La yerba carnicera o conyza (Conyza sumatrensis) es una maleza de elevada capacidad adaptativa a los sistemas productivos uruguayos, en especial por presentar fallas de control después de la aplicación de los herbicidas glifosato e inhibidores de la acetolactato sintasa (I-ALS). El objetivo del trabajo fue confirmar la presencia y nivel de resistencia de C. sumatrensis a glifosato (GLI), diclosulam (DIC) y clorimuron (CLO), a partir de ensayos de curvas de dosis respuesta e investigar la ocurrencia de mutaciones en el gen ALS como mecanismo de resistencia asociado a los I-ALS.

ABSTRACT.- Silvopastoral systems may provide important production and environmental benefits. The loss of cool-season (C3) grasses from temperate grazed native grasslands is associated with selective grazing and excessive solar radiation that limit their survival. Silvopastoral systems integrate trees with grasslands that provide shade to both cattle and herbaceous plants, potentially favoring C3 species. There is limited information about the effect of trees on the species and functional composition of native grasslands in the Campos biome in South America.

ABSTRACT.- Determining the optimal defoliation frequency is essential to increase the productivity of pasture-based dairy systems. An experiment was carried out to study the effect of the defoliation regimen around flowering time on the evolution of chemical composition and nutritional value of orchardgrass. The experiment was conducted on a 4-year-old orchardgrass (Dactylis glomerata cv 'INIA Perseo') pasture at the experimental station "La Estanzuela" (INIA, Uruguay).

ABSTRACT.- Efficient pasture-based animal production systems require optimisation of forage production with the highest nutritive value. Increasing the defoliation regimen of pastures allows to improve the nutritive value of forage for ruminants but it can be detrimental for total biomass production. An experiment was carried out to study the effect of the defoliation regimen around flowering time on productivity, chemical composition and nutritional value of tall fescue.

ABSTRACT.- Two experiments evaluated the effect of different hormonal treatments to synchronize follicle wave emergence on follicle dynamics and pregnancies per AI (P/AI) in estradiol (E2)/progesterone (P4) timed-AI (TAI) protocols in lactating dairy cows. © 2024 Elsevier Inc.