Ruminal escape and apparent degradation of amino acids administered intraruminally in mixtures to cows.

The apparent ruminal degradation and escape of amino acids (AA) administered in 9 different mixtures of essential AA and 8 different mixtures of nonessential AA were studied using two cows fitted with ruminal cannulas. The 600-mmol AA mixtures, which were administered intraruminally using polyethylene glycol as a liquid marker, contained equal amounts of two, four, or eight AA. The amounts of each of the AA in the mixtures were 300, 150, and 75 mmol, respectively.

Apparent ruminal degradation and rumen escape of lysine, methionine, and threonine administered intraruminally in mixtures to high-yielding cows.

We studied the kinetics of lysine, methionine, and threonine in six high-yielding dairy cows at peak lactation (stage 1) and 6 mo later (stage 2). The cows were fitted with cannulas in the rumen and duodenum and were automatically fed every 4th h. The three amino acids (AA) were administered intraruminally in mixtures at dosages of 100, 200, 300, and 400 mmol of each, together with polyethylene glycol (PEG) as a liquid marker.

Rumen escape and apparent degradation of amino acids after individual intraruminal administration to cows.

Apparent rumen degradation and escape of 18 amino acids (AA) after individual administration intraruminally were studied using two nonpregnant, nonlactating, rumen-cannulated cows fed a ration containing hay and concentrate twice daily. The pulse-dosages of AA were 75, 150, 300, and 600 mmol. Polyethylene glycol was used as the liquid marker.

Bilateral maxillectomy and midfacial reconstruction.

Extensive bilateral midfacial defects including the upper jaw, palate, and sinuses present a formidable reconstructive challenge. Prosthetic restorations require a solid anchor point to be successful, since orofacial motion would otherwise cause instability of the prosthesis. We report on a series of eight patients who underwent transmalar placement of a Steinmann pin at the time of definitive tumor resection.