References of "Hanzen, Christian"
     in
Bookmark and Share    
Full Text
See detailMOOC et classes inversées ou cours magistraux. Données générales .
Hanzen, Christian ULiege

Scientific conference (2017, November 11)

Cette conférence avait pour objectif de conscientiser des enseignants universitaires aux potentialités offertes par les MOOC et la classe inversée pour favoriser l'apprentissage des apprenants.

Detailed reference viewed: 34 (3 ULiège)
Full Text
See detailLes métiers de l’enseignant chercheur : quelle professionnalisation ?
Hanzen, Christian ULiege

Scientific conference (2017, November 08)

Detailed reference viewed: 29 (3 ULiège)
Full Text
See detailApproche pluridimensionnelle de l’évaluation en enseignement supérieur
Hanzen, Christian ULiege

Learning material (2017)

Les objectifs spécifiques de cette formation de 14 heures sont 1. définir docimologie, édumétrie, évaluation, connaissances, savoirs, compétences, formatif, certificatif, self-assessment 2. citer les ... [more ▼]

Les objectifs spécifiques de cette formation de 14 heures sont 1. définir docimologie, édumétrie, évaluation, connaissances, savoirs, compétences, formatif, certificatif, self-assessment 2. citer les différentes facettes de l’évaluation 3. donner des exemples d’évaluation 4. citer les 6 niveaux de la pyramide de Bloom 5. commenter les 6 niveaux de la pyramide de Bloom 6. comparer les objectifs de connaissance, de compréhension et d’application 7. commenter les biais liés à la copie, au correcteur et à l’évalué 8. énoncer les trois aspects de la concordance 9. faire le choix d’un type d’évaluation adaptée aux domaines et niveaux 10. créer une question QCM 11. commenter le barême d’évaluation d’une QCM SGI DC 12. énoncer les différentes étapes d’un cycle de qualité d’une évaluation 13. comparer avantages et inconvénients des QROL, QROC et oraux 14. expliquer l’intérêt d’une évaluation de l’enseignement par les étudiants [less ▲]

Detailed reference viewed: 36 (2 ULiège)
Full Text
See detailPathologies of reproduction in beef cattle
Hanzen, Christian ULiege; Rao, Anne-Sophie ULiege

Scientific conference (2017, October 14)

The aim of this conference is to describe - Some characteristics on bovine meat production - What kind of reproduction performances for beef cattle - Some figures for first calving and calving interval in ... [more ▼]

The aim of this conference is to describe - Some characteristics on bovine meat production - What kind of reproduction performances for beef cattle - Some figures for first calving and calving interval in France and Belgium - Some specific factors affecting the reproduction performances in beef cattle (Uterine hypoplasia in Belgian Blue heifers, Dystocia and C section, Aseptic fibrinous parietal peritonitis, Pathologies of the postpartum (Postpartum anoestrus, Fertility) - Hormonal management of reproduction : heat synchronisation [less ▲]

Detailed reference viewed: 18 (2 ULiège)
Full Text
Peer Reviewed
See detailAtypical polypoid leiomyosarcoma in an ouessant ewe.
Bayrou, Calixte ULiege; Casalta, Hélène ULiege; Cassart, Dominique ULiege et al

Poster (2017, October 05)

Detailed reference viewed: 22 (1 ULiège)
Full Text
Peer Reviewed
See detailFragmentation index of DNA sperm in llama semen (Lama glama)
Cucho, Hernan; Ordonez, Cesar; Ampuero, Enrique et al

Poster (2017, August 25)

DNA fragmentation of spermatozoa is an important indicator of seminal quality and fertility. The quality of the genetic information contained in the DNA molecule transmitted by the spermatozoa is ... [more ▼]

DNA fragmentation of spermatozoa is an important indicator of seminal quality and fertility. The quality of the genetic information contained in the DNA molecule transmitted by the spermatozoa is important for the proper development of the embryo. In humans it has been shown that there is a significant correlation between sperm DNA damage and oocyte fertilization, embryo quality, development to blastocyst and embryo implantation. The objective of this study was to analyze the fragmentation of DNA sperm in llama semen collected by post-copulation vaginal aspiration. The collection of 4 llamas was performed on three occasions per animal. The volume, motility, concentration, vitality, sperm membrane functionality assessed with the Integrated Semen Analysis System - ISAS®. The DNA fragmentation index was tested with the Halomax system ®(Halotech company). Volume, motility, vitality and sperm concentration respectively were 1.3 ± 0.8 ml, 12.30 ± 2.02%; 64.69 ± 11.39% and 183.55 ± 28.48 x 106 spz/ml. The functionality of the sperm membrane was 64.95 ± 11.63% and sperm DNA fragmentation index 11.58 ± 13.25%. The values of these different parameters indicate the high quality of the collected semen. [less ▲]

