Rotational grazing has been mentioned as a potential tool to reduce losses caused by high tick loads. This study aimed: (1) to evaluate the effect of three grazing modalities (rotational grazing with 30- and 45-day pasture rest and continuous grazing) on Rhipicephalus microplus infestation in cattle, (2) to determine population dynamics of R. microplus in cattle under the three grazing modalities mentioned in the humid tropics. The experiment was carried out from April 2021 to March 2022 and consisted of 3 treatments of grazing with pastures of African Stargrass of 2 ha each. T1 was continuous grazing (CG00), and T2 and T3 were rotational grazing with 30 (RG30) and 45 d of recovery (RG45), respectively. Thirty calves of 8–12 months of age were distributed to each treatment (n = 10). Every 14 days, ticks larger than 4.5 mm were counted on the animals. Concomitantly, temperature (°C), relative humidity (RH), and rainfall (RNFL) were recorded. Animals in the RG45 group had the lowest count of R. microplus compared to the RG30 and CG00 groups; these results suggest that RG45 days of rest could be a potential tool to control R. microplus in cattle. Yet, we also observed the highest population of ticks on the animals under rotational grazing with a 30-day pasture rest. A low tick infestation characterized rotational grazing at 45 days of rest throughout the experiment. The association between the degree of tick infestation by R. microplus and the climatic variables was nil (p > 0.05).

Se determinó el rendimiento y calidad del forraje en un sistema silvopastoril con Leucaena leucocephala cv. Cunningham (5000 árboles ha^-1) asociado con Megathyrsus maximus cv. Tanzania, en cuatro intervalos de descanso (20, 30, 40 y 50 d), en dos épocas (lluvias y seca) en clima cálido Subhúmedo. Los tratamientos se distribuyeron aleatoriamente a las unidades experimentales (12 parcelas, 24 m² c/u) y se evaluó el rendimiento y calidad nutritiva del forraje en la época húmeda (agosto-octubre, 2014) y seca (marzo-abril, 2015). La gramínea aportó la mayor proporción de forraje a la biomasa disponible (80 vs. 20%) y se produjo más biomasa total a 50 días en lluvias (5300 kg MS ha^-1) y seca (1620 kg MS ha^-1); en lluvias, la proteína cruda (PC) de los arboles aumentó gradualmente a 22% (P0.05); fibra detergente neutro (FDN) se mantuvo (44%) (P>0.05) y fibra detergente ácido (FDA) aumentó (25%) (P<0.05) a 50 días, mientras digestibilidad in vitro de la materia seca (DIVMS) disminuyó (49%) (P<0.05). En la gramínea, la PC (10%) (P<0.001) y DIVMS (58 %) se mantuvieron hasta 40 días y después declinaron (P<0.03), aunque FDN y FDA aumentaron significativamente a 50 días, en ambas épocas. la asociación L. leucocephala y M. maximus, alcanza su mayor producción entre 40-50 días, con mejor calidad nutritiva de la gramínea a 40 días, que se puede compensar con el valor nutritivo del follaje de los árboles hasta los 50 días de descanso, independientemente de la época.

Se determinó producción, calidad nutritiva y preferencia de T. diversifolia por ovinos Pelibuey a diferentes edades, en tres épocas del año. Se midió la producción de materia seca (MS) y calidad nutritiva de forraje cada 14 días, desde el corte hasta 84 días de edad. Se tomaron muestras de hoja y tallo para determinar proteína cruda (PC), fibra detergente neutro (FDN) y fibra detergente ácida (FDA). Se utilizaron ocho ovinos Pelibuey adultos para determinar su preferencia por el follaje de T. diversifolia a los 42, 56 y 70 días de rebrote. La producción de MS total fue similar en otoño e invierno y ambas mayores que primavera. En otoño a los 56 días y en invierno a los 70 días después del corte, la producción de MS fue 9 t ha-1, mientras que en primavera a los 84 días fue cercana a las 3 t ha-1. El incremento o decremento de los componentes morfológicos de la biomasa a través del tiempo fue distinto entre las épocas evaluadas y mostró un comportamiento curvilíneo en el tiempo, dentro de cada época. La PC aumentó en forma lineal con la edad de corte. En otoño e invierno hubo mayor porcentaje de FDN y FDA. Las plantas de 42 días tuvieron menor porcentaje de FDA. El rendimiento de MS y la calidad nutritiva de T. diversifolia difiere según la época del año y la edad de rebrote. La edad de corte de la planta afectó su preferencia por los ovinos Pelibuey (P=0.0091), fue mayor por el follaje de 42 días, seguido por 56 y 70 días.

