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The objective of this study was to evaluate sexual behaviour and semen quality of St. Croix ram lambs bred in a semi-desert region. In Experiment 1, 24 yearling rams were assigned to two groups: T1 with 12 males confined for 11 months; T2 with 12 males confined individually for the same period of time. In Experiment 2, 20 four-month-old ram lambs were assigned to two groups of 10 animals each. In each experiment, sexual behaviour and semen quality were evaluated every 2 weeks over 11 months. In Experiment 1, rams that were individually confined showed better sexual activity than lambs confined together (P<0.05), whereas in Experiment 2 ram lambs confined individually only showed shorter time to first mount with ejaculation (P<0.05). In experiment 1, sperm with better progressive motility (P<0.05) was recorded per yearling ram confined individually (63.4±0.2%) in comparison with rams confined together (51.60.1%). In Experiment 2, ram lambs confined together showed better semen quality (P˂0.05). In both trials, an effect of the season was observed on both sexual behaviour and semen quality (P<0.05). In conclusion, this study of St. Croix males showed different sexual behaviours according to age and type of enclosure.

The objective was to determine the frequency of gastrointestinal parasites (GP) genera affecting water buffalo (Bubalus bubalis) reared under humid tropical conditions of Mexico. Three hundred eighty-three Munrah breed water buffalo were included, 251 adult females and 132 calves. Feces were directly collected form the rectum of the animals and processed by the McMaster technique. Coprocultures were made to identify the genera of the nematodes. The frequency of GP in B. bubalis was 42%, independently of their age, 60% of calves resulted parasitized. Age had a strong association with the presence of GP (Xi = 77.4014, d.f. = 1, p = 0.001). The family Trichostrongylidae was found in both age groups. The genera identified were Strongyloides sp. (47.2%), Cooperia sp. (33.9%), and Haemonchus sp. (10.4%), as well as Eimeria sp., Moniezia sp., Trichuris sp., and Strongyloides sp. The highest parasite burden corresponded to the genus Strongyloides sp. with 1108.9 EPG. There is a need to carry out further studies in order to know the prevalence and incidence of nematode affecting to B. bubalis as an introduced animal species to Mexican tropics.

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Relación de temperatura rectal y frecuencia respiratoria con temperaturas de pelo obtenidas por termografía en ovejas gestantes estresadas por calor Resumen El estudio tuvo como objetivo establecer la relación de temperatura rectal y frecuencia respiratoria con temperaturas de superficie del pelo (cabeza, espalda, ijar, cadera y vientre) obtenidas a través de imágenes termográficas en ovejas de pelo gestantes y estresadas por calor. Las variables se obtuvieron de 24 ovejas gestantes multíparas Katahdin x Pelibuey cada 15 días, dos veces por día (07:00 y 16:00 h), entre el día 100 de gestación y el parto. El análisis estadístico consideró correlación de Pearson y regresión lineal simple. La temperatura rectal (r = 0,66 a 0,74) y la frecuencia respiratoria (r = 0,60 a 0,66) correlacionaron positivamente (P < 0,0001) con las diferentes temperaturas de capa de pelo. Las ecuaciones desarrolladas con cada temperatura del pelo explicaron (P < 0,0001) entre 36 y 55% de la variación observada en la temperatura rectal y la frecuencia respiratoria. La temperatura de cabeza explicó la mayor variación (R 2 = 0,48 a 0,55) en ambas variables fisiológicas. Se concluye que las temperaturas de superficie del pelo tienen una relación moderadas con la temperatura rectal y la frecuencia respiratoria en ovejas de pelo gestantes mantenidas en hipertermia, asimismo, la temperatura de cabeza puede ser usada en el desarrollo de ecuaciones de predicción para ambas variables fisiológicas.Palabras clave: Hipertermia, ovinos de pelo, temperatura de cabeza, capa de pelo. AbstractRelationship of rectal temperature and respiratory frequency with hair coat temperatures obtained by thermography in heat-stressed pregnant ewes