References of "Beckers, Jean-François"
     in
Bookmark and Share    
See detailEffect of Azawak colostrum administration on plasma protein profile in red kid
Abdoul, H; Marichatou, H; Beckers, Jean-François ULg et al

in Proceedings of the 2nd Scientific Meeting of the Faculty of Veterinary Medicine (2012, October 19)

Detailed reference viewed: 27 (8 ULg)
See detailPlacental and gastric aspartic proteinases: new insights from bovine species
Bella, Amina ULg; Beckers, Jean-François ULg; Melo de Sousa, Noelita ULg

in Proceedings of the 2nd Scientific Meeting of the Faculty of Veterinary Medicine (2012, October 19)

Detailed reference viewed: 9 (0 ULg)
See detailImmature equine oocyte vitrification
Gatez, Carine ULg; Ectors, F.J.; Farnir, Frédéric ULg et al

Scientific conference (2012, October 19)

Detailed reference viewed: 23 (9 ULg)
Full Text
Peer Reviewed
See detailCharacterisation of pregnancy losses after embryo transfer by measuring plasma progesterone and bovine pregnancy-associated glycoprotein-1 concentrations
Breukelman, S. P.; Perényi, Z.; Taverne, M. A. M. et al

in Veterinary Record : Journal of the British Veterinary Association (2012), 194(1), 71-76

The aim of this analysis was to determine whether pregnancy loss (PL) after embryo transfer (ET) in cattle was related to maternal progesterone (P4) concentrations during and shortly after ET, and ... [more ▼]

The aim of this analysis was to determine whether pregnancy loss (PL) after embryo transfer (ET) in cattle was related to maternal progesterone (P4) concentrations during and shortly after ET, and maternal bovine pregnancy-associated glycoprotein-1 (bPAG-1) concentrations in plasma at days 25–35 of gestation. Embryos (n = 260) were produced either in vivo after superovulation (n = 115), or in vitro from oocytes (obtained with ovum pick-up) in co-culture (n = 44) or cultured in a synthetic medium (n = 101). Overall, PL was 56.9% (148) and no significant differences occurred in calving rate among the three embryo production groups. There was no difference in P4 concentrations on days 7–14 of gestation in the three groups, nor between ongoing and interrupted pregnancies. Between days 25 and 35 of pregnancy, bPAG-1 concentrations were unaffected by embryo production, but in cattle that had PL between days 26 and 120, four bPAG-1 profiles could be detected. Between days 25 and 32, bPAG-1 concentrations were influenced by PL, and concentrations were significantly lower in animals in which PL occurred between days 26 and 120 than in those animals that aborted later or calved at term. Early P4 concentrations suggested that maternal luteal factors were not responsible for PL which appeared to be caused by impaired conceptus development (regardless of embryo type) as reflected by low maternal bPAG-1 concentrations prior to embryonic death [less ▲]

Detailed reference viewed: 32 (6 ULg)
Full Text
Peer Reviewed
See detailAssessment of pregnancy-associated glycoprotein (PAG) concentrations in swamp buffalo samples from fetal and maternal origins by using interspecies antisera.
Nguyen, V. H.; Barbato, O.; Bui, X. N. et al

in Animal Science Journal (2012), 83(10), 683-689

Pregnancy-associated glycoproteins (PAG) constitute a large family of glycoproteins found in the outer placental epithelial cell layer of the placenta in Eutherian species. In ruminants, they are noted to ... [more ▼]

