Chilean Journal of Agricultural & Animal Sciences

IMMEDIATE AND RESIDUAL EFFECT OF BIOCHAR ON SELECTED SOIL PROPERTIES OF COARSE-TEXTURED-SOIL AND AGRONOMIC PERFORMANCE OF MAIZE

2025-03-13T09:05:01-04:00

The management of large volumes of abattoir waste generated in Nsukka metropolis has been a serious environmental concern. This study investigated the immediate and residual effects of cow dung biochar on selected properties of coarse-textured soil and agronomic parameters of maize in Nsukka, southeastern Nigeria. The treatments consisted of biochar application rates of 0, 10, 20 and 30 t ha-1, replicated six times in a Completely Randomized Design, with maize (Zea mays) as the test crop. Agronomic data (leaf length, leaf width, plant height, plant girth, number of leaves) were collected throughout the 12-week experimental period. Soil samples were collected and analyzed at
the end of the study. Both soil and agronomic data were analyzed statistically using the GENSTAT software. The results showed that biochar-amended plots had a significant effect (P < 0.05) on most
of the soil and agronomic properties evaluated. Soil pH, soil organic matter (SOM), total nitrogen (TN), available phosphorus (P), calcium (Ca), leaf length, leaf width, plant height and number of leaves increased with increasing rates of biochar application in both the 2020 and residual planting seasons. In addition, macro-, micro- and total porosity, saturated hydraulic conductivity, magnesium (Mg), hydrogen (H), cation exchange capacity (CEC), and plant girth significantly increased with increasing biochar application rates during the 2020 planting season only. Aluminum (Al3+) was not significant in either planting seasons. Bulk density decreased with increasing biochar rates in both planting seasons. It can be concluded that cow dung biochar improves both soil properties and maize agronomic performance. Further studies are recommended to determine the optimal minimum application rate, with 10 t ha-1 suggested as a potentially effective threshold for improving soil quality and maize productivity.

REPRODUCTIVE FUNCTIONALITY OF BULLS FROM THREE CREOLE BREEDS BY SEMINAL EVALUATION OF FRESH, FROZEN, AND POST-THAW SEMEN

2025-02-28T09:43:13-05:00

Creole cattle are an important zoogenetic resource that has been historically overlooked and marginalized. Consequently, their conservation is vital for preserving genetic biodiversity. The objective of this study was to evaluate the reproductive functionality of bulls from three Creole breeds through the seminal analysis of fresh, frozen, and post-thaw semen. Semen was collected using an artificial vagina from 60 bulls belonging to the Rodeo Creole, Longhorn, and Senepol breeds. The evaluated characteristics in fresh semen included body weight (BW), scrotal circumference (SCi), ejaculate volume (EV), sperm concentration (SCo), mass sperm motility (MSM), individual sperm motility (ISM), pH, viability, and total abnormal sperm (TA). In addition, semen straws were frozen, and the post-thaw individual sperm motility (PISM) was evaluated. Senepol bulls exhibited higher BW, SCi, and PISM, as well as lower TA (567.3 kg, 35.95 cm, 64.90% and 8.8%, respectively) compared to Rodeo Creole and Longhorn bulls. SCo and sperm viability were similar between Senepol and Longhorn bulls (P>0.05). No significant differences were found among the three Creole breeds for EV and MSM. BW and pH were significantly correlated (P<0.05) with sperm viability and TA percentage; SCi was correlated with EV; MSM with ISM, viability, pH and TA; and ISM was correlated with viability, TA and PISM. Additionally, sperm viability was correlated with both TA and PISM, and TA was also correlated with PISM. In conclusion, the quality parameters of fresh semen in these Creole bulls fall within the established reference values for the bovine species. Therefore, their semen can be cryopreserved for conservation and genetic dissemination purposes

INGESTIVE BEHAVIOR OF FINISHING SANTA INÊS SHEEP USING BY-PRODUCTS FROM ETHANOLTO REPLACE CORN GRAIN IN THE DIET

2025-01-21T10:14:59-05:00

Research shows that the use of dry distiller grain in ruminant diets can improve daily weight gain and feed efficiency, being regarded as a promising feed source in intensive production systems. The objective was to evaluate the effect of different levels of dietary inclusion of dry distiller grain with high-fiber solubles (DDGS FS OURO®) on the ingestive behavior of confined sheep. Eight animals of the Santa Inês breed were used, males and castrated, with an initial body weight of 30 kg, aged 7 months. The animals were distributed in a double 4 x 4 Latin square design, with four experimental periods of 21 days each. For comparison of different fiber levels in DDGS, the regression test was adopted using mutually orthogonal contrasts. Ingestive behavior was determined on the 21st day of each experimental period by visual observation for 12 hours, with 5- inute intervals to determine the time spent on feeding, rumination, idleness, and water intake. Ingestive behavior (min/day and/or %), referring to the time spent in idleness, rumination, feeding, and water intake, was not influenced by the inclusion of high-fiber DDGS in DM of the diet. The increased inclusion of dry distiller grain with high-fiber solubles replacing corn grain had no effect on the ingestive behavior of confined sheep.

