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La mosca de los cuernos Haematobia irritans es un ectoparásito hematófago cosmopolita de gran importancia en la ganadería. En México, H. irritans se distribuye por todo el país y se encuentra durante todo el año. La fluctuación de la población de H. irritans está relacionada con las condiciones climáticas. A pesar de su amplia distribución, los efectos sobre la salud animal y su impacto negativo en la producción de carne y leche, existen pocos datos sobre su infestación y su epidemiología es limitada. Este trabajo es una revisión sobre la situación actual de H. irritans en bovinos en México, su impacto económico, métodos de control, perspectivas y oportunidades de investigación.

Neospora spp. es un parásito protozoario causante de abortos y enfermedad del Sistema Nervioso Central (SNC) en diversas especies domésticas y silvestres. En equinos, se le ha involucrado como causa de aborto, mortalidad neonatal y enfermedades del SNC. La especie identificada en equinos es distinta a Neospora caninum y se denomina Neospora hughesi. El objetivo del presente, fue detectar la presencia de anticuerpos anti-Neospora spp., asociados a factores de riesgo en caballos de México. Se realizó una encuesta de cada cuadra y animales individuales de cuatro regiones del país (Centro, Norte, Occidente y Sur) para identificación de los factores de riesgo. Se obtuvo un total de 684 muestras de sueros de caballos de las diferentes regiones, 52.3 % (358) machos y 47.7 % (326) hembras. Los sueros fueron conservados a -20 °C. El diagnóstico se realizó mediante la técnica de inmunofluorescencia indirecta (IFI), los resultados de este fueron analizados para estimar la asociación entre la seropositividad y los factores de riesgo. La seroprevalencia a Neospora spp. fue de 2.34 % en la población estudiada; los casos positivos se encontraron principalmente en tres de las cuatro regiones incluidas, que presentaron una relación significativa a la presencia de anticuerpos anti-Neospora spp.; la convivencia de los caballos con otros animales obtuvo un valor de OR de 2.34 (IC 95%: 0.28 - 19.0; P

La contaminación de productos agrícolas y pecuarios con aflatoxinas (AF) está distribuida mundialmente. Las AF son tóxicas, inmunodepresoras y carcinogénicas, pero en México es escasa la información sobre Aspergillus flavus, principal hongo que las produce. El objetivo fue caracterizar morfológica, molecular y aflatoxigénicamente aislados de A. flavus y cuantificar AF en pienso y en leche de vacas Holstein en Aguascalientes (México). Se seleccionó por conveniencia una unidad de producción lechera (2,749 vacas) y se recolectaron muestras mensuales (24 meses) de ingredientes alimenticios y ración total mezclada (n= 267), leche cruda (n= 288) y suelo agrícola (n= 40), las cuales se cultivaron (PDA) mediante vaciado en placa con diluciones seriadas. Los hongos se caracterizaron mediante MEB, TLC y vapores de amonio en agar coco; se secuenciaron los genes de calmodulina y regulador de la ruta biosintética de AF, así como la región de los espaciadores internos de la transcripción. Se cuantificaron AF en pienso con HPLC y en leche con ELISA. Se caracterizaron molecularmente 283 aislados fúngicos; 88 resultaron ser Aspergillus spp, de los que 5 fueron A. flavus con capacidad aflatoxigénica y uno no aflatoxigénico. El 99.3 % de las muestras de alimento y 39.9 % de las muestras de leche presentaron niveles detectables de AF (14.8 y 0.021 µg/kg). Las vacas ingirieron diariamente 621 µg de AF y eliminaron el 0.09 % como aflatoxina M1 en leche. Lo anterior sugiere que la ocurrencia A. flavus aflatoxigénico en el alimento de vacas lecheras conduce a una amplia contaminación por AF de las dietas y de la cadena alimenticia.

The objectives of the study were to estimate the prevalence of anti-Toxoplasma gondii antibodies in free-range chickens in Aguascalientes, Mexico, its association with certain risk factors, and the frequency of parasite DNA in the heart. Eighty-one small rural family farms were included, and blood and heart samples were taken from 150 clinically healthy, adult, free-range chickens. Serum samples were processed by indirect immunofluorescence antibody test considering a dilution of 1:16 as a positive reaction, while the DNA detection was done by PCR. The correlation between the presence of antibodies and the potential risk factors was estimated with logistic regression. The overall seroprevalence in the examined populations was 67%, with a range from 33% to 100% among municipalities, and 78% of the farms having at least one seropositive bird. The PCR test identified the presence of parasite DNA for one case only. Among the variables, the presence of cats and the presence of other animal species on the farm were the ones that had the highest values, while the presence of feral cats and the presence of noxious fauna were also identified as potential risk factors. The results indicate high soil contamination by T. gondii oocysts, which implies the active role of cats living on the farms.

Ecological degradation on Marine Protected Areas (MPAs) still occur as a result of anthropogenic pressure and environmental variation. Considering that protected areas can be restrictive to human activities, it is essential to assess their effectiveness. In this study, we evaluated the spatial and temporal effects of management on the seascape of the Cozumel Reefs National Park (CRNP) in the Mexican Caribbean. Quantitative estimates of the percentage of coverage of benthic substrates, and the location of coral reefs, were used to construct benthic habitat maps based on the supervised classifications of high resolution satellite images. Using spatially explicit analyses, the variation of seascape metrics for the period 2004–2015, was compared between two adjacent areas (inside and outside the protected area). Habitat β-diversity and connectivity between the Marine Protected Area (MPA) and the adjacent uncontrolled area, suggest that the CRNP is having an effect over time on the coral reef seascape (p

