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.
Ticks are one of the main problems in production units, mainly because they have become resistant to the chemicals used to control them. Several alternative methods to chemicals have been sought to ...control tick infestations in cattle, which are practical and friendly to the environment. In this work, we implement rotational grazing to combat ticks at the pasture level. We found that a 30-day rest period for pastures (without animals) is not enough to reduce the presence of ticks in animals but that a 45-day rest period does reduce the presence of ticks in cattle. These studies are critical since they would help cattle producers design better strategies that help reduce the use of chemical acaricides and the presence of chemicals in milk, meat, and the environment. 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).
Background. Pasture growth rate (PGR, kg/ha/day) depends on climatic and management practices. However, studies on the influence of the environment on pasture production and productivity of dry ...matter are scarce in tropical, hot, and humid regions of México. Objective. To estimate the pasture growth curve using time and climatic variables. Methodology. We related, through nonlinear models, the accumulated growth of a pasture composed of native grasses mixed with exotic grasses, using time and the variables temperature and day length as independent variables, the latter integrated into a single variable called thermal photo units (PTU). We estimated the daily growth rates of five divisions; from these, the forage yields for ten days until completing 29 periods. The best-fit models had the largest coefficients of determination and the lowest Akaike’s information criterion. Results. The model that best described the relationship between cumulative yield (Y) and cumulative growing days (X) was reciprocal-quadratic: y = x/(0.097535 – 0.0000881x + 0.0000006810x2) with R2Adj, of 0.9988 and an AICC of 222.6. The model that best described the relationship between the accumulated performance and the accumulated PTU was rational: y = (- 317.8 + 1.594x + 0.00001307x2)/(1 + 0.001059x + 0.00000001964x2), with R2Adjt.=0.9985 and AICC=233.4. Likewise, a two-segment model showed a close fit. The logarithmic model described the first segment: y1 = -2268 + 417.2*(ln(x)), when y2 =1079.3e0.00003932X, if x > 8415; with R2Adj. = 0.9975 and AICc = 245.1. The value 8415 PTU was when the first derivative of both models coincided. Implications. The information generated is useful because it allows grazing system adjustment concerning the correct stocking rate application and designing more efficient grazing rotations. Conclusions. The conversion of growth rates to accumulated yield for ten-day periods produced a smooth curve that allowed fitting high-precision nonlinear models to predict forage accumulation from time and climatic variables.
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.
Tithonia diversifolia (Hemsl.) A. Gray, puede producir hasta 19.5 t MS/ha/ año (Gallego-Castro et al., 2017), con alta PC y degradabilidad de MS (Botero-Londoño et al., 2019), pero se conoce poco de ...la edad de mayor consumo por ovinos.
Tithonia diversifolia (Hemsl.) A. Gray, puede producir hasta 19.5 t MS/ha/ año (Gallego-Castro et al., 2017), con alta PC y degradabilidad de MS (Botero-Londoño et al., 2019), pero se conoce poco de ...la edad de mayor consumo por ovinos.
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
0.75
) using the Cr
2
O
3
/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
0.75
. 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.
En sistemas silvopastoriles se requiere promover especies potencialmente útiles y adaptadas a condiciones edafoclimáticas. Las especies forestales que se promueven y se distribuyen en muchos casos, ...no consideran clima y suelo, densidad de plantación y/o marco de plantación. Un ejemplo de arbóreas de poco follaje, adaptadas o naturalizadas a un clima semicálido húmedo con 2,000 mm de precipitación pluvial anual son, Melia azederach (piocho) y Cinnamomun leptophyllum (aguacate silvestre). Piocho en una plantación, registró a un año 5.2±1.82 m de altura, con una tasa de crecimiento diaria (TCD) de 0.7±0.7 cm y aguacate creció de 1.53±0.41 m a 2.46±0.64 m en un año y su TCD fue de 3 mm. Al correlacionar el crecimiento de las mismas plantas a ocho años de edad, con 812 árboles/ha, piocho alcanzó una altura de 16.6±1.72 m y aguacate de a 16.04±1.65 m y la ecuación del modelo de crecimiento de Gompertz para aguacate y piocho de la siembra a ocho años de edad fue Y = 16.48 (1 – e-7.069X)0.01688 , (R2= 0.99) y Y = 16.92 (1 – e- 3.71X) 0.01606, (R2=0.99), respectivamente. El modelo de Gompertz, muestra al inicio un crecimiento lento que después de 1.5 años se acelera. El uso de árboles maderables nativos o naturalizados, de poco follaje y dispuestos en callejones en potreros con densidades mayores de 400 árboles/ha, son aptos para crecimiento rápido y caída de ramas basales, lo que puede favorecer ecológica y financieramente a los sistemas silvopastoriles.
Dry matter intake, nutritional contribution of forage to the diet and Lamb foraging behavior were assessed in a silvopastoral system. Twelve Pelibuey female lambs (6.3 months of age, 23.74 ± 3.5 kg ...live weight), were randomly assigned to two treatments: pastures of Digitaria eriantha (monoculture) or pastures of D. eriantha and Guazuma ulmifolia (silvopastoral). During a 15 day period, lambs foraged individually in 20.14 m2 paddocks each day; time spent grazing and browsing were assessed by scan sampling; dry matter intake was estimated (day 11-15), using the chromic oxide (Cr2O3) method, and metabolizable energy (ME) and protein (CP) ingested by the lambs were estimated. Data analyses were performed using a complete randomized design (dry matter intake) and a repeated-measure design (ME and CP, foraging time) with factorial treatment structure of season (windy and dry) and pasture (monoculture and silvopastoral). Voluntary intake (season*treatment interaction, p = 0.015) was lower in the windy-silvopastoral treatment (448.5±38.2 g day-1) than in the other treatments (625.8±38.2 to 680.5±38.2 g day-1). The contribution of ME (719.7-1190.2 kcal·day-1) and CP (53.7-100.7 g day-1) was low to cover the lamb requirements in all treatments, because forage availability and dry matter intake were low. Lambs dedicated from 6.65±0.26 to 7.50 ± 0.26 h to foraging; time spent grazing was longer that browsing in the silvopastoral system (p < 0.0001). The time dedicated to foraging, intake, and nutritive quality of forage from in both pasture types did not provide nutrients and energy during any season for maintenance of the lambs.
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