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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. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencias Pecuarias is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Methane production is a waste of energy for ruminants and contributes to greenhouse gas emissions. The objective of the present study was to evaluate the anti-methanogenic effect of increasing the supplementation levels of Cymbopogon citratus (CC) on the dry matter intake (DMI), digestibility, methane (CH4) production, and partitioning of the gross energy intake in growing beef heifers fed with a diet high in forage (68.6% forage: 31.4% concentrate). An experiment was conducted using Holstein × Charolais heifers distributed in a 4 × 4 Latin square design. The experimental treatments were: (1) control diet (CO), (2) CO + 30 g CC DM/d, (3) CO + 60 g CC DM/d CC, and (4) CO + 90 g CC DM/d. A reduction of 22.4% in methane yield (CH4 g/kg DMI) and a reduction of 21.2% in the Ym factor was observed with the 30 CC treatment (p ≤ 0.05). However, no significant differences (p > 0.05) were observed for the total daily CH4 production, DMI, nutrient digestibility, and gross energy intake partitioning in the heifers. Therefore, we concluded that the supplementation of 30 g CC DM/d reduced the CH4 yield without affecting the animal performance. However, the anti-methanogenic properties of Cymbopogon citratus deserve more investigation. [ABSTRACT FROM AUTHOR]

The legume Cratylia argentea associated to Brachiaria brizantha-Toledo-grass ( Bb + Ca) and Toledo-grass alone ( Bb) were evaluated under grazing conditions by Holstein × Zebu heifers. Three evaluation periods during three consecutive years, were performed. We measured, daily live-weight gains of heifers (DWG, g/day); biomass dry matter (BDM, kg/ha) at beginning and end of each grazing period. On plant samples, were measured percentages of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, in situ DM degradability (ISDMD), and voluntary biomass DM intake (VBI, g/LW) using the CrO/in situ indigestibility technique. A completely randomized design was applied, using heifers as experimental units for DWG gains and VBI. At the beginning of the grazing, the BDM for Bb + Ca and Bb-considering the three periods-averaged, 3065 and 936 kg/ha, respectively. Crude protein content of C. argentea was around 20 %; and for Bb + Ca or Bb, ranged from 8.7 to 4.6 %. In either treatment, in situ DM degradability averaged 72.6 % ( P ≥ 0.05), regardless of the botanical component type. Biomass DM intake was 83.02 ( Bb + Ca) and 89.22 ( Bb) g/LW. The DWG gains (g/heifer) for Bb + Ca and Bb were (per period): 829 and 574 (first); 469 and 118 (second); and 534 and 508 (third). This study showed that the Bb + Ca association was better to improve the daily gain of F1 Holstein × Zebu heifers, as compared to Bb alone. Also, C. argentea associated to a low to medium-quality grass improved the nutritional value of the diet without affecting the biomass DM intake. [ABSTRACT FROM AUTHOR]

A study was conducted in the humid tropics of the state of Veracruz during the rainy season, in order to determine the effect of introducing the legume Arachis pintoi CIAT 17434 (AP) into a native pasture, upon the grazing ingestive behavior of cows. Treatments were the native pasture (PN, control) and PN associated with AP (PNA). A 1 d grazing/ 20 d recovery rotation and a stocking rate of 3.2 F1 (Holstein x Cebú) cows/ha were used. Significance was set at P<0.05. Means ± standard error are presented for PNA first and then for PN. There were differences in standing dry matter (kg/ha) before grazing (4,225 ± 212 vs 3,314 ± 212 kg/ha), and crude protein (15.1 ± 0.4 vs 10.6 ± 0.5) and digestible organic matter (OM) (67.6 ± 1.7 vs 64.1 ± 2.0 %) of oesophageal extrusa. Grazing time (min/24 h) was similar between treatments (367 ± 11 vs 380 ± 11), but ruminating time was not (291 ± 8 vs 379 ± 8). OM intake (kg OM/100 kg LW) calculated by Cr-in situ digestibility was similar between treatments (2.09 ± 0.11 vs 2.16 ± 0.11), while intakes calculated by ingestive behavior were different (1.54 ± 0.12 vs 2.02 ± 0.12). Saleable milk yield and milk intake by calf (kg/animal/d) were similar between treatments: 6.8 ± 0.4 vs 6.1 ± 0.4; and 4.4 ± 0.4 vs 3.8 ± 0.5, but total milk yield was different: 9.0 ± 0.6 vs 7.2 ± 0.6. [ABSTRACT FROM AUTHOR]

