Relationship between selected indicators of milk and blood in sheep

Transmammary transfer of toxicity to nursing kids from Isocoma pluriflora (rayless goldenrod) dosed to lactating goats

Rayless goldenrod (RG; Isocoma pluriflora) poisons livestock in the southwestern U.S., west Texas, and northern Mexico. The putative toxin(s) have historically been thought to be benzofuran ketones. Goats have been used successfully as a model of RG poisoning. The transmammary transfer of toxicity to offspring from lactating goats has not been studied, thus the objective of this study was to determine if nursing kids would become poisoned via mother's milk when the dams were dosed with RG. Twelve lactating goats (6 controls and 6 treated; all with twin kids) were dosed via oral gavage with alfalfa or rayless goldenrod at 2% of BW per day for 14 days. Two kids showed overt clinical signs near the end of the study; however, no dams showed clinical signs, and none developed exercise intolerance or muscle weakness. After day 11 of treatment, the RG kids showed increased (P < 0.05) serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine kinase (CK) activities until exposure to the plant via mothers' milk ended. Serum CK activity of kids declined rapidly over 7 days after transmammary exposure ended. Histopathology revealed that one kid had extensive myonecrosis that involved both myocardium and skeletal muscles. The other kids from RG-treated does had minimal myocyte degeneration and necrosis characterized by individual myofiber swelling, hypereosinophilia and loss of striation. Benzofuran ketones were not detected in the milk of lactating goats; further, dosing with RG did not alter milk composition. In summary, milk ingestion from does dosed with >300 mg/kg BW of benzofuran ketones from RG over 14 days increased mean CK concentrations in treated kids compared to controls; however kids rapidly recovered when exposure ended. Additional work is needed to better define benzofuran ketone metabolism, toxicity, and animal susceptibility.

Milk composition of dromedary camels (Camelus dromedarius): nutritional effects and correlation to corresponding blood parameters

This study has been conducted in order to study the possible correlations between the nutritional value of plants selected by camels during the dry and green season and the corresponding blood and milk composition of the dromedary camels. The study has been conducted on 50 indigenous Arabian camels of different age and kept under natural range in Southern Darfur. The dromedary camels selected plants with significantly (p<0.05) higher crude protein content during the dry season and kept the serum albumin concentration and milk protein content at the same levels as those observed during the green season. However, the significantly (p<0.05) higher lipogenic content (ether extract + crude fiber) of the plant selected during the dry season resulted in significantly (p<0.05) higher serum triacylglycerides concentration and significantly (p<0.05) higher milk fat content compared to that of the green season. Although, the camels selected plants with significantly (p<0.05) higher nitrogen free extract content during the dry season, the plasma glucose level and the milk lactose content were significantly (p<0.05) reduced compared to that of the green season. The significantly (p<0.05) lower ach content of the plants selected during the dry season resulted in significantly lower serum calcium + phosphorus concentration, but did not reflect on the ash content of the milk. The results indicate that despite camels selectivity and unique adaptation to arid conditions, the milk lactose-and fat content were affected by the nutritional scarcity during the dry season. Therefore, it could be beneficial to provide energy-rich feed supplemented with calcium and phosphorus to camels kept under dry tropical conditions.

Evaluation of flow injection analysis for determination of urea in sheep's and cow's milk

Difficulties in measuring the urea content in sheep's milk often occur with spectral photometry due to the high protein and fat concentrations of the milk. In this study an enzymatic flow procedure (QuickChem 8000 Ion Analyser, Lachat Instruments, Milwaukee, USA) to determine the urea content in ovine and bovine milk was evaluated. Urea content is determined by the Berthelot reaction after splitting it enzymatically with urease. The free ammonia diffuses through a teflon membrane into a stream of reagent solutions. Detection takes place by means of a reaction between the ammonium ions with hypochlorite and salicylate producing a green colour, which is measured spectrometrically in a flow meter at 660 nm. By using a diffusion cell chemical deproteinisation of milk is not necessary and capacity is high. The assessed procedure exhibited high accuracy and precision and reached a sample capacity of 55 samples an hour. Storage of the milk samples for several days as well as chemical preservation with bronopol had no effect on the measurement procedure. Due to the complexity of the apparatus and the costs associated therewith, the device proves less suitable for routine diagnostics but rather serves as a reference method for the measurement of urea concentration in milk.

Effect of dietary energy and protein concentration on the concentration of milk urea nitrogen in dairy ewes

To study the effects of dietary crude protein (CP) and energy on milk urea N concentrations in dairy sheep, eight pelleted total mixed rations were prepared to obtain two levels of energy density (1.65 and 1.55 Mcal of net energy for lactation per kilogram of dry matter for high energy and low energy rations, respectively) and four concentrations of CP within each energy level (mean CP concentrations, 14.0, 16.4, 18.7, and 21.2% of dry matter). The experimental design consisted of two 4 x 4 Latin squares (one per energy level) with two replications per treatment within each 3-wk period. Milk urea N concentrations were similar between dietary energy levels. Within each energy level, milk urea N was linearly and positively associated with dietary CP content and intake (range of milk urea N concentrations, 12.2 to 25.8 mg/dl for ewes fed high energy rations and 12.9 to 26.7 mg/dl for ewes fed low energy rations). The comparison of these results with those from other trials suggested that milk and blood urea N concentrations are closely correlated with dietary CP concentrations and less closely correlated with dietary CP intake. Our results suggest that milk or blood urea N concentrations can be used as indicators of protein metabolism and intake of lactating ewes.