Reproductive response of crossbred Bos taurus × Bos indicus cows to biostimulation by pre-pubertal and pubertal teasers.

Although the beneficial effect of biostimulation on reproduction has been reported, the influence of selectivity and social factors on the response to biostimulation has not received sufficient research attention in both Bos indicus and Bos indicus influenced cattle. Furthermore, 'green and cheap' strategies to improve cattle reproduction are currently in demand while Bos indicus influenced cattle with inferior reproductive performance, and farmers with economic limitations are common in tropical zones. Hence, to assess the reproductive response of crossbred taurus × indicus cows to biostimulation by pre-pubertal (PPM) or pubertal (PM) teasers males, two trials of 2 years each were conducted. Trial 1 n = 187 cows (Year 1:85 cows exposed to PPM and Year 2:102 cows exposed to PM). Trial 2 n = 196 cows (Year 1:101 cows exposed to PPM and Year 2:95 cows exposed to PM). The effect of exposing cows to PPM and PM on the intervals calving to first service (ICFS), calving to conception (ICC) and economic cost of days open (ECDO) was analysed using Kruskal-Wallis ANOVA and the effect of exposing cows to PPM and to PM on reproductive status at 90 days (RS90) and proportion of cows requiring hormonal protocols (PRH) was compared using χ2 analysis. Both ICFS and ICC were shorter (p < .0001) for PM-exposed females (96.12 ± 4.1 and 110.93 ± 2.9 days; respectively) compared with those PPM-exposed (134.41 ± 3.3 and 135.64 ± 2.4 days; respectively). With RS90, more (p < .0001) PM-exposed cows (50.7%) were pregnant compared with PPM-exposed cows (16.1%). The PRH was greater (p < .0001) in PPM-exposed cows (79.0%) compared with PM-exposed (27.9%). The ECDO was less (p < .0001) in PM-exposed cows (US$ 142.9 ± 3.8) compared with PPM-exposed (US$ 176.3 ± 2.9). In conclusion, cows exposed to PM had shorter ICFS and ICC compared with cows exposed to PPM. More cows exposed to PM were pregnant after 90 days, and PRH was less than cows exposed to PPM. Cows exposed to PM had a reduced ECDO than those exposed to PPM.

Seasonal variation of the estrous cycle length, corpus luteum area, and size of the pre-ovulatory follicle in Criollo Limonero heifers.

In order to determine whether seasonal variations may influence the estrous cycle length (ECL), corpus luteum size (CLS), maximum area of CL (MACL), day of cycle with maximum area of CL (DCMACL), and pre-ovulatory follicles size (PFS), ten Criollo Limonero heifers were subjected to daily ultrasound ovary scanning throughout their estrous cycles during three seasons: hot-dry (HD), hot-humid (HH), and wind-rain (WR). The effect of season on ECL, MACL, DCMACL, and PFS was analyzed with an ANOVA (PROC GLM, SAS), whereas, for the effect of season on CLS, an ANOVA with repeated measures (PROC MIXED, SAS) was used. Results showed no effect (P > 0.05) of season on ECL, MACL, and DCMACL. However, size of PFS was larger (P < 0.02) during the WR season and the CLS tended (P < 0.09) to be lower during the HH. In conclusion, the relative stability of ECL, MACL, DCMACL, PFS, and CLS measures suggests no major seasonal variations which could imply adaptation capability of Criollo Limonero cattle to the tropical environment.

Effect of season and genotype on values for bull semen variables under tropical conditions.

To assess the effects of season and genotype on fresh semen quality for freezing and subsequent use for AI, 32 healthy, mature (>4 to <6 years old) and habituated bulls (Bos indicus n = 14, Bos taurus n = 5, Crossbred taurus x indicus n = 6, and tropically adapted Bos taurus composites n = 7) were evaluated at a Venezuelan AI center for 12 months in which four distinct seasons (Hot-dry, Transition, Hot-humid, Cool-rainy) occur. Ejaculates were collected weekly from Bos taurus (n = 260), Bos indicus (n = 669), tropically adapted Bos taurus composites (n = 389), and crossbred Bos taurus x Bos indicus (n = 340) bulls. Routine AI Center assessments were conducted i.e., ejaculate volume (EV), sperm mass-motility (MM), total sperm number/ejaculate (TSE), sperm concentration/mL (SC), pre-freezing (PREF), and post-freezing minimum criteria rate for AI use (POSTF). Genotype affected EV (P < 0.0001), TSE (P < 0.0001), and SC (P < 0.0001) but not MM (P>0.05). Season affected EV (P < 0.001), TSE (P < 0.0001), SC (P < 0.01), and MM (P < 0.05). There were genotype x season interactions for EV, MM, TSE, and SC. The PREF averaged 74.0% during the study, although was less (P < 0.0001) during the hot-humid season than the other seasons. Even though, percent ejaculates considered unsuitable for freezing differed (P < 0.03) among the Hot-dry (20.2%), transition (30.9%), Hot-humid (32.4%), and Cool-rainy (24%) seasons. For POSTF, there were no seasonal differences (P>0.05). It is concluded that in tropical regions, season and genotype can affect bull semen variables, particularly those which affect the success of semen freezing and AI.

Valoración dosis-respuesta del efecto diurético de un extracto acuoso de pericarpio de Cucumis melo var. reticulatus Ser. / Dose-response assessment of the diuretic effect in a pericarp aqueous extract of Cucumis melo L. var. reticulatus Ser.

Introducción: la investigación se realizó para determinar la relación dosis-respuesta del pericarpio de melón, validar su empleo en la medicina tradicional venezolana y promover su uso racional como planta medicinal, mediante el conocimiento científico. Objetivo: valorar la relación dosis-respuesta del efecto diurético de la concha del fruto de Cucumis melo var. reticulatus Ser. en ratas. Métodos: se licuó el pericarpio del fruto fresco y se colocó en solución fisiológica por 48 h para luego colarlo. Se administraron vía oral dosis de 1, 3 y 6 mL/300 g, se compararon con un grupo control respectivo y se midió el volumen de orina producido transcurrida 1 h. Resultados: la primera dosis no tuvo efecto diurético en ningún caso. La excreción urinaria de las 2 mayores dosis fue diferente de su respectivo grupo control. Los grupos tratados con extracto acuoso a 3 y 6 mL resultaron diferentes entre sí, igual que los grupos control a esos volúmenes. No se encontró diferencia en la acción diurética. Se halló una relación dosis-respuesta de regresión no-lineal. Conclusiones: se evidencia la relación dosis-respuesta basada en la excreción urinaria, tras administrar el extracto acuoso de la concha de melón, lo que sustenta su empleo como diurético en la medicina tradicional venezolana.

Introduction: research was conducted to determine the dose-response of melon pericarp, validate its use in traditional medicine in Venezuela and promote its rational use as a medicinal plant, through scientific knowledge. Objective: to assess the dose-response diuretic effect of the shell of the fruit of Cucumis melo var. reticulatus Ser. in rats. Methods: fresh fruit pericarp was liquefied and placed in saline solution for 48 hours to strain it later. Oral doses of 1, 3 and 6 mL/300g were administered, compared with a respective control group, and the volume of urine produced an hour later was measured. Results: the first dose had no diuretic effect in any case. Urinary excretion of the two higher doses differed from their respective control group. The groups treated with aqueous extract at 3 and 6 mL were different among them, as well as the control groups in those volumes. No difference was found in the diuretic action. The study found a dose-response of nonlinear regression. Conclusions: there is a clear dose-response relationship based on urinary excretion after administration of the aqueous extract of melon shell, which supports its use as a diuretic in traditional medicine in Venezuela.