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Extracts of ovine squamous-cell carcinoma (OSCC) prepared by different procedures, were injected at varying concentrations into 184 tumour-bearing sheep. At a total protein of 0.5 mg and greater, there was significant enhancement and metastasis in all 120 sheep examined. Extracts of OSCC containing less than 0.5 mg protein, or of human squamous-cell carcinoma and normal sheep skin containing high levels of protein, had no effect on subsequent tumour development. Extracts of foetal sheep skin at the 3mg-protein level produced significant enhancement and metastasis. The degree of enhancement was inversely proportional to the developmental stage of the tumour at the time of treatment. Images Fig. 6 Fig. 7 Fig. 8

Environmental heat stress in tropical sheep suppressed lamb birth weight, but the animals which did not experience hyperthermia under natural environmental conditions gave birth to significantly heavicr (P

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 � 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.