Resumen El objetivo fue identificar la especie, prevalencia, manifestaciones clínicas y evaluar la eficacia de dos tratamientos para el control de piojos en búfalos de agua del trópico de México. Se realizó un estudio observacional descriptivo prospectivo, con visitas semanales a un rancho de búfalos durante dos meses. Se inspeccionaron 300 búfalas, para conocer la prevalencia y especie de piojo, adicionalmente en dos grupos de 20 búfalos se describieron lesiones en piel y el nivel de infestación. En dos grupos de 10 animales se aplicaron los tratamientos: 1) cipermetrina (15%) + diclorvos (30%) por aspersión y 2) ivermectina 1% vía subcutánea (0.2 mg/kg1 de pv). Se determinó que la prevalencia de la infestación fue del 100% en el hato y se identificó al piojo como Haematopinus tuberculatus. Las infestaciones por piojos adultos fueron bajas en el 60% de las búfalas y del 95% en los bucerros. La eficacia de los insecticidas fue de 80% en búfalas y 100% en bucerros.

Abstract The objective was to identify the species, prevalence, clinical manifestations and two treatments to control an outbreak of lice in water buffalo in the tropics of Mexico. A prospective descriptive observational study was carried out, with weekly visits for two months to a buffalo farm. A total of 300 female buffaloes were inspected to determine the prevalence and species of louse. The level of infestation by adult lice and skin lesions (n = 40) were determined, and two treatments were applied in two groups (n = 10), cypermethrin (15%) + dichlorvos (30%) was applied by spray and ivermectin 1% subcutaneous route (0.2 mg/kg1 of bw). The prevalence of the infestation was 100%, the louse was identified as Haematopinus tuberculatus. Adult lice infestations were low in 60% of buffaloes and 95% in calves. The efficacy of the insecticides was 80% in buffaloes and 100% in calves.

Resumen El objetivo fue realizar una evaluación económica de la eficiencia reproductiva y productiva en unidades de producción (UP) con bovinos criollos de Nunkiní en Campeche, México. Se evaluó en 10 UP la tasa de gestación, intervalo interparto, natalidad, becerros destetados, ingresos y rentabilidad. Las UP mostraron baja eficiencia reproductiva (tasa de gestación de 41.0% ± 1.95%), elevado intervalo interparto (577.0 d ± 3.64 d), bajos índices de natalidad (37.7% ± 2.03%), becerros destetados (75.40% ± 39.30%), ingresos de USD 1359.17 (p > 0.05), y una estructura de costos fijos y variables de USD 850.57 y USD 1750.58. Las secciones con mayor impacto en los costos fueron la alimentación (34.14%) y mano de obra (30.38%), los cuales afectaron de manera negativa la rentabilidad (-48.28%). En conclusión, las UP evaluadas presentaron una baja rentabilidad como consecuencia de la baja eficiencia reproductiva y productiva del pie de cría.

Abstract The objective was to carry out an economic evaluation of reproductive and productive efficiency in production units (PU) with creole cattle from Nunkiní in Campeche, Mexico. The pregnancy rate, calving interval, birth rate, weaned calves, income, and profitability were evaluated in 10 PU. The PU showed low reproductive efficiency (pregnancy rate of 41.0% ± 1.95%), high intercalving interval (577.0 d ± 3.64 d), low birth rates (37.7% ± 2.03%), weaned calves (75.40% ± 39.30%), income of USD 1359.17 (p > 0.05), and a structure of fixed and variable costs of USD 850.57 and USD 1750.58. The sections with the greatest impact on costs were food (34.14%) and labor (30.38%), which negatively affected profitability (-48.28%). In conclusion, the evaluated PU presented low profitability because of the low reproductive and productive efficiency of the breeding stock.

Abstract In order to carry out a technological characterization of the productive system with criollo cattle from Nunkini in Campeche, Mexico, 10 production units (PU) were evaluated. Their technological level (TL) was determined based on their technical-productive variables and it was classified as low (50%), medium (30%), or high (20%). Producers’ average age, education, and experience (years) was 62.3±3.2, 7.3±0.9, and 25.2±5.4, respectively (p < 0.05). The average age and weight at first estrus in females was 30.9±4.9 months and 276.5 kg±17.3 kg, respectively (p < 0.05). The average age and weight at first service was 36.9±5.7 months and 306.0 kg±28.8 kg, respectively (p < 0.05). The average of open days and calving interval was 205.0±38.1 days and 15.9±1.3 months, respectively (p < 0.05). The productive parameters varied according to the TL of the PU. This criollo breed is rustic and precocious. The Nunkini criollo cattle nucleus is in risk of extinction.

