Dutch Dairy Farms Research Articles

Cross-sectional serological survey on gastrointestinal and lung nematode infections in first and second-year replacement stock in The Netherlands: relation with management practices and use of anthelmintics

A cross-sectional survey was carried out on 86 farms randomly distributed in The Netherlands. After housing following the first and the second grazing season (FGS and SGS) serum samples were collected to determine IgG levels against Cooperia oncophora and Dictyocaulus viviparus, and the pepsinogen content. A questionnaire was used to inquire on grazing management practices and the use of anthelmintic drugs. On 80.7 and 60.2% of the farms FGS and SGS animals, respectively, were treated at least once with an anthelmintic drug. The percentage for the SGS animals indicates that the use of anthelmintic drugs in those animals has increased enormously over the last 10–15 years. Generally, parasitic nematode control in the FGS is good on most farms, but it can be characterised as being overprotective. There is a tendency that if anthelmintic drugs are used in the FGS they also are used more often in the SGS. On 12 farms (14%), no anthelmintic drugs were given in the FGS and the SGS. These farms did not differ from the others with respect to management practices in any obvious way. The serological results were in general very low, indicating low levels of exposure to gastrointestinal nematode infection in both FGS and SGS animals. This was not surprising in view of the good to high level of nematode control practices reported by the farmers. Although not statistically significant, a consistent result was that serological results for the SGS animals were more often positive or on average higher on those farms where FGS parasite control tended to be excessive. For D. viviparus, a prevalence rate of 41% positive farms was found. Following comparison with previous data, it is speculated that lungworm (sero-)prevalence in replacement stock may be declining as a result of continuing high levels of parasite control in replacement stock. It is concluded that the results confirm previous surveys, lending support to the conclusion that parasitic nematode control on Dutch dairy farms, certainly in FGS calves, is good but tends to be overprotective.

Introduction of seasonal and spatial specification to grass production and grassland use in a dairy farm model

A linear programming model of a dairy farm, in which grass production and grassland use was originally modelled using one growing period and one area of land, is extended. To include seasonal and spatial elements of variation not allowed for in the original model, the model was modified to reflect three growing periods in the season and then to reflect management of two separate areas of land. The resulting three models were used to assess farm physical planning, economic results and nutrient balances for an average Dutch dairy farm in a situation without and with levies on nutrient surpluses. It is concluded that incorporating seasonal and spatial elements provides greater insight into grassland management. Seasonal model specification does not result in significant changes in farm physical planning, income and nutrient surpluses. Spatial specification has a larger impact if one of the two areas cannot be grazed by dairy cattle.

Nitrogen efficiency of Dutch dairy farms: a shadow cost system approach

In this paper we analyse the cost efficiency and nitrogen efficiency of an unbalanced panel of Dutch dairy farms. Nitrogen efficiency is defined as the ratio of minimal to observed use of nitrogen (N-containing inputs), conditional on output and quasi-fixed inputs. Nitrogen efficiency is computed in a shadow cost system framework. Nitrogen-efficient production is found at the optimal mix of variable inputs, determined by the nitrogen content of these inputs. The optimal nitrogen content ratio is introduced using price distortion factors in the estimated cost function. The mean input-oriented technical efficiency is 84 per cent. The mean nitrogen efficiency is 56 per cent. The nitrogen surplus at the nitrogen-efficient point is less than half of the observed surplus, whereas production costs increase by only 3 per cent.

Nitrogen and phosphorus management on Dutch dairy farms: legislation and strategies employed to meet the regulations

The high input of nutrients through the use of fertilizers, manure and animal feed make it possible to reach high levels of agricultural production. However, high nutrient inputs may also result in large nutrient losses and thus have adverse effects on groundwater, surface water, and the atmosphere. To minimize nutrient emissions from agriculture, the Dutch government has introduced regulations on nutrient use. These include: (1) a ban on spreading animal manure on agricultural land during the winter, (2) the obligation to cover storage facilities for animal manure, (3) compulsory low-emission applications of animal manure to land, and (4) applying levies when the maximum permissible annual N and P surpluses for farms are exceeded. The nutrient surplus is the difference between nutrient input into the farm and nutrient output from the farm. The maximum permissible N surpluses for 2000 are 250 kg N ha–1 year–1 and 125 kg N ha–1 year–1 for grassland and arable land, respectively, and for P, 35 kg P2O5 ha–1 year–1 for both grassland and arable land. When the annual permissible levels are exceeded, farmers are charged with a levy. Results obtained at the experimental dairy farm "De Marke" showed that a reduction in nutrient inputs via fertilizers and purchased food, in combination with restricted grazing, reduced the N surplus in such a way that the NO3– concentration in the groundwater decreased to about the maximum permissible level of 50 mg NO3– l–1. Since these results were obtained on a sandy soil that is very sensitive to NO3– leaching, it is suggested that all dairy farmers should be able to sufficiently reduce NO3– leaching by improving their farm management.

