Reviewing the current state of knowledge on reproductive performance and productive traits in rams has many advantages. First, the compilation of this information will serve as a literature resource for scientists conducting research around the world and will contribute to the understanding of the data collected and interpreted by researchers on the different hormonal strategies used to improve reproductive performance in rams. Second, it will allow scientists to identify current knowledge gaps and set future research priorities in ram reproduction. Rams play an important role in the global flock economy, but their reproductive analysis has been limited in the use of hormonal technologies to increase the productivity of sheep flocks. In this review, we cite the most important works on six hormones that, in one way or another, modify the hypothalamus-pituitary-gonadal axis, at different doses, in and out of the reproductive season, breeds, application methods, among other factors. The overall aim is to increase the reproductive efficiency of rams in different scenarios and, in some cases, of other species due to the lack of limited information on rams.

Background: The honeybee (Apis mellifera L.) represents one of the most important species in the maintenance of ecosystems, since it contributes to crop pollination, which improves crop yields and the reproduction of other plants. However, some factors such as climate change, africanization and various pathological processes, including the presence of the Varroa destructor mite, have led to a decline in A. mellifera populations. Objective: To collect scientific information on the plants used for mite control, as well as the organic derivatives and secondary compounds with bioacaricidal potential used for such control. Main findings: Due to the fact that infestations of this mite have become a major problem, numerous control methods have been developed and tested, mainly based on synthetic acaricides; however, these have generated disadvantages such as the development of resistance and contamination of products such as honey and pollen. Implications: Therefore, it is necessary to implement an organic, environmentally friendly control method that reduces mite populations without developing resistance, and that does not generate contamination of hive sub-products. Conclusions: In general, the most common types of extracts tested were essential oils and hydroalcoholic extracts, which reported mortality ranging from 26.4 to 99.5% on V. destructor. Likewise, some species of plants endemic to Matorral Espinoso Tamaulipeco (MET) have been tested against other arthropods and that could be an important source of components that act as acaricides; however, it is necessary to identify and analyze the secondary compounds, as well as the molecules and their activity on V. destructor.

Background: Xerophilous scrubland is a semi-desert ecosystem characterized by a wide diversity of shrubs, which have secondary compounds with nutraceutical potential that could be used as feed for livestock, specifically by goats, since this species has developed behavioral and physiological adaptations that allow it to take advantage of the plant resources of said scrubland. Objective: To evaluate the nutraceutical potential of Havardia pallens and Vachellia rigidula, native species of the xerophilous scrubland, when incorporated as ingredients in goat diets. Methods: Integral diets for male goats were prepared, formulated with 35% inclusion of Havardia pallens, Vachellia rigidula, and Medicago sativa, the latter used as a plant control species. The content of flavonoids and total phenols was compared using colorimetric methods, and the antioxidant capacity was measured using the FRAP method. RP-HPLC-ESI-MS characterized the bioactive compounds in the different extracts. Statistical analysis was performed by ANOVA. Results: The aqueous extraction of Vachellia rigidula showed the highest concentration of total phenols ($\overline{\mathrm{x}}$ = 18.22 mg GAE/g⁻¹), followed by the ethanolic extract in the same species ($\overline{\mathrm{x}}$ = 17.045 mg GAE/g⁻¹). Similarly, Vachellia rigidula presented the highest antioxidant capacity ($\overline{\mathrm{x}}$ = 144,711.53 µmol TE/g⁻¹), while Medicago sativa presented the lowest ($\overline{\mathrm{x}}$ = 11,701.92 µmol TE/g). The RP-HPLC-ESI-MS analysis revealed that Vachellia rigidula presented a higher abundance of flavones, catechins, flavonols, methoxyflavones, and tyrosols. However, Harvardia pallens presented higher levels of methoxycinnamic and hydroxycinnamic acids. One-way ANOVA results showed that diets containing 35% Vachellia rigidula and Havardia pallens significantly contrasted (p < 0.05), increased the content of secondary compounds and antioxidant capacity compared to the control species. Furthermore, including Vachellia rigidula led to a significantly higher antioxidant capacity (p < 0.05) than diets with Havardia pallens or Medicago sativa. Conclusions: Incorporating the leguminous shrubs Vachellia rigidula and Havardia pallens into the formulation of comprehensive diets for buck goats improves the content and availability of phenols, flavonoids, and antioxidants. However, in vivo evaluation of these diets is important to determine their physiological and productive effects on the animals.