Resumen Con el objetivo de realizar una caracterización tecnológica del sistema productivo con bovinos criollos de Nunkiní en Campeche, México, se evaluaron diez unidades de producción (UP). Su nivel tecnológico (NT) se determinó con base en sus variables técnico-productivas y se clasificó como bajo (50%), medio (30%) o alto (20%). La edad, escolaridad y experiencia (años) promedio de los productores fue 62.3±3.2, 7.3±0.9 y 25.2±5.4, respectivamente (p < 0.05). El promedio de edad y peso al primer estro de las hembras bovinas fue 30.9±4.9 meses y 276.5 kg±17.3 kg, respectivamente (p < 0.05). El promedio de edad y peso al primer servicio fue 36.9±5.7 meses y 306.0 kg±28.8 kg, respectivamente (p < 0.05). El promedio de días abiertos y periodo interparto fue 205.0±38.1 días y 15.9±1.3 meses, respectivamente (p < 0.05). Los parámetros productivos variaron según el NT de la UP. Se observa rusticidad y precocidad en la raza. El núcleo criollo de Nunkiní se encuentra en peligro de extinción.

Abstract Preweaning growth of lambs and ewe productivity are vital indicators of sheep production system success. An evaluation was done of the effects of birth season and year, birth type, sex and parturition number on preweaning growth and ewe productivity in Pelibuey sheep in a semi-extensive system in the humid tropics of Mexico. Data were from the production records of 323 ewes over a 7-yr period (2011-2017). Birth weight (BW), weaning weight (WW, at 60 d) and litter weight at weaning (LWW) were evaluated. Other evaluated factors included ewe prolificacy, preweaning mortality and lamb weight per ewe in a 240-d cycle (LW240d). All the factors affected (P≤0.05) the response variables. Lambs from multiple births had lower (P<0.05) BW and WW, but higher (P<0.05) LWW, LW240d, and mortality than lambs from single births. Lambs born in the dry season had higher (P<0.05) BW and WW, and ewes had higher LWW and LW240d, than in other seasons. Compared to multiparous ewes (≥3 parturition), primiparous ewes had lighter lambs (P<0.05) at birth and weaning, as well as lower (P<0.05) prolificacy, LWW and LW240d. Birth year affected (P<0.05) BW, WW, mortality and productivity characteristics. Preweaning growth performance was best in lambs born from multiparous sheep with a single parturition in the dry season. However, ewe productivity was highest in the dry season in multiparous ewes with two parturitions a year.

Resumen El objetivo fue evaluar los efectos de época y año de nacimiento, tipo de parto, sexo y número de parto sobre el crecimiento predestete y la productividad de las ovejas en ovinos de raza Pelibuey que producen bajo un sistema semi-extensivo en el trópico húmedo de México. Se usaron datos de 323 ovejas Pelibuey a partir de registros de producción de 2011-2017. Se evaluaron los pesos al nacimiento (PN) y al destete (PD, a 60 d), así como los pesos de camada al destete (PCD). Adicionalmente, se evaluó prolificidad, mortalidad hasta el destete y kilos de cordero producido por oveja en un ciclo de 240 días (PC240d). Todos los factores afectaron (P≤0.05) las variables de respuesta. Los corderos procedentes de partos múltiples tuvieron menor (P<0.05) PN y PD, pero mayor (P<0.05) PCD, PC240d y mortalidad que los corderos procedentes de partos simples. Los corderos nacidos en época de seca tuvieron mayores (P<0.05) PN y PD, mientras que las ovejas tuvieron mayores PCD y PC240d, comparado con otras épocas del año. Las ovejas primíparas tuvieron corderos más livianos (P<0.05) al nacimiento y al destete, así como menor (P<0.05) prolificidad, PCD y PC240d que las ovejas multíparas (≥3 partos). El año de nacimiento afectó (P<0.05) PN, PD, tasa de mortalidad y características de productividad. En conclusión, se observó un mejor desempeño en el crecimiento predestete para corderos Pelibuey nacidos de ovejas multíparas y con parto simple en la época de seca. Sin embargo, la productividad de la oveja fue mejor con la presencia de partos dobles, en tiempo de sequía, y con el aumento en número de partos.

Abstract This study aimed to determine the frequency for the seizure of livers with damages attributed to the presence of Fasciola sp. and associated risk factors. It was conducted a prospective observational study with daily visits, for 12 months, to a municipal slaughterhouse in the Sierra area in the state of Tabasco. Of the seized livers, 25.8 % tested positive for the parasite presence; seizure was the same in male and female animals (X2= 0.011, gl= 1, P<0.05). The highest proportion of seized livers was observed during the rainy season (9.36 %). This study concludes that the prevalence of fascioliasis in the Jalapa area has not decreased in recent years and is related to animal origin. Fascioliasis is a disease that must be monitored to detect the factors that allow it to remain in a geographic region, in order to establish and propose strategic control and preventive measures adapted to the particular conditions of endemic areas.