The objective of the present study was to investigate the epidemiology of natural infection by N. caninum in free-range chickens from Aguascalientes, Mexico, through identifying the presence of antibodies, its association with certain risk factors, and estimate the frequency of parasite DNA detection in the brain. The study included 150 clinically healthy chickens from 81 small family farms distributed throughout the state, from which blood and brain samples were taken. Serum samples were processed by indirect immunofluorescence considering a dilution of 1:50 as a positive reaction, while the DNA detection was done by PCR; the association between the presence of antibodies and the potential risk factors was estimated through logistic regression. The general anti-N. caninum presence of antibodies in the studied population was 46% (69/150, CI 95% 38–54), with titers of 1:50 in 38, 1:100 in 24, and 1:200 in 7, finding positive cases in 49% of the farms and in 91% of the municipalities that integrate the state. The presence of antibodies found in the municipalities was estimated in a range of 20 to 75%. The frequency of DNA detection was 6% (9/150, CI 95% 2–11). The grain supplementation was identified as the unique risk factor for infection (OR = 2.82; 95% CI, 1.18–6.73, p

The purpose of this study was to describe the prevalence and incidence of Neospora caninum infection in dogs that are in close contact with dairy cattle and to identify possible risk factors associated with the infection in this population. Twenty-four dogs located in 8 different dairy farms of Aguascalientes, Mexico, were evaluated for a 6-mo period. Once a month a sample of serum and a sample of peripheral blood was collected. The serum was used to detect antibodies against N. caninum by means of the indirect immunofluorescence technique, and the blood was used to detect parasite's DNA. The association between seroprevalence and possible risk factors was estimated using logistic regression. The prevalence of anti-N. caninum antibodies was 54% in the first month, 62% in the last month, and the incidence was 8.69%. One farm had no positive cases. Antibody titers ranged from 1:50 to 1:800. Parasite DNA was not detected in any of the samples. Only the age (>6 yr) of the dogs was identified as a risk factor for infection by N. caninum (P ≤ 0.05).

Virulence of 10 isolates of entomopathogenic fungi native to Mexico and their effect on reproductive behavior were evaluated in nonfed larvae and engorged females of R. sanguineus sensu lato (Latreille). Virulence was evaluated by immersion in a concentration of 1 x 108 conidia per milliliter, while checks received the same aqueous formulation but without conidia. Reproductive potential was determined by calculating Reproductive Efficiency Index (eggs laid per engorged female weight) and Reproductive Aptitude Index (eggs hatched as larvae per engorged female weight). Results of bioassays on nonfed larvae showed that 40% of the isolates were able to kill ≥90% at 20 days post-treatment. Isolate Metarhizium anisopliae (Metchnikoff) Sorokin 135 with an LC50 of 1 x 106 killed 97%, while Beauveria bassiana (Bals.-Criv.) Vuill. Bb154 with an LC50 of 8 x 106 killed 90%. In engorged females, 70% of isolates killed ≥90% at 15 days post-treatment; isolate Bb154 reduced egg oviposition 83% and hatchability 96%. The isolates should be considered potential biological control agents for R. sanguineus.

El objetivo fue determinar la frecuencia de la infección por Cryptosporidium spp., y realizar la identificación de especie o genotipo de los ooquistes en corderos lactantes Pelibuey, Black Belly y Katahdin mantenidos en pastoreo en la región de la Huasteca Alta del estado de Veracruz, México. Las muestras de excremento se recolectaron de 210 corderos de 7 a 21 días de edad, procedentes de 21 granjas; se procesaron mediante frotis fecal teñido con Kinyoun y por PCR anidada para amplificar la región del gen 18S rARN del parásito (830 pb); las muestras positivas fueron secuenciadas. La frecuencia de corderos positivos a Cryptosporidium spp., por microscopía fue 19.5 % (41/210), con una escala entre rebaños de 10 a 50 %; en tanto que por técnicas moleculares fue de 26.8 % (11/41) con un intervalo de 14 a 50 %; las demás muestras fueron negativas a ambas pruebas. Las 11 muestras secuenciadas tuvieron una homología del 100 % con la región 18S rARN de C. parvum. Estos resultados confirman la importancia de C. parvum como principal agente de la criptosporidiosis en corderos lactantes y su amplia distribución en esta región de México. Esta identificación destaca que las ovejas pueden considerarse como una fuente potencial notable de criptosporidiosis humana, porque se considera una enfermedad zoonótica, principalmente para las personas que manipulan los rebaños.

The aim of the study was to assess the virulence of five Metarhizium anisopliae (Ma) and three of Beauveria bassiana (Bb) isolates, and the effect of the fungal infection to the reproduction of engorged females from two colonies of Rhiphicephalus microplus; one colony was collected from naturally infested cattle (Native) and the other one from a laboratory colony (Media Joya). Virulence was evaluated using the immersion technique at a concentration of 1 × 108 conidia/ml; control groups received a water suspension with Tween 80 (0.1%). The Reproductive Efficiency Index ‘REI’ (eggs laid/engorged female weight) and the Reproductive Aptitude Index ‘RAI’ (eggs hatched as larvae/engorged female weight) were calculated for both groups. This experiment shows that two entomopathogenic fungal isolates, Bb115 and Ma136, caused high mortality from 5 days post-treatment (PT), reaching mortality rates of 99–100% at 15 days PT in both R. microplus colonies. The Bb115 isolate caused 98 and 79% reduction in egg ov...