Environmental efficiency with multiple environmentally detrimental variables; estimated with SFA and DEA

The objective of this paper is to estimate comprehensive environmental efficiency measures for Dutch dairy farms. The environmental efficiency scores are based on the nitrogen surplus, phosphate surplus and the total (direct and indirect) energy use of an unbalanced panel of dairy farms. We define environmental efficiency as the ratio of minimum feasible to observed use of multiple environmentally detrimental inputs, conditional on observed levels of output and the conventional inputs. We compare two methods for the calculation of efficiency; namely Stochastic Frontier Analysis (SFA) and Data Envelopment Analysis (DEA). This paper reveals the strengths and weaknesses for estimating environmental efficiency of the methods applied. Both SFA and DEA can estimate environmental efficiency scores. The mean technical efficiency scores (output-oriented, SFA 89%, DEA 78%) and the mean comprehensive environmental efficiency scores (SFA 80%, DEA 52%) differ between the two methods. SFA allows hypothesis testing, and the monotonicity hypothesis is rejected for the specification including phosphate surplus. DEA can calculate environmental efficiency scores for all specifications, because regularity is imposed in this method.

Factors Associated with Cure after Therapy of Clinical Mastitis Caused by Staphylococcus aureus

One hundred and fifty-nine cases of clinical Staphylococcus aureus mastitis were analyzed to detect factors associated with bacteriological cure after therapy. On 100 Dutch dairy farms, data were collected from four clinical trials with five intramammary treatment regimes designed to treat β-lactamase-positive pathogens. Infected quarters were treated three times, with a 12-h interval between treatments. Treatment was extended for 2 d if results of the trial treatment were, according to the owner, not satisfactory. The overall bacteriological cure rate was 52%. The bacteriological cure rate of clinical β-lactamase-negative S. aureus mastitis was significantly higher than that of clinical β-lactamase-positive S. aureus mastitis. Bacteriological cure was also significantly higher if somatic cell count of the cow was low at the milk recording prior to the onset of the clinical mastitis. The bacteriological cure rate of clinical β-lactamase-negative S. aureus mastitis was also significantly higher after an extended treatment compared with no extended treatment. The seriousness of the various clinical symptoms and the bacteriological cure rate of clinical S. aureus mastitis were not associated.

Dynamic programming to determine optimum investments in information technology on dairy farms

The feasibility of integrating the information about a number of information technology (IT) applications on dairy farms is gaining interest because of the potential to improve economic results. In this study optimal investment patterns involving five IT applications are evaluated: (1) automated concentrate feeding systems; (2) measurement of daily physical activity of cows; (3) in-line automated parlour systems recording milk production; (4) milk temperature; and (5) electrical conductivity of milk. The investment decisions are optimised by dynamic programming taking into account price reduction and technical progress over time. The objective is to determine the pattern value of (stepwise) IT investments that maximises the net present over a given planning horizon. Optimal investment patterns are calculated under different assumptions of technical progress, farm characteristics and farm scale. In this way it is determined under which conditions the applications under research would be incorporated. Results for a typical Dutch dairy farm show that the optimal investment pattern includes automated concentrate feeders. The incorporated electronic individual cow identification and hardware facilitates the appraisal of other in-line sensor investments such as activity measurement of cows.

Potential economic benefits from changes in management via information technology applications on Dutch dairy farms: a simulation study

Economic benefits of information technologies were assessed at farm level by means of a dynamic probabilistic simulation model. The model included biological performances with respect to oestrus detection and concentrate feeding. In this way, main benefits of activity meters, automated concentrate feeders and on-line automated parlour systems for recording of milk production and milk temperature could be estimated. In comparison with the default situation, improvement in oestrus detection from 50% to 90% increased gross margin by Dfl. 1.28 per 100 kg fat and protein corrected milk (FPCM) per year under Dutch production conditions. This equals 8.0% of a farmer’s typical net return to labour and management. Using an individual feeding system increased gross margin by Dfl. 0.77 per 100 kg FPCM per year and the net return to labour and management by 4.8%. Feeders increased the frequency of concentrate provision from two to four times a day. Moreover, a more accurate performance-related concentrate provision was achieved from total daily amount in portions of 1–0.1 kg. In addition feeders enabled the possibility of overcoming the limited concentrate intake for high-producing animals in the milking parlour in the beginning of the lactation. A more accurate milk production estimation increased gross margin and the net return to labour and management by Dfl. 0.17 per 100 kg FPCM and 1.1% respectively. In the latter case equilibrium feeding was compared with a feeding method in which concentrate supply was based on an standard deviation of 5% in the estimated energy requirements for milk production. The results of this study will be used to evaluate theoretically the economic viability of the investigated IT applications.