Resumen El objetivo fue determinar la frecuencia por decomiso de hígados con daños atribuidos a la presencia de Fasciola sp y los factores de riesgo asociados. Se realizó un estudio prospectivo observacional en el que se efectuaron visitas diarias durante un periodo de 12 meses, a un rastro municipal en la zona Sierra del estado de Tabasco. El 25.8 % de los hígados fueron positivos a la presencia del parásito, siendo el decomiso por sexo igual para machos y hembras (X2 = 0.011, gl= 1, P<0.05). La mayor proporción de decomiso, se concentró en la época de lluvias (9.36 %). Se concluye que la prevalencia de la fasciolosis en la zona de Jalapa no ha disminuido en los últimos años y está relacionada con el origen del animal. La fasciolosis es una enfermedad que debe ser monitoreada para detectar los factores que permiten su permanencia en una región geográfica, con el fin de poder establecer y plantear medidas estratégicas de control y de prevención adaptadas a las condiciones particulares de las zonas endémicas.

Abstract The objective was to determine the effect of some factors on pregnancy rate of fixed-time embryo transfer (FTET), in cows and heifers kept under Mexican tropical conditions. Recipients females (n=405) grazing in pastures were selected according to breed group (Zebu and crosses), parity (nulliparous and multiparous), body condition score (BCS) and the presence of a corpus luteum (CL). The females were synchronized on day 0 using a progesterone vaginal device and 2 mg estradiol benzoate (EB), two groups were established. Group 1 (conventional protocol) were animals in which the progesterone device was removed on day 7. At this time, also received an injection of 50 mg cloprostenol sodium and 1 mg estradiol cypionate. Animals also received 300 IU (heifers) or 360 IU (cows) of eCG. Group 2 (J-Synch protocol) were animals in which the progesterone device was removed on day 6. Cloprotenol and eCG injections were applied as in Group 1. Additionally, on day 9, animals of group 2 received 0.01 mg buserelin acetate. Embryo transfer of in vivo or in vitro was done on day 16 and pregnancy diagnosis was realized by ultrasonography on days 23 and 53 after FTET. Statistical analyses were carried out using Chi-square tests and logistic regression. Pregnancy rate varied between farms (P<0.05). The highest pregnancy rate was for multiparous cows (66%). The recipient utilization rate was better in the J-Synch protocol (85%), and in vivo embryos (75%) had higher pregnancy rate. The diameter of the follicle and the CL had no effect on pregnancy rate (P>0.05). However, the logistic regression determined that the only significant factor on pregnancy rate was the type of embryo. In conclusion, pregnancy rate in FTET females was higher for in vivo embryos than for in vitro embryos in cows evaluated under humid tropical conditions in Mexico.

Resumo Fungos nematófagos das fezes de búfalo de água e do solo no sudeste do México foram isolados, e a atividade predatória in vitro contra larvas infectantes de Haemonchus contortus (L3) (HcL3) foi avaliada.Os fungos foram isolados por aspersão de solo e de fezes em placas de agar água. Foram preparadas seis séries de 10 placas de Petri contendo uma cultura de 7 dias de idade de cada fungo e uma série sem fungos como controle. Quinhentos HcL3 foram adicionadas a cada placa. As placas foram incubadas à temperatura ambiente. O número médio de HcL3 recuperadas foi considerado para estimar a taxa de redução larval. Quatro isolados de fungos nematófagos corresponderam a Arthrobotrys oligospora, var microspora (estirpes 4-276, 269 e 50-80) e um isolado identificado como A. oligospora, var. oligospora (isolados 48-80 de fezes de búfalo de água. Do solo, dos cinco isolados três corresponderam a A. musiformis (Bajío, Yumca e Macuspana isolados), e dois isolados foram identificados como A. oligospora (isolados de Comalcalco e Jalapa de Méndez). A atividade predatória de isolados de fezes de búfalo de água variou entre 85,9 e 100%. Enquanto isso, os fungos do solo variaram entre 55,5 e 100% (p≤0,05). Os fungos nematófagos obtidos podem ter importantes implicações nesse controle de parasitos de importância na indústria pecuária.

