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Chantier qualité GA; International audience; This study aimed to compare the growth performances and carcass characteristics of tropical-breed steers reared in 2 contrasted feeding systems (indoor vs. pasture) and slaughtered at different ages (early vs. late). A total of 309 Creole steers (growing at an initial BW of 173 +/- 3 kg and an initial age of 252 +/- 4 d) were used over a continuous 12-yr study. Indoor steers were housed in a cattle shed, fed fresh-cut grass plus concentrate, and slaughtered at 14.5 or 17.1 +/- 0.1 mo of age. Pasture steers were pasture grazed without supplemental feed, and slaughtered at 17.6 and 21.2 +/- 0.1 mo of age. Indoor-fed steers had a greater ADG (786 vs. 517 +/- 29 g.d(-1); P < 0.0001) and more carcass fat (164 vs. 145 +/- 4.5 g.kg(-1); P = 0.001) than pasture-fed steers. Late-slaughtered steers had decreased ADG (630 vs. 673 +/- 27 g.d(-1); P = 0.001) but greater dressing percentages (hot dressing percentage = 55.7 vs. 54.7 +/- 0.34%; chilled dressing percentage = 54.5 vs. 53.4 +/- 0.34%; P < 0.0001) than early-slaughtered steers. The interaction between feeding system and slaughter age was significant for carcass tissue composition. Whole-carcass muscle content was greater in late-slaughtered steers than early-slaughtered steers, especially in pasture-fed steers (720 vs. 698 +/- 6.0 g.kg(-1); P < 0.0001), but less so in indoor-fed steers (707 vs. 700 +/- 5.9 g.kg(-1); P = 0.046). Furthermore, increasing slaughter age had no effect on carcass fat in indoor-fed steers (162 vs. 166 +/- 4.8 g.kg(-1); P = 0.342), but decreased carcass fat in pasture-fed steers (150 vs. 140 +/- 5.0 g.kg(-1); P = 0.014). The results showed that slaughter age and feeding system are 2 major factors that independently affect most of the growth and carcass traits of tropical-breed steers but jointly influence tissue deposition. Our study found that in tropical-breed steers that are grazing, late slaughtering grazing steers increased carcass muscle content without extra fat, thus yielding a carcass quality better suited to consumer choices.

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International audience; En Guadeloupe, et plus généralement aux Antilles, se pratique un élevage dit "au piquet" ou encore à l'attache, bien implanté, avec des bovins ou des caprins au bout de leur chaîne, au bord des routes, mais aussi dans les profondeurs des campagnes, dans des contextes très variés, en vraies prairies, aux abords des plages, des mangroves, des habitations ou des champs de canne.

National audience; Due to the complex mechanisms involved in their constitution, in relation with the regional history, local animal breeds represent an important heritage. They are also deeply involved in the local production systems, through their management practices and their specific use. Therefore, they developed useful zootechnical abilities, in terms of production and adaptation traits. The most recent investigations, using modern tools in genotyping and genetic variability evaluation, have shown their originality. These local breeds are also interesting models for studying adaptation traits for animal husbandry in tropical environment. Hence, they represent valuable genetic resources, particularly in the present context when a special concern is paid to adaptive traits. It is therefore of prime interest for breeders to highlight skills of their animal breeds. Tools are available to preserve genetic resources, and to promote a better use of these breeds, through adequate animal breeding programs. Their economic valuation could also be based on specific niche products, of recognized quality. Indeed, local animal breeds represent a valuable heritage, which could be resources to meet future challenges in animal production.; Les races locales représentent un patrimoine original et unique du fait des processus qui ont les ont façonnés, en relation avec l’histoire de la région. Elles sont également profondément inscrites dans les systèmes de production locaux, à travers leurs modes d’élevage et leurs usages. Elles ont ainsi développé des aptitudes zootechniques particulièrement utiles, en termes de performances de production et de qualités d’adaptation. Les travaux scientifiques les plus récents, utilisant les méthodes modernes de génotypage et d’analyse de la variabilité, mettent en avant leur originalité. Ces races locales constituent ainsi un modèle d'étude d’intérêt pour la connaissance des caractères d'adaptation des animaux aux conditions d’élevage tropicales. Elles représentent donc une ressource génétique de premier plan, alors que les préoccupations pour les caractères d’adaptation deviennent une priorité dans le contexte actuel du changement climatique et de l’augmentation du coût des intrants. Les éleveurs trouvent ainsi un intérêt croissant à valoriser au mieux les aptitudes de leurs races locales. Les outils existent pour assurer la conservation de ces ressources et améliorer la gestion des populations à travers les programmes de sélection. Leur valorisation économique pourrait s’appuyer sur la promotion de produits spécifiques, basés sur des qualités reconnues. Les races animales locales constituent ainsi un patrimoine à préserver, source d’innovations pour l'élevage de demain.