Pregnancy-associated glycoproteins (PAG) constitute a large family of glycoproteins found in the outer placental epithelial cell layer of the placenta in Eutherian species. In ruminants, they are noted to be structurally closely related among the different species. This study was designed to determine PAG concentrations in maternal and fetal plasma, allantoic and amniotic fluids in buffalo species. Antisera (AS) generated in rabbits against distinct PAG molecules were used in three RIA-PAG systems: RIA-1 (raised against bovine PAG67kDa; AS#497), RIA-2 (raised against caprine PAG55+62kDa; AS#706) or RIA-3 (raised against buffalo PAG; AS#859). Samples were collected at slaughterhouse (n = 67). PAG concentrations determined by RIA-2 gave significantly higher results in both allantoic and amniotic fluids (12.7 ± 2.1 ng/ml and 24.0 ± 7.3 ng/ml, respectively). Regarding maternal and fetal plasma, PAG concentrations obtained by RIA-2 (21.8 ± 2.4 ng/ml and 20.2 ± 2.5 ng/ml, respectively) and RIA-3 (25.0 ± 2.2 ng/mL and 21.9 ± 3.2 ng/ml, respectively) were higher than those obtained by RIA-1 (15.5 ± 1.4 ng/ml and 16.1 ± 1.8 ng/ml, respectively). The correlation among the three systems was very high. The study clearly reveals the ability of PAG-RIA systems to determine PAG concentration in swamp buffalo samples. [less ▲]

Detailed reference viewed: 62 (6 ULg)
Full Text
Peer Reviewed
See detailIn vitro oocyte IGF-I priming increases inner cell mass proliferation of in vitro-formed bovine blastocysts
Velazquez, MA; Hadeler, KG; Herrmann, D et al

in Theriogenology (2012), 78(3), 517-527

Studies addressing the effects of supraphysiological levels of IGF-1 on oocyte developmental competence are relevant for unravelling conditions resulting in high bioavailability of IGF-1, such as the ... [more ▼]

Studies addressing the effects of supraphysiological levels of IGF-1 on oocyte developmental competence are relevant for unravelling conditions resulting in high bioavailability of IGF-1, such as the polycystic ovary syndrome (PCOS). This study investigated the effects of supraphysiological levels of IGF-1 during in vivo folliculogenesis on the morula-blastocyst transition in bovine embryos. Compacted morulae were non-surgically collected and frozen for subsequent mRNA expression analysis (IGF1R, IGBP3, TP53, AKT1, SLC2A1, SLC2A3, and SLC2A8), or underwent confocalmicroscopy analysis for protein localization (IGF1R and TP53), or were cultured in vitro for 24 h. In vitro-formed blastocysts were subjected to differential cell staining. The mRNA expression of SLC2A8 was higher in morulae collected from cows treated with IGF-1. Both IGF1R and TP53 protein were present in the plasma membrane and cytoplasm. IGF-1 treatment did not affect protein localization of both IGF1R and TP53. In vitro-formed blastocysts derived from morulae recovered from IGF-1-treated cows displayed a higher number of cells in the inner cell mass (ICM). Total cell number (TCN) of in vitro-formed blastocysts was not affected. A higher mean ICM/TCN proportion was observed in in vitro-formed blastocysts derived from morulae collected from cows treated with IGF-1. The percentage of in vitro-formed blastocysts displaying a low ICM/TCN proportion was decreased by IGF-1 treatment. In vitro-formed blastocysts with a high ICM/TCN proportion were only detected in IGF-1 treated cows. Results show that even a short in vivo exposure of oocytes to a supraphysiological IGF-1 microenvironment can increase ICM cell proliferation in vitro during the morula to blastocyst transition [less ▲]

Detailed reference viewed: 9 (5 ULg)
Full Text
Peer Reviewed
See detailPregnancy-associated glycoprotein, chymosin and pepsinogen immunoreactivity of proteins extracted from fetal gastric tissue in bovine species.
Bella, Amina ULg; Melo de Sousa, Noelita ULg; Dehimi, M. L. et al

in Research in Veterinary Science (2012), 92(3), 378-386

The objective of this work was to investigate the expression of gastric aspartic proteinases in fundic and pyloric mucosa removed from bovine fetuses. For this purpose, fractions issued from classical ... [more ▼]

