Second-order cybernetics as a tool to understand why pastoralists do what they do

The notion that pastoralists are irrational managers due to strong adherence to tradition and culture is still common in livestock production sciences. Researchers and development practitioners tend to fall back on this notion when target groups do not adopt their proposed innovations without any obvious reason. It is however difficult to identify innovations that fit into resource-poor systems, and often this lack of fit is the reason why innovations are not taken up. Understanding why pastoralists do what they do, and learning about the constraints they face when regulating production processes, is a prerequisite for identifying viable improvement possibilities.This study focuses on understanding the reasoning behind pastoralists’ actions. The knowledge underlying pastoralists’ regulation of production processes is analysed with a method based on second-order cybernetics that offers insight in the system view of the actors in the system. It uses feedback and control principles of cybernetics to understand human control in human activity systems. For analysis purposes, a control loop model is proposed to systematically assess, for each management practice, the livestock keepers’ observations and the rules upon which they base their actions.This cybernetic knowledge analysis is illustrated using the example of milk offtake management in a pastoral camel production system in northern Kenya. The example is chosen because lack of knowledge on the complex milk offtake management led to the widespread preconception of poor pastoral management as the cause for high calf mortality.The cybernetic knowledge analysis reveals what livestock keepers consider as information in their production process, as well as the rules that inform their actions. The analysis enables to distinguish between management practices that serve as: (i) routine control; (ii) problem-solving control; or (iii) selection. This information is useful in transdisciplinary studies that involve local actors and other stakeholders in finding solutions to real-world problems. Through the proposed knowledge analysis methodology, scientists can learn about livestock keepers’ reasoning and problem-solving abilities, but also about aspects of the production processes where control is weak and new control possibilities are sought after. The analysis also yields information on how livestock keepers try to achieve their production goals despite restrictions and disturbances given by the production environment. This understanding is of high importance in low-external-input systems that have little scope to control production conditions but that do adapt to them.     

Pathology of ocular lesions associated with gas supersaturation in white seabass

Cultured juvenile white seabass Atractoscion nobilis (WSB) can suffer from intraocular emphysemas and exophthalmia in the hatchery environment. To identify the cause, two size-groups of WSB were exposed to five gas saturation levels, ranging from 98% to 122% total gas pressure (TGP), over a 96-h exposure period in 18 degrees C and 23 degrees C seawater. Histological examination revealed that the gross and subgross lesions associated with gas supersaturation included corneal and orbital emphysema, along with subretinal, optic nerve, and iridial hemorrhage. Corneal emphysema was the most prominent gross lesion, with the severity and prevalence increasing between size-groups and water temperatures as TGP increased. Following the same pattern was orbital emphysema, which affected more than 93% of the fish examined and caused hemorrhage in the subretinal space, around the optic nerve, in the iris, or a combination thereof. Iridial hemorrhage occurred in 91% of the fish examined and decreased significantly with fish size. The prevalence and severity of hemorrhage in the subretinal space increased significantly with TGP and fish size but not with temperature. Optic nerve hemorrhage was absent in small fish exposed at 18 degrees C but increased significantly with temperature and fish size. The reverse was true for the large fish.     

Identification of plasma and hepatic parameters related to metabolic robustness in dairy cows

Blood plasma and hepatic parameters were identified that describe the differences between metabolically robust or vulnerable dairy cows grouped according to their past health status. Data from a field study on dairy cows were used from which metabolically challenged dairy cows were selected that had a milk fat percentage of >4.5 mg/g and a fat to protein ratio of >1.5 in their previous early lactation. The selected cows were either classified as metabolically robust or vulnerable based on the occurrence of various metabolic and (re)production disorders in their previous lactations. Blood and liver tissue samples were collected in week 3 ante partum (a.p.) (-3 wk), in week 4 (+4 wk) and in week 13 (+13 wk) post-partum (p.p.). Plasma concentrations of metabolites and hormones and mRNA expression of genes involved in metabolic pathways in the liver were used as variables for a two-group discriminant analysis (DA). Average discriminant scores (centroids) were different (p < 0.05) in -3 wk, +4 wk and in +13 wk. In -3 wk, significant variables that best explained the differences between metabolically robust and vulnerable cows were parity, plasma triglycerides, glucose and mRNA abundance of carnitine palmitoyltransferase 2 (CPT2). In addition, based on the classification matrix, 69% of the dairy cows were correctly classified. In +4 wk, identified significant parameters were parity, plasma glucose and urea, and 67% of the cows were correctly classified. In +13 wk, significant variables that explained the differences between the groups were parity, mRNA abundance of acyl-CoA synthetase long-chain 1 and CPT1, and 66% of the cows were correctly classified. In conclusion, the identified variables may distinguish from metabolically challenged cows, those cows that had a poorer health performance in their previous lactations.     

CD4+CD25+ T cells expressing FoxP3 in Icelandic horses affected with insect bite hypersensitivity

Insect bite hypersensitivity (IBH) is an IgE-mediated dermatitis caused by bites of midges from the genus Culicoides. We have shown previously that peripheral blood mononuclear cells (PBMC) from IBH-affected horses produce higher levels of IL-4 and lower levels of IL-10 and TGF-β1 than those from healthy horses, suggesting that IBH is associated with a reduced regulatory immune response. FoxP3 is a crucial marker of regulatory T cells (Tregs). Here we have determined the proportion of CD4(+)CD25(+)FoxP3(+) T cells by flow cytometry in PBMC directly after isolation or after stimulation with Culicoides extract or a control antigen (Tetanus Toxoid). There were no differences between healthy and IBH horses either in the proportion of FoxP3(+)CD4(+)CD25(+) cells in freshly isolated PBMC or in the following stimulation with Tetanus Toxoid. However, upon stimulation of PBMC with the allergen, expression of FoxP3 by CD4(+)CD25(+high) and CD4(+)CD25(+dim) cells was significantly higher in healthy than in IBH horses. Addition of recombinant IL-4 to PBMC from healthy horses stimulated with the allergen significantly decreased the proportion of FoxP3 expressing cells within CD4(+)CD25(+high). These results suggest that IBH is associated with a decreased number of allergen-induced Tregs. This could be a consequence of the increased IL-4 production by PBMC of IBH-affected horses.