El objetivo del presente estudio fue determinar el comportamiento sexual de carneros agrupados en diadas de acuerdo con su jerarquía social, durante dos épocas de empadre de 30 días cada uno. Se utilizaron 12 carneros adultos distribuidos en parejas (6 parejas/época de empadre), para cada empadre formado de 17 y 18 ovejas se introdujo un carnero dominante y un subordinado. Se evaluó el comportamiento sexual por un periodo de 4 horas/día en forma visual para cada grupo de carneros. No se presentaron diferencias en cuanto a la Jerarquía, a excepción para Flehmen (<0.0001). Para la época de empadre y el grupo de carneros se presentaron diferencias estadisticas (P<0.05) sobre desarrollo corporal y circunferencia escrotal, asi como las caracteristicas de inspección sexual. La semana de empadre tuvo un efecto sobre cada una de las variables de comportamiento sexual (P<0.05). Se presentaron interacciones para la grupo de carneros con jerarquia época y semana de empadre (P<0.05), no así para la Jerarquia con época y semana de empadre. Se concluye que los grupos de carneros donde se evaluó el dominante y el subordinado varía a traves de la época y semana de empadre y por lo tanto se adaptan a las condiciones de estres bajo un esquema de empadre controlado a corral.

The impact of social rank among hair rams on reproductive efficiency has been extensively studied, particularly regarding its influence on ewes and rams under various lambing scenarios, both within and outside the breeding season. However, limited information exists on the specific effects of social rank on lamb paternity. The present study aimed to evaluate the influence of social rank during a 35 d mating period on paternity outcomes and the postnatal development of lambs during the breeding season. A total of 108 adult ewes were divided into six groups, with 18 ewes per group. Each group was paired with two rams: one dominant ram (DRam) and one subordinate ram (SRam). Lamb development was monitored from birth through weaning and up to 150 d of age. Paternity was determined for 107 lambs using a panel of 116 single-nucleotide polymorphism (SNP) markers to assign sires from among the 12 rams included in the study. Social rank showed significant differences in lambing outcomes depending on the type of birth (P<0.05). DRams sired 67 % of lambs, while SRams sired 33 %. DRams exhibited a significantly higher proportion of twin births (52.9 %) compared to SRams (32.4 %; P<0.01). However, no significant differences were observed between the ram groups for other lambing types. Lambing type also significantly influenced lamb weight gain, with single-born lambs achieving greater weight gain than twins and triplets (P<0.05). Additionally, lamb sex ratios differed significantly between ram groups, with DRams producing a higher proportion of male lambs (50.7 %) compared to SRams (41.2 %; P<0.05). This study demonstrates that social rank significantly affects reproductive outcomes, including lamb paternity, lambing type, birth weight and body weight at 3 months of age. These findings highlight the importance of considering social hierarchy when managing breeding programs to optimize reproductive efficiency in hair sheep production systems.

El objetivo del presente trabajo fue evaluar el efecto del consumo de dietas formuladas con Acacia rigidula (Benth) Seigler & Ebinger y Havardia pallens (Benth) Britton & Rose, en la capacidad reproductiva de machos caprinos criollos en crecimiento en condiciones de estabulado en Ciudad Victoria, Tamaulipas. Se utilizaron 15 machos caprinos jóvenes (3-4 meses de edad aproximadamente) los cuales fueron asignados al azar a las dietas con las plantas nativas o dieta control, conteniendo el 35% de inclusión. Los aspectos evaluados fueron: circunferencia escrotal (Ces), Motilidad masal (MM) y Morfología espermática que se determinaron dos veces al mes, a partir de agosto hasta diciembre. Con la finalidad de evaluar diferencias en la motilidad y la morfología espermática entre los grupos (Acacia rigidula AR, Havardia pallens HP y Medicago sativa CON) se obtuvieron frecuencias y porcentajes que se compararon mediante la prueba de Kruskal-Wallis. Además, se realizó un análisis de varianza entre los tres grupos para establecer diferencias de las características bromatológicas, metabolitos secundarios y la circunferencia escrotal. Los resultados obtenidos muestran diferencias en el contenido de proteína cruda y de pared celular (p < 0.05). La concentración de compuestos secundarios fue distinta entre los grupos (p < 0.05) así como también la motilidad masal (escala de cinco puntos, p < 0.05). Por lo tanto, se concluye que el uso de las arbustivas como HP y AR se puede ofrecer en un porcentaje del 35% sin afectar la morfología espermática en machos caprinos. Futuras investigaciones pueden probar niveles superiores al 35% y en animales adultos pues no existen trabajos hasta el momento que evalúen el efecto de dicha inclusión.