PUBLISHING MEDWELL Journal of Animal and Veterinary Advances 8 (2): 208-212, 2009 ISSN: 1680-5593 © Medwell Journals, 2009 Corresponding Author: C. Lemus, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Nayarit, Tepic, Mexico 208 Studies on Growth of Pelón Mexicano Pigs: Effect of Rearing Conditions on Performance Traits M. Becerril, C. Lemus, J.G. Herrera, M. Huerta, M. Alonso-Spilsbury, 1 2 3 1 4 R. Ramírez-Necoechea, D. Mota-Rojas and J. Ly 4 4 5 Unidad Académica de Ingeniería Agrohidráulica, 1 Benemérita Universidad Autónoma de Puebla, Puebla, Mexico Facultad de Medicina Veterinaria y Zootecnia, 2 Universidad Autónoma de Nayarit, Tepic, Mexico Colegio de Postgraduados, Montecillo, km 36.5 Carretera México-Texcoco, 3 Estado de México 56230, Mexico Department of Producción Agrícola y Animal, 4 Universidad Autónoma Metropolitana, Xochimilco, D.F. México Instituto de Investigaciones Porcinas, Carretera del Guatao Km 1, Punta Brava. La Habana, Cuba 5 Abstract: A 2×2 factorial arrangement was used for evaluating performance traits during 16 weeks in 2 groups of 22 Yorkshire x Landrace (YL) and 13 Pelón Mexicano (PM) castrate male and female pigs 63 days old which were allotted at random into 2 rearing systems consisting of total (15 and 7 pigs) or partial confinement (7 and 6 pigs). Partial confinement included rearing animals outdoors in a grass prairie (Brachiaria brizantha) from 9:00-16:00 h. No significant differences (p<0.05) for the interaction rearing system x genotype were found in any measured performance trait. It was observed that treatments involving Yorkshire x Landrace animals had a high significant (p<0.001) live weight at any age, as compared to the PM pigs. It was evident that YL pigs had a higher daily feed intake than PM animals and on the other hand, results from animals in confinement clearly indicated that feed intake in those pigs was higher than in the others, permitted to graze during 8 h every day. Calculated daily gain was 820 and 757 g in YL pigs when reared in total confinement or partially outdoors, whereas this same trait was 414 and 335 g in PM pigs. When a comparison was made between improved and local pigs reared in total confinement, feed conversion was on average, 3.07 kg kgG in the YL animals and 1 5.03 kg kgG in the PM pigs. 1 Key words: Pigs, Pelón Mexicano, performance traits, rearing systems INTRODUCTION In fact, the hairless, Pelón Mexicano pig offers indeed Local pigs in Mexico are known as Pelón Mexicano (PM) or Mexican hairless and Cuino pigs. It has been said that these animals are not good for marketing, since they have a market price very low, due to the fact that they show a high backfat thickness, which has to be discounted from the original price, which accounts for some 30-40% of lowering of its original monetary value (López et al., 1999; Lemus and Alonso, 2005; Méndez et al., 2002; Lemus et al., 2003), even though it has been shown that human consumption of this type of fatty meat does not imply any harmful consequence, since its composition in unsaturated fatty acid is high (Pérez et al., 1999a, b). several advantages for rearing from the point of view of management and feeding, since this type of animal can be fed on forage, fruits, roots, tubers, crop residues and kitchen wastes generated from the family which keep them. Furthermore, neither special housing nor sophisticated management is required by the Pelón Mexicano pig, which in turn allows the exploitation of these animals under a low input system. Besides, the Pelón Mexicano pig is a productive alternative, because meat sausage and products elaborated from meat of these animals are of better quality, appearance and taste than those from improved breeds. The objective of the current investigation was to define the influence of the rearing regime on performance traits of growing Pelón Mexicano pigs as compared to an improved pig breed.