The objective of this work was to investigate the expression of gastric aspartic proteinases in fundic and pyloric mucosa removed from bovine fetuses. For this purpose, fractions issued from classical biochemical protocols were analyzed by proteolytic method, by PAG-RIA and by Western blot with the use of antisera raised against both pepsinogens and PAG. A strong reaction of proteins extracted from the fundic mucosa collected at the beginning of pregnancy was revealed with both anti-bPAG-I and anti-bPAG-II antisera, suggesting the expression of pepsinogen F in bovine species. Concerning pyloric mucosa, the analysis by Western blot highlighted a very strong immunoreaction with the anti-bovine chymosin serum. Amino-terminal sequencing allowed to identify bovine fetuin and albumin in fundic extracts, chymosin in the pyloric mucosa extracts, as well as some unknown proteins in both mucosa. Despite no N-terminal microsequence corresponding to the hypothetical pepsinogen F could be identified, it cannot be excluded that an existing bovine pepsinogen F-like molecule could be degraded during the purification procedure or that co-purified proteins could be responsible for masking its N-terminal microsequence. [less ▲]

Detailed reference viewed: 61 (17 ULg)
Full Text
Peer Reviewed
See detailThe inseminating bull and plasma pregnancy-associated glycoprotein levels were related to peripheral leukocyte counts during the late pregnancy/early postpartum period in high-producing dairy cows.
Abdelfatah-Hassan, A.; Almeria, S.; Serrano, B. et al

in Theriogenology (2012), 77(7), 1390-1397

The interest in the immunology and endocrinology aspects of the peripartum in dairy cows has been increasing in the last years, since the animal status during the pre- and postpartum period determines the ... [more ▼]

The interest in the immunology and endocrinology aspects of the peripartum in dairy cows has been increasing in the last years, since the animal status during the pre- and postpartum period determines the subsequent productive and reproductive performance of the animal. At parturition, a drop in the immune functions of the peripheral blood polymorph-nuclear cells (PMN) was observed after a peak of Pregnancy-Associated Glycoproteins (PAGs) and recently, the inseminating bull was found to affect the plasma levels of bovine Pregnancy-Associated Glycoproteins (bovine PAGs) in the pregnant Holstein-Friesian dairy cows. The present work was aimed to determine whether changes in leukocyte counts during the peripartum, indicative of the animal immune status, could be related to the inseminating bull and to the levels of plasma pregnancy-associated glycoproteins (PAGs). Ninety six clinically healthy, single pregnant cows were selected in a commercial dairy herd. Six blood samples (four prepartum and two postpartum) were obtained every two weeks, and total and differential blood cell counts were analyzed. Based on procedures of General Linear Model analysis of variance for repeated measures, the inseminating bull affected counts of total leukocytes and lymphocytes (P<0.001; between-subject effects) throughout the peripartum period. In addition, cows with high plasma levels of PAGs (>900 ρg/µL) on Day 262-268 of gestation had higher numbers of total leukocytes and neutrophils throughout the peripartum period (P<0.001; between-subject effects). Young animals (≤ 1 lactation) had higher total leukocyte and lymphocytes counts than older cows (two or more lactations) throughout the study period. These results showed a clear relationship between the inseminating bull and plasma PAG levels and peripheral leukocyte counts during the peripartum period of dairy cows. [less ▲]

Detailed reference viewed: 27 (3 ULg)
Full Text
See detailInvestigations sur les protéines placentaires extraites des cotylédons fœtaux du Cervus elaphus
Fondja, E.; Okuyama, M.; Petrova, A. et al

Poster (2012, February)

Detailed reference viewed: 17 (2 ULg)
Full Text
Peer Reviewed
See detailFollicular status and embryo production in Ouled Djellal (Algeria) ewes breed pretreated with a GnRH agonist
Gharbi, I; Ferrouk, M; Dechicha, A et al

in Asian Journal of Animal and Veterinary Advances (2012), 7(2), 117-127

Variability in ovulation rate and number of embryos in response to superovulation is the main limiting factor in small ruminants transfer programs. The objective of this study was to evaluate the ovarian ... [more ▼]

