ABSTRACT. The knowledge of the parasites present in wild animals of especial area can give us an overview of the general state and conservation of these as well as the degree of alteration of the site where they are. The main of this research was to determine the winter prevalence and parasitic load in coyote feces of the Médanos de Samalayuca Protected Natural Area (PNA), Chihuahua, Mexico. The collection of feces was carried out in two areas of the PNA, area 1 with human intervention and area 2 less disturbed, 70 feces were collected throughout the winter 2018/19, they were analyzed by coproparasitoscopic techniques of Centrifuge-Flotation in NaCl, Formalin and egg count per gram in Mc Master chambers, to determine the mean parasitic intensity and the prevalence of parasites. The results were the following: the total prevalence was 70%, being the Toxocara genus the most prevalent and Entamoeba the least prevalent, the highest prevalence of parasites was recorded in area 2 being 93% and for area 1 of 53%. Parasitic genus Strongyloides 800hpg, Toxocara 535hpg, Physaloptera 200hpg, Taenia 200hpg, Ancylostoma 175hpg and Toxascaris 140hpg found no differences or trends between both areas.

RESUMEN. El conocimiento de los parásitos presentes en animales silvestres de un área determinada nos puede dar un panorama del estado general y conservación de éstos como también del grado de alteración del sitio donde se encuentran. Este trabajo tuvo como objetivo determinar la prevalencia y la carga parasitaria invernal en heces de coyotes del Área Natural Protegida (ANP) Médanos de Samalayuca, Chihuahua, México. La colecta de heces se realizó en dos áreas del ANP, el área 1 con intervención humana y el área 2 menos perturbada, se colectaron 70 heces a lo largo del invierno 2018/19, las mismas fueron analizadas por las técnicas coproparasitoscópicas de Centrifugo-Flotación en NaCl, Formalina y conteo de huevos por gramo en cámaras de Mc Master, para determinar la intensidad parasitaria media y la prevalencia de parásitos. Los resultados fueron los siguientes: la prevalencia total fue de 70%, siendo el género Toxocara el más prevalente y Entamoeba el menos prevalente, la mayor prevalencia de parásitos se registró en el área 2 siendo ésta del 93% y para el área 1 de 53%. Por Género parasitario Strongyloides 800hpg, Toxocara 535hpg, Physaloptera 200hpg, Taenia 200hpg, Ancylostoma 175hpg y Toxascaris 140hpg. No se encontró diferencias ni tendencias entre ambas áreas.

ABSTRACT Poultry farmers in the southeastern of Mexico consider that the productivity of the hens that comes from rearing on floor has a higher productive performance than reared hens in cages, mainly due to higher percentage of egg laying and lower mortality. The aim of this study was to evaluate the productive performance of the laying hen in relation to the type of rearing. A total of 79680 pullets Bovans White of 17 weeks of age were housed in cages with five pullets cage-1 (405 cm2pullet-1). They were divided in two treatments according to their type of rearing (floor vs cage) with four replicates. The study period was from week 20 to week 40 of age. The variables evaluated were daily (%) and cumulative mortality (%), egg production (%), egg weight (g), feed intake (g pullet d-1), cumulative feed intake (g pullet-1), daily and cumulative egg mass, number of eggs per hen housed, egg loss (%) and productivity index. The variables were analyzed using a randomized block design. It was observed that daily and cumulative mortality, feed intake and egg loss was higher (p< 0.05), while the number of eggs per hen housed and productivity index (p< 0.05) was lower for hens in cages. We conclude that it is possible to associate detriments in the productive performance of laying hens based on the type of housing during its growth phase.