This study, carried out in 13 sheep flocks of central-western Mexico, aimed to identify the prevalence of anti-N. caninum antibodies, to develop a risk analysis of the infection and to estimate the prevalence of parasite DNA in blood. A total of 368 serum and blood samples were subjected to ELISA and PCR tests, respectively, and the association between the prevalence of antibodies and some management factors was estimated. The overall prevalence of anti-N. caninum antibodies was 13.5% [50/368; 95% confidence interval (CI) 10–17], ranging from 2.7 to 90% per flock, and 92% of the farms had seropositive animals. In ewes the prevalence was 14% (48/348, 95% CI 10–17) and in rams 10% (2/20; 95% CI 1– 33). The mean prevalence of Neospora DNA in blood was 27% (99/368, 95% CI 22–31), implying a range between 16 and 82%. In rams, the prevalence was 5% (1/20 95% CI 2–26), while in ewes it was 28% (98/348, 95% CI 23–33). The agreement between the tests was k = 0.19. The presence of other domestic animal species in the farms [odds ratio (OR) 4.4] and the consumption of placental debris, fetuses and stillborn lambs by dogs living in the farms (OR 5.8) were demonstrated to be risk factors.

The aim of this study was conducted to evaluate the effect of natural infestation by Stomoxys calcitrans on the behavioral and adrenocortical responses of dairy cattle. Twenty Holstein cows randomly selected were individually sprayed with insecticide once every 7d, whereas no insecticide was applied to the other 20 animals. The average number of flies per cow was estimated daily, and the frequency of fly-avoidance behaviors was measured daily; plasma cortisol concentration was measured each morning. No flies were ever counted on the treated cows at any time during the experiment, whereas an average of 17.13±1.14 (±standard error) flies/d were recorded on untreated cows. Tail movement was the most frequent behavior displayed, with stamps or kicks showing the highest increment rate (41.2×) when fly population increased from zero to greater than 51 flies/cow. Cortisol concentration increased to a maximum of 56.81±39.53ng/mL with 26 to 30 flies/cow per day. Coefficients of determination between the number of flies, cortisol concentration, tail movements, and stamps or kicks were 0.73, 0.78, and 0.81, respectively. The multiple correlation coefficient was 0.90, with 81% of the variation in cortisol concentration explainable by variation in the number of flies per cow and the frequency of fly-avoidance behaviors. It was concluded that plasma cortisol concentration is linearly related to a combination of the number of flies and the frequency of fly-dislodging behaviors, producing a maximum response before reaching maximum fly loads.

5 páginas, 1 tabla, 1 figura., The cyst-forming protozoan parasite Neospora caninum is one of the main causes of bovine abortion worldwide and is of great economic importance in the cattle industry. Recent studies have revealed extensive genetic variation among N. caninum isolates based on multilocus microsatellite genotyping. Currently, the most extensive study reported is based on the N. caninum genotyping of 96 samples from four countries on two continents (Spain, Argentina, Germany and Scotland) that demonstrate different clusters of multilocus genotypes (MLGs) implicated in cattle abortions as well as the population sub structuring of N. caninum, which is partially associated with the geographical origin. The aim of this study was to genotype N. caninum from aborted bovine foetuses that originated from Mexico within the region of Aguascalientes and to investigate their genetic diversity. Parasite DNA was detected in 27 out of the 63 analysed foetuses recovered from 10 different herds. Complete or nearly complete profiles based on 9 microsatellite markers were obtained from 11 samples. Diverse N. caninum MLGs were implicated in the occurrence of abortion in each herd. All of the Mexican MLGs differed from the MLGs previously determined for the Argentinean, Spanish, German and Scottish N. caninum populations. The Mexican MLGs failed to cluster by eBURST analyses. The MLG relationships using PCoA showed a close genetic relationship between the Spanish population and a portion of the Mexican population, but a more distant genetic relationship with the Argentinean genotypes. These results demonstrate the genetic diversity of N. caninum in the studied areas that differed from other populations of N. caninum around the world. (C) 2016 Elsevier B.V. All rights reserved., This project was financed by DGEST-SEP 3503.10-P and CYTED (Iberoamerican Science and Technology Programme for Development) (113RT0469).

The annual infestation pattern of R. sanguineus sensu lato (Latreille) was studied for dogs in a tropical sub-humid region of Mexico. Infestation was monitored for a year at five veterinary clinics in different parts of the urban area of Colima City, Mexico. Dogs were considered positive for infestation when at least one specimen of any stage of the parasite was identified by physical search. R. sanguineus occurred throughout the year, with 21.4% average (446/2083; 95% C.I. 19-23) and infestation ranging from 17% in January to 29% in May. Seasonal distribution was homogeneous: spring 22.2% (96/432), summer 21.5% (103/477), autumn 21.4% (132/616), and winter 20.6% (115/558). No correlation was found between seasonal prevalence and weather during a season (p > 0.01). Tick specimens and all parasitic stages were found throughout the year. There were more larvae in March to June, September, and November; nymphs in March to May and December; and more adults in January, February, July, and October. Activity of each stage of ticks where dogs are always available indicated that R. sanguineus develop at least three generations per year.