Variability in ovulation rate and number of embryos in response to superovulation is the main limiting factor in small ruminants transfer programs. The objective of this study was to evaluate the ovarian follicular status and in vivo embryo production in Ouled djellal ewes following a pre-treatment with a Gonadotropin Releasing Hormone (GnRH) agonist. Twenty (n = 20) cycling ewes were allotted into two groups, the first (n = 10) received subcutaneously a daily injection of 40 micrograms buserelin for 14 days prior to superovulatory treatment (pretreated group) while the second group (n = 10) did not receive GnRH agonist before superovulatory treatment (control group). Before batching, the ovarian follicular population was assessed by laparoscopy numbering of the ovarian follicles. In the pretreated ewes, a significant increase in small follicles (8.50±1.64 vs. 15.50±2.74, p<0.01) and a suppression of large follicles (≥4 mm) (4, 3±0.76 vs. 0.0, p<0.001) was observed after treatment with Buserelin. In addition to the pretreated group, the number of small follicles prior to porcine Follicle-Stimulating Hormone (pFSH) treatment was higher and the number of large follicles smaller than the control group. The ovulatory response and the number of transferable embryos per ewe treated was significantly higher in ewes pretreated than in control ewes (ovulatory response: 17,8±1,56 vs. 9,1±1,11; p<0.001) (transferable embryos: 10.2±1.87 vs. 4.1±0.40, p≤0.01). Compared to the pretreated group a higher percentage of degenerated embryos was recorded in the control group (control: 20.40 vs. 7.27 pretreated, p<0.05). The pre-treatment with a GnRHa to the superovulation protocol improve embryo production in Ouled Djellal ewes, in allowing the terminal follicular growth inhibition and increasing of small follicles number at the start of p FSH treatment. [less ▲]

Detailed reference viewed: 13 (4 ULg)
Full Text
Peer Reviewed
See detailÉtude de la cyclicité en relation avec le poids vif et l’état corporel chez les agnelles Ouled Djellal nées en automne dans la région Est de l’Algérie
Lamrani, F; Benyounes, A; Sulon, J et al

in Annales de Médecine Vétérinaire (2012), 156

The objective of the present work was to describe the cyclicity of Ouled Djellal ewes born one year before regarding their live weight and body condition score, during the autumn season. The study has ... [more ▼]

The objective of the present work was to describe the cyclicity of Ouled Djellal ewes born one year before regarding their live weight and body condition score, during the autumn season. The study has been driven in the region of Guelma, East of Algeria, on 104 ewes belonging to two farms. At the beginning of the study, ewes from farms A and B had similar ages but differed in live weight and body condition scores. The concentration of progesterone wasdetermined by radioimmunoassay. The level of spontaneous cyclicity, as well as the plasmatic level of the progesterone, were influenced significantly by both live weight and body condition score (P<0.0001). If the first was in favor of ewes with high body weight and body condition score, the second seemed to be higher in slim cyclic ewes. The body fatness appears to influence positively the age of puberty. [less ▲]

Detailed reference viewed: 16 (3 ULg)
Full Text
Peer Reviewed
See detailPhysiologie de la production et composition chimique du colostrum des grands mammifères domestiques: généralités
Abdou, Harouna; Marichatou, H; Beckers, Jean-François ULg et al

in Annales de Médecine Vétérinaire (2012), 156

In most mammals, the ingestion of colostrum is essential to the survival of the newborn. The main objective of this work is to synthesize data from studies on colostrum, especially on the physiology of ... [more ▼]

