Alfons Weersink

Direct production losses and treatment costs from bovine viral diarrhoea virus, bovine leukosis virus, Mycobacterium avium subspecies paratuberculosis, and Neospora caninum

Our purpose was to determine direct production losses (milk loss, premature voluntary culling and reduced slaughter value, mortaliy loss, and abortion and reproductive loss) and treatmetn costs (veterinary services, medication cost, and extra farm labour cost) due to four infectious diseases in the maritime provinces of Canada: bovine viral diarrhoea (BVD), enzootic bovine leukosis (EBL), Johnes Disease (JD), and neosporosis. We used a partial-budget model, and incorporated risk and sensitivity analyses to identify the effects of uncertainty on costs. Total annual costs for an average, infected, 50 cow herd were: JD

Economic aspects of persistency of lactation in dairy cattle

2472; BVD

Semiparametric Estimation of Stochastic Production Frontier Models

2421; neosporosis

Economic Feasibility of Variable-Rate Technology for Nitrogen on Corn

2304; EBL

Damage Control and Increasing Returns

806. The stochastic nature of the proportion of infected herds and prevalence of infection within a herd were used to estimate probability distributions for these ex post costs. For all diseases, these distributions were right skewed. A sensitivity analysis showed the largest effect on costs was due to milk yield effects. For example, changing milk production loss from 0 to 5% for BVD increased the costs for the disease by 266%.

Farm-Level Modeling for Bigger Issues

Abstract Persistency of lactation is a trait of economic importance in dairy cattle because of its impact on fertility, health, and feed costs. When level of production is based on a 305-day lactation, persistency also affects returns from milk production for lactations with lengths different from 305 days. The objective here was to quantify the impact of persistency of lactation on feed costs and milk returns, relative to constant 305-day yield. A bio-economic model that allowed for optimisation of insemination and culling decisions was used. For individual lactations of 305 days, persistency affected feed costs only but for other lactation lengths, persistency had a greater impact on milk returns per lactation than on feed costs. Under an optimised insemination and culling strategy, which resulted in an average calving interval of 12.4 months, the economic value of persistency was

Multiple job holdings among dairy farm families in New York and Ontario

13.6 (Canadian) per phenotypic standard deviation but increased with level of persistency. On a genetic standard deviation basis and with a heritability of 0.15, the economic value of persistency was 3.4% relative to the economic value of 305-day production. The economic value of persistency was almost tripled when average calving interval was 13 months. Consideration of health and reproductive costs will further increase the economic value of persistency. Persistency had a substantial impact on optimum insemination decisions. With high persistency, insemination was profitable longer into the lactation and the optimum time of first insemination was delayed for high producing cows.

Marginal Abatement Costs of Reducing Groundwater-N Pollution with Intensive and Extensive Farm Management Choices

This article extends the linear stochastic frontier model proposed by Aigner, Lovell, and Schmidt to a semiparametric frontier model in which the functional form of the production frontier is unspecified and the distributions of the composite error terms are of known form. Pseudolikelihood estimators of the parameters characterizing the two error terms of the model are constructed based on kernel estimation of the conditional mean function. The Monte Carlo results show that the proposed estimators perform well in finite samples. An empirical application is presented. Extensions to a partially linear frontier function and to more flexible one-sided error distributions than the half-normal are discussed

Agriculture and ISO 14000

The economic feasibility of three different fertilizer management strategies (constant rate, three-rate and multiple-rate technology) in the application of nitrogen fertilizer to corn are compared under different probability distributions for field fertility. A constant rate was more profitable than either variable-rate technology system for homogeneous fields with low fertility. The application area at which the relative profitability between systems changed was largely determined by the characteristics of the fertility distribution rather than by assumptions regarding costs. Variable-rate technology improves groundwater quality in low-fertility fields by reducing total fertilizer applied and in high-fertility fields by increasing corn yield. Copyright 1999, Oxford University Press.

Causality between Dairy Farm Size and Productivity

The indirect action of damage control inputs means the marginal productivity of these inputs depends on their effectiveness in controlling the level and size of production loss caused by the damage agent. Increasing returns to damage control inputs can occur even when control and damage functions are concave. The result implies more attention needs to be paid to the functional form selection for damage and control functions in empirical work on pest control and other types of damage control inputs. In addition, the possibility of increasing returns may undermine the general use of taxes to reduce pesticide use.