The objective of the study was to identify the seroprevalence of anti-Toxoplasma gondii antibodies in sheep herds from 3 municipalities from Jalisco, Mexico, as well as estimate the association between seroprevalence and certain factors presents in the farms. In total, 12 sheep farms that maintain only hair breeds were included in the work. From these farms, 336 blood samples were collected, corresponding 324 to ewes and 12 rams. Serum samples were subjected to ELISA test, and the association between the frequency of antibodies and some potential risk factors was estimated. The overall seroprevalence to anti-T. gondii antibodies in the population studied was 17.8% (60/336; 95% confidence interval [C.I.] 14–22), all farms had positive animals, and the seroprevalence of antibodies ranged between 7 to 32%. Seroprevalence in specific municipalities was 18.7% in Lagos de Moreno, 17.8% in Encarnacion de Diaz, and 16.9% in San Juan de los Lagos. Seroprevalence in ewes was 17.5% (57/324; 95% C.I. 13–22), and seroprevalence in rams was 25% (3/12; 95% C.I. 6–57), while among breeds it was 17.8% in Pelibuey (20/112; 95% C.I. 11–26), 16.6% in Kathadin (14/ 84; 95% C.I. 9–26), 15.4% in Blackbelly (13/84; 95% C.I. 8–25), and 23.2% in Dorper (13/56; 95% C.I. 13–36); no differences were observed among breeds (p < 0.05). The presence of cats on the farms was associated with seroprevalence (odds ratio [OR] 2.8; 95% C.I. 1.8–7.3, p < 0.001), as was the absence of a rodent-control program (OR 1.5; 95% C.I. 0.8–3.2, p < 0.05). No other factors were identified as associated with seroprevalence.

El objetivo del estudio fue determinar la frecuencia de Cryptosporidium spp, así como llevar a cabo la identificación de algunos factores de riesgo asociados a la infección en perros asociados a establos lecheros en Aguascalientes, México, y en perros procedentes del área urbana de la capital del mismo estado. Se colectaron muestras de excremento de 168 perros domiciliados en 30 establos lecheros distribuidos en diez municipios del estado, y de 144 residentes del Centro de Control, Atención y Bienestar Animal del municipio de Aguascalientes (área urbana), las cuales se procesaron mediante frotis fecal teñido con Kinyoun para identificar la presencia de ooquistes del parásito. Se levantó una encuesta para identificar diferentes características de los individuos y se realizó un análisis de riesgos mediante regresión logística. La frecuencia general de perros infectados por Cryptosporidium spp., fue de 20.5% (64/312; IC95% 16-25), mientras que en los perros procedentes del CCABA fue de 9% (13/144; IC95% 5-15), y en los asociados a establos fue de 30% (51/168; IC95% 23-38). El 70% de los establos tuvieron animales positivos, mientras que el promedio de perros por establo fue de 5.6, y la densidad fue de 2 a 12 perros. Se identificó como como factor de riesgo a la infección por Cryptosporidium a la variable excremento diarreico, tanto en los perros de origen urbano (OR, 3.2; IC95% 1.06-9.79 p

The purpose of this paper is to evaluate the effect of five strains of Metarhizium anisopliae (Ma) and three strains of Isaria fumosorosea (Ifr) at a concentration of 1 × 108 colony forming units/ml applied by spraying onto bovines with controlled infestation of Haematobia irritans under stable conditions in the Mexican dry tropics. Four experiments were performed, in each of which three treatments (two fungal strains and one control) were evaluated with eight repetitions for each one, by carrying out a single application of the aqueous suspension of each strain. The animals were isolated in individual cages and direct counts of the infestation were carried out for 13 days. It was observed that strains Ma2, Ma6, Ma10, Ma14, and Ma34 caused 94–100% reduction in infestation between days 12 and 13 post-treatment, while strains Ifr19, Ifr11, and Ifr12 reduced infestation from 90% to 98% up to day 13 post-application. There was an effect in the generation of horn flies from the excrement of bovines that were treated with different strains, reducing the reproduction of subsequent generations. It was concluded that the strains of M. anisopliae and I. fumosorosea evaluated in this study can be used as biocontrol agents in infestations of H. irritans in stabled bovines.

We carried out an inter-laboratory trial to compare the serological tests commonly used for the detection of specific Neospora caninum antibodies in cattle in Ibero- American countries. A total of eight laboratories participated from the following countries: Argentina (n = 4), Brazil (n = 1), Peru (n = 1), Mexico (n = 1), and Spain (n = 1). A blind panel of well-characterized cattle sera (n = 143) and sera representative of the target population (n = 351) was tested by seven in-house indirect fluorescent antibody tests (IFATs 1–7) and three enzyme-linked immunosorbent assays (ELISAs 1–3; two in-house and one commercial). Diagnostic performance of the serological tests was calculated and compared according to the following criteria: (1) the BPre-test information,^ which uses previous epidemiological and serological data; (2) the BMajority of tests,^ which classifies a serumas positive or negative according to the results obtained by most tests evaluated. Unexpectedly, six tests showed either sensitivity (Se) or specificity (Sp) values lower than 90%. In contrast, the best tests in terms of Se, Sp, and area under the ROC curve (AUC) values were IFAT 1 and optimized ELISA 1 and ELISA 2. We evaluated a high number of IFATs, which are the most widely used tests in Ibero-America. The significant discordances observed among the tests regardless of the criteria employed hinder control programs and urge the use of a common test or with similar performances to either the optimized IFAT 1 and ELISAs 1 and 2., Facultad de Ciencias Veterinarias

Veterinaria Mexico OA ISSN: 2448-6760 Cite this as: Cruz Vazquez C, Carvajal Marquez J, Lezama Gutierrez R, Vitela Mendoza I, Angel Sahagun CA. Efficacy of Metarhizium anisopliae in the control of the horn fly, Haematobia irritans ( Diptera: Muscidae ), under natural infestation conditions. Veterinaria Mexico OA. 2017;4(2). doi: 10.21753/vmoa.4.2.384 . The aim of this study was to determine the efficacy of the entomopathogenic fungus, Metarhizium anisopliae strain 134 (Ma134), for dairy cattle naturally infested with Haematobia irritans (L.) An aqueous formulation of 1 x 10 8 conidia/ml was applied by aspersion on a group of eight cows every seven days for a total of four applications, while a control group was sprayed with the same solution without conidial content. The degree of horn fly infestation was estimated daily in both groups by the direct count of adult flies found resting or feeding on the animals, and Abbott’s formula was used to calculate the effectiveness of the formulation. The Ma134 formulation resulted in a 68.6 % reduction of the fly infestation during the study period, and a significant reduction was observed from the first week post-application ( p < 0.05). The results show that the Ma134 formulation is effective in reducing infestations of horn fly, H. irritans , on dairy cattle under natural conditions. Thus, the fungus, Ma134, can be considered a candidate for biological control for the integrated management of H. irritans . Figure 1. Infestation index of horn flies, Haematobia irritans , on cows treated with the aqueous formulation of Ma134

