Reduced Fertility in High‐yielding Dairy Cows: Are the Oocyte and Embryo in Danger? Part II
Mechanisms Linking Nutrition and Reduced Oocyte and Embryo Quality in High‐yielding Dairy Cows*     

JLMR Leroy  A Van Soom  G Opsomer  IGF Goovaerts  PEJ Bols 《Reproduction in domestic animals》2008,43(5):623-632

Dairy cow fertility has been declining during since the mid‐80s and this has given rise to numerous scientific studies in which important parts of the pathogenesis are elucidated. Reduced oocyte and embryo quality are acknowledged as major factors in the widely described low conception rates and in the high prevalence of early embryonic mortality. Apart from the importance of the negative energy balance (NEB) and the associated endocrine and metabolic consequences, there is a growing attention towards the effect of the milk yield promoting diets which are rich in energy and protein. Starch‐rich diets can improve the energy status and thus the ovarian activity in the early postpartum period but the oocyte and embryo quality can suffer from such insulinogenic diets. Supplementation of dietary fat has a similar dual effect with a beneficial stimulation of the ovarian steroid production while the oocyte and the embryo display an altered energy metabolism and excessive lipid accumulation. High‐protein diets can elevate the ammonia and urea concentrations in the blood, leading to changed intrafollicular, oviductal and uterine environments. Oocytes and embryos are highly sensitive to such changes in their microenvironment, possibly leading to a disturbed maturation, fertilization or early cleavage. Several nutrition‐linked mechanisms, through which oocyte and/or embryo quality can be affected in modern dairy cows, well after the period of NEB, are proposed and comprehensively reviewed in the present report.  相似文献   

First insights into Puumala orthohantavirus circulation in a rodent population in Alsace,France          下载免费PDF全文

E. Monchatre‐Leroy  S. Murri  G. Castel  D. Calavas  F. Boué  V. Hénaux  P. Marianneau 《Zoonoses and public health》2018,65(5):540-551

In‐depth knowledge on the mechanisms that maintain infection by a zoonotic pathogen in an animal reservoir is the key to predicting and preventing transmission to humans. The Puumala orthohantavirus (PUUV), the most prevalent orthohantavirus in Western Europe, causes a mild form of haemorrhagic fever with renal syndrome (HFRS) in humans. In France, this endemic illness affects the north‐eastern part of the country. We conducted a 4‐year capture–mark–recapture study in a bank vole population, combined with molecular analyses, to explore the epidemiological situation of PUUV in Alsace, a French region where human cases have occurred, but for which no studies have been conducted on this reservoir host. PUUV‐infected bank voles were detected in the 2 years that showed high bank vole density with a prevalence of 4%. The individual PUUV sequences identified in this study were similar from year to year and similar to other French sequences. On a very small spatial scale, the distribution of seropositive bank voles was very heterogeneous in time and space. The short distances travelled on average by bank voles resulted in spatial clusters of seropositive rodents, which spread only very gradually throughout the year.  相似文献   

The In Vitro Development of Bovine Oocytes after Maturation in Glucose and β-Hydroxybutyrate Concentrations Associated with Negative Energy Balance in Dairy Cows     

JLMR Leroy  T Vanholder  G Opsomer  A Van Soom  A de  Kruif 《Reproduction in domestic animals》2006,41(2):119-123

Negative energy balance (NEB) in high yielding dairy cows early postpartum may affect oocyte quality. Therefore, we tested the effect of two different beta-hydroxybutyrate (BHB) and glucose concentrations, which are associated with subclinical or clinical ketosis, during in vitro maturation (IVM) on the developmental competence of bovine oocytes. In Expt 1, subclinical ketosis conditions were imitated. Oocytes were matured in four different serum-free media with two glucose concentrations (g1=2.75 mm or G1=5.5 mm glucose) and with or without BHB (BHB1=1.8 mm BHB). Following maturation groups were used: g1, G1, g1:BHB1 and G1:BHB1. In Expt 2, clinical ketosis conditions were mimicked by using the concentrations: g2=1.375 mm or G2=3.1 mm glucose and BHB2=4.0 mm BHB. The combinations used were: g2, G2, g2:BHB2 and G2:BHB2. After IVM and in vitro fertilization (IVF), presumptive zygotes were routinely cultured for 7 days in synthetic oviduct fluid [SOF; 5% fetal calf serum (FCS)]. At 48 h and 8 days pi, cleavage rate and number of blastocysts were recorded respectively. The results demonstrated that the maturation conditions mimicking subclinical (g1:BHB1) and clinical ketosis (g2 : BHB2) resulted in an impaired developmental competence of the oocyte after maturation. Especially the moderately low (g1) or extremely low glucose (g2) concentrations were responsible for this detrimental effect that was associated with a blocked cumulus expansion. Only in moderately low glucose conditions (g1:BHB1), BHB exerted an additive toxic effect during oocyte maturation resulting in a reduced blastocyst rate. Conclusively, our results may suggest that subclinical and clinical ketosis can affect the oocyte's developmental competence most likely through a directly adverse effect of the low glucose concentrations on oocyte maturation. Only in subclinical conditions this harmful effect may be aggravated by BHB.  相似文献   

