2012, June), (Special Edition),

Detailed reference viewed: 43 (7 ULg)
Full Text
Peer Reviewed
See detailEpidemiology of trace elements deficiencies in Belgian beef and dairy cattle herds.
Guyot, Hugues ULg; Saegerman, Claude ULg; Lebreton, Pascal et al

in Journal of Trace Elements in Medicine and Biology (2009), 23(2), 116-23

Selenium (Se), iodine (I), zinc (Zn) and copper (Cu) deficiencies in cattle have been reported in Europe. These deficiencies are often associated with diseases. The aim of the study was to assess trace ... [more ▼]

Selenium (Se), iodine (I), zinc (Zn) and copper (Cu) deficiencies in cattle have been reported in Europe. These deficiencies are often associated with diseases. The aim of the study was to assess trace element status in Belgian cattle herds showing pathologies and to compare them to healthy cattle herds. Eighty-two beef herds with pathologies, 11 healthy beef herds, 65 dairy herds with pathologies and 20 healthy dairy herds were studied during barn period. Blood and/or milk samples were taken in healthy animals. Plasma Zn, Cu, inorganic I (PII) and activity of glutathione peroxidase in erythrocytes (GPX) were assayed. In milk, I concentration was measured. Data about pathologies and nutrition in the herds were collected. According to defined thresholds, it appeared that a large proportion of deficient herds belonged to "sick" group of herds. This conclusion was supported by the mean value of trace elements and by the fact that a majority of individual values of trace elements was below the threshold. Dairy herds had mean values of trace elements higher than beef herds. More concentrates and minerals were used in healthy herds versus "sick" herds. These feed supplements were also used more often in dairy herds, compared to beef herds. Trace elements deficiencies are present in cattle herds in Belgium and are linked to diseases. Nutrition plays a major role in the trace elements status. [less ▲]

Detailed reference viewed: 69 (32 ULg)
Full Text
Peer Reviewed
See detailDevelopment and validation of a radioimmunoassay for thyrotropin in cattle
Guyot, Hugues ULg; Sulon, Joseph ULg; Beckers, Jean-François ULg et al

in Journal of Veterinary Diagnostic Investigation (2007), 19(6), 643-651

In mammals, thyrotropin, or thyroid-stimulating hormone (TSH), assay is used for the diagnosis of primary hypothyroidism. Hypothyroidism is the most common type of thyroid disorder in cattle. The aim of ... [more ▼]

In mammals, thyrotropin, or thyroid-stimulating hormone (TSH), assay is used for the diagnosis of primary hypothyroidism. Hypothyroidism is the most common type of thyroid disorder in cattle. The aim of this study was to develop and validate, under physiologic and pathologic conditions, a radioimmunoassay (RIA) for bovine TSH (bTSH). Double RIA was performed with purified bTSH and specific bovine antiserum. Laboratory validation included research of minimal detection limit, accuracy, and reproducibility. The physiologic validation included a thyrotropin-releasing hormone (TRH) challenge performed on euthyroid cows and a follow-up of bTSH concentration over a 24-hour period. Furthermore, bTSH concentration was assayed in a large population of healthy dairy and beef cows to define reference interval. The pathologic validation was made by assaying bTSH and thyroid hormones on healthy and goitrous newborn calves. The minimum detection limit (MDL) for bTSH assay was 1.3 microU/ml. The recovery was 101% to 106%. The intra- and interassay coefficients of variation (CVs) ranged from 5% to 11% and 11% to 15%, respectively. The RIA covered the whole range of physiologic bTSH values, as shown by bTSH values induced by TRH-challenge. A pulsatile secretion of bTSH was observed, accompanied by a diurnal variation with lower night values than day values. Reference intervals of bTSH ranged from 1.3 to 13.0 microU/ml for beef and dairy breeds. Finally, bTSH easily discriminated goitrous newborn calves from healthy ones, leading to the definition of a cutoff value of 35 microU/ml. The bTSH assay positively reacted to physiologic and pathologic conditions. The accuracy and precision of the RIA were satisfying. [less ▲]

