Plasmatic urea levels influence on citogenetic parameters of wool-less rams

Abstract

The experiment was planned to verify the effects of increasing blood urea levels resulting from increasing urea in the diet on cytogenetic parameters of Santa Ines Brazilian breed rams (Ovis aries), aged 13 to 18 months. Eighteen animals were divided into three experimental treatments consisted of: diet A ration with nitrogen levels, according to NRC (1985); diet B - ration with a 133% higher level of nitrogen than diet A; and C- ration with a 166% higher level of nitrogen than diet A. The increase in nitrogen level was obtained by adding 20, 40 g of feed grade urea in treatments B and C, respectively. Blood was collected on a weekly basis to determine urea concentration. Blood was also collected from each animal, 60 days after desired diet urea levels were reached, to obtain a lymphocyte culture in order to count chromosome number and determine mitotic index. Increases in plasma urea level were observed (p < 0.0001), but did not affect the observed traits.