We evaluated the behavior and skin temperature of dual-purpose cattle that grazed pastures having high (HC), low (LC), and no (NC) tree cover during the rainy and dry seasons in the hot and humid tropics of Mexico. We observed twenty-four adult cows (eight per treatment) over 24 days during each season, recording skin temperature and the time related to different daily activities. Across treatments, cows spent the same amount of time foraging during the rainy season (P > 0.05), but cows under HC spent less time during the dry season (P < 0.0001). During the rainy season, cows under HC showed more motivation to continue grazing than becoming restless or beginning rumination (P < 0.001) or roaming more than in other treatments (P < 0.001). During the dry season, cows under HC and LC also had less probability of initiating rest than NC (P < 0.001). Cows under HC had greater motivation to transition from grazing to roaming and less incentive to pass from rumination to rest than cows under LC and NC (P < 0.001). The frequency of water consumption was greater during the dry season (P < 0.001) and consistently high under NC (P < 0.0001). Skin temperature did not differ among treatments during the rainy season (P = 0.261), but during the dry season, it was greater under NC (P < 0.001). Tree cover improves cow behaviors by increasing the impetus to graze and perform daily activities, which contributes to reduced skin temperature during hotter seasons.

Grazing management through pasture rotation has been mentioned as a viable alternative for the control of Rhipicephalus microplus; however, there is limited information on rotational grazing at field level. The objectives of this research were (1) to evaluate the effect of rotational grazing with 30 and 45 days of pasture rest and continuous grazing (without rest) on R. microplus tick loads in Brahman heifers and its most common crosses with Holstein; (2) to know the parasite dynamics of R. microplus under the three grazing systems in the humid tropics of Mexico; and (3) to determine the effect of the treatments on the characteristics of the pastures (availability of forage biomass, plant height, and soil cover). The experiment was carried out for 1 year from April 2022 to March 2023, with three grazing treatments: Treatments 1 and 2 considered rotational grazing with 30 (RT30) and 45 days of rest (RT45), respectively, and Treatment 3 as continuous grazing (CT00). Thirty calves from 8 to 12 months of initial age were distributed in each treatment (n = 10). Every 14 days, the number of engorged and semiengorged female ticks in cattle was determined. Concomitantly, the region’s temperature, relative humidity, and rainfall were recorded, as well as the agronomic characteristics of the pasture. Rotational grazing animals with 30 days of rest had the highest number of ticks, while grazing animals with 45 days of rest had the least. Tick load dynamics among groups did not correlate with climatic variables (p > 0.05). The height and grass cover presented significant changes due to grazing (p < 0.05), which could influence the tick cycle by the exposure of the soil, modifying the microclimatic conditions and consequently harming the survival and development of R. microplus in the evaluated systems. The negative effect of rotational grazing on the nonparasitic phase of R. microplus deserves further studies.

Background. Forage trees and shrubs are an alternative that improve dry matter intake and digestibility in ruminants, due to their high ruminal degradation rate, higher nitrogen contribution for rumen microorganisms, low percentage of neutral and acid detergent fiber. Objective. To estimate the availability, nutritional quality and degradability for Tithonia diversifolia (Hemsl.) A. Gray were estimated at different cutting age, in three seasons of the year. Metodology. Forage production and nutritional quality were measured every 14 d, from cutting to 84 d of age. Leaf and stem samples were taken to determine crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and the "in situ" degradability of dry leaf matter (DM). Results. Total DM production was similar in autumn and winter, and both were greater than for spring. In autumn, at 56 d and in winter at 70 d after cutting, DM production was 9 t ha-1, while in spring at 84 d it was close to 3 t ha-1. Crude protein content increased linearly with days after cutting. Implications. In autumn and winter, the highest percentages of NDF and ADF were observed. Plants at 42 d of regrowth had a lower percentage of ADF. Conclusions. The DM production and the nutritional quality of T. diversifolia differ according to the season of the year and the age of regrowth, at 42, 70 and 84 days of regrowth in autumn, winter and spring, respectively, under the agroecological conditions of the growing area. study, the best conditions for growth occur in Autumn. The DM degradability is similar between the ages of 42, 56 and 70 days of regrowth. However, harvesting plants at 42 days could sacrifice biomass yield at a very early age.