National audience; Due to the complex mechanisms involved in their constitution, in relation with the regional history, local animal breeds represent an important heritage. They are also deeply involved in the local production systems, through their management practices and their specific use. Therefore, they developed useful zootechnical abilities, in terms of production and adaptation traits. The most recent investigations, using modern tools in genotyping and genetic variability evaluation, have shown their originality. These local breeds are also interesting models for studying adaptation traits for animal husbandry in tropical environment. Hence, they represent valuable genetic resources, particularly in the present context when a special concern is paid to adaptive traits. It is therefore of prime interest for breeders to highlight skills of their animal breeds. Tools are available to preserve genetic resources, and to promote a better use of these breeds, through adequate animal breeding programs. Their economic valuation could also be based on specific niche products, of recognized quality. Indeed, local animal breeds represent a valuable heritage, which could be resources to meet future challenges in animal production.; Les races locales représentent un patrimoine original et unique du fait des processus qui ont les ont façonnés, en relation avec l’histoire de la région. Elles sont également profondément inscrites dans les systèmes de production locaux, à travers leurs modes d’élevage et leurs usages. Elles ont ainsi développé des aptitudes zootechniques particulièrement utiles, en termes de performances de production et de qualités d’adaptation. Les travaux scientifiques les plus récents, utilisant les méthodes modernes de génotypage et d’analyse de la variabilité, mettent en avant leur originalité. Ces races locales constituent ainsi un modèle d'étude d’intérêt pour la connaissance des caractères d'adaptation des animaux aux conditions d’élevage tropicales. Elles représentent donc une ressource génétique de premier plan, alors que les préoccupations pour les caractères d’adaptation deviennent une priorité dans le contexte actuel du changement climatique et de l’augmentation du coût des intrants. Les éleveurs trouvent ainsi un intérêt croissant à valoriser au mieux les aptitudes de leurs races locales. Les outils existent pour assurer la conservation de ces ressources et améliorer la gestion des populations à travers les programmes de sélection. Leur valorisation économique pourrait s’appuyer sur la promotion de produits spécifiques, basés sur des qualités reconnues. Les races animales locales constituent ainsi un patrimoine à préserver, source d’innovations pour l'élevage de demain.

National audience; The research works conducted since the middle of last century in animal production science make it possible to offer a technical approach to ruminant farming systems, which provides elements to achieve the best balance between production objectives, climate and health constraints, and plant and animal resources brought into play in the Antillo-Guyanese context. Although several options are possible depending on the type of production and the farm size, rearing system design must take into account all aspects related to feeding, health, reproduction, or breed choice; Les résultats des recherches menées depuis le milieu du siècle dernier en zootechnie permettent de proposer une approche bio-technique des systèmes d'élevage de ruminants qui fournit des éléments pour réaliser la meilleure adéquation entre les objectifs de production, les contraintes climatiques et sanitaires, les ressources végétales et animales mises en jeu dans le contexte Antillo-Guyanais. Bien que plusieurs options soient possibles en fonction du type de production et de la taille de l'élevage, la conception du système d'élevage doit en prendre en compte toutes les dimensions, qu'elles se rapportent à l'alimentation, à la santé, à la reproduction, ou aux choix génétiques.

National audience; The research works conducted since the middle of last century in animal production science make it possible to offer a technical approach to ruminant farming systems, which provides elements to achieve the best balance between production objectives, climate and health constraints, and plant and animal resources brought into play in the Antillo-Guyanese context. Although several options are possible depending on the type of production and the farm size, rearing system design must take into account all aspects related to feeding, health, reproduction, or breed choice; Les résultats des recherches menées depuis le milieu du siècle dernier en zootechnie permettent de proposer une approche bio-technique des systèmes d'élevage de ruminants qui fournit des éléments pour réaliser la meilleure adéquation entre les objectifs de production, les contraintes climatiques et sanitaires, les ressources végétales et animales mises en jeu dans le contexte Antillo-Guyanais. Bien que plusieurs options soient possibles en fonction du type de production et de la taille de l'élevage, la conception du système d'élevage doit en prendre en compte toutes les dimensions, qu'elles se rapportent à l'alimentation, à la santé, à la reproduction, ou aux choix génétiques.

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International audience; This paper deals with designing a cheap and easy-to-attain method to replace weighing for estimating the body mass of goats. Several models on the relationship of heart girth (HG) to live weight (LW) were evaluated using Creole of Guadeloupe goats (376 males and 258 growing females). The best fit was obtained with a Gompertz model: LW = 155 * exp(-7.91 * exp(-0.0215 * HG)), which provided an adjusted R² = 0.98 and a 95% confidence interval of the prediction values below 5% within most of the LW range. The LW of breeding goats (420) was fitted by the following quadratic model taking into account the HG and paunch girth (PG): LW = -28.1 + 0.539 * HG + 0.00221 * PG², which provided an adjusted R² = 0.95 and a 95% confidence interval of the prediction values below 1% within most of the LW range. The first model allows a tape measure graduated in kg to be used on goats except breeding females. The second model allows the building of an abacus to provide the estimated LWs of breeding goats from the HG and PG values. Further correction might be achieved by adding the goat body condition score. Such cheap tools should be very useful for goat farmers, most of whom lack reliable weighing devices.

