Five multiparous, ruminally cannulated Holstein cows (two lactating and three dry) weighing (X +/- SD) 667 +/- 35 kg were used to study the effect of abomasal purine infusion on the excretion of purine derivatives. Cows were fed corn silage four times daily at 90% of ad libitum intake (X = 9.16 kg of dry matter/d). Purines were infused into the abomasum as brewer's yeast suspensions in five inc...

Two studies were conducted to assess whether routine applications of near infrared reflectance spectroscopy could predict the effects of silage proteolysis on ruminal crude protein (CP) degradation of legume and grass silages. A preliminary study was conducted to assess the effect of laboratory drying method on ruminal CP degradation of silages. Thirty legume and grass silages were freeze-, ove...

Recent surveys have identified the presence of perchlorate, a natural compound and environmental contaminant, in forages and dairy milk. The ingestion of perchlorate is of concern because of its ability to competitively inhibit iodide uptake by the thyroid and to impair synthesis of thyroid hormones. A recent study established that milk perchlorate concentrations in cattle highly correlate with...

Choline is usually supplemented as ruminally protected choline chloride to prevent its degradation in the rumen, but effects of unprotected on ruminal fermentation are unclear. Some research indicates a possible role dietary fiber microbial choline; therefore we aimed evaluate and investigate whether those depend neutral detergent (NDF) concentration. Our hypothesis was that NDF concentration w...

BACKGROUND Many different guidelines have been presented for the construction of multiple choice items. Those guidelines have been based on the observation of errors when constructing items but not on any clear scientific criterion. Our main objective was to draw up guidelines for the development of multiple choice items based on validity criteria. METHOD We used the properties of adjustment,...