
%0 Journal Article
%A Stephenson, RGA 
%A Edwards, JC 
%A Hopkins, PS 
%T The use of urea to improve milk yields and lamb survival of Merinos in a dry tropical environment
%J Australian Journal of Agricultural Research
%D 1981/06/01
%V 32
%N 3
%P 497-509
%K 
%R https://doi.org/10.1071/AR9810497
%U https://www.publish.csiro.au/paper/AR9810497 
%X Urea supplementation of lambing Merino ewes increased milk yield and lamb growth and survival rates in both pen and paddock studies. These productivity gains occurred in a semi-arid environment characterized by poor reproductive efficiency in Merinos. In pens, urea supplenlents fed to lactating ewes at the rate of c. 12 g/day stimulated intake of poor quality pasture hay (0.9 %nitrogen) by c. 30% and increased total nitrogen intake by c. 100%. Milk yield was improved by c. 50% and lamb growth rate by c. 140%. Sorghum grain supplements stimulated milk yield and lamb growth to a lesser extent than urea. The correlations found in pen studies between nitrogen intake and milk yield of ewes (r ÿ 0.85; P < 0.05), and between ewe milk yield and lamb growth (r % 0.80; P < 0.01), prompted further investigations under paddock conditions. Ewes grazing dry pastures and supplemented with urea (8-10 glday) via drinking water yielded more milk (11-32%) than unsupplemented counterparts. Similarly, there were improvements in lamb growth (80-100%) and survival (c. 10%) in the supplemented groups. 