Chantier qualité GA; Admixed populations represent attractive biological models to study adaptive selection. Originating from several waves of recent introduction from European (EUT), African (AFT) and zebus (ZEB) cattle, New World Creole cattle allow investigating the response to tropical environmental challenges of these three ancestries. We here provide a detailed assessment of their genetic contributions to the Creole breed from Guadeloupe (CGU). We subsequently look for footprints of selection by combining results from tests based on the extent of haplotype homozygosity and the identification of excess ⁄ deficiency of local ancestry. To tackle these issues, 140 CGU individuals and 25 Brahman zebus from Martinique were genotyped at 44 057 SNPs. These data were combined to those available on 23 populations representative of EUT, AFT or ZEB. We found average proportions of 26.1%, 36.0% and 37.9% of EUT, AFT and ZEB ancestries in the CGU genome indicating a higher level of African and zebu ancestries than suggested by historical records. We further identified 23 genomic regions displaying strong signal of selection, most of them being characterized by an excess of ZEB local ancestry. Among the candidate gene underlying these regions, several are associated with reproductive functions (RXFP2, PMEPA1, IGFBP3, KDR, PPP1R8, TBXA2R and SLC7A5) and metabolism (PDE1B and CYP46A1). Finally, two genes (CENTD3 and SAMD12) are involved in cellular signalization of immune response. This study illustrates the relevance of admixed populations to identify footprints of selection by combining several tests straightforward to implement on large data sets.

Les résultats des recherches menées depuis le milieu du siècle dernier en zootechnie permettent de proposer une approche bio-technique des systèmes d'élevage de ruminants qui fournit des éléments pour réaliser la meilleure adéquation entre les objectifs de production, les contraintes climatiques et sanitaires, les ressources végétales et animales mises en jeu dans le contexte Antillo-Guyanais. Bien que plusieurs options soient possibles en fonction du type de production et de la taille de l'élevage, la conception du système d'élevage doit en prendre en compte toutes les dimensions, qu'elles se rapportent à l'alimentation, à la santé, à la reproduction, ou aux choix génétiques., The research works conducted since the middle of last century in animal production science make it possible to offer a technical approach to ruminant farming systems, which provides elements to achieve the best balance between production objectives, climate and health constraints, and plant and animal resources brought into play in the Antillo-Guyanese context. Although several options are possible depending on the type of production and the farm size, rearing system design must take into account all aspects related to feeding, health, reproduction, or breed choice

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National audience; Dans les régions tropicales, les performances animales sont réputées médiocres, du fait notamment des conditions d’élevage et des problèmes sanitaires, mais aussi de la méconnaissance des aptitudes réelles des populations animales locales. Le mouton Martinik est une race rustique allaitante, de format moyen, issue de croisements entre populations de mouton à poils de la Caraïbe. Bien adapté au milieu tropical humide, il résiste également à des périodes de sécheresse. Il est exploité en race pure pour la production d’agneaux gris au pâturage, pesant de 25 à 35 kg. Aux Antilles Françaises, le mouton est surtout exploité à la Martinique avec 28000 têtes, principalement regroupées dans le sud de l’île. Le mouton Martinik y est fortement majoritaire avec près de 95 % du cheptel. Depuis une vingtaine d’années et particulièrement depuis la création de l’Unité de Sélection du mouton Martinik (USOM) en 1993, l’image de cette race n’a cessé de progresser. Cette communication présente les outils mis en place par la Chambre d’Agriculture et l’USOM pour exploiter le mouton Martinik, ainsi que les résultats obtenus par l’INRA quant à son potentiel de production.

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International audience; Genetic parameters of rectal temperature measured at 0700 and 1200 (RT7 and RT12), the difference between RT12 and RT7 (dRT), daily feed intake during ad libitum period in lactation (DFI), litter growth rate (LGR) and sow relative body weight loss during lactation (BWL) were estimated in the Large White lactating sows reared in a tropical humid climate. The h² were 0.28 ± 0.03, 0.32 ± 0.05 and 0.49 ± 0.14 for RT7, RT12 and dRT. The h² for DFI, LGR and BWL were low. Genetic correlations between thermoregulation and performance traits in lactation ranged from -0.63 ± 0.13 (between RT12 and LGR) to 0.87 ± 0.42 (between dRT and BWL).These preliminary results show the existence of genetic variability for thermoregulation.

International audience; Genetic by environment interactions for post weaning traits were studied in a local breed of cattle, well adapted to tropical conditions. After weaning, 444 beef calves of both sexes were separated within two management systems, either in intensive fattening or at pasture. The traits analysed included weights at standard age, of 365 days (W12), 455 days (W15) and 545 days (W18), and post weaning growth rates from weaning until 15 months (PWG15) or 18 months (PWG18). (Co)variance components for all characters were analysed using restricted maximum likelihood (REML) methodology. Different bi-variate animal models were studied, involving separate traits measured one in intensive fattening and the other at pasture. Very low correlations between growth traits obtained in both management systems were observed. These results indicates that there exists an important interaction between genetic merit and environment for post weaning growth traits, and indicate that it may necessary to take into account the real management conditions for the selection on such traits in tropical conditions.

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