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Increasing the level of feed autonomy (self-sufficiency) is usually considered as a prerequisite for conversion of cattle farms to organic farming. Technically it requires adjusting fodder production and feed purchases in terms of quantity and quality to the requirements of the herd. A joint technical and economic assessment of feed autonomy in organic cattle farms was conducted. Data were collected in 2014 and 2015 on 11 Belgian farms located in distinct agricultural regions and characterised by different proportions of grassland area. Dry matter yield and nutritional quality were determined at each harvest for each fodder crop, including permanent and temporary grasslands, immature cereal-legume crops and grain crops. Animal productions and economic data, including all cash inflows and outflows, were recorded. Economically efficient farms had high levels of feed autonomy, ranging from 89 to 100%. Three economically-efficient feeding strategies were identified for organic cattle production. Strategies differed from each other according to the proportion of grassland area, level of animal production and the achieved level of feed autonomy.
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Increasing input self-sufficiency is often viewed as a target to improve sustainability of dairy farms. However, few studies have specifically analysed input self-sufficiency, by including several technical inputs and without only focussing on animal feeding, in order to explore its impact on farm sustainability. To address this gap, our work has three objectives as follows: (1) identifying the structural characteristics required by specialised dairy farms located in the grassland area to be self-sufficient; (2) analysing the relationships between input self-sufficiency, environmental and economic sustainability; and (3) studying how the farms react to a decrease in milk price according to their self-sufficiency degree. Based on farm accounting databases, we categorised 335 Walloon specialised conventional dairy farms into four classes according to their level of input self-sufficiency. To this end, we used as proxy the indicator of economic autonomy - that is, the ratio between costs of inputs related to animal production, crop production and energy use and the total gross product. Classes were then compared using multiple comparison tests and canonical discriminant analysis. A total of 30 organic farms - among which 63% had a high level of economic autonomy - were considered separately and compared with the most autonomous class. We showed that a high degree of economic autonomy is associated, in conventional farms, with a high proportion of permanent grassland in the agricultural area. The most autonomous farms used less input - especially animal feeding - for a same output level, and therefore combined good environmental and economic performances. Our results also underlined that, in a situation of decrease in milk price, the least autonomous farms had more latitude to decrease their input-related costs without decreasing milk production. Their incomes per work unit were, therefore, less impacted by falling prices, but remained lower than those of more autonomous farms. In such a situation, organic farms kept stable incomes, because of a slighter decrease in organic milk price. Our results pave the way to study the role of increasing input self-sufficiency in the transition of dairy farming systems towards sustainability. Further research is required to study a wide range of systems and agro-ecological contexts, as well as to consider the evolution of farm sustainability in the long term.
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In 1991 a new protein evaluation system replaced the Digestible Crude Protein (DCP) system in the Netherlands: the DVE/OEB-system. The system was mainly developed with the aim to prevent avoidable losses of nitrogen, by feeding according to more exactly defined requirements of dairy cows. A second aim was to predict milk protein production more accurately. Protein requirements for maintenance, milk protein production, growth, mobilisation, metabolic losses in the digestive tract and gestation are expressed in DVE, the sum of digestible feed and microbial true protein available in the small intestine. In the system each feed has a DVE-value composed of the digestible true protein contributed by feed protein escaping rumen degradation (1), microbial protein synthesized in the rumen (2) and a correction for endogenous protein losses in the digestive tract (3). Each feed also has a degraded protein balance (OEB) reflecting the difference between the potential microbial protein synthesis based on degraded feed crude protein and that based on energy available for microbial fermentation in the rumen. The framework of the new system is based on what are considered strong elements of other recently developed protein evaluation systems. Additionally new elements are introduced, including undegraded starch (USTA), fermentation products (FP) in ensiled feeds, the role of energy balance in protein supply and the way in which requirements change in the course of lactation. Data within the framework of the system are mainly of Dutch origin. This is particularly true for the regression equations developed to predict the protein values of forages and protein values of a number of by-product ingredients.
Intervention présentée aux Journées de l'AFPF, "Le pâturage au coeur des systèmes d'élevage de demain", les 21 et 22 mars 2017
A general description of energy lossesf from food through faeces, methane, fermentation heat, urine and heat production in lactating cows in given. It is said that the conventional feed evaluation systems for dairy cows, although evaluating ration size correctly, underestimate some components of the rations and overestimate others. This interferes with a correct evaluation of the separate feedstuffs, so important for optimal pasture and concentrate use. The separate parts of feed utilisation are treated more closely: digestibility, metabolizable energy (ME) content of the digested energy and the utilisation of this ME. It is argued that in lactating cows the ration's ME content can be derived from composition and sheep digestibility data and that the influence on it of feeding level for most rations is moderate and predictable. A survey of most balance trials with lactating cows performed so far in the world - more than 1 000 - shows that 60% of the ME present above the quantity needed for maintenance (117 kcal ME per unit of metabolic weight) was converted into milk and body tissue energy. The efficiency of the ME utilisation, both for maintenance and milk production, was slightly higher at higher contents of ME in the ration's gross energy. It is concluded that the available information of balance trials with dairy cows by far exceeds the information of similar trials with fattening steers on which the starch equivalent system of feed evaluation for dairy cows is based. The information available today shows that the starch equivalent system evaluates the separate feedstuffs for lactating cows incorrectly and that a system derived from balance trials with lactating cows is to be preferred. A survey of such a system suited for use in practice is presented.
Analyse de la valorisation des ressources auto-produites que représentent les fourrages et engrais de ferme au sein d'exploitation d'élevage d'un parc naturel en Belgique
  • A Bernes
  • S Cremer
  • D Amerlynck
  • V Decruyenaere
  • C Clément
  • D Jamar
  • S Hennart
  • D Stilmant
Bernes, A., Cremer, S., Amerlynck, D., Decruyenaere, V., Clément, C., Jamar, D., Hennart, S. and Stilmant, D. (2011) Analyse de la valorisation des ressources auto-produites que représentent les fourrages et engrais de ferme au sein d'exploitation d'élevage d'un parc naturel en Belgique. 3R, 18: 305-308.