In most mammals, the ingestion of colostrum is essential to the survival of the newborn. The main objective of this work is to synthesize data from studies on colostrum, especially on the physiology of its production and its chemical composition. The sequence of events leading to the production of colostrum is identical in all species. However, the duration of these phases varies. Colostrum is rich in immunoglobulins (IgG, IgA, IgM, IgE and IgD), nutrients (proteins, lipids, lactose, minerals), hormones and growth factors (prolactin, insulin, estrogens, IgF), immune cells (leukocytes cells, epithelial cells), vitamins (carotene, vitamin E) and finally in enzymes such as lactoperoxidase and alkaline phosphatase. Its composition is dependent on many factors that can be divided into intrinsic ones, related to the animal, and extrinsic or environmental ones. Colostrum contains all the elements necessary to not only protection against attacks of pathogens but also to rapid growth of young animals. [less ▲]

Detailed reference viewed: 35 (4 ULg)
Full Text
Peer Reviewed
See detailEffect of restraint stess on plasma concentrations of cortisol, progesterone and pregnancy associated-glycoproteins-1 in pregnant heifers during late embryonic development.
Szenci, O.; Karen, A.; Bajcsy, A. C. et al

in Theriogenology (2011), 76(8), 1380-1385

The aim of the present study was to evaluate the effect of restraint stress, which is commonly practised in the field, on plasma concentrations of cortisol, progesterone (P4) and bovine pregnancy ... [more ▼]

The aim of the present study was to evaluate the effect of restraint stress, which is commonly practised in the field, on plasma concentrations of cortisol, progesterone (P4) and bovine pregnancy-associated glycoprotein-1 (boPAG-1) in pregnant heifers between Days 30 to 40 of gestation. Twelve Holstein-Friesian heifers between Days 30 (Day 0 of experiment) and 40 (Day 10 of experiment) of pregnancy in a Hungarian dairy farm were used in the present study. The heifers were exposed to an acute stressor consisting of immobilisation (restraint stress) in a crush for 2 h (Group 1, n = 6) on Day 2 (Hour 48) and for 2 × 2 h (Group 2, n = 6) on Days 2 and 3 (Hour 72) of the experiment. Transrectal ultrasonography (7.5 MHz linear-array rectal transducer) was performed daily from Day 0 to Day 10 of the experiment to detect embryonic heartbeat or the fate of the conceptus. Blood samples were withdrawn before each ultrasonographic examination. Additional blood samples were withdrawn by 1 and 2 h (at Hours 49 and 50 in Groups 1 and 2 and Hours 73 and 74 in Group 2) of the onset of applying the stressor. Plasma cortisol, P4 and boPAG-1 concentrations were measured by radioimmunoassay. Acute restraint stress significantly (P < 0.001) increased the plasma cortisol level in pregnant heifers at 1 h of the exposure to the stressor at Days 2 (48 h) and 3 (72 h) of the experiment. On the other hand, the restraint stress did not affect the concentration of P4 and boPAG-1 concentrations in both groups. In conclusion, restraint stress for 2 h during early pregnancy in heifers increased blood cortisol, but it did not affect the concentrations of P4 and boPAG-1 between Days 30 to 40 of gestation. [less ▲]

Detailed reference viewed: 15 (2 ULg)
Full Text
See detailDevelopment of a new radioimmunoassay by using antiserum against pregnancy-associated glycoprotein II : concentrations in holstein dairy cattle .
Bella, Amina ULg; Melo de Sousa, Noelita ULg; Lopez-Gatius, F. et al

in Proceedings of the 6th European Congress of Bovine Health and Management (ECBHM) (2011, September 07)

Bovine pregnancy-associated glycoproteins (boPAG) can be classified into two main subfamilies: the boPAG–1 and the boPAG–2 groups. RIA systems allow quantifying boPAG-1 molecules in pregnant cattle ... [more ▼]