The purpose of this study was to determine the seroprevalence of anti-Neospora caninum antibodies, the prevalence of the parasite's DNA in blood and to estimate the association between seroprevalence and potential risk factors in sheep herds in Aguascalientes, Mexico. A total of 324 blood samples were taken from 13 farms and tested using ELISA in order to detect N. caninum antibodies and nested PCR was used to determine the prevalence of the parasite's DNA in blood. The association between seroprevalence and some potential risk factors was estimated. The general seroprevalence reached 5.5% (18/324; 95% C.I. 3–8), ranging between 4 and 15% with the presence of seropositive animals in 61.5% of the farms; seroprevalence in ewes was 5.2% (15/286; 95% C.I. 3–8) while in rams it reached 7.9% (3/38; 95% C.I. 2–22). The prevalence of the parasite's DNA in blood was 25% (81/324; 95% C.I. 20–30), with a range from 7.7 to 50%, with 84.6% of the flock with at least one positive animal. Were identified as positive to both tests the 3% of the animals probed (10/324; 95% C.I. 1–5) of which nine were ewes and only one ram. The agreement between tests was k = 0.12. No association statistically significant was found between seroprevalence and the risk factors considered in this study.

The purpose of this study was to detect the presence of Neospora caninum in tissues from wild rodents associated with dairy farms in Aguascalientes, Mexico. Individuals from Mus musculus, Rattus novergicus and Spermophilus variegatus were caught in dairy farms with history of positive status to N. caninum. A total of 33 rodents were caught from which samples were taken of brain, spinal cord, liver and heart and were tested with nested PCR and Immunohistochemistry (IHC). Results obtained with PCR showed that M. musculus had 77% (10/13) positive samples to N. caninum, S. variegatus had 71% (10/14) and R. novergicus had 50% (3/6). The results obtained with IHC showed that 15% (2/13) of M. musculus individuals were positive, while 43% (6/14) of S. variegatus and 33% (2/6) R. novergicus were also positive. This is the first report of the presence of N. caninum in S. variegatus.

The pathogenicity and virulence of 10 isolates of entomopathogenic fungi from the soil of lodging pens of dairy production units in Aguascalientes, Mexico, on adults of Stomoxys calcitrans and Musca domestica were determined. All isolates were pathogenic when exposed by aspersion to a concentration of 1×108 conidia/ml, causing between 20.3 and 91.7% mortality in S. calcitrans and between 31 and 91.7% in M. domestica at 7 days post-exposure; in S. calcitrans isolates of Beauveria bassiana (Bb114) and Metarhizium anisopliae (Ma135), sensu lato, were the most noteworthy as mortality reached above 90% with an LC50 of 3.5×105 conidia/ml for Bb114, while for Ma135 reached 1.6×104 conidia/ml. In M. domestica Ma134 and Ma135 showed mortality above 90% with an LC50 of 4.3×104 and 1.4×105 conidia/ml, respectively.

SRCRSP (Small Ruminant Collaborative Research Support Program) loci are polymorphic 100-300 base pair-long microsatellite sequences of repeated dinucleotides that can be amplified by the polymerase chain reaction (PCR). Alleles of a given locus are the PCR products of unique length amplified with a set of specific primers. SRCRSP loci have been used to identify individuals but not to assess paternity in goats. We have developed a method to assess caprine paternity by polymorphism analysis of SRCRSP loci in a herd of 20 goats from two breeds, nine Nubia and 11 Boer, respectively. Thirty six alleles were amplified: 6 SRCRSP-1; 5 SRCRSP-2; 4 SRCRSP-3; 5 SRCRSP-4; 5 SRCRSP-5; 6 SRCRSP-6 and 5 SRCRSP-9. four alleles appeared only in the Nubia group and eight only in the Boer group. Polymorphism analysis led to a 0.995 certainty for correct exclusion of the second parent. The loci described in this work could be used to control goat paternity as well as to identify individuals. &nbsp, Los loci SRCRSP (Small Ruminant Collaborative Research Support Program) son secuencias de microsatélites polimórficos de 100-300 pares de bases de dinucleótidos repetidos que pueden ser amplificados por la reacción en cadena de la polimerasa (PCR). Los alelos de un determinado locus son los productos de PCR de longitud única amplificados con iniciadores específicos. Los loci SRCRSP se han utilizado para identificar individuos, pero no para determinar la paternidad en el ganado caprino. En el presente trabajo se reporta el desarrollo de un método para evaluar la paternidad en caprinos mediante el análisis del polimorfismo de loci SRCRSP en un rebaño de 20 animales, que incluía nueve de raza Nubia y 11 Boer. Se amplificaron 36 alelos: 6 del SRCRSP-1, 5 del SRCRSP-2, 4 del SRCRSP-3, 5 del SRCRSP-4, 5 del SRCRSP-5, 6 del SRCRSP-6 y 5 del SRCRSP-9. Cuatro alelos aparecieron exclusivamente en el grupo Nubia, mientras que sólo ocho en el grupo Boer. El análisis del polimorfismo llegó a 0.995 de certeza en la exclusión correcta del segundo padre. Los loci descritos en este trabajo podrían ser utilizados para controlar la paternidad así como para identificar a los individuos en ganado caprino. &nbsp

