The objective was to describe the physicochemical changes during the early phase of subclinical mastitis and to associate them with pathological findings. A Mannheimia haemolytica strain was deposited into one teat duct of 25 ewes and the clinical, bacteriological, cytological, physicochemical (pH, milk composition), gross-pathological and histological findings were subsequently recorded. The organism was consistently isolated from samples of teat duct material (140/150) but not from mammary secretion (50/150). California Mastitis Test (CMT) scores increased (>1) and remained high (143/150 samples) after challenge; polymorphonuclear neutrophils (PMN) predominated in milk films, but the proportion of lymphocytes and macrophages progressively increased. Increased pH values (>7·0) were recorded in the mammary secretion from the challenged side. Furthermore, content of fat, total proteins and lactose therein decreased markedly. Histological changes (leucocytic infiltration, destruction of epithelial cells) were observed in the mammary parenchyma of the ewes. The present results confirm that the reduction of milk constituents is the effect of cellular damage and can occur soon after infection.

We assessed the use of a microswitch cluster (i.e. a combination of two micro-switches) plus contingent stimulation for promoting adaptive responding and reducing aberrant behaviour in a woman with profound developmental disabilities. The woman was initially taught an adaptive hand response that activated a pressure microswitch and produced preferred stimuli. Subsequently, her hand response led to preferred stimuli only if it occurred free from face hiding (i.e. aberrant behaviour detected through a mercury microswitch). The study also included a 3-month post-intervention and generalization check, and a social validation assessment. Data showed that the woman increased her adaptive responding, learned to perform this responding largely free from aberrant behaviour, and maintained and generalized the new performance across settings. Forty-five psychology students provided positive social validation of the woman's new performance and the use of microswitch-cluster technology.