Bovine pregnancy-associated glycoproteins (boPAG) can be classified into two main subfamilies: the boPAG–1 and the boPAG–2 groups. RIA systems allow quantifying boPAG-1 molecules in pregnant cattle. Concerning boPAG-2, as no radioimmunoassay was developed, its quantification in peripheral blood of pregnant cows remains to be investigated. The present work aimed to develop a new heterologous RIA allowing the measurement of boPAG-2 concentrations in bovine species. A total of 77 Holstein dairy cows were used for this study. They were bled at Days 45, 90, 120, 150, 180, 210 after AI, at parturition and at Day 30 postpartum. Polyclonal antiserum against boPAG-2 (AS438) was raised in New Zealand rabbits. Due to the instability of boPAG-2 molecule, we used boPAG-1 (67 kDa) as standard (dilutions ranging from 100 to 0.8 ng/mL) and for iodination with 125-I isotope. The optimal dilution for primary AS438 was 1:1,1500. Mean concentrations of boPAG-2 increased continuously from Day 45 of pregnancy (0.78 ± 0.07 ng/mL) reaching a peak at Day 210 (32.78 ± 3.02 ng/mL). Thereafter, they decreased until parturition (7.73 ± 0.59). Lower PAG concentrations were observed at Day 30 postpartum (3.62 ± 0.31 ng/mL). In conclusion, boPAG-2 profile differed from boPAG-1. In general, concentrations of boPAG-2 reached lower values, with no dramatic increase being observed at peripartum period. Due to the lower postpartum concentrations, it is expected that this new RIA can be available for pregnancy diagnosis of cows inseminated in early postpartum, minimizing the risk of false positive concentrations due to the previous pregnancy. [less ▲]

Detailed reference viewed: 51 (10 ULg)
Full Text
See detailConcentrations of pepsinogens A and C in peripheral blood of cattle at different developmental stages.
Melo de Sousa, Noelita ULg; Michiels, Jean-Albert ULg; Terroni, D. et al

in Proceedings of the 6th European Congress of Bovine Health and Management (ECBHM) (2011, September 07)

Measurements of global proteolytic activity of pepsinogens are successfully used for diagnosis of gastric nematode parasitism in cattle. Higher pepsinogen concentrations detected in peripheral circulation ... [more ▼]

Measurements of global proteolytic activity of pepsinogens are successfully used for diagnosis of gastric nematode parasitism in cattle. Higher pepsinogen concentrations detected in peripheral circulation were found to be associated with damage in gastric mucosa The aim of the present study was to investigate the ontogenesis of PgnA and PgnC in cattle. Bovine PgnA and PgnC were isolated in our laboratory. Both antigens were labeled to 125I by using chloramine T method. Standard curves ranged from 125 to 1.0 ng/mL. Antisera were raised in rabbits: AS866 (anti-PgnA) and AS869 (anti-PgnC). The optimal dilutions for primary antisera were 1:15,000 and 1:20,000 for AS866 and AS869, respectively. In order to establish the ontogenesis of both PgnA and PgnC, samples were collected from 50 bovine fetuses (3rd to the 9th month), 18 calves and 57 adult cattle. Mean(±SEM) concentrations of PgnA were 4.6±0.7 ng/mL, 78.9±6.7 ng/mL and 133.2±17.6 ng/mL in fetuses, calves and mature cows, respectively. Concentrations of PgnC were <0.9 ng/mL, 13.5±1.1 ng/ml and 201.5±26.5 ng/ml in fetuses, calves and mature cows, respectively. The ratio PgnA/PgnC concentrations decrease from fetal age (maximal ratio due to undetectable PgnC concentrations), being 5.8 in young calves and lowest (0.7) in mature cows. In conclusion, PgnA and PgnC concentrations can be distinctly measured by specific RIA systems. Ratio PgnA/PgnC concentrations can be useful to better understand the ontogenesis of gastric aspartic proteinases in cattle. It is expected that clinical application of these assays will help vet practitioners to establish diagnosis of gastric nematode parasitism in dairy and beef herds taking into account the age of the animal. [less ▲]

