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International audience; This study was carried out to evaluate muscle characteristics, meat ten derness and nutritional qualities of Benin indigenous cattle raised on natural pasture. Thus, 10 Zebu Fulani, 10 Borgou and 5 Lagunaire were slaughtered at 5 years old and their Longissimus thoracis muscle samples were collected for analyses. Lactate dehydrogenase activity of Zebu Fulani was higher (p0.05). As for isocitrate dehydrogenase, citrate synthase, cytochrome oxidase and phosphofructokinase, no significant difference was observe d between the three breeds (p>0.05). By contrast, the total collagen content of Borgou (5.2 mg OH - proline/mg dry matter) was higher (p0.05) while the Zebu Fulani had the highest values (p

Thirty-six young fattening bulls from three breeds (Belgian Blue, Limousin and Aberdeen Angus) were fattened over 5 months with fattening diets based either on sugar-beet pulp or on cereals. Fattening performance as well as carcass and meat characteristics were measured. There were few relevant effects of the diets on the parameters. The breeds also showed similar fattening features. However, the BB had higher killing-out proportion and their carcasses presented better scores in terms of conformation and fattening. The meat quality of the breeds differed, especially in terms of luminosity, redness and cooking losses. There were also significant influences of breed on the chemical composition of meat; fat content was lowest in Belgian Blue and highest in Aberdeen Angus. Such specificities could help to allocate breeds in appropriate niches in Belgium.

Animal performance, composition and quality of meat from Belgian Blue bulls either fattened indoors (FI) or finished indoors after a previous grazing period were studied during six years. During the grazing period, three intensification managements were tested on a permanent pasture conducted as set stocking. The intensification levels were either high (HN: 140 kg N·ha −1 with 6 bulls·ha −1 ) or moderate with a 33% reduction of nitrogen fertilisation but with the same stocking rate (MN: 93 kg N·ha −1 , 6 bulls·ha −1 ) or low with no nitrogen fertiliser but with a reduced stocking rate (ON, 4 bulls·ha −1 ). The levels of intensification did not affect sward characteristics and chemical composition of the grass. The apparent nitrogen efficiency per ha was larger in the ON plot than in the HN and MN plots (26 vs. 14%). The average daily gain of bulls during the grazing season was similar in the three groups at 1.0 kg·d −1 . The bulls from the FI group were characterised by average daily gains significantly higher than the bulls which were previously grazed and then finished indoors (1.5 vs. 1.2 kg·d −1 ; P < 0.01). The slaughter weight, the carcass composition, the dressing percentage and most of the meat quality parameters were similar between the treatment groups. The inclusion of a grazing period in the fattening system produced a meat which was darker (lower L*, P < 0.01), more red (higher a*, P < 0.05) and had a higher content of linolenic acid (C18:3 n-3) than that of the animals fattened indoors.

Lorsqu’on les compare à des sujets mixtes de la même race, les taurillons Blanc Bleu Belge (BBB) culards réalisent des gains quotidiens moyens au moins aussi élevés tout en consommant moins d’aliments. L’amélioration de l’efficacité alimentaire est expliquée principalement par la composition des gains de poids : la carcasse d’un sujet BBB culard contient au moins 60 kg de muscle en plus et 30 kg de graisse en moins que celle d’un sujet mixte abattu au même poids vif. Lorsque le poids vif augmente, on observe, dans les deux types, une augmentation du rendement à l’abattage et de la proportion de viande maigre dans la carcasse. La composition chimique et les qualités organoleptiques des viandes sont, elles aussi, influencées par le caractère culard. La teneur en gras est réduite et la proportion d’acides gras polyinsaturés est augmentée chez le culard, ce qui constitue un avantage nutritionnel. L’évolution plus rapide du pH post mortem chez le taurillon culard ne peut expliquer que très partiellement les différences observées pour les qualités sensorielles. La couleur plus pâle de la viande est liée en grande partie à sa faible teneur en myoglobine. L’avantage du culard en matière de tendreté, expliqué par une teneur faible en collagène, n’apparaît pas dans un morceau noble de la carcasse à faible teneur en collagène. Enfin, dans la majorité des études disponibles à ce jour, la capacité de rétention d’eau de la viande produite par les culards apparaît peu différente de celle des non culards. Les concentrations de plusieurs métabolites sanguins indiquent une répartition des nutriments favorable au dépôt de protéines et défavorable au dépôt de graisses chez le culard. Lors de l’engraissement, les particularités endocriniennes concernent essentiellement l’hormone de croissance et l’insuline ; elles peuvent expliquer la répartition particulière des nutriments., When compared to animals of the dual purpose type in the same breed, Belgian Blue double muscled bulls exhibit, at least, similar average daily gain with lower feed intake. The higher feed efficiency in the double muscled type is mainly explained by the composition of the weight gains, the muscle content is minimum 60 kg higher and the fat content 30 kg lower than in the dual pur pose type when slaughtered at a similar live weight. In both types, the dressing percentage and the lean meat proportion in the carcass increase with final liveweight. The chemical composition and the sensory characteristics of meat are also influenced by double muscling. The fat content is reduced and the polyunsaturated fatty acids proportion is increased in the double muscled type, resulting in a nutritional advantage. The difference in sensory characteristics could be, only partially explained by the fas ter post mortem pH drop. The paler meat is mainly related to the myoglobin content. The advantage of the double muscled type in terms of tenderness, due to a low collagen content, is not exhibited in a << choice >> cut of the carcass with a low level of collagen, Finally, according to most of the available data, the water holding capacity of meat of double muscled animals seems not very different. The concentrations of several blood metabolites indicate a partition of the absorbed nutrients propitious to protein deposition and unpropitious to fat deposition in double muscled animals. During the fattening period, this specific partition can be related to endocrine characteristics, mainly growth hormone and insulin.

Un mais plante entiere a ete ensile a trois stades de maturite differents (S1, S2, S3) correspondant a des teneurs respectives en matiere seche de 25,1 (S1), 29,8 (S2) et 32,3 % (S3). La production de matiere seche s'elevait a 10,7 ; 11,1 et 11,7 tonnes par hectare. Chacun de ces ensilages, distribue a des taureaux a l'engraissement, a ete supplemente par des pulpes sechees, du tourteau de soja, des sels mineraux et des vitamines. Le stade de maturite n'a pas affecte les teneurs en cendres, cendres insolubles, extrait ethere ou proteines ; cependant une reduction significative de la teneur en fibre ADF a ete enregistree avec S3. La digestibilite de la matiere seche et de la matiere organique de la ration mesuree in vivo sur des taureaux en cages a bilan ainsi que celle du mais ensilage n'ont pas ete non plus influencees par le stade de maturite. En revanche, la digestibilite de la fibre ADF a ete significativement plus faible pour S3 par rapport a S1 et S2 (62,1 vs 67,2 ou 65,6 %, p < 0,05 pour la ration; 54,1 vs 63,3 ou 60,7 %, p < 0,001 pour le mais). Quant aux potentialites du rumen a degrader les aliments, il est a noter que la degradabilite totale par la methode in sacco des differents composants testes a ete superieure dans le rumen des animaux qui recevaient le mais a teneur en matiere seche elevee. Il n'y a pas eu d'effets significatifs du stade de maturite sur les performances animales durant un essai de 5,5 mois dans le cas d'une alimentation ad libitum. A partir de l'indice de consommation, du gain total de poids vif et de la production de matiere seche par hectare, il etait possible d'estimer que 13,8, 14,2 et 15,7 taurillons pouvaient etre engraisses respectivement a partir des ensilages de mais S1, S2 et S3 produits par ha.