Litter decomposition in peatlands is promoted by mixed plants     

Fabien Leroy  Sébastien Gogo  Alexandre Buttler  Luca Bragazza  Fatima Laggoun-Défarge 《Journal of Soils and Sediments》2018,18(3):739-749

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Merging pedigree databases to describe and compare mating practices and gene flow between pedigree dogs in France,Sweden and the UK          下载免费PDF全文

S. Wang  G. Leroy  S. Malm  T. Lewis  E. Strandberg  W.F. Fikse 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2017,134(2):152-161

Merging pedigree databases across countries may improve the ability of kennel organizations to monitor genetic variability and health‐related issues of pedigree dogs. We used data provided by the Société Centrale Canine (France), Svenska Kennelklubben (Sweden) and the Kennel Club (UK) to study the feasibility of merging pedigree databases across countries and describe breeding practices and international gene flow within the following four breeds: Bullmastiff (BMA), English setter (ESE), Bernese mountain dog (BMD) and Labrador retriever (LBR). After merging the databases, genealogical parameters and founder contributions were calculated according to the birth period, breed and registration country of the dogs. Throughout the investigated period, mating between close relatives, measured as the proportion of inbred individuals (considering only two generations of pedigree), decreased or remained stable, with the exception of LBR in France. Gene flow between countries became more frequent, and the origins of populations within countries became more diverse over time. In conclusion, the potential to reduce inbreeding within purebred dog populations through exchanging breeding animals across countries was confirmed by an improved effective population size when merging populations from different countries.  相似文献   

Assessing the diversity of preferences of suburban smallholder sheep keepers for breeding rams in Ouagadougou,Burkina Faso     

K. Tindano  N. Moula  A. Traoré  P. Leroy  N. Antoine-Moussiaux 《Tropical animal health and production》2017,49(6):1187-1193

Urbanisation in developing countries entails deep changes in the livestock sector and the management of animal genetic resources (AnGR). Sheep breeding around Ouagadougou (Burkina Faso) illustrates these changes and the need to coordinate genetic improvement in general and the use of crossbreeding in particular. For this, it is important to understand breeders’ choices and improvement strategy, to accompany them within a national plan for AnGR management. In a context of missing market for breeding rams, a stated choice experiment was conducted with 137 farmers, together with a characterisation of herd management practices. This survey analyses farmers’ preferences for breeding rams, estimating their willingness to pay (WTP) for different traits (attributes). Their practices were characterised by a high reliance on natural pastures (82% of farmers) and a minority of crossbreeding (23%). The highest WTP was observed for disease resistance. However, the subgroup of farmers practicing crossbreeding showed a tolerance to high susceptibility. A strong preference for the white colour was revealed. Although significant, the influence of sheep body size on decision-making showed a lesser importance, again with a distinct behaviour in the subgroup practicing crossbreeding. These results illustrate the need to take account of the diversity of goals and preferences among smallholder sheep keepers to gain their adhesion to a coordinated genetic improvement framework.  相似文献   

Trypanosomiasis challenge estimation using the diminazene aceturate (Berenil) index in Zebu in Gabon     

Cossic  Brieuc G. A.  Adjahoutonon  Brice  Gloaguen  Pierre  Dibanganga  Gui Lov  Maganga  Gael  Leroy  Pascal  MacLeod  Ewan T.  Picozzi  Kim 《Tropical animal health and production》2017,49(3):619-624

A longitudinal study was conducted within a cattle ranch in Gabon to determine the diminazene aceturate (Berenil) index (DAI) in a group of Zebu, raised under low tsetse density; this measure providing an assessment of trypanosomiasis risk. The objective was to evaluate the trypanosomiasis pressure thus informing trypanosomiasis control methods and cattle management. Twenty female adult Zebu were monitored for 24 weeks during the dry season. Blood samples were collected on a weekly basis and subjected to parasitological and haematological analysis (n?=?480), using the buffy-coat method and the packed cell volume value (PCV), respectively, infected animals were treated with a single intramuscular injection of diminazene aceturate (8 mg/kg). Twenty-nine single infectious events were recorded and a DAI of 1.45 was calculated. Two trypanosome species were identified: Trypanosoma congolense (96.2%) and Trypanosoma vivax (3.8%). The mean PCV value of the infected animals was lower (26.6) compared to non-infected animals (32.0). This study shows that DAI may be a useful tool to assess trypanosomiasis. However, this is a time-consuming method that may be improved by using randomly selected sentinel animals to adapt the chemoprophylactic schemes, hence decreasing the costs and the drug resistance risk.

