Resumen El objetivo del estudio fue caracterizar el nivel tecnológico (NT) de las unidades de producción (UP) de ganaderos de los distritos de desarrollo rural (DDR) 01 y 02 en Guerrero, México, y conocer su percepción sobre la transferencia de embriones (TE). Se estudiaron 31 UP de los DDR 01 (n = 16) y 02 (n = 15). La edad, escolaridad y experiencia (años) promedio de los productores fue 50.0 ± 11.4, 10.6 ± 1.4 y 24.5 ± 7.9, respectivamente (p < 0.05). El NT se determinó con base en sus variables técnico-productivas y se clasificó en bajo, medio y alto. Se obtuvo NT bajo, medio y alto en 37.5%, 43.8% y 18.8%, respectivamente, de las UP del DDR 01, así como 33.3%, 20.0% y 46.7%, respectivamente, de las del DDR 02 (p < 0.05). Los ganaderos de UP con NT alto tienen mejor percepción sobre la TE (7/10, 70%), comparados con los de UP de NT bajo (0/11, 0%) y medio (2/10, 20%). En conclusión, se observó mejor percepción sobre la TE a medida que aumenta el NT de la UP, independientemente del DDR.

Abstract The objective of the study was to characterize the technological level (TL) of production units (PU) belonging to cattle producers from the rural development districts (RDD) 01 and 02 in Guerrero, Mexico, and to know their perception about embryo transfer (ET). Thirty-one PU from RDD 01 (n = 16) and 02 (n = 15) were studied. The average age, education, and experience (years) of the producers were 50.0 ± 11.4, 10.6 ± 1.4, and 24.5 ± 7.9, respectively (p < 0.05). The TL was determined based on the technical-productive variables of the PU and was classified as low, medium, and high. Low, medium, and high TL was obtained in 37.5%, 43.8%, and 18.8% of PU from RDD 01, respectively, as well as 33.3%, 20.0%, and 46.7% of PU from RDD 02, respectively (p < 0.05). Cattle producers from PU with high TL have better perception about ET (7/10, 80%), compared with those from PU with low (0/11, 0%) and medium (2/10, 20%) TL. In conclusion, better perception about ET was observed as the TL of the PU increases, independently of the RDD.

Resumo Os objetivos do presente estudo foram: (1) determinar a prevalência de oocistos esporulados de Eimeria spp. em bezerros de 26 municípios na zona central do estado de Veracruz, México; (2) identificar as espécies de Eimeria que infectam bezerros; e (3) identificar os factores de risco associados à presença de Eimeria spp. em bovinos de região tropical. Um total de 930 amostras individuais de fezes foi analisado usando-se a técnica McMaster. Depois oocistos foram mantidos em 2,5% de dicromato de potássio para esporulação. A prevalência geral de animais com oocistos de Eimeria spp. foi de 39,7% (370/930). De um total de 10 espécies identificadas, Eimeria canadensis foi a mais observada, seguida de Eimeria bovis e Eimeria zuernii. A análise estatística indicou uma associação entre a idade dos bezerros (5 a 9 meses), a presença de outros animais, as regiões fisiográficas e o tipo restrito de criação com a presença de Eimeria spp. em bezerros (P<0,05). Os fatores de risco protetores, tais como a análise coprológica de rotina, foram também associados a uma diminuição da infecção. Esses dados indicaram a presença de coccídios em bovinos do estado de Veracruz, além das medidas necessárias que devem ser tomadas para controlar essa parasitose.

Abstract The objectives of the present study were: (1) to determine the prevalence of Eimeria spp. sporulated oocysts in calves from 26 Municipalities in the Central Zone of the State of Veracruz, Mexico, (2) to identify the Eimeria spp. infecting calves, and (3) to identify the risk factors associated with the presence of Eimeria spp. in tropical cattle. A total of 930 individual fecal samples were analyzed by using the McMaster technique; then, oocysts were maintained in 2.5% potassium dichromate to allow sporulation. The general prevalence of calves with Eimeria spp. oocysts was 39.7% (370/930). Of a total of 10 identified species, Eimeria canadensis was the most observed, followed by Eimeria bovis and Eimeria zuernii. The statistical analysis showed an association between the age of the calves (5 to 9 months), the presence of other animals, the physiographic regions and the restricted type of husbandry with the presence of Eimeria spp. in calves (P<0.05). Protective risk factors, such as: routine coprological analysis was also associated with a decrease in infection. These data demonstrate the presence of coccidia in cattle from the State of Veracruz, additionally to the necessary measures that must be taken to control this parasitosis.