Detailed reference viewed: 52 (7 ULg)
Full Text
See detailPregnancy-associated glycoprotein levels in cattle exhibiting prolonged pregnancy: case reports.
Beckers, Jean-François ULg; Melo de Sousa, Noelita ULg

in Proceedings of the 6th European Congress of Bovine Health and Management (ECBHM) (2011, September 07)

Prolonged gestation (PG) is a complex clinical entity which occurs in bovine species. This pathology has been described in Belgian Blue cattle. PG may require termination by cesarean section. Fetuses ... [more ▼]

Prolonged gestation (PG) is a complex clinical entity which occurs in bovine species. This pathology has been described in Belgian Blue cattle. PG may require termination by cesarean section. Fetuses often exhibit increased body weight, long hair and well erupted teeth. All calves die within minutes or hours after birth. From endocrinological point of view, PG is highly correlated to fetal adenohypophyseal aplasia. The aim of the present study was to investigate the usefulness of PAG RIA for diagnosis of prolonged gestation in Belgian Blue cattle. Blood samples were collected from five Blue Belgian cows having an abnormally long pregnancy length (10 to 15 months). PAG was measured by routine RIA with the use of antiserum AS497 as primary antibody. A purified bovine PAG preparation (boPAG67kDa) was used as standard (0.8 to 100 ng/mL) and for radio-iodination (125I). Cesarean section was used for termination of pregnancy of those cows exhibiting abnormal PAG concentrations. Morphological aspect and viability of fetuses were reported. Concentrations of PAG were very low (94.1 ng/mL, 50 ng/mL, 5 ng/mL, 110 ng/mL and 26 ng/mL) in the five females suffering of prolonged gestation. Fetuses issued from prolonged gestation exhibited long hair, well erupted teeth and died within few minutes after birth. In conclusion, PAG concentration is a good indicator of prolonged gestation in cattle. Concentrations are much lower than those expected in normal ongoing pregnancy (<120 ng/mL versus >1,000 ng/mL). [less ▲]

Detailed reference viewed: 52 (9 ULg)
Full Text
See detailPrediction of stillbirth in Holstein-Friesian dairy cows by monotoring endocrine profiles in the periparturient period.
Szenci, O.; Bajcsy, A.Cs; Nagy, K. et al

in Proceedings of the 6th European Congress of Bovine Health and Management (ECBHM) (2011, September 07)

During the last decades, there is a declining trend in conception and calving rates in high yielding Holstein dairy cattle. At the same time, the gradual increase in stillbirth rates, especially in ... [more ▼]

