To what extent is climate change adaptation a novel challenge for agricultural modellers?

Modelling is key to adapting agriculture to climate change (CC), facilitating evaluation of the impacts and efficacy of adaptation measures, and the design of optimal strategies. Although there are many challenges to modelling agricultural CC adaptation, it is unclear whether these are novel or, whether adaptation merely adds new motivations to old challenges. Here, qualitative analysis of modellers' views revealed three categories of challenge: Content, Use, and Capacity. Triangulation of findings with reviews of agricultural modelling and Climate Change Risk Assessment was then used to highlight challenges specific to modelling adaptation. These were refined through literature review, focussing attention on how the progressive nature of CC affects the role and impact of modelling. Specific challenges identified were: Scope of adaptations modelled, Information on future adaptation, Collaboration to tackle novel challenges, Optimisation under progressive change with thresholds, and Responsibility given the sensitivity of future outcomes to initial choices under progressive change.

DairyWise, a whole-farm dairy model.

A whole-farm dairy model was developed and evaluated. The DairyWise model is an empirical model that simulated technical, environmental, and financial processes on a dairy farm. The central component is the FeedSupply model that balanced the herd requirements, as generated by the DairyHerd model, and the supply of homegrown feeds, as generated by the crop models for grassland and corn silage. The output of the FeedSupply model was used as input for several technical, environmental, and economic submodels. The submodels simulated a range of farm aspects such as nitrogen and phosphorus cycling, nitrate leaching, ammonia emissions, greenhouse gas emissions, energy use, and a financial farm budget. The final output was a farm plan describing all material and nutrient flows and the consequences on the environment and economy. Evaluation of DairyWise was performed with 2 data sets consisting of 29 dairy farms. The evaluation showed that DairyWise was able to simulate gross margin, concentrate intake, nitrogen surplus, nitrate concentration in ground water, and crop yields. The variance accounted for ranged from 37 to 84%, and the mean differences between modeled and observed values varied between -5 to +3% per set of farms. We conclude that DairyWise is a powerful tool for integrated scenario development and evaluation for scientists, policy makers, extension workers, teachers and farmers.

Investigating the eggshell conductance and embryonic metabolism of modern and unselected domestic avian genetic strains at two flock ages.

The objective of this study was to determine if broiler strain and breeder flock age affect eggshell conductance, fertility, and hatchability parameters; heart and hepatic glycogen concentrations at hatch; and embryonic metabolism throughout incubation. The 3 broiler strains investigated were HBY, a modern commercial broiler strain selected for high breast yield; WBM, a modern commercial broiler strain selected for the whole bird market; and UN78, a female broiler parent strain unselected since 1978. Fertility and hatchability parameters for each of the 3 strains were determined when the flocks were 32, 34, 37, and 38 wk of age. Eggshell conductance was measured on separate eggs produced from flocks at 37, 45, and 53 wk of age. Concurrently, fertile hatching eggs from the 3 broiler strains at 2 flock ages (33 and 38 wk) were incubated in individual metabolic chambers. Total daily CO2 production of each embryo was measured. Strain and flock age did not influence any of the fertility or hatchability parameters. Strain had no effect on conductance, but eggs from the 37-wk-old flocks had higher conductance than eggs from the 45- or 53-wk-old flocks, which did not differ from one another. Strain had no significant effect on average total CO2 production over the entire 21.5 d of incubation. However, embryos from the 38-wk-old flock produced more total CO2 than did embryos from the 33-wk-old flocks. Also, there was an interaction between strain and flock age for total CO2 production; UN78 embryos from the 33-wk flocks had higher CO2 production than WBM embryos, and the CO2 production of HBY did not differ from either strain. When embryos from the 38-wk flocks were compared, WBM embryos had higher CO2 production than did UN78 embryos, and HBY embryos did not differ from either strain. The data showed that in the 3 strains examined in this study, genetic differences in embryonic metabolic rate were dependent upon breeder flock age.

Lack of a relationship between concentrations of plasma luteinising hormone, thyroxine and prolactin at nine week's of age and subsequent egg production in the domestic hen.

1. The concentrations of plasma luteinising hormone (LH), thyroxine and prolactin were measured in about 200 birds from each of two homogenous strains of White Leghorn hens at 9 weeks of age and related to subsequent egg production. 2. Within each strain, no relationships were found in individual birds between the concentrations of the plasma hormones and subsequent egg production after 90, 180 and 270 d of laying. 3. Single measurements of plasma LH, thyroxine or prolactin before the onset of lay do not appear to be useful criteria for the selection of egg-laying strains.