Abstract: The aim of the study was to evaluate the effect of cryopreserved equine semen in the presence of trehalose-loaded liposomes on the integrity and function of sperm cells. Six ejaculations of five stallions collected with an artificial vagina were used. The ejaculates were diluted with INRA 96® 2:1 v/v and transported at 22 °C to the laboratory. Before cryopreservation, the semen was diluted with INRA Freeze® to obtain the following treatments: T1) INRA Freeze® (control), T2) INRA Freeze® + liposomes, T3) INRA Freeze® + liposomes+trehalose. Data were analysed using the Kruskal Wallis test. The percentages of sperm with intact DNA were 54.5, 57.9, and 64.8% for T1, T2 and T3, respectively (P>0.05). When evaluating the acrosomal and capacitation state after filtering with Percoll®, the percentages of spermatozoa without acrosome reaction and without capacitation were 67.8, 79.2 and 68.1% in T1, T2, and T3, respectively (P>0.05), while the capacitated sperm without acrosome reaction and without capacitation was similar in T1 (47%) and T3 (32%) (P>0.05), and lower in T2 (16%) before filtering with Percoll®. The use of liposomes and liposome-trehalose did not affect on the functional status and nuclear chromatin of the equine sperm after freezing, but it did affect the percentage of capacitated sperm without acrosome reaction after selecting the thawed semen using the Percoll® gradient.

El objetivo del estudio fue investigar el efecto de la criopreservación sobre la integridad del acrosoma y de la subestructura de la teca perinuclear (PTS) del espermatozoide de verraco. Se utilizó semen proveniente de seis verracos. El semen se colectó, se diluyó y se determinó la motilidad y concentración espermática, incluyendo en el estudio sólo los eyaculados con motilidad ≥70%. El semen diluido se dividió en dos muestras: una para evaluarse en fresco y otra para evaluarse después de la congelación-descongelación. Ambos tipos de muestras se utilizaron para evaluar la viabilidad espermática y la integridad del acrosoma mediante microscopía de luz usando la técnica de triple tinción y para evaluar la integridad de la PTS mediante microscopía electrónica. El semen congelado-descongelado tuvo mayor proporción (P<0,05) de espermatozoides vivos con reacción acrosomal, comparado con el semen fresco. El proceso de congelamiento-descongelamiento redujo (P<0,05) la proporción de espermatozoides con PTS intacta. El valor de espermatozoides con reacción acrosomal se correlacionó con la proporción de espermatozoides con PTS alterada o ausente, tanto en semen fresco (r=0,93; P<0,05) como en semen congelado-descongelado (r=0,71; P<0,05). En conclusión, el semen criopreservado de verraco presentó alteraciones en la integridad del acrosoma y de la PTS que pudieron ser debidas al fenómeno de criocapacitación.

The objective of this study was to investigate the effect of cryopreservation on the integrity of the acrosome and the perinuclear theca substructure (PTS) of boar spermatozoa. Semen from six boars was used. The semen was collected, diluted, and sperm motility and concentration determined. Only ejaculates showing ≥70% motility were used in this study. Diluted semen was divided in two samples: one to be evaluated fresh, and other to be evaluated after freezing-thawing. Fresh and frozen-thawed semen samples were used to assess sperm viability and acrosome integrity by light microscopy using the triple staining technique and to evaluate the PTS integrity by electron microscopy. The frozen-thawed semen had a greater proportion (P<0.05) of acrosome reacted live spermatozoa, compared to the fresh semen. The freezing-thawing process reduced (P<0.05) the proportion of intact PTS spermatozoa. The value of acrosome reacted spermatozoa was correlated with the proportion of spermatozoa with altered or absent PTS, both in fresh (r=0.93; P<0.05) and in frozen-thawed (r=0.71; P<0.05) semen. In conclusion, cryopreserved boar semen showed some alterations in the integrity of the acrosome and the PTS that might be due to cryocapacitation.