Effect of different levels of dietary nitrogen supplementation on the relative blood urea nitrogen concentration of beef cows.

The objective of this study was to determine if individual beef cows in a herd have an inherent ability to maintain their blood urea nitrogen (BUN) concentration when exposed to different levels of dietary nitrogen supplementation. Ten Hereford and 12 Nguni cows, aged between 2 and 16 years, were utilized in two crossover experiments. In the first experiment, cows were exposed to two diets: a balanced diet with a crude protein (CP) level of 7.

Pre-breeding blood urea nitrogen concentration and reproductive performance of Bonsmara heifers within different management systems.

This study investigated the association between pre-breeding blood urea nitrogen (BUN) concentration and reproductive performance of beef heifers within different management systems in South Africa. Bonsmara heifers (n = 369) from five herds with different estimated levels of nitrogen intake during the month prior to the commencement of the breeding season were sampled in November and December 2010 to determine BUN concentrations. Body mass, age, body condition score (BCS) and reproductive tract score (RTS) were recorded at study enrolment.