Detailed reference viewed: 18 (2 ULiège)
Full Text
Peer Reviewed
See detailEvaluation of two intravaginal implants for the synchronization of estrus in Criollo cattle in Peru
Ordonez, Cesar; Ampuero, Enrique; Huanca, Nancy et al

Poster (2017, August)

The objective of this study was to compare the effect of two vaginal implants protocols on the follicular characteristics, the vaginal electrical resistance and the pregnancy rate of criollo cattle reared ... [more ▼]

The objective of this study was to compare the effect of two vaginal implants protocols on the follicular characteristics, the vaginal electrical resistance and the pregnancy rate of criollo cattle reared in altitude (3100 meters). All the cows (n=53) were selected after manual palpation and ultrasound examinations of their genital tract. All the cows had a body condition between 2.5 and 3.5 (range 1 to 5). On day 1 et for 7 days the first group of cows (n=23) was treated with 1,38 g of progesterone (Easi-breedTM CIDR® Zoetis) and the second group (n=30) with 1 g of progesterone (DIB system Agrihealth New Zealand). All the cows were treated at day 1 with 2 mg of estradiol benzoate (im), at day 9 with 2 ml of prostaglandin (im) and at day 10 with 1 mg of estradiol benzoate. A timed artificial insemination was realized 54 hours after the CIDR® or DIB removal. The pregnancy diagnosis was made by ultrasound 45 days later. Vaginal conductivity, diameter and perimeter of the follicle were measured at the time of insemination. There were no significant differences (p> 0.05) between both treatments in the electrical resistance of the vaginal mucus, diameter and perimeter of the preovulatory follicule. The averages of these variables respectively were 233 ± 36 ohms, 9.1 ± 1.9 mm and 24.6 ± 4.7 mm. Pregnancy rates of cows treated with DIB and CIDR respectively were 63.3 % and 69.6%. No significant statistical differences (p> 0.05) have been seen. In conclusion, both treatments showed similar ovarian response, electrical resistance and pregnancy rate in criollo cattle reared in altitude. [less ▲]

Detailed reference viewed: 19 (3 ULiège)
Full Text
See detailL’insémination artificielle bovine : un traitement qui nécessite le constat d’oestrus. Comprendre pour agir.
Hanzen, Christian ULiege

Conference given outside the academic context (2017)

Au cours de ces 70 dernières années d’utilisation de l’insémination artificielle (IA) (1946 année de naissance du premier veau issu de l’IA), la fertilité bovine n’a fait que décliner. Le taux de ... [more ▼]

Au cours de ces 70 dernières années d’utilisation de l’insémination artificielle (IA) (1946 année de naissance du premier veau issu de l’IA), la fertilité bovine n’a fait que décliner. Le taux de gestation était compris entre 44 et 48 % il y a 40 ans, elle est comprise entre 33 et 40 % actuellement. L’oestrus (dont la durée moyenne a également diminué au cours des années) constitue la phase clé de l’IA. Naturel ou induit, il constitue une étape indispensable à l’obtention d’une gestation. Ses caractéristiques hormonales et comportementales sont susceptibles d’être modifiées par de multiples facteurs inhérents à la production laitière ou à des pathologies liées au système reproducteur mais pas seulement. L’IA se définit comme une biotechnologie de la reproduction qui consiste à déposer un sperme de qualité au moyen d’une méthode et d’un matériel adéquat à l’endroit anatomique le plus approprié, au moment le plus opportun et d’une technique. Cet acte est tout sauf banal compte tenu des conséquences économiques importantes tant positives que négatives qu’il peut entraîner. Répondre à la question de savoir si la vache est « inséminable » n’est pas chose simple. Les moyens propédeutiques disponibles se sont avec le temps étoffés. Un état des lieux s’imposerait donc. A l’analyse de l’anamnèse et des symptômes et signes cliniques manifestés par la vache en oestrus, des stratégies hormonales ou non peuvent le cas échéant être mises en place. Encore convient-il d’en mesurer la pertinence. Au terme de la formation, l’apprenant sera capable de… - comprendre l’effet des facteurs hormonaux ou non susceptibles de modifier les manifestations oestrales et la fertilité - mettre en place le cas échéant des méthodes propédeutiques alternatives visant à confirmer ou non la décision d’inséminer une vache - décider du recours ou non à des stratégies thérapeutiques ou techniques pour augmenter le taux de gestation suite à une insémination [less ▲]

