Background: The use of reproductive biotechnologies in equine practice has shown that some stallions are subfertile, so ways to improve fertility have been sought.Objective: This study aimed to evaluate the effect of nutraceutical supplementation on improving semen quality in Quarter Horse stallions.Methods: Semen from six Quarter Horse stallions was assessed for 4 months every 20 days using the computer‐assisted semen analysis system. They were evaluated for 60 days before supplementation; then, the same stallions were re‐evaluated for 60 days with nutraceutical supplementation (30 g/day).Results: Volume showed no significant difference (p > 0.05) with nutraceuticals. Sperm concentration (10x⁶) was significantly higher with supplementation (339.4 ± 17.5 sperm/mL) than without supplementation (224.6 ± 19.9). Sperm abnormalities (%) were significantly (p < 0.05) lower with supplementation (14.3 ± 0.6) than without supplementation (19.1 ± 0.4). Sperm kinematic parameters, total motility (TM), progressive motility (PM), rectilinear velocity (VSL), the velocity of the trajectory (VAP) and curvilinear velocity (VCL), were significantly better with supplementation (p < 0.05).Conclusions: Based on the results, it is concluded that nutraceutical supplementation improved semen parameters in Quarter Horse stallions.

The objective was to evaluate the influence of the seasons of the year on the seminal quality of Quarter Horses. 12 stallions aged 9 to 12 years were used, a Colorado artificial vagina was used for semen collection, motility, concentration and volume were immediately evaluated, it was considered as spring (March 20-June 21); summer (June 22-September 23); autumn (September 24-December 21) and winter (December 22-March 19). The parameters showed no significant difference in volume (P>0.05) between stations. However, there was a difference between the months of May (81.1±15.2) vs February (46.6±2.8), in sperm motility it was higher (P<0.05) in summer (85.6±2.6) vs winter (71.5±19.0), the sperm concentration 10x6 was significantly higher (P0.05) entre estaciones. Sin embargo, hubo diferencia entre los meses de mayo (81.1±15.2) vs febrero (46.6±2.8), en motilidad espermática fue mayor (P<0.05) en verano (85.6±2.6) vs invierno (71.5±19.0), la concentración espermática 10x6 fue significativamente mayor (P<0.05) en verano (269.8±51.4) vs invierno (207.9±80.4). Estos resultados permiten concluir que la estación del año tiene influencia sobre la calidad seminal. Por lo cual al implementar biotecnologías reproductivas en el Norte de México podemos utilizar el semen equino de sementales Cuarto de Milla, preferentemente obtenido en la época con mayor producción y calidad seminal. http://dx.doi.org/10.21929/abavet2023.21 e2022-48 https://www.youtube.com/watch?v=yDnUvD3MqeQ http://dx.doi.org/10.21929/abavet2023.21 e2022-48 https://www.youtube.com/watch?v=yDnUvD3MqeQ

Nowadays, it is central to generate innovations that convert agricultural by-products and food waste into valuable animal products while promoting the long-term resilience and sustainability of vulnerable animal production systems. Nutraceuticals (i.e., ‘nutrition + pharmaceutical’) are derived from foods that offer health benefits. In animal production, nutraceutical supplementation with Withania somnifera and Lepidium meyenii has shown positive effects on the endocrine, cardiopulmonary, and central nervous systems. We aimed to evaluate the possible impact of nutraceutical supplementation on rams fed a diet based on surplus feed from a highly industrialized Holstein cow production system, on corporal (live weight [LW], kg; body condition score [BCS], units), metabolic (blood glucose [GLU], mg dL⁻¹; serum protein [PRO], g 100 mL⁻¹), and sexual–testicular variables [sexual odor (ODOR, units); scrotal circumference (SC, cm); testicular volumes (TVOL, cm³); and estimated daily sperm production (EDSP, millions)]. Black Belly rams (n = 12; LW = 70.36 ± 1.2 kg; BCS = 2.96 ± 0.03 units; age = 3.8 ± 0.2 years; 25° N) were divided into 3 experimental groups: (1) WITH, supplemented with Withania somnifera (400 mg kg⁻¹ LW d⁻¹); (2) LEPI, supplemented with Lepidium meyenii (400 mg kg⁻¹ LW d⁻¹); and (3) CONT, not supplemented. The variables LW, BCS, GLU, PRO, and SC, as well as some components of TVOL, did not differ (p > 0.05) among the main effects of treatment or time; only ODOR, right transverse testicular diameter, and total testicular volume differed among treatments, generally favoring the WITH group. Furthermore, the TRT × T interaction demonstrated superior performance (p < 0.05) in the WITH group, with the largest values for LW, GLU, PRO, ODOR, SC, width of the right testicle, volume of the right testicle, total testicular volume, and EDSP. From a productive–reproductive perspective, the Robin Hood Effect—through the use of rejected dairy cattle rations as the base diet for rams—and supplemented with nutraceuticals (WITH and LEPI), emerges as a viable alternative to improve not only the productive–reproductive performance of Black Belly rams, but also other productive and socioeconomic outcomes; the latter contributing to the strengthening of producer and family well-being.

One of the most important aspects of animal production is the reproductive behavior, where a widely used strategy in small ruminants is the “male effect”. However, the response to this effect can vary depending on several factors, including the social rank (SR) of both sexes. The objective of this study was to evaluate how SR influences morphometric and socio-sexual variables in Dorper sheep in Northern Mexico. Through behavioral tests, 33 rams and 59 ewes were divided into two groups taking into account their SR. Rams included high SR (HSR; n = 14) and low SR (LSR; n = 19), while ewes included HSR (n = 23) and LSR (n = 36). Morphometric response variables included age, live weight, body condition, thoracic circumference, wither height, presence of horns, and testicular circumference, whereas reproductive variables included estrus rate, ovulation rate, corpus luteum, left ovary, right ovary, pregnancy rate, and embryos’ number. The results showed no differences (p > 0.05) for the morphometric variables considered, whilst, regarding the reproductive variables, the LSR rams × HSR ewes group showed the highest number of embryos (p < 0.05), and the corpus luteum number was higher in the HSR rams × HSR ewes group (p < 0.05). However, no significant differences were found for the remaining variables (p > 0.05). Improving productive and reproductive performance can contribute to increased income for sheep farmers.