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Practical methods for non-destructive measurement of tree leaf area     

Céline Leroy  Laurent Saint-André  Daniel Auclair 《Agroforestry Systems》2007,71(2):99-108

In an agroforestry context, the knowledge of leaf area is an important parameter to take into consideration because tree foliage shades the intercrop. Single leaf measurement (for example leaf length and width) is a widely used method to estimate leaf area in a rapid non-destructive way. In this study, the objectives were to estimate the leaf area of different leaf sizes and shapes for Acacia mangium Willd. (Mimosaceae), Tectona grandis L. (Verbenaceae), Hevea brasiliensis Muell.-Arg. (Euphorbiaceae), and Swietenia macrophylla King. (Meliaceae) Indonesian agroforestry trees. In order to characterise leaf area in field conditions a digital photograph method was used. Leaf length was measured in order to build relationships between leaf length versus actual leaf area. Additional measurements obtained from the digital pictures such as lamina width, number of leaflets, leaflet length and width were recorded in order to test the benefit regarding leaf area estimation based only on the leaf length model. The combination of these different linear leaf measurements led to various degrees of precision of leaf area estimation. The different models can then be chosen according to a compromise between the accuracy of leaf area estimation and the time allocated to field measurements.  相似文献   

Reciprocal recurrent selection applied to Coffea canephora Pierre. I. Characterization and evaluation of breeding populations and value of intergroup hybrids     

T. Leroy  C. Montagnon  A. Charrier  A. B. Eskes 《Euphytica》1993,67(1-2):113-125

Summary Two breeding populations have been identified with Coffea canephora, based on geographical and genetic differences: the Guinean group from West Africa and the Congolese group from central Africa. A reciprocal recurrent selection programme based on these groups was initiated in Côte d'Ivoire in 1984. Genotypes of both groups available in field collections are either of cultivated or wild origin.Genotypic and phenotypic variability was evaluated within and between the groups for the following characteristics: isozyme patterns, architecture, drought tolerance and vigour, technological and organoleptic traits, pest and disease resistance. Variation between and within groups was found to be large. Based on isozyme analysis and phenotypic observations, two subgroups were identified within the Congolese group. Phenotypic values of parents and testers used in the first cycle of reciprocal recurrent selection are presented.Results of two intergroup hybrid trials indicate high yield and vigour for these hybrids compared to intragroup hybrids, justifying the reciprocal selection approach. Furthermore, the variation observed indicates that recurrent selection would allow progress for selection traits for both populations and intergroup hybrids.  相似文献   

Reciprocal recurrent selection applied to Coffea canephora Pierre. III. Genetic gains and results of first cycle intergroup crosses     

T. Leroy  C. Montagnon  C. Cilas  A. Yapo  P. Charmetant  A.B. Eskes 《Euphytica》1997,95(3):347-354

Breeding of the allogamous Coffea canephora species in Côte d'Ivoire is based, from 1984 onward, on a reciprocal recurrent selection scheme exploiting the good performance of crosses between two genetically distinct populations (‘Guinean’ and ‘Congolese’). Results are presented here on intergroup cross progenies evaluated on individual plant basis over a six year period in three fully randomized trials planted in 1985 and 1986. Yields of the bi-parental crosses varied from 16 to 1407% of the mean of the two commercial clonal cultivars and the most productive crosses were also the most vigourous. Selection of individual trees and cross progenies, based on a combined individual-family index, was carried out for high yield, good vigour of young plants and moderate canopy diameter of adult trees. Expected genetic gains, as estimated in relation to the mean of all crosses, for selection of 5% of the best trees, were high for yield (over 60%), moderate for young plant vigour (14 to 18%), and, as intended, low for canopy diameter. In addition, selection by independent culling for leaf rust resistance and bean weight was carried out. As a result, 6 promising crosses with yield similar or higher than those of the control cultivars, were selected as candidates for commercial use, as well as 65 individual trees, within 19 different crosses. Expected genetic gain for yield for these selected trees is about 60% compared to the average yield of the most productive control clone. Continuation of the programme is discussed, with specific attention to further progress expected for quality traits.  相似文献