Application of survival analysis to identify management factors related to the rate of BHV1 seroconversions in a retrospective study of Dutch dairy farms

The prevalence of Bovine herpes virus type 1 (BHV1) at dairy farms is dependent on several factors. First, the prevalence is influenced by introduction of BHV1 at the farms, which is dependent on the risk factors for introduction. Second, the BHV1 prevalence might also be influenced by reactivation of BHV1 within the farm, which might be affected by the management of the farm. In this study the relations between risk factors, management factors and the estimated time since latest BHV1 outbreak were investigated by means of Cox regression analysis. The results showed that direct animal contacts (i.e. purchase of cattle and returning export cattle) and occasional visitors increased the rate of BHV1 outbreaks on dairy farms. Management factors related to reactivation of BHV1 at dairy farms were all related to a loose housing system which incurred an increased risk of reactivation of BHV1 at the farm. The reactivation was facilitated when the barn was overcrowded (i.e. more cows than cubicles in the barn). To minimise the risk of introduction of BHV1 at a farm the farmer should banish direct animal contacts and limit the number of contacts with visitors. Stress and an overcrowded barn should be avoided.

Modeling the effect of an outbreak of bovine herpesvirus type 1 on herd-level milk production of Dutch dairy farms.

One of the impacts of disease is its effect on milk production. In the present study the effect of an outbreak of bovine herpesvirus type 1 on milk production at the herd level of certified bovine herpesvirus type 1-free dairy farms was modeled. The objective was to study several linear models to quantify the effects of a bovine herpesvirus type 1 outbreak on milk production accounting for the repeated measurements and incorporating our assumptions about the most likely duration of effects of this virus. Because milk production is measured at regular intervals, the data consisted of repeated measurements at the herd and cow levels. A marginal model, a subject-specific random-effect model, and a transition model were developed. The effect of a bovine herpesvirus type 1 outbreak was statistically significant in the random-effect model, and this model fitted the investigated farms best. However, a transition model might be a better model for generalizing the results to the whole population of Dutch dairy farms. The effect of a bovine herpesvirus type 1 outbreak on milk production derived from the random-effect model amounted to, on average, a loss of 0.92 kg of milk per cow per day during a period of 9 wk. The milk production loss varied from almost none to 2 kg of milk per cow per day. This reduction resulted in an average loss of Dfl 372 (Dfl1 = $US $0.50) with lower and upper confidence limits of, respectively, Dfl 12 and Dfl 730 per bovine herpesvirus type 1 outbreak.

Econometric Estimation of Technical and Environmental Efficiency: An Application to Dutch Dairy Farms

AbstractIn this article we estimate the technical and environmental efficiency of a panel of Dutch dairy farms. Nitrogen surplus, arising from the application of excessive amounts of manure and chemical fertilizer, is treated as an environmentally detrimental input. A stochastic translog production frontier is specified to estimate the output‐oriented technical efficiency. Environmental efficiency is estimated as the input‐oriented technical efficiency of a single input, the nitrogen surplus of each farm. The mean output‐oriented technical efficiency is rather high, 0.894, but the mean input‐oriented environmental efficiency is only 0.441. Intensive dairy farms are both technically and environmentally more efficient than extensive farms.

Two-tier pricing and Agenda 2000. Consequences of EU dairy policy reform for Dutch dairy farming