Detailed reference viewed: 109 (3 ULg)
Full Text
Peer Reviewed
See detailThyrotropin in newborn calves as a tool for diagnosing hypothyroidism
Guyot, Hugues ULg; Lebreton, Pascal; Alves de Oliveira, Laurent et al

in Cattle Practice (2007), 15(Part 3), 271-275

The hypothalamic-pituitary-thyroid axis is of particular importance for the adaptation of mammals to their environment. Hypothyroidism is the most common type of thyroid disorders in cattle. Thyrotropin ... [more ▼]

The hypothalamic-pituitary-thyroid axis is of particular importance for the adaptation of mammals to their environment. Hypothyroidism is the most common type of thyroid disorders in cattle. Thyrotropin (TSH) is used in several mammalian species for the diagnosis of primary hypothyroidism. Currently in cattle, thyroid hormone assays are used to diagnose such disease. The aim of the study was to compare different tools for diagnosing hypothyroidism in newborn calves. Twelve goitrous newborn calves from two beef herds were studied as well as 45 healthy newborn calves. Bovine TSH, thyroxine (T4), tri-iodothyronine (T3), reverse-T3 (rT3), plasmatic inorganic iodine (PII) and glutathione peroxidase in erythrocytes (GPXe) were assayed in these calves during the first day of life. T4/T3 and T4/TSH ratio were calculated. Furthermore, TSH, T4, PII and GPXe were also assayed in their dams at calving. Results were analysed using Wilcoxon rank sum test and Spearman's rank correlation coefficient. A significant higher value (P < 0.01) of TSH was seen for the group of goitrous calves compared to healthy calves. There was no difference between healthy and goitrous calves for GPXe (P > 0.1) and PII (P > 0.05). Significantly higher values were seen for healthy calves compared to goitrous calves concerning T4, T4/T3 ratio, T4/TSH ratio, rT3 (P < 0.0 1) and T3 (P < 0.05). Regarding the group of goitrous calves, those that had larger goitre at palpation and were hairless (n=8) died within the first day of life while the four other with moderate goitre and normal hair stayed alive. Goitrous-dead calves had higher TSH values than goitrous-alive ones (P < 0.01), lower T4, T3, T4/TSH (P < 0.0 1) and rT3 (P < 0.05) but similar T4/T3 ratio (P > 0.1). Furthermore, it appeared that T4 and rT3 values in goitrous-alive calves were not different compared to healthy calves (P > 0.1). Regarding TSH (rho=0.44), T4 (rho=-0.44), PII (rho=0.70) and GPXe (rho=0.87), there was a correlation between healthy calves and their dams, with significantly higher values being found in the calves (P < 0.01). There was no correlation between values of TSH and T4 in goitrous calves and their dams (P > 0.1). However, for these animals there was a strong relationship in the values of PH (rho=0.82) and GPXe (rho=0.94) (P < 0.01). TSH, PII and GPXe were significantly higher in goitrous calves compared to their dams (P < 0.01). Regarding T4, only goitrous-dead calves showed significantly lower values than their dams (P < 0.01). Dams with goitrous calves had higher TSH (P < 0.01) and PII (P < 0.05) compared to dams with healthy calves but similar T4 and GPXe (P > 0.1). This study revealed that TSH alone is a good marker for hypothyroidism in newborn calves. In the absence of TSH assay, the T4/T3 ratio may be used to diagnose hypothyroidism in newborn calves. In our study, although T4/T3 ratio was helpful in identifying goitrous calves, it did not allow to discriminate goitrous-dead from goitrous-alive calves, contrary to TSH. In our study, the presence of a goitre in newborn calves could not be explained by the iodine (PII) and thyroid (via T4) status of their dams. [less ▲]

Detailed reference viewed: 207 (14 ULg)
Full Text
Peer Reviewed
See detailTools to assess iodine deficiency in calves born from deficient and non deficient dams
Guyot, Hugues ULg; Uyttenhoef, Aude; Lebreton, Pascal et al

Poster (2006)

Detailed reference viewed: 17 (5 ULg)
Full Text
Peer Reviewed
See detailTrace elements deficiencies in Belgian beef and dairy herds in 2000-2001
Rollin, Frédéric ULg; Lebreton, Pascal; Guyot, Hugues ULg

Conference (2002)

Detailed reference viewed: 19 (7 ULg)