Objetive. To determine the seroprevalence of N. caninum antibodies and prevalence of parasite DNA in blood, and estimate the association between seroprevalence and the potential risk of some factors in beef cattle under grazing conditions in north-central Mexico. Materials and methods. Blood samples from 139 cows and only 10 bulls belonging to 13 farms were collected and evaluated by ELISA test to detect antibodies against N. caninum. Furthermore, to determine the presence of parasite DNA, nested PCR probe was performed on blood samples. Association between potential risk factors and seroprevalence was estimated. Results. Overall seroprevalence was 23% (35/149 samples), while the prevalence of parasite DNA in blood was 28% (42/149 samples). Of the 149 animals examined 28 (19%) were positive to both tests (25 cows and 3 bulls). Concordance between tests was k = 0.63. All herds had seropositive animals with positive parasite DNA detection in blood. The only risk factor identified was the presence of dogs (OR= 2.65). Conclusions. This study showed that bovine neospososis should be considered as an important infectious disease in north-central Mexico herds. Therefore, an epidemiological control should be taken into consideration to avoid the negative effect of this disease on mexican beef industry., Objetivo. Determinar la seroprevalencia de anticuerpos contra N. caninum y la prevalencia de ADN del parásito en sangre y estimar la asociación entre la seroprevalencia y algunos potenciales factores de riesgo de ganado de carne mantenido bajo condiciones de pastoreo en el centro–norte de México. Materiales y métodos. Se seleccionaron trece hatos ganaderos, en los cuales se recolectaron muestras de suero sanguíneo de 139 vacas y de solo 10 sementales, que fueron evaluados mediante la prueba de ELISA para detectar anticuerpos contra N. caninum. Por otra parte, se realizó una prueba de PCR anidado en muestras de sangre para determinar la presencia de ADN del parásito. Se estimó la asociación entre la seroprevalencia y algunos potenciales factores de riesgo. Resultados. La seroprevalencia general fue de 23%, mientras que la prevalencia a la presencia de ADN del parásito en sangre fue de 28%. Veintiocho muestras de 149 fueron positivas en ambas pruebas, mientras que 3/10 sementales fueron positivos en las dos pruebas. La concordancia entre las pruebas fue k=0.63. Todos los hatos tuvieron animales seropositivos y con presencia de ADN del parásito en sangre. El único factor de riesgo identificado fue la presencia de perros (OR=2.65). Conclusiones. La infección por N. caninum determinada en este estudio es importante, y deberá de ser más documentada; del mismo modo, algunas medidas de control deberán de considerarse para limitar sus efectos negativos en la industria mexicana de la carne.

Objetive. To determine the seroprevalence of N. caninum antibodies and prevalence of parasite DNA in blood, and estimate the association between seroprevalence and the potential risk of some factors in beef cattle under grazing conditions in north-central Mexico. Materials and methods. Blood samples from 139 cows and only 10 bulls belonging to 13 farms were collected and evaluated by ELISA test to detect antibodies against N. caninum. Furthermore, to determine the presence of parasite DNA, nested PCR probe was performed on blood samples. Association between potential risk factors and seroprevalence was estimated. Results. Overall seroprevalence was 23% (35/149 samples), while the prevalence of parasite DNA in blood was 28% (42/149 samples). Of the 149 animals examined 28 (19%) were positive to both tests (25 cows and 3 bulls). Concordance between tests was k = 0.63. All herds had seropositive animals with positive parasite DNA detection in blood. The only risk factor identified was the presence of dogs (OR= 2.65). Conclusions. This study showed that bovine neospososis should be considered as an important infectious disease in north-central Mexico herds. Therefore, an epidemiological control should be taken into consideration to avoid the negative effect of this disease on mexican beef industry.

The first objective was laboratory evaluation of the virulence of 53 Mexican isolates of fungi against larvae of Rhipicephalus (Boophilus) microplus. Thirty-three isolates of Metarhizium anisopliae var. anisopliae (Metschnickoff) Sorokin (Hypocreales: Clavicipitaceae) and 20 isolates of Isaria (Paecilomyces) fumosorosea (fumosoroseus) (Wize) (Eurotiales: Trichomaceae) were tested on 7-day-old larvae under laboratory conditions. Larvae were immersed in a suspension containing 108 conidia/mL and the CL50 values were estimated. Then, field tests were conducted to determine the efficacy of formulations of the isolate with the highest virulence. M. anisopliae (Ma 14 isolate) was formulated with four carriers: Tween, Celite, wheat bran, and Citroline (mineral oil) and applied on pasture beds of Cynodon plectostachyus (L.), at a dose of 2 × 109 CFU/m2. In the first trial, M. anisopliae was applied on plots naturally infested with larvae; in the second trial, tick populations in the experimental plots were eliminated and then re-infested with 20,000 7-day-old larvae. In the laboratory, all M. anisopliae isolates infected larvae with a mortality range between 2 and 100%; also, 13 of 20 I. fumosorosea isolates caused mortality rates between 7 and 94%. In the first field trial, 14 days post-application, conidial formulations in Celite and wheat bran caused 67.8 and 94.2% population reduction, respectively. In the second trial, the Tween formulation caused the highest larval reduction, reaching up to 61% (28 days post-application). Wheat bran formulation caused 58.3% larval reduction (21 days post-application) and was one of the most effective. The carriers and emulsifiers have a large impact on the effectiveness of conidial formulations.