Les conséquences de la réforme de la politique laitière de l'UE pour le secteur laitier néerlandais. Cet article analyse les effets, pour le secteur laitier néerlandais, i) d'un système de double prix, étant donné différents niveaux des prix mondiaux, ii) d'une baisse de 15 % du prix du lait, compensée par un paiement direct et accompagnée d'une augmentation de 1,5% des quotas, au niveau national (Agenda 2000) et iii) de la suppression des quotas. Notre analyse montre qu'en présence d'un système de double prix et d'un marché libre des quotas, la production de lait de catégorie B (valorisée au prix mondial, inférieure au prix du lait sous quota A) serait positive pour un prix du marché mondial supérieur à 0,31 NG (0,14 euro) par kilogramme. Le profit des producteurs néerlandais évoluerait alors positivement du fait de l'accroissement de la production. En revanche, dans le scénario «Agenda 2000», les producteurs subissent une perte de profit résultant de la diminution de la rente liée au quota, par suite de la baisse du prix du lait. Le paiement direct par tonne de quota est en effet trop faible pour compenser l'effet négatif de la réduction de la rente du quota. Ces scénarios de réforme de la politique laitière communautaire sont simulés à l'aide d'un modèle micro-économétrique du secteur laitier néerlandais qui détermine les effets des changements de politique envisagés au niveau des producteurs individuels. Les résultats obtenus sont ensuite agrégés (au moyen d'un système de pondérations) au niveau du secteur laitier national.

Occurrence of verocytotoxin-producing Escherichia coli O157 on Dutch dairy farms.

During the period from September 1996 through November 1996, 10 Dutch dairy farms were visited to collect fecal samples from all cattle present. The samples were examined for the presence of verocytotoxin (VT)-producing Escherichia coli (VTEC) of serogroup O157 (O157 VTEC) by immunomagnetic separation following selective enrichment. Cattle on 7 of the 10 dairy farms tested positive for O157 VTEC, with the proportion of cattle infected varying from 0.8 to 22.4%. On the seven farms positive for O157 VTEC, the excretion rate was highest in calves ages 4 to 12 months (21.2%). In a follow-up study, two O157 VTEC-positive farms and two O157 VTEC-negative farms identified in the prevalence study were revisited five times at intervals of approximately 3 months. Cattle on each farm tested positive at least once. The proportion of cattle infected varied from 0 to 61.0%. Excretion rates peaked in summer and were lowest in winter. Again, the highest prevalence was observed in calves ages 4 to 12 months (11.8%). O157 VTEC strains were also isolated from fecal samples from horses, ponies, and sheep and from milk filters and stable flies. O157 VTEC isolates were characterized by VT production and type, the presence of the E. coli attaching-and-effacing gene, phage type, and pulsed-field gel electrophoretic genotype. No overlapping strain types were identified among isolates from different farms except one. The predominance of a single type at each sampling suggests that horizontal transmission is an important factor in dissemination of O157 VTEC within a farm. The presence of more than one strain type, both simultaneously and over time, suggests that there was more than one source of O157 VTEC on the farms. Furthermore, this study demonstrated that the O157 VTEC status of a farm cannot be ascertained from a single visit testing a small number of cattle.

Adaptive conjoint analysis to determine perceived risk factors of farmers, veterinarians and AI technicians for introduction of BHV1 to dairy farms

A study was carried out to determine the possibility of a more-closed farming system for (Dutch) dairy farms. The objective of the study was to provide effective and economically profitable management advice for improving the animal-health status of farms. Management measures will only be successfully applied if supported by farmers and their advisors (such as veterinarians). Therefore, the perception of farmers and advisors of the importance of various risk factors for the introduction of diseases to a farm was determined by using bovine herpes virus type 1 (BHV1) as an example. As part of the study, an evening-long workshop was organized and run thrice. In total, 49 farmers, veterinarians and AI technicians participated in these workshops. The computerized questionnaire technique was based on adaptive conjoint analysis (ACA). ACA has the advantage that participants can work with a large number of risk factors in a relatively short period of time. Another advantage of ACA (compared with standard questionnaires) is that the answers from each participant can be checked with regard to consistency with respect to the importance assigned to them. Data from participants with inconsistent responses can be excluded from further analyses. The results of the ACA interview were compared with the risk factors reported in the literature as being associated with BHV1 status (e.g. purchase of cattle, participation in cattle shows) and with farmers' actual management to prevent the introduction of diseases. The workshop participants were all operating in the dairy sector and they seemed well aware of the risk of direct animal contacts for the introduction of BHV1. Farmers thought visitors to be more risky than did AI technicians and (especially) veterinarians. Farmers who purchased cattle or participated in cattle shows were of the opinion that the risks of direct animal contacts were more important than did farmers who were not involved in those practices. Farmers whose farms were BHV1-positive (and participated in cattle shows more often) thought the risk of participation smaller than did farmers with BHV1-negative farms.