Detailed reference viewed: 60 (7 ULiège)
Full Text
Peer Reviewed
See detailRisk Factors of Clinical and Subclinical Endometritis in Cattle: a Review.
Adnane, Mounir; Kaidi, Rachid; Hanzen, Christian ULiege et al

in TURKISH JOURNAL OF VETERINARY AND ANIMAL SCIENCES (2017), 41

The postpartum period is a critical period in the life of dairy cattle and management of the most important problems and diseases at an early stage represents the key to successful dairy herd management ... [more ▼]

The postpartum period is a critical period in the life of dairy cattle and management of the most important problems and diseases at an early stage represents the key to successful dairy herd management. Endometritis is one of the most important and dramatic diseases that disrupt the reproductive performance of cows and reduce the livestock profitability. Because endometritis is a multifactorial disease and is caused by nonspecific bacteria, determining all the factors that enhance its risk of occurrence is more important than treating the disease. This review considers the evidence regarding the risk factors for postpartum endometritis in dairy cattle in an attempt to explain the causality between each risk factor and both clinical and subclinical endometritis. The present article will discuss the importance of determining the risk factors of endometritis that must be considered for the treatment of cows. For example, antibiotics must be associated with improvement of the rations in the case of nutritional deficit and metabolic problems. Furthermore, these risk factors represent an alternative to treatment by including them in an adequate preventive strategy to master at least the most important risk factor to limit the prevalence and severity of endometritis. We conclude that some factors are specific for one form of endometritis and some others are common between clinical and subclinical endometritis, but all of them make the disease more severe and frequent. [less ▲]

Detailed reference viewed: 84 (5 ULiège)
Full Text
Peer Reviewed
See detailStudy on reproductive performance of Holstein x Lai Sind crossbred heifers and cows at smallholdings in Ho Chi Minh City, Vietnam.
Nguyen-Kien, Cuong; Nguyen, Van Khanh; Hanzen, Christian ULiege

in Tropical Animal Health and Production (2017), 49

The reproductive performance of Holstein x Lai Sind crossbred dairy heifers and cows was evaluated at small-holdings in Ho Chi Minh City (HCMC). The data of 232 heifers and 244 cows (261 lactations) from ... [more ▼]

The reproductive performance of Holstein x Lai Sind crossbred dairy heifers and cows was evaluated at small-holdings in Ho Chi Minh City (HCMC). The data of 232 heifers and 244 cows (261 lactations) from 35 small dairy farms was collected over a 2-year period, from 2013 to 2014. The overall mean for age at first service (AFS), days between first and last service (DFLS), and age at conception (AC) of heifers was 479 (±80), 38 (±80), and 517 (±114) days, respectively. Average number of services per conception (NSC), conception rate (CR), and conception rate at first ser-vice (CRFS) was 1.8 (±1.4), 55, and 58%, respectively. The overall mean for the waiting period (WP), DFLS, and days open (DO) of cows was 109 (±52), 133 (±114), and 242 (±129) days, respectively. The mean for NSC, CR, and CRFS was 4.3 (±2.7), 23, and 14%, respectively. A very sig- nificant decrease in AFS and AC according to the year of birth, and a significant increase in AFS according to body weight at first insemination (>320 kg) were observed. The CRFS of heifers inseminated in 2013 was significantly higher than in 2014. Monthly mean CR in heifers and cows was negatively correlated with THI. The WP, DFLS, DO, and NSC of cows significantly decreased according to the year of calving. Cows that calved in rainy season had a significant-ly longer WP than in dry season. The occurrence of postpar-tum (PP) diseases was accompanied by an increase in WP, DO, and NSC. A decrease in body condition score (BCS) between calving and 60th day (C60) and also between 60th and 120th day of lactation resulted in a significant increase in WP and DO. A decrease in BCS between C60 was also ac-companied by a considerable reduction in CRFS of cows. Season and BCS at insemination had a significant effect on NSC and CR of cows. Reproductive performance was satis-factory for heifers, but poor for cows. Losses of BCS during the first months of lactation and at insemination were the major risk factors for this poor performance. Moreover, the season had a more negative effect on fertility in cows than in heifers. [less ▲]

Detailed reference viewed: 40 (10 ULiège)
Full Text
See detailProduction laitière et santé mammaire (Bio Ingénieurs)
Hanzen, Christian ULiege

