Efficiency of Guelph's and S CK7 extenders for prolonged preservation of liquid boar semen M. PAQUIGNON, T. BUSSIÈRE, F. BARITEAU, G. LE MAIGNAN DE KERANGAT and M. COUROT Ann. Zootech., 29 2 (1980) 215-216 DOI: 10.1051/animres:19800223