1st Conference on Enhancement of Small Ruminant Productivity. Dokki, Giza, Egypt (7-9 February 2006) EFFECT OF β-CAROTENE ON SOMATIC CELL COUNT OF HALF UDDER IN DAIRY EWES C. Gonzalo 1 , B. Linage 1 , J. A. Carriedo 1 , M. A. Blanco 2 , and U. M. El-Saied 3 1 Dpt. Producción Animal, Universidad de León. 24071-León (Spain) 2 Consorcio de Promoción del Ovino, 49630-Villalpando, Zamora (Spain) 3 Cattle Breeding Res. Dep. Animal Prod. Res. Institute (APRI), Ministry of Agric. & Land Reclamation. Nadi El-Said St., Dokki, Giza (Egypt). INTRODUCTION In dairy ewes the effects of β-carotene on milk SCC are not known and the purpose of this paper was to study the effect of β-carotene on SCC of milk half udders and the duration of this effect throughout lactation in a flock with low SCC mean values. MATERIAL AND METHODS The study was carried out after weaning on a total of 90 Spanish Assaf dairy ewes (180 half-udders) randomly assigned to two lots: a) Treated lot with 45 ewes (90 half-udders), which were given at 75 d postpartum an intramuscular injection of 200 mg β-carotene (5 ml Dalmavital®, Fatro Uriach Veterinaria, Barcelona, Spain) administered as a single dose, and b) Untreated lot or control lot of 45 ewes (90 half-udders). Half udder foremilk (50 ml) of all the animals was sampled for SCC study at 75, 85, 95, 105, 115, 125, 135, and 150 d postpartum, just before the morning milking. SCC was determined by Fossomatic 5000 (A/SN Foss Electric, Hillerφd, Denmark). The statistical study was carried out using GLM proced. of SAS (1998). In the statistical model used, half udder effect was considered random and the other effects fixed: Y ijklm = µ + T i + P j + TP ij + H k(ij) + L l + TL il + bx ijklm + e ijklm Where: Yijklm = dependent variable logSCC, Ti = effect of treatment (two levels: β-carotene treated and untreated lot), Pj = effect of parity (two levels: primiparous and multiparous (second and later parities up to 5)), TPij = effect of treatment x parity interaction, Hk(ij) = random effect of half udder nested within treatment x parity, Ll = effect of lactation stage (divided into seven levels: 85, 95, 105, 115, 125, 135, and 150 d postpartum), C. Gonzalo et al. 1