The objective of this work was to study the reproductive behavior of two strains of R. (B.) microplus, one wild-caught (Native) and one reference strain (Media Joya) for two years, measuring the reproductive efficiency index (REI) and reproductive aptitude index (RAI). Engorged ticks from each strain were collected monthly from February 2002 to February 2004. These were weighed and kept in the laboratory until egg-laying. Oogenic masses were individually weighed and incubated until larvae emergence. REI and RAI were calculated from each sample, grouping ticks by weight in 100 mg range classes. An analysis of variance and Duncan's multiple rank tests were carried out on the data (P < 0.05). Pearson's correlation coefficients were estimated (P < 0.01) in order to determine the relationship between engorgement weight and the weight and number of laid and hatched eggs. The Native strain showed a higher engorgement weight than Media Joya strain. In both strains REI and RAI were similar in all weight classes; with a quadratic tendency in Media Joya and linear-quadratic in the Native strain (P < 0.05). Significant differences where observed when REI and RAI of both strains were compared along the duration of the study (P < 0.01) with the Native strain performing better in both indexes, including better performance during the dry season. All parameters studied showed highly significant correlation; eggs laid and eggs hatched were notably highly correlated, 0.94 and 0.91, for Media Joya strain and Native strain respectively.O objetivo deste trabalho foi estudar a conduta reprodutiva de duas cepas de R. (B.) microplus, uma coletada no campo (Nativa) e outra de referência (Média Jóia), por dois anos, calculando o índice de eficiência reprodutiva (REI) e o índice de aptidão reprodutiva (RAI). Foram coletados mensalmente carrapatos fêmeas engurgitadas de cada cepa no período de Fevereiro de 2002 a Fevereiro de 2004. Estas foram pesadas e conservadas no laboratório até ovipositar. As massas de ovos foram pesadas individualmente e incubadas até a eclosão das larvas. O REI e o RAI foram calculados para cada coleta, agrupando os carrapatos em classe de peso de 100 mg. Os dados foram submetidos a uma análise de variância e prova de classe múltipla de Duncan (P < 0,05). Foram calculados os coeficientes de correlação de Pearson (P < 0,01) para estimar a associação entre o peso dos carrapatos engurgitados e o peso e número de ovos postos e eclosionados. A cepa Nativa mostrou um peso ao engurgitamento mais alto do que a cepa Média Jóia. Os valores de REI e de RAI em ambas cepas foram similares em todos as classes de peso, mostrando tendência cuadrática na Média Jóia e linear-cuadrática na cepa Nativa (P < 0,05). Ambos os índices por classe de peso no engurgitamento foram sempre mais altos na cepa Nativa (P < 0,05). Os valores de REI e de RAI de ambas cepas ao longo do estudo mostraram diferenças (P < 0,01), sendo a cepa Nativa a de melhor desempenho em ambos índices, incluindo um melhor desenvolvimento durante a estação seca. Observou-se uma correlação altamente significativa em todos os parâmetros, sobressaindo o número de ovos postos com o número de ovos eclodidos, 0,94 e 0,91, para a cepa Média Jóia e a Nativa, respectivamente.

The objective of this work was to study the reproductive behavior of two strains of R. (B.) microplus, one wild-caught (Native) and one reference strain (Media Joya) for two years, measuring the reproductive efficiency index (REI) and reproductive aptitude index (RAI). Engorged ticks from each strain were collected monthly from February 2002 to February 2004. These were weighed and kept in the laboratory until egg-laying. Oogenic masses were individually weighed and incubated until larvae emergence. REI and RAI were calculated from each sample, grouping ticks by weight in 100 mg range classes. An analysis of variance and Duncan's multiple rank tests were carried out on the data (P < 0.05). Pearson's correlation coefficients were estimated (P < 0.01) in order to determine the relationship between engorgement weight and the weight and number of laid and hatched eggs. The Native strain showed a higher engorgement weight than Media Joya strain. In both strains REI and RAI were similar in all weight classes; with a quadratic tendency in Media Joya and linear-quadratic in the Native strain (P < 0.05). Significant differences where observed when REI and RAI of both strains were compared along the duration of the study (P < 0.01) with the Native strain performing better in both indexes, including better performance during the dry season. All parameters studied showed highly significant correlation; eggs laid and eggs hatched were notably highly correlated, 0.94 and 0.91, for Media Joya strain and Native strain respectively. O objetivo deste trabalho foi estudar a conduta reprodutiva de duas cepas de R. (B.) microplus, uma coletada no campo (Nativa) e outra de referência (Média Jóia), por dois anos, calculando o índice de eficiência reprodutiva (REI) e o índice de aptidão reprodutiva (RAI). Foram coletados mensalmente carrapatos fêmeas engurgitadas de cada cepa no período de Fevereiro de 2002 a Fevereiro de 2004. Estas foram pesadas e conservadas no laboratório até ovipositar. As massas de ovos foram pesadas individualmente e incubadas até a eclosão das larvas. O REI e o RAI foram calculados para cada coleta, agrupando os carrapatos em classe de peso de 100 mg. Os dados foram submetidos a uma análise de variância e prova de classe múltipla de Duncan (P < 0,05). Foram calculados os coeficientes de correlação de Pearson (P < 0,01) para estimar a associação entre o peso dos carrapatos engurgitados e o peso e número de ovos postos e eclosionados. A cepa Nativa mostrou um peso ao engurgitamento mais alto do que a cepa Média Jóia. Os valores de REI e de RAI em ambas cepas foram similares em todos as classes de peso, mostrando tendência cuadrática na Média Jóia e linear-cuadrática na cepa Nativa (P < 0,05). Ambos os índices por classe de peso no engurgitamento foram sempre mais altos na cepa Nativa (P < 0,05). Os valores de REI e de RAI de ambas cepas ao longo do estudo mostraram diferenças (P < 0,01), sendo a cepa Nativa a de melhor desempenho em ambos índices, incluindo um melhor desenvolvimento durante a estação seca. Observou-se uma correlação altamente significativa em todos os parâmetros, sobressaindo o número de ovos postos com o número de ovos eclodidos, 0,94 e 0,91, para a cepa Média Jóia e a Nativa, respectivamente.