Learning material (2016)

Ce cours de 2 heures s'inscrit dans cadre du module "Production laitière par le ruminant" dispensé aux étudiants de master bio-ingénieur en sciences agronomiques. Les objectifs spécifiques ont été définis ... [more ▼]

Ce cours de 2 heures s'inscrit dans cadre du module "Production laitière par le ruminant" dispensé aux étudiants de master bio-ingénieur en sciences agronomiques. Les objectifs spécifiques ont été définis en accord avec le professeur Yves Beckers co-responsable du module. Ce cours a pour objectif général de définir la mammite, ses conséquences, ses signes d'alerte au niveau de l'individu et du troupeau, son approche diagnostique, ses facteurs de risque au niveau individuel et d'élevage et ses grandes lignes d'approche thérapeutique. [less ▲]

Detailed reference viewed: 430 (105 ULiège)
Full Text
Peer Reviewed
See detailThe effects of timing of insemination and GnRH treatment on pregnancy rates of N’Dama females after induction of oestrus with progestin
Okouyi M’foumou W’otari, Marcel; Hanzen, Christian ULiege

in Revue d'Elévage et de Médecine Vétérinaire des Pays Tropicaux (2016), 69(2), 73-78

The aim of this clinical trial was to quantify the results of pregnancy after treating trypanotolerant N'Dama female cattle (n=168) using a CIDR® (1.38g of progesterone) inserted for seven days. An ... [more ▼]

The aim of this clinical trial was to quantify the results of pregnancy after treating trypanotolerant N'Dama female cattle (n=168) using a CIDR® (1.38g of progesterone) inserted for seven days. An intramuscular (IM) PG injection (500µg of cloprostenol) was administered two days before removal of the device. Subsequently, an IM injection of 400UI of eCG was administered when the device was removed. The animals were inseminated respectively 48 (Group 1) and 72 hours (Group 2) after removal of the CIDR®. In both groups, half the animals were treated with 4.2µg of buserelin acetate and the other half with 1ml of physiological saline. Four protocols were thus tested: CIDR-PG-eCG/IA48h, CIDR-PG-eCG/IA48h/GnRH+, CIDR-PG-eCG/IA72h, and CIDR-PG-eCG/IA72h/GnRH+. A pregnancy diagnosis has been done by echography 45 to 60 days after insemination. The average pregnancy rate was 37.5% (n=168). That of the adult cows (43.2%, n=111) was significantly (P < 0.03) higher than that of the heifers (26.3%, n=57). The pregnancy rate observed in animals in Group 2 (48.8%) was significantly higher (P < 0.002) than that observed in the animals in Group 1 (26.2%). Physiological condition and the injection of GnRH at the time of insemination had no significant impact on the pregnancy rate. The hormonal protocol using CIDR-PG-eCG (400UI) and a timed artificial insemination 72 h later improves the pregnancy rates in the N’Dama female. [less ▲]

Detailed reference viewed: 39 (3 ULiège)
Full Text
Peer Reviewed
See detailEtude in vivo et in vitro des fonctions ovariennes gauche et droite chez les bovins.
Hanzen, Christian ULiege

in Abstract-Vet (2016), 32

Detailed reference viewed: 31 (2 ULiège)
Full Text
Peer Reviewed
See detailEffects of equine chorionic gonadotropin (eCG) on the sexual behaviour and ovulatory characteristics of female african N'Dama cattle.
Okouyi, M.W. Marcel; Hanzen, Christian ULiege

in Revue de Médecine Vétérinaire (2016), 167(7-8), 211-215

This paper evaluated the effects of eCG on the characteristics of oestrus and ovulation after heifers and cows had been synchronised following vaginal administration of progesterone for seven days ... [more ▼]

This paper evaluated the effects of eCG on the characteristics of oestrus and ovulation after heifers and cows had been synchronised following vaginal administration of progesterone for seven days (Controlled Internal Drug Released) and a PGF2α injection two days after the end of treatment. The animals were randomly split into a non-treated control group (n=26) and four groups with increasing doses of eCG: 300 IU (n=25), 400 IU (n=24), 500 IU (n=23) and 600 IU (n=23), which were injected on the day of CIDR withdrawal. The animals were then followed (24 hours a day) for six days. Oestrus was confirmed on the basis of identifying 'standing oestrus', i.e., when the cow stood to be mounted. Seven to ten days after the CIDR® was withdrawn, the animals were slaughtered, and their ovaries were examined to identify and count the number of follicular and/or luteal structures. The onset of heat was 48.6 ± 5.3 hours after eCG injection, and the average length of oestrus was 9.9 ± 2 hours. The eCG dosage had no significant effect on these two parameters. In contrast, the observed rate of oestrus was significantly (p<0.05) higher in animals that had been treated (70.8 to 84.0%) in comparison with animals that had not been treated (50%). Similarly, the ovulation rate was significantly (p<0.05) higher in treated animals (88.0 to 100%) than in untreated animals (73.1%). The percentage of animals that presented multiple ovulations increased significantly (p <0.001) with the dosage of eCG administered (4.5% to 36.4%). [less ▲]

