OptiVal+: Optimisation des Valorisations issues du Contrôle des Performances à travers le développement d’outils pratiques de management visant à augmenter la rentabilité de toutes les exploitations laitières wallonnes

Report (2010)

Implementing pedagogic strategies between vets and farmers to create synergies in udder health management: Project Mammipack®

Poster (2009, December)

Udder health is usually considered as a health and economic problem for farmers. We now consider that mastitis is the result of many factors related to the environment, the pathogen and the host. What may ... [more ▼]

Udder health is usually considered as a health and economic problem for farmers. We now consider that mastitis is the result of many factors related to the environment, the pathogen and the host. What may have been forgotten in the process is the fact that nowadays, the main interface with mastitis is the farmer, and their knowledge about mastitis is very heterogeneous. This reflexion has led to the creation of a technical and pedagogical pack called “Mammipack” which contains different tools, from all actors of the dairy chain. We included small charts explaining the most important risk factors identified through epidemiology, good dairy practices and its effect on milk flow, milking machine check-up, how-to for mastitis milk sample, a how-to for performance records use for udder health management, a resume on genetic selection of sires and mastitis, charts upon nutrition factors and their main effect on udder physiology during lactation and dry-off, resume on veterinary drugs good management in the farm. Small laminated sheets upon milk sampling for bacteriology and teats evaluation were also joined in order to be use in parlors, sterile sampling tubes were also given in the pack. A mastitis record pad was designed to record the main clinical forms and the treatment chosen. Eventually, the book Udder Health® was added to have a complete modern look on that problem in dairy farms. 25 farmers were selected on a voluntary base by 12 veterinarians, and they answered to questionnaires about their main practices regarding herd structure, mastitis treatment, and southern Belgium main 19 risk factors. They had to answer basic questions concerning udder health on 15 points. They agreed to keep a record of all next mastitis cases in their farms and take milk samples for bacteriology each time at day 0 and day 21 during 3 months. The main objective is to show to a group of dairy farmers that mastitis could take several different forms from one farm to another, in term of incidence, pathogens and clinical forms. One other purpose is to show the difficulty to have bacteriological cure, even when physical cure has happened. After all, one collateral objective was to create the Mammipack®, designed for farmers and vets to increase their ability to collaborate on mastitis management through most dairy chain actors’ expertise. [less ▲]

Adding value to test-day data by using modified best prediction method

Conference (2009, August 27)

Computation of lactation yields from test-day yield has lost much of its importance for genetic evaluations as the use of test-day models is rather widespread. At the same time its importance for intra ... [more ▼]

Computation of lactation yields from test-day yield has lost much of its importance for genetic evaluations as the use of test-day models is rather widespread. At the same time its importance for intra-farm management increases at farms as a base for advanced management tools. The most common official method to compute lactation yield is the Test Interval Method (TIM). Alternative methods for computing cumulated productions were developed. These methods can be considered as improvements of TIM as the interpolation method, or completely different methods as multiple-trait prediction (MTP) and best prediction (BP). Research in this field has shown the potential to compute lactation parameters (e.g., cumulated production) with test-day models. The aim of this study was to develop a new method which takes into account advantages and disadvantages of existing methods, and to test its potential to provide useful tools to help farmers to make management decisions. The second objective was to compare the accuracy and the robustness of this method with those of BP and TIM. Because of its similarities with BP, the method developed here was called mBP, for modified-BP. The main difference from BP is the definition of the standard lactation curve. To minimize bias, components of standard lactation curves proper to each herd are computed jointly with random individual effects. Recently a new version of mBP was tested that puts expectations of constant animal effects to observed average values using Bayesian prediction, a feature also used by MTP. [less ▲]

Associations among BCS, milk production and days-open in Walloon primiparous dairy cows

in Book of abstracts of the 60th annual meeting of the European Association for Animal Production (2009, August)

Potential estimation of major mineral contents in cow milk using mid-infrared spectrometry.

in Journal of Dairy Science (2009), 92(6), 2444-2454

Milk and dairy products are a major source of minerals, particularly calcium, involved in several metabolic functions in humans. Currently, several dairy products are enriched with calcium to prevent ... [more ▼]

Milk and dairy products are a major source of minerals, particularly calcium, involved in several metabolic functions in humans. Currently, several dairy products are enriched with calcium to prevent osteoporosis. The development of an inexpensive and fast quantitative analysis for minerals is required to offer dairy farmers an opportunity to improve the added value of the produced milk. The aim of this study was to develop 5 equations to measure Ca, K, Mg, Na, and P contents directly in bovine milk using mid-infrared (MIR) spectrometry. A total of 1,543 milk samples were collected between March 2005 and May 2006 from 478 cows during the Walloon milk recording and analyzed by MIR spectrometry. Using a principal component approach, 62 milk samples were selected by their spectral variability and separated in 2 calibration sets. Five outliers were detected and deleted. The mineral contents of the selected samples were measured by inductively coupled plasma atomic emission spectrometry. Using partial least squares combined with a repeatability file, 5 calibration equations were built to estimate the contents of Ca, K, Mg, Na, and P in milk. To assess the accuracy of the developed equations, a full cross-validation and an external validation were performed. The cross-validation coefficients of determination (R(2)cv) were 0.80, 0.70, and 0.79 for Ca, Na, and P, respectively (n = 57), and 0.23 and 0.50 for K and Mg, respectively (n = 31). Only Ca, Na, and P equations showed sufficient R(2)cv for a potential application. These equations were validated using 30 new milk samples. The validation coefficients of determination were 0.97, 0.14, and 0.88 for Ca, Na, and P, respectively, suggesting the potential to use the Ca and P calibration equations. The last 30 samples were added to the initial milk samples and the calibration equations were rebuilt. The R(2)cv for Ca, K, Mg, Na, and P were 0.87, 0.36, 0.65, 0.65, and 0.85, respectively, confirming the potential utilization of the Ca and P equations. Even if new samples should be added in the calibration set, the first results of this study showed the feasibility to quantify the calcium and phosphorus directly in bovine milk using MIR spectrometry. [less ▲]