The possible relationships between stable fly infestation with dairy farm facilities and sanitation practices were studied using path analysis. Twelve dairies located in four counties of Aguascalientes dairy region were selected. The dairies were monitored from May to November 2003. In each occasion, fly infestation, individual physical facility characteristics, and sanitation practices were recorded. In all, 11 independent variables were involved in the study and related variables were grouped together and analyzed in two blocks by path analysis for each one of five population events (begin of fly season, first peak, fluctuation, second peak and decrease). There were significant regression coefficients only in the second peak for two variables, the distance to the silos and the distance to the dung heap (r(2)=0.96 for the full model). Among the 11 variables examined in the study, none had a statistical significant indirect contribution to fly infestation; direct contribution was observed for distance to the silos and for distance to the dung heap variables. However, only the distance to the silos variable was significantly related to stable fly Infestation.

The objective of this study was to evaluate the efficacy of an isolate of Metarhizium anisopliae applied by aspersion to control of Stomoxys calcitrans flies in dairy cattle naturally infested. Was applied by aspersion an aqueous formulation of M. anisopliae sensu lato (Ma134), at a concentration of 1×10(8)conidia/ml, four times with seven day intervals, on a group of eight Holstein cows; a control group of eight Holstein cows, received a water solution with Tween 80 (0.1%). The average number of flies per animal was estimated one day before each application, and then daily counts were done in both groups. The effectiveness of the formulation was calculated using the Abbott's formula. At the same time, defensive behaviors of stamp/kicks and tail movements were evaluated daily, estimating relative frequency per hour. The Ma134 formulation had an infestation control efficacy of 73%, taking into consideration the four study weeks. The population reduction effect was observed since the first week post-application (p0.05), and the effect increased with the subsequent applications. Defensive behaviors were reduced beginning from the first application, reaching a reduction of 66% and 70%, respectively, during the four weeks of study. These results demonstrated the effectiveness of the formulation to control infestation by S. calcitrans, as well as reduce defensive behaviors which involves the infestation.

Se evaluó el efecto de un preparado de enzimas fibrolíticas exógenas (celulasas y xilanasas) en la degradabilidad in situ de la materia seca (DisMS), fibra detergente neutro (DFDNr) y fibra detergente ácido residual (DFDAr), en dietas altas o bajas en harina de nopal deshidratado. Se aplicaron concentraciones de 0, 1, 2 y 3 g de enzima por kilogramo de materia seca al inicio y 24 horas antes de la degradación in situ. Se determinó la concentración de ácidos grasos volátiles totales y de nitrógeno amoniacal a las 0, 3, 6, 9, 12 y 24 horas después de aplicarse la enzima. No se observaron efectos en DisMS, DFDNr y DFDAr; la aplicación al inicio de la degradación in situ mostró valores más altos que a 24 horas para DisMS y DFDNr, pero fue menor para DFDAr. No se observaron diferencias en las interacciones entre niveles de enzima, tipo de dieta y tiempo de pretratamiento. La aplicación de 1 y 3 g de enzima, en la dieta con bajo contenido de harina de nopal, tuvo efectos en el incremento de los ácidos grasos volátiles totales; para el nitrógeno amoniacal, los mejores resultados ocurrieron con 0 y 1 g de enzima. It was evaluated the effect of a fybrolitic enzyme product (cellulases and xylanases) on in situ digestibility of dry matter (DisMS), residual neutral detergent fiber (DFDNr) and acid detergent fiber (DFDAr), in dehydrated ground prickly pear diets with a low or high level. Enzyme concentrations of 0, 1, 2, and 3 g kg-1 of dry matter applied at the beginning (0 hour) and 24 hours before starting in situ digestibility were used. Total volatile fatty acids and ammonia nitrogen were determined at: 0, 3, 6, 9, 12, and 24 hours after the enzyme application. There were no effects on DisMS, DFDNr, and DFDAr. Initial application of enzyme concentrations (0 hour) was higher than 24 hours for DisMS and DFDNr but lower for DFDAr. No differences were observed in interactions among enzyme level, diet and application time. Application of 1 and 3 g of the enzyme to the diet with the low level of prickly pear forage had effects on the increasing of volatile fatty acids; for ammonia nitrogen, the best results were obtained using 0 and 1 g of the enzyme.

This study investigated the effect of controlling stable flies (Stomoxys calcitrans) on the number of dairy cows lying down and their pen distribution. The study randomly assigned 80 Holstein cows to 1 of 2 groups. The treated group (T) included cows individually sprayed with insecticide when found with an average of 10 stable flies per cow; in the control group (C), cows received no application of insecticide. The pen had 4 equal-size areas: (a) feeding, (b) drinking and sunny, (c) covered, and (d) manure. The study recorded the number of cows lying and the area of the pen where the nonhuman animal was located. The study found no difference (p.05) between the proportion of T and C cows lying. However, cows preferred to lie down in pen area 3 when fewer than 10 stable flies per cow were found. Area 4 was the most avoided section of the pen, except when a high incidence of flies was present. The study concluded that high populations of S. calcitrans (10 flies per cow) did not affect the number of dairy cows lying down. However, it modified site preferences for lying.