Analysis of the influence of variation factors on electrical conductivity of milk in Murciano-Granadina goats

The aim of this study was to obtain further knowledge on electrical conductivity (EC) of milk as a tool for detecting mastitis in goats. The effect of farm, parity, stage of lactation, and health status of the glands on EC, and the somatic cell count (SCC) of milk was analyzed. Additionally, relationships between EC and chemical composition and SCC were studied. Finally, characteristics of EC and SCC (sensitivity and specificity) as diagnostic tests used to detect mastitis were studied. One hundred and five Murciano-Granadina goats were enrolled in the study. Milk samples (by gland) were collected monthly for 7 mo on 3 farms in the southeastern Spain. To establish the health status, milk samples were aseptically collected before milking by gland. Foremilk (by gland) was collected to analyze EC, SCC, and chemical composition. Glands were classified according to the health status as free of mastitis, bacterial mastitis, or unspecific mastitis. The effects of farm, parity, and stage of lactation, as well as the interactions between health status and parity, parity and stage of lactation, and health status and stage of lactation were associated with EC. Changes in the milk's chemical composition (particularly of chloride ions) explained most of the variance in EC (R(2)=0.91). The strongest association between EC and SCC was found at SCC >2×10(6) cells/mL (r=0.42). The use of a single EC threshold for all animals and farms for detecting mastitis led to limited results for mastitis detection, which, in any case, favors negative predictive values over positive predictive values. This study revealed that factors, other than the health status, affecting EC hamper the use of an EC threshold for mastitis detection with sufficient specificity on all animals. Any detection system based on EC of milk should consider these factors, as well as specific variations for each of the animals.

Construction documents

Contractors base their bids on construction documents and use them as their daily "nuts and bolts" guide in constructing the building. They are the owner's legal instrument to insure that the building they want is constructed as they intended. This article defines and examines the vital significance of construction documents. Of particular interest is the discussion of owner and architect responsibilities during the construction documents (CD) phase, contractual agreements on these responsibilities, and how to minimize potential problems.

Nalidixic acid: intrarenal distribution and its effect upon para-aminohippurate excretion

Studies performed on the intrarenal distribution of nalidixic acid in dogs show that this weak organic acid is indeed accumulated in the kidney, the highest concentration being attained in the cortex and followed in order by the outer medulla, papillae, and inner cortex. Our results also show that nalidixic acid produces significant changes in the para-aminohippuric concentration and on the filtered load, secretion and clearance of para-aminohippuric acid. Stop-flow experiments confirmed the inhibitory effect of nalidixic acid upon para-aminohippuric acid secretion. It is plausible that nalidixic acid may inhibit the secreted moiety of creatinine. This inhibitory effect is localized in the proximal tubule, where para-aminohippuric acid is known to be secreted. Based on our data it is suggested that nalidixic acid competes with para-aminohippuric acid for the same transport system or that the decreased secretory para-aminohippuric acid activity after nalidixic acid may be caused by a direct inhibition produced by the latter.