Exploratory study on the economic value of a closed farming system on Dutch dairy farms

A closed farming system may prevent the introduction of infectious diseases on to dairy farms and could be a good starting point for the eradication of these diseases. In order to introduce a closed farming system, farmers need to be made aware of how these are introduced into the herd.
 Full article published in Veterinary Record (1998) 142, 240-242.

Exploratory study on the economic value of a closed farming system on Dutch dairy farms

A closed farming system may prevent the introduction of infectious diseases on to dairy farms and could be a good starting point for the eradication of these diseases. In order...

Risk factors for existence of Bovine Herpes Virus 1 antibodies on nonvaccinating Dutch dairy farms

A more closed farming system may prevent introduction of infectious diseases on dairy farms and can be a good starting point for control of these diseases. Data were available on the presence of Bovine Herpes Virus 1 (BHV1) antibodies in bulk milk and/or blood samples of Dutch dairy farms. Furthermore, information about the possible risk factors for introduction of infectious diseases was collected on 214 of these dairy farms. Data of 107 farms which had been never vaccinated against BHV1 remained for the analysis. A positive BHV1 status on these 107 farms could only be caused by introduction of BHV1. Risk factors for introduction of BHV1 on the farms were quantified using logistic regression. BHV1-positive farms purchased cattle and participated in cattle shows more often compared with BHV1-negative farms. A BHV1-positive farm also had more (professional) visitors in the barn who used farm clothing less often. The BHV1-positive farms were found to be situated closer to other cattle farms compared with the BHV1-negative farms.

Conversion from Conventional to Biological Dairy Farming: Economic and Environmental Consequences at Farm Level

ABSTRACTBiological dairy farming is often advocated as a solution for environmental problems caused by Dutch dairy farming. At the same time, biological farming can improve animal welfare and increase income due to a higher milk price. In this paper the central issue is to quantify economic and environmental consequences for dairy farms when converting to biological dairy farming. A linear programming model is used to model an extensive and an intensive dairy farm typical for the Province of Utrecht, The Netherlands. The objective function of the model maximizes labour income of the farm. From the results it appears that the extensive farm benefits from conversion while the intensive farm loses income. The environmental consequences are quite diverse. The nitrogen surplus after conversion is much lower than before because nitrogen fixation by legumes is omitted from the calculation. On the other hand, ammonia emission is higher after conversion to biological farming due to a higher number of animals. On the extensive farm the phosphate surplus in the biological situation is much higher than in the conventional situation due to the fact that a shortage of nitrogen in the biological situation can only be made up by applying animal manure (slurry) from other farms with consequential overfertilization of phosphate. When environmental legislation is introduced, the biological farms appear to lose more income than the conventional farms. From the sensitivity analysis it appears that assumptions about milk yield per cow and milk price are crucial for the economic results of biological farms.

Economic and environmental consequences of technical and institutional change in Dutch dairy farming

A linear programming model of a dairy farm was used to explore the future for different types of Dutch dairy farms under different scenarios. The scenarios are consistent sets of changing factors that are considered external at farm level. The factors included are technical, such as efficiency of milk production and feed production, or institutional, such as national environmental legislation and EU market and price policy. Income and nutrient losses for farms differing in intensity and size are generated for the base year 1992 and for the year 2005. The results show that technical change up to the year 2005 has a positive influence on labour income as well as on nutrient losses. The increase of labour income is higher for farms with a higher total milk production in the basis situation. The influence of environmental policy on labour income and environmental results is bigger for farms with a higher intensity, as these farms have to take more measures to comply with governmental policy. Replacement of the price support policy for milk by a 2-price system with a high price for a restricted amount of milk and a low price for an unrestricted amount of milk has negative consequences for labour income, especially for intensive farms.

Economic losses due to clinical lameness in dairy cattle

Effects of clinical digital diseases on milk production, calving interval, culling rate and incidence of other diseases were derived from data on 2183 cows and 6273 lactations, routinely collected by veterinarians on 21 dairy farms served by the School of Veterinary Medicine in Utrecht, Netherlands. Effects that could not be obtained from the dataset (i.e., fluctuations in live weight, labour requirement and treatments) were derived from literature. All physical effects were built into a Partial Budgeting model to calculate the economic losses on the farms. The results showed that the average losses from clinical digital diseases per foot-lame cow were NLG 230 per year. The incidence in these herds averaged 21%, resulting in a loss of almost NLG 50 per average cow present in the herd. This equals 4–5% of a typical income on Dutch dairy farms, and ranks third after mastitis (NLG 150 per cow) and fertility problems (NLG 125 per cow). Differences in losses among farms were found to be even greater than the average losses, indicating that there is potential for improvement.