Feed utilization of beef steers fed grass as hay or silage with or without nitrogen supplementation.

Six Hereford steers averaging 256 kg were used in a 2 x 3 factorial arrangement within a 6 x 6 Latin square design to study the effect of forage conservation (silage vs hay) and N supplementation (0, 200 g of fish meal plus 43 g of urea, or 400 g of fish meal) on ruminal characteristics, digestibility, blood urea, and in situ degradability of DM, N, and ADF. Dry matter intake of forage and total DMI did not differ among treatments (P greater than .05) and averaged 5.

Source and feeding level of nitrogen on growth and carcass characteristics of beef steers fed grass as hay or silage.

Sixty medium-framed Hereford steers averaging 243 kg were used in an experiment including a growing period (28 wk) and a finishing period ending when the animals had approximately 4 to 10 mm of fat thickness (Canadian grade A1). Steers were assigned randomly to a 2 x 3 factorial arrangement of treatments for 28 wk (growing period). From the end of the growing period until slaughter, all steers received the same diet to study the residual effect of treatments fed during growth.

[The influence of previous infections on the development of experimental swine pleuropneumonia in specific pathogen free pigs].

This study was designed to determine in six-week old specific pathogen free pigs, the effect of previous experimental exposure to Mycoplasma hyopneumoniae and transmissible gastroenteritis virus on a challenge infection with Actinobacillus pleuropneumoniae. Pigs exposed simultaneously to M. hyopneumoniae and transmissible gastroenteritis virus appeared more resistant to challenge (one week later) with A.

Enzootic pneumonia in feeder pigs: Observations on causal factors.

A number of factors were studied in eight feeder pig herds, affected with severe or mild enzootic pneumonia, in order to identify those associated with this disease. Piggeries with poor facilities and management and where procurement of piglets was from sales barns were more severely affected with enzootic pneumonia than were those with good facilities and where pigs originated directly from breeding units. Serological tests and virus isolation revealed that all herds had been exposed to Mycoplasma hyopneumoniae and to many viruses; transmissible gastroenteritis virus infection was the only viral infection that was apparently associated with the severity of enzootic pneumonia and the performance observed in the herds.

Effect of peripartum energy concentration on production performance of Holstein cows.

Ninety multiparous Holstein cows were used to measure the effect of energy during the prepartum and postpartum periods. During the prepartum period (63 d) half of the cows were fed grass silage ad libitum and a concentrate (16% protein) was offered daily at .25% of BW.