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El objetivo de este ensayo fue estimar algunas características de la vegetación en pasturas de grama nativa sola (G) o asociada con Arachis pintoi CIAT 17434 (GA) sometidas a pastoreo rotacional intensivo en el trópico húmedo de Veracruz, luego de cinco años de haberse sembrado la leguminosa. Se usaron cinco divisiones de G y tres de GA. Los muestreos se efectuaron del 7/VIII/ 95 al 28/V/96, totalizando 27 para G y 18 para GA; las cargas animal instantáneas fueron 29.9±5.2 y 32.9±5.6 vacas/ha/día y los días de recuperación 43±4 y 50±4. No hubo diferencia entre pasturas (P>0.05) en cuanto a materia seca disponible, residual y el consumo, con promedios respectivos de 29.3 ± 2.0, 25.1 ± 1.9 y 3.31 ± 0.20 kg MS/100 kg PV. El nivel de uso de la pastura de GA (18.5±1.1 %) superó (P<0.05) al de G (14.6±0.9 %). La proteína cruda de hojas y tallos tanto antes como después del pastoreo, fue siempre superior (P<0.05) en GA, superando casi siempre el valor crítico de 7 %. Los contenidos de hoja y tallo fueron similares entre pasturas, produciendo una relación hoja:tallo de 1. Las tasas de crecimiento no fueron afectadas por la pastura, con promedios de 37.7±8.1 kg MS/ha/día para la absoluta y 0.0110±0.0002 MS/kg/ha/día para la relativa. Las gramíneas dominaron la composición botánica de G (74.1 %) y A. pintoi dominó en la asociación (62.1 %). La leguminosa benefició el nivel de proteína cruda del forraje, pero no a las demás variables. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate some characteristics of pasture vegetation in native grass pastures alone (G) or associated with Arachis pintoi CIAT 17434 (GA) under intensive rotation in the humid tropics of Veracruz, five years after legume establishment. Five pasture divisions of G and three of GA were used. Samplings took place from 7/VIII/95 to 28/V/96, for a total of 27 for G and 18 for GA; the instantaneous stocking rates were 29.9±5.2 and 32.9±5.6 cows/ha/d and days of recovery were 43±4 and 50±4. There were no differences (P>0.05) between pastures for available dry matter, residual dry matter and dry matter intake, being the respective means: 29.3±2.0, 25.1±1.9 and 3.31±0.20 kg DM/100 kg LW. Pasture use in GA (18.5 ± 1.1 %) was greater (P<0.05) than that of G (14.6 ± 0.9 %). The CP content of leaves and stems both before and after grazing was always higher (P<0.05) in GA than in G; CP was nearly always above the critical value of 7 %. The leaf and stem contents were similar (P>0.05) between pastures, giving a mean leaf:stem ratio of one. Crop growth rates were not affected (P>0.05) by pastures, with means of 37.7 ± 8.1 kg DM/ha/d for the absolute and 0.0110 ± 0.0002 DM/kg/ha/d for the relative. Botanical composition was dominated by grasses in G and by A. pintoi in GA. The legume benefited the protein of forage but other variables were not improved. [ABSTRACT FROM AUTHOR]

Production, nutritional quality and preference of T. diversifolia by Pelibuey sheep was determined, at different ages, in three seasons of the year. Dry matter (DM) production and nutritional quality of forage were measured every 14 d, from the cut to 84 d of age. Leaf and stem samples were taken to determine crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). Eight adult Pelibuey sheep were used to determine their preference for T. diversifolia foliage at 42, 56 and 70 d of regrowth. Total DM production was similar in autumn and winter and both greater than spring. In autumn at 56 d and in winter at 70 d after the cut, the production of DM was 9 t ha-1, while in S at 84 d, it was close to 3 t ha-1. The increase or decrease of the morphological components of the biomass over time was different between the seasons evaluated and showed a curvilinear behavior over time, within each season. CP increased linearly with the cutting age. In autumn and winter, there was a higher percentage of NDF and ADF. The 42-d plants had a lower percentage of ADF. The yield of DM and the nutritional quality of T. diversifolia differs depending on the season of year and the age of regrowth. The cutting age of the plant affected its preference by Pelibuey sheep (P=0.0091), it was higher for the foliage of 42 d, followed by 56 and 70 d. [ABSTRACT FROM AUTHOR]