Abstract Nematophagous fungi from the feces of water buffalo and soil from southeastern Mexico were isolated, and their in vitro predatory activity against Haemonchus contortus infective larvae (L3) (HcL3) was assessed. The fungi were isolated by sprinkling soil or feces on water agar plates. Six series of 10 Petri dishes containing a 7-day-old culture of each fungus and a series without fungi as the control were prepared. Five hundred HcL3 were added to each plate. The plates were incubated at room temperature. The average of recovered HcL3 was considered to estimate the larval reduction rate. Four nematophagous fungi isolates corresponding to Arthrobotrys oligospora, var microspora (strains 4-276, 269 and 50-80) and one identified as A. oligospora,var. oligospora (isolates 48-80) were obtained from water buffalo feces. From the soil, five isolates were isolated; three corresponded to A. musiformis (Bajío, Yumca and Macuspana isolates), and two isolates were identified as A. oligospora (Comalcalco and Jalapa de Méndez isolates). The predatory activity of isolates from water buffalo feces ranged between 85.9 and 100%. Meanwhile, the fungi from the soil ranged between 55.5 and 100% (p≤0.05). The nematophagous fungi obtained could have important implications in the control of parasites of importance in the livestock industry.

ABSTRACT We evaluated the effect of some environmental factors on age at first lambing (AFL) and lambing to conception interval (LCI) of Pelibuey ewes under the humid tropical conditions of Mexico. Ewes grazed on Tanzania (Panicum maximum), Bermuda (Cynodon dactylon), and Brachiaria grass (Brachiaria humidicola) and received hay in the corral in the months of grass scarcity. Reproduction was continuous during the year. Data of 839 lambings from 334 ewes registered from 2009 to 2017 were analyzed using survival analysis procedures. The statistical model for AFL included the effects of year, season, and litter size at lambing, whereas that for LCI included year and season plus parity number of ewe and litter size at weaning. The overall means ± SD for AFL and LCI were 551.6±144.8 and 145.4±113.1 days, and their medians were 510 and 98 days, respectively. Only year of lambing had a significant effect on AFL, whereas LCI was affected by year, parity number, and litter size at lambing (P<0.05). Both AFL and LCI means did not show any trend with advancing years. The largest AFL and LCI means and medians corresponded to the first-parity ewes. In addition, single birth ewes had the longest LCI means and median. Therefore, year of lambing affects AFL, whereas year of lambing, parity number, and litter size at weaning affect LCI of Pelibuey ewes, indicating that these factors should be considered in the development of sound strategies to improve sheep production.

Resumo O objetivo geral deste estudo foi estimar a prevalência de parasitas gastrointestinais (GI) em cães na cidade de Vilhahermosa, em Tabasco, México. A população estudada consistiu de 302 cães com donos, com acesso limitado a áreas públicas. Uma amostra fecal de cada animal foi coletada e examinada para parasitas GI por análise macroscópica convencional e centrífugo-flutuação. Amostras fecais de 80 (26,5%) cães apresentaram parasitas GI. Destes, 58 (19,2%) foram positivos para helmintos e 22 (7,3%) foram positivos para protozoários. Pelo menos 7 espécies parasitas foram identificadas. O parasita mais comum foi Ancylostoma caninum, detectado em 48 (15,9%) cães. Outros parasitas detectados em diversas ocasiões foram Cystoisospora spp. (n = 19), Toxocara canis (n = 7) e Giardia spp. (n=3). Adicionalmente, três parasitas foram detectados em apenas um cão – Dipylidium caninum, Trichuris vulpis e Uncinaria spp. Nenhuma infecção mista foi observada. Em resumo, nós identificamos neste trabalho uma prevalência moderadamente alta de parasitas GI em cães com donos, em Villahermosa, Tabasco. Várias espécies de parasitas identificados são reconhecidamente patógenos zoonóticos, o que indica a necessidade de monitorar rotineiramente e tratar infecções parasitárias em cães que vivem em proximidade a populações humanas.

Abstract The overall goal of this study was to estimate the prevalence of gastrointestinal (GI) parasites in dogs in the city of Villahermosa in Tabasco, Mexico. The study population consisted of 302 owned dogs that had limited access to public areas. A fecal sample was collected from each animal and examined for GI parasites by conventional macroscopic analysis and centrifugal flotation. Fecal samples from 80 (26.5%) dogs contained GI parasites. Of these, 58 (19.2%) were positive for helminths and 22 (7.3%) were positive for protozoan parasites. At least seven parasitic species were identified. The most common parasite was Ancylostoma caninum which was detected in 48 (15.9%) dogs. Other parasites detected on multiple occasions were Cystoisospora spp. (n = 19), Toxocara canis (n = 7) and Giardia spp. (n = 3). Three additional parasites, Dipylidium caninum, Trichuris vulpis and Uncinaria spp., were each detected in a single dog. No mixed parasitic infections were identified. In summary, we report a moderately high prevalence of GI parasites in owned dogs in Villahermosa, Tabasco. Several parasitic species identified in this study are recognized zoonotic pathogens which illustrates the important need to routinely monitor and treat dogs that live in close proximity to humans for parasitic infections.