Detailed reference viewed: 33 (13 ULiège)
Full Text
See detailPostpartum anoestrus in Holstein x Lai Sind crossbred dairy cows in small farms of Ho Chi Minh City
Nguyen, Kien Cuong; Hanzen, Christian ULiege

in Vo Thi, Tra; Ho Thi Kim, Hoa; Le Thanh, Hien (Eds.) et al Proceedings of the 19th Federation of Asian Veterinary Association Congress (2016, September 08)

The aim of the study was to assess the prevalence of postpartum (PP) anestrus and the effect of factors on this prevalence in small dairy farmers. The data of 419 calvings and PP periods from 35 small ... [more ▼]

The aim of the study was to assess the prevalence of postpartum (PP) anestrus and the effect of factors on this prevalence in small dairy farmers. The data of 419 calvings and PP periods from 35 small dairy farms was collected during two years 2013 and 2014. Cows which failed to express estrus signs by day 60th after calving were submitted for manual palpation and transrectal ultrasonography to evaluate ovarian state. 49.9% of observed cows were not detected in estrus by the stockman during the first 60 days PP. The prevalence of type I, type II, cystic, pyometral and detective anestrus (or subestrus) was 27.0, 6.7, 0.5, 0.7 and 15.0%, respectively. The presence of dystocia or uterine infection was accompanied by an increase in risk of the type I anestrus (36.7% vs 23.1%, P = 0.005; 41.4% vs 21.5% , P < 0.001, respectively). Cows with a low BCS at calving (< 3) or at the 30th day PP (< 2.5) significantly showed a high risk of the type I anestrus than cows with a medium or high BCS at the same periods. In conclusion, the anestrus type I and subestrus mainly contriduted to high risk of PP anestrus in small dairy farms in HCMC. The dystocia, uterine infection, low BCS at calving and at day 30th PP constituted major causes of the type I anestrus. [less ▲]

Detailed reference viewed: 30 (2 ULiège)
Full Text
See detailBetween bovine milk production and reproduction : the challenge.
Hanzen, Christian ULiege; Nguyen Kien, Cuong

in Vo Thi Tra; Ho Thi Kim, Hoa; Le Thanh, Hien (Eds.) et al Proceedings of the 19th Federation of Asian Veterinary Association Congress (2016, September 07)

Huge differences in dairy milk production can be observed around the world. They can be explained by differences in genetic, nutritional resources and management including the capacities of the farmers ... [more ▼]

Huge differences in dairy milk production can be observed around the world. They can be explained by differences in genetic, nutritional resources and management including the capacities of the farmers and veterinarian to prevent and treat the different pathologies inducing of the wellbeing of the animals. According to the world market of milk production, the challenge of each farm is not only to produce a milk of quality but also to reduce the costs of milk production by improving reproductive performances. Anywhere in the world we are responsible to encourage and develop a sustainable approach of milk production and agriculture development according to his three pillars: environment, economic and social. Our presentation will present (1) the mains figures about the milk production in the world, (2) the definitions and prevalences of the different periods involved in the reproductive life of a cow, (3) the nutritional, genetic and pathological factors involved in the milk production on general and more specifically in reproduction (dystocia, placental retention, uterine infections, postpartum anoestrus), the relationships between these factors, (‘) the state of art of the definition, methods of diagnostic state of art of the main reproduction pathologies (dystocia,) affecting the dairy cows during the waiting and reproduction periods. [less ▲]

Detailed reference viewed: 113 (9 ULiège)
Full Text
Peer Reviewed
See detailEffect of curve traits and Age at first calving on productive life of Holstein primiparous Walloon cows
Grayaa, Marwa; Hammami, Hedi ULiege; Hanzen, Christian ULiege et al

Poster (2016, September 02)

Detailed reference viewed: 81 (16 ULiège)