Le BCS, une méthode simple à la source de conseils variés : ration, repro et santé

Poster (2009, February 11)

Modeling milk urea of Walloon dairy cows in management perspectives.

in Journal of Dairy Science (2009), 92(7), 3529-40

The aim of this study was to develop an adapted random regression test-day model for milk urea (MU) and to study the possibility of using predictions and solutions given by the model for management ... [more ▼]

The aim of this study was to develop an adapted random regression test-day model for milk urea (MU) and to study the possibility of using predictions and solutions given by the model for management purposes. Data included 607,416 MU test-day records of first-lactation cows from 632 dairy herds in the Walloon Region of Belgium. Several advanced features were used. First, to detect the herd influence, the classical herd x test-day effect was split into 3 new effects: a fixed herd x year effect, a fixed herd x month-period effect, and a random herd test-day effect. A fixed time period regression was added in the model to take into account the yearly oscillations of MU on a population scale. Moreover, first autoregressive processes were introduced and allowed us to consider the link between successive test-day records. The variance component estimation indicated that large variance was associated with the random herd x test-day effect (48% of the total variance), suggesting the strong influence of herd management on the MU level. The heritability estimate was 0.13. By comparing observed and predicted MU levels at both the individual and herd levels, target ranges for MU concentrations were defined to take into account features of each cow and each herd. At the cow level, an MU record was considered as deviant if it was <200 or >400 mg/L (target range used in the field) and if the prediction error was >50 mg/L (indicating a significant deviation from the expected level). Approximately 7.5% of the MU records collected between June 2007 and May 2008 were beyond these thresholds. This combination allowed for the detection of potentially suspicious cows. At the herd level, the expected MU level was considered as the sum of the solutions for specific herd effects. A herd was considered as deviant from its target range when the prediction error was greater than the standard deviation of MU averaged by herd test day. Results showed that 6.7% of the herd test-day MU levels between June 2007 and May 2008 were considered deviant. These deviations seemed to occur more often during the grazing period. Although theoretical considerations developed in this study should be validated in the field, this research showed the potential use of a test-day model for analyzing functional traits to advise dairy farmers. [less ▲]

Le BCS, une méthode simple à la source de conseils variés : ration, repro et santé

in 14ième Carrefour des Productions animales: Les filières bovines dans la tourmente, Produire plus et mieux avec moins: Gembloux, le 11 février 2009 (2009)

Développement d’un outil de prédiction de la probabilité de réussite à l’insémination chez la vache laitière à partir des données du Contrôle Laitier

in 15ème Rencontres Recherches Ruminants, Paris, les 3 et 4 décembre 2008 (2008, December)

Variation of delta(9)-desaturase activity in dairy cattle

in Journal of Dairy Science (2008), 91(8), 3211-3224

The endogenous production of unsaturated fatty acids (FA), particularly some monounsaturated FA (%MONO) and nearly all conjugated linoleic acids, is regulated by the 9-desaturase activity. The aims of ... [more ▼]

The endogenous production of unsaturated fatty acids (FA), particularly some monounsaturated FA (%MONO) and nearly all conjugated linoleic acids, is regulated by the 9-desaturase activity. The aims of this study were to assess the variation of this enzymatic activity within lactation, across dairy breeds, and to estimate its genetic parameters. The ratios of C14:1 cis-9 to C14:0, C16:1 cis-9 to C16:0, and C18:1 cis to C18:0 were calculated from FA contents predicted by mid-infrared spectrometry. Variance components and standard errors were estimated using average information REML. The multitrait mixed model included as fixed effects herd × test date × class of lactation number, class of days in milk × class of lactation number, class of age × class of lactation number, and regressions on breed composition. Four random effects were also included: animal genetic effect, 2 permanent environments (within and across lactations), and residual effect. Under the assumption that the calculated ratios are an approximate measurement of 9-desaturase activity, this study showed different sources of variation for this enzymatic activity. A slight difference was observed within lactation. The ratios of C14:1 cis-9 to C14:0 and C16:1 cis-9 to C16:0 increased as a function of days in milk. Differences across 7 dairy breeds were observed. The values of 9-desaturase indices observed for Jersey and Brown-Swiss cows were lower compared with Holstein. The opposite was observed for dual-purpose Belgian Blue cows. Values of heritability for the ratios of C14:1 cis-9 to C14:0, C16:1 cis-9 to C16:0, and C18:1 cis to C18:0 were 20, 20, and 3%, respectively. Negative genetic correlations observed between fat or protein contents and the 3 indices suggested that an increased activity of 9-desaturase could inhibit the synthesis of fat and protein in bovine milk. Negative correlations were also observed between fat or protein contents and the contents of 3 studied unsaturated FA in milk fat (C14:1 cis-9, C16:1 cis-9, and C18:1 cis). The positive genetic correlations observed between %MONO and the ratios of C14:1 cis-9 to C14:0 (0.72), C16:1 cis-9 to C16:0 (0.62), and C18:1 cis to C18:0 (0.97) showed that %MONO is linked to the 9-desaturase activity. [less ▲]