During the last decades, there is a declining trend in conception and calving rates in high yielding Holstein dairy cattle. At the same time, the gradual increase in stillbirth rates, especially in Holstein heifers, has until recently received relatively little attention. Birth weight and gender of the calf, parity, age and breed of the dam, and season of calving are all factors associated with calving difficulties and stillbirths. Other causes of stillbirths not related to calving difficulties are, for example, herd size, infections (e.g. BVD), insufficient placenta development and/or function, metabolic disorders of the cow, and congenital malformations of the calf. The objective of the present study was to investigate the possible effect of hormonal disturbances on the incidence of stillbirth in dairy cows on a Holstein-Friesian dairy farm in Hungary. Dairy cows (n=173) were sampled three times during the periparturient period (at drying-off, 3 weeks prior to expected calving, and within 1 h after calving) in 2006 and two times (3 weeks prior to expected calving, and within 1 h after calving) in 2007. Dairy cows were grouped according to the incidence of stillbirth: Group 1 (control): n=165 and Group 2 (stillbirth): n=8. Hormone and pregnancy protein parameters measured by RIA were as follows: progesterone (P4), estradiol (E2), cortisol, triiodine-thyronin (T3), thyroxin (T4), insulin, insulin-like growth factor (IGF-1) and pregnancy associated glycoprotein (PAG). To determine, which of the hormones and PAG were the best predictors of the presence or absence of stillbirth at a given time (2 months and 3 weeks before calving and within 1 h after calving), a generalised linear model was used with binomial error distribution and logit link function (multivariate logistic regression). All analyses were carried out by R 2.7.2. Statistical Software. The significant level was set at P< 0.05 and an effect was considered a trend when P was between 0.05 and 0.10. The overall prevalence of stillbirth was 4.6 % (4.0% in 2006 and 5.4% in 2007). Interestingly, most calves (7 out of 8) with stillbirth were bulls, but this difference was not significant. Weight of the calves, body score condition of the cows and number of people needed to assist at calving also did not affect the presence or absence of stillbirth significantly, and there was no significant difference among the groups regarding the gestation length or parity either (P>0.100 in all cases). Regarding hormone and pregnancy protein parameters, no significant differences were found during the periparturient period (at 2 months and 3 weeks before expecting calving), however, there was a trend for lower IGF-1 values (P=0.079, OR=0.96) in stillbirth group compared to controls at dry off (2 months before expecting calving). Within one hour after calving significant differences were observed in case of P4 (P<0.001, OR= 3.06), and IGF-1 (P=0.021, OR= 0.94), resulting significantly higher values in P4 and lower values in IGF-1 in stillbirth cows compared to controls. The higher P4 values observed in stillbirth cows also resulted a higher P4/E2 ratio compared to controls (P=0.003, OR= 1.60). Changes in the IGF-1, P4 and P4/E2 ratio may be one of the reasons for stillbirth in Holstein-Friesian dairy cows however more examinations are needed to be confirmed. Other hormones (P4, cortisol, T3, T4, insulin, PAG) did not mirror dependency due to the incidence of stillbirth in dairy cows. [less ▲]

Detailed reference viewed: 71 (2 ULg)
Full Text
See detailDevelopment of a new ELISA for measurement of pregnancy-associated glycoprotein.
Delahaut, Ph; Melo de Sousa, Noelita ULg; Huet, A. C. et al

in Proceedings of the 6th European Congress of Bovine Health and Management (ECBHM) (2011, September 07)

In the present study we report the development of a new ELISA for PAG measurement (Ref. code E.G.7, CER, Maloie) in ruminant species. Purified boPAG67kDa protein was purified in our laboratory and used as ... [more ▼]

In the present study we report the development of a new ELISA for PAG measurement (Ref. code E.G.7, CER, Maloie) in ruminant species. Purified boPAG67kDa protein was purified in our laboratory and used as standard. Antiserum raised against caprine PAG 55kDa+62kDa (AS707) was used as capture antibody (1:40,000). Antiserum raised against PAG purified from buffalo placentas (AS859) was used as detection antibody (1:32,000 dilution). Avidin-HRP and TMB completed the ELISA system. Reproducibility was determined by calculating the intra- and inter-assay CV. Accuracy was determined by adding increasing concentrations of purified boPAG67kDa to bovine sera containing low PAG concentrations. Specificity was tested regarding 25 different compounds: carbohydrates, aspartic proteinases, hormones and major plasma proteins. Parallelism was assessed by serially diluting pregnant cow serum containing high PAG concentrations. Sera was collected from pregnant cows (n=4) during the whole duration of gestation. Samples were tested by both RIA and ELISA. Samples giving high PAG concentrations were serially diluted in order to fit with optical density (OD) of the ELISA standard curve. Intra-and inter-assay CV ranged from 5.5 to 9.1%. Accuracy ranged from 92.9 to 105.5%. No cross reaction was observed with almost all tested compounds excepting lactic acid at supra-physiological levels (1 mg/ml). Dilutions of bovine maternal sera were parallel to standard curve. Profiles obtained by ELISA in pregnant cows were very similar to those obtained by RIA. In conclusion, a new PAG-ELISA is available for measurement of PAG concentrations in cattle. This new test was validated in vitro and can be used for pregnancy diagnosis and follow-up of gestation in cattle. [less ▲]

Detailed reference viewed: 51 (3 ULg)