Urea Utilization by Lactating Cows

Effects of Grain Variability and Processing on Starch Utilization by Lactating Cows

One of the fundamental principles of dairy nutrition is the need to formulate rations to maximize energy intake for high producing cows. We have improved our ability to predict dry matter intake (DMI) and can formulate rations for increasingly precise fractions of carbohydrate, but a major limitation to the science of carbohydrate allocation continues to be the unaccounted variability in starch...

Effect of Steam Heating Alfalfa Hay on Utilization by Lactating Dairy Cows

Alfalfa hay was steam heated for an average of 47 min at 100 to 110°C; net ruminal protein escape (total escape minus ADIN x 6.25), estimated in vitro, was 50% versus 29% for control hay. Heating increased ADIN content from 4.6 to 15.3% of total N and increased NDF from 43 to 53% of DM. In trial 1, 14 cows averaging 81 DIM and 30 kg/d of milk were fed, in a switchback design, diets containing 1...

Influence of mechanical processing on utilization of corn silage by lactating dairy cows.

We conducted three experiments to determine the influence of mechanical processing on corn silage utilization by lactating dairy cows. Total mixed rations contained either unprocessed or processed corn silage harvested between 1/4 and 3/4 milk line. In trial 1, 12 multiparous Holstein cows were used in a replicated double switchback design with 21-d periods. Intake of dry matter (DM) was increa...

Evaluation of Urinary Nitrogen Excretion from Plasma Urea Nitrogen in Dry and Lactating Cows

Data of 42 balance measurements from dry and lactating Holstein cows and blood and urine samples from 24 Japanese Black cows were collected to evaluate the potential for predicting urinary nitrogen (N) excretion from plasma urea nitrogen (PUN). Similar positive correlations were obtained between N intake and apparent N absorption in dry and lactating cows. The regression equations of N intake o...

Estrous Synchronization in Lactating Cows