Nitrogen Balance and Soil Nitrates in Suckler Cow Pastures Fertilised with Mineral Fertiliser, Pig Slurry or Cattle Compost

A code of good practice was established by each European member state according to the EU Nitrate Directive. In Belgium, the nitrogen (N) inputs on pastures from slurry or compost are limited to 210 kg N/ha. Bigger quantities can be applied if the farmer follows a programme of additional measurements, including soil nitrate (NO3) analysis. This investigation aimed to measure animal performance, N balance and soil NO3 in pastures fertilised with mineral N, pig slurry or cattle compost, the pastures being grazed by Belgian Blue cows and their calves

Influence de facteurs environnementaux influençant la teneur en urée dans le lait de vache en Wallonie et estimation des rejets azotés

Study on environmental factors influencing the urea content of cow's milk in Wallonia and estimation of nitrogen rejection. In Wallonia (South of Belgium), the urea content of milk produced on farms is assessed by the "Comité du lait". A total of 8,295,337 pieces of data recording the urea content in milk tanks was collected on Walloon farms in 2000 and during the period 2002-2011. These data were analyzed using a linear model. The fixed effects of the agricultural area or vulnerable zone, the month, the year and the interactions between these parameters were included in the model. The levels of fat and protein content in the milk were used as covariates. The average urea content in milk was found to be 255 mg·l-1. Four percent of the observations recorded a urea content of over 350 mg·l-1 and 14% recorded a urea content of over 400 mg·l-1. The models explained 38% and 35% of the variation in milk urea for the agricultural area and the vulnerable area variables, respectively. Within these models, the variables of month, region, year and the month-year interaction were the components that provided the most information. Milk urea content was higher in the summer period – April to October – than during the winter period – November to March – (287 vs 210 mg·l-1). This observation can be explained by the change in the cows' diet. During the summer, most of the cows grazed; ingestion of grass can lead to a nitrogen surplus in the diet. In the so-called "Limoneuse" and "Sablo-limoneuse" agricultural areas, recorded urea content was lower than in "Ardenne" and "Haute-Ardenne" (223 and 220 mg vs 278 and 284 mg·l-1, respectively). This difference can be explained by a greater use of grass in the diet in Ardenne and Haute-Ardenne. In vulnerable areas, urea content was lower (236 vs 273 mg·l-1). Annual nitrogen production calculated using different prediction equations ranged from 82 to 119 kg N per cow depending on the agricultural area

Amélioration des bilans d'excrétion d'azote dans deux exploitations laitières de la région wallonne par un suivi raisonné des rations

Improvements after precision dietary management of nitrogen rejection in two commercial dairy farms in Wallonia. Two dairy farms located in Pays de Herve and in Ardennes were followed at regular intervals in order to assess levels of nitrogen rejection. In Farm 1, the cows were divided into two groups: group HP contained high production cows and group BP contained cows with a lower production yield. Each group was offered a specific basal diet. In Farm 2, only one group of cows was assessed. The feed rations on both farms were characterized by a imbalance between the yields allowed by the energy or the nitrogen supplies and by an extremely high OEB balance of 794, 582 and 726 g, respectively, in groups HP and BP and in the Farm 2 group. Dietary changes were proposed in order to balance milk yields and to reduce the hypothesized nitrogen balance. The yield and urea content data from each milk record, along with data regarding nitrogen rejection, were statistically analyzed using a mixed model, which included an autoregressive covariance. The data from records 2, 3, 4 and 5 were then compared to the data from record 1. The advised changes implemented in the feeding management plan maintained milk yields at values similar to the yields observed in record 1 – 36.2, 24.3 and 23.0 l of 4% fat-corrected milk expressed for fixed days in milk produced by groups HP and BP and the Farm 2 group. The changes induced a significant reduction in the milk urea content (220 vs 300 mg·l-1) and a significant reduction in nitrogen rejection, whether expressed in terms of g per day per cow, g·l-1 or kg per year per cow. The cows in the Farm 2 group rejected less nitrogen in absolute terms (217.9 vs 260.1 g per day). However, it is interesting to note that the management approach in Farm 1 was more efficient in terms of nitrogen rejection since the level was on average 9 g·l-1 in comparison with 10 g·l-1 in Farm 2. In conclusion, it appears that, for either farm, whether an intensive or extensive management regime was being employed, the provision of well balanced feed rations led to a reduction in nitrogen rejection. It should, however, be noted that management advice needs to be provided on a farm by farm basis

Influence du caractère culard sur la production et la qualité de la viande des bovins Blanc Bleu Belge

National audienceWhen 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 > 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.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

Influence du stade de maturité de la plante de maïs récoltée pour ensilage sur la composition, la digestibilité apparente, les caractéristiques de fermentation dans le rumen et les performances zootechniques chez le taurillon à l'engraissement

International audienc

Effets de la vitesse de croissance au pâturage chez des taurillons finis en stabulation : I. Performances zootechniques

peer reviewe

La production de viande bovine à partir de femelles de réforme

National audienceIn the European Union, half of slaughtered adult cattle are female, including 60 % of adult cows and 40 % of heifers, mainly from dairy races. The animals are culled for multiple reasons that vary from one country to another and even from one herd to another. Fattening is therefore more difficult and haphazard than that of young bulls, due to the heterogeneity of their characteristics at the culling time, such as: age, race and format, medical and physiological statutes, and body condition score. The methods of finishing (outside or inside) and of feeding are also significant sources of variation. This article proposes to review the principal factors influencing the finishing of culled females.Dans l’Union Européenne, la moitié des gros bovins abattus sont des femelles, dont 60 % de vaches adultes et 40 % de génisses, essentiellement de races laitières. Les causes qui conduisent ces animaux à la réforme sont multiples et varient fortement d’un pays à l’autre et même d’un troupeau à l’autre. Leur engraissement est de ce fait nettement plus difficile et aléatoire que celui des jeunes taurillons, eu égard à l’hétérogénéité de leurs caractéristiques lors de la réforme. Parmi celles-ci, on peut citer : l’âge, la race et le format, l’état sanitaire, l’état physiologique, l’état corporel. Les modalités de finition (au pâturage ou à l’auge) et d’alimentation sont également des sources de variations importantes. Cet article propose de passer en revue les principaux facteurs pouvant influer sur la finition des femelles de réform

Composition de la carcasse et qualité de la viande chez le taurillon culard soumis à un engraissement intensif ou à une croissance faible suivie d'une croissance accélérée

International audienc