NON-NUTRITIONAL COW-LEVEL AND AMBIENT TEMPERATURE RISK FACTORS FOR THE OCCURRENCE OF LEFT DISPLACED ABOMASUM IN HOLSTEIN COWS

2024-10-21T13:05:52-04:00

This retrospective cohort study (n= 13411 lactations) aimed to evaluate the association between temperature-humidity index at calving and cow-related variables with the occurrence of left displaced abomasum (LDA) in Holstein cows in a hot environment. Variables eligible for multiple logistic models were age at first calving, lactation number, temperature-humidity index at calving, metritis, lactation commenced following an abortion, dystocic parturition, premature calving, twin births, body weight at parturition, body condition score (BCS) at parturition, BCS change between calving and first artificial insemination (AI), and wither height at parturition. Significant risk factors for LDA were number of calvings [5.2% for primiparous vs. 8.3% for multiparous cows; odds ratio (OR)=1.3, P < 0.01], BCS at calving (6.6% for BCS ?3.5 and 8.4 for BCS <3.5; OR=0.75, P < 0.01), BCS change from calving to first AI (7.2% for <0.85 and 9.2 for ?0.85 units; OR=1.5, P < 0.01) and lactation initiated with abortion (1.6 for abortion and 10.2 for no abortion; OR=0.2, P < 0.01). Heat stress at calving was not associated with LDA. It was concluded that BCS <3.5 at calving and a greater BCS loss from calving to the first AI were associated with an increased risk of LDA. In contrast, initiation of lactation with abortion was related to a lower incidence of LDA.

IMPACT OF STARTER FEED AND FIBER COMBINATION ON RUMEN DEVELOPMENT AND PRODUCTIVITY IN NEONATAL LAMBS

2025-03-20T17:14:47-04:00

The feeding of neonatal lambs in the tropics is based on milk and low-quality forages, which limits ruminal development and productivity. The objective of the study was to evaluate the rumen development and productivity of neonatal lambs raised under three dietary regimes: a) a liquid diet based on whole cow’s milk (MILK); b) a solid diet based on fiber from low-quality forage, administrated by star grass (Cynodon nlemfuensis, FIBER); c) a solid diet based on the combination of fiber (40% FIBER and 60% starter feed, F40+SF60). Twelve 15-day-old lambs were evaluated over a 38- day period to assess: initial live weight, final live weight, dry matter intake, and daily weight gain, as well as the length, width, and number of ruminal papillae per cm2 ; the volume of the reticulum, rumen, omasum, abomasum; ruminal pH; and concentration of total bacteria. A completely randomized design was used, with three treatments and four lambs per treatment. Data were analyzed using the PROC GLM procedure in SAS and means were compared using Tukey’s test. In MILK, there was a greater number of rumen papillae in the cranial, ventral sac and ventral blind sac (p < 0.05); The number of papillae in the dorsal sac and dorsal blind sac, length and width of the ruminal papillae, reticulum volume and concentration of total bacteria were greater in F40+SF60 lambs (p < 0.05). Dry matter intake and daily weight gain were similar between the MILK and F40+SF60 dietary treatments (p < 0.05). The consumption of a combination of fiber and starter feed in neonatal lambs stimulated the development of rumen papillae, allowing weaning without affecting daily weight gain.

ANTIBIOTIC RESISTANCE OF Salmonella spp. ISOLATED FROM POULTRY MEAT AND THE ANTIMICROBIAL EFFECT OF PLANTS EXTRACTS

2025-04-01T12:13:03-04:00

Salmonella spp. is one of the major pathogens causing foodborne disease outbreaks worldwide. It is a priority public health concern due to antimicrobial resistant strains. Poultry is considered to be a major source of transmission of Salmonella spp. The objective of this study was to determine the prevalence and susceptibility of Salmonella spp. strains isolated from poultry to antibiotics and to oregano essential oil (Origanum vulgare L.), chestnut shell extract (Castanea sativa) and grape pomace extract (Vitis vinifera). Samples were collected from chickens, hens and broilers (cloacal swabs) (n=120), poultry meat (n=98) and eggs (n=138). Salmonella spp. were isolated by selective enrichment and culture method and confirmed by polymerase chain reaction (PCR) (identification of hilA gen). ERIC fingerprinting PCR was used to select strains according to their genetic diversity. Susceptibility of selected strains to antibiotics and plant extracts was determined by disk diffusion method and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by dilution method. The total prevalence of Salmonella spp. was 6.53% (23/356) and only meat samples were positive, with a higher prevalence in packaged meat (P ? 0.05). All selected strains were multi-drug resistant, i.e. resistant to three or more classes of antibiotics. Oregano essential oil and chestnut shell extract had antibacterial activity against resistant Salmonella spp. isolates. However, grape pomace extract showed no inhibitory activity. Therefore, the use of oregano essential oil and chestnut shell extract at some stages of the poultry production chain should be evaluated in future studies to have solutions for the industry.

COIRÓN DULCE (Festuca gracillima Hook, f.) GROWTH PHYSIOLOGY UNDER DIFFERENT DEFOLIATION INTENSITY LEVELS AND WATER RESTRICTION REGIMES

2025-03-19T11:16:17-04:00

Festuca gracillima Hook, f. is a tussock grass species that grows and dominates the rangelands of the Magellan Region in Chile. It may exhibit tolerance to water restriction, while low defoliation intensity could encourage F. gracillima growth regardless of the severity of water deficit. This study aimed to evaluate the effects of defoliation intensity under two water restriction regimes. Two factors were evaluated, defoliation intensity and water restriction regimes. The first factor was defoliation intensity, with four defoliation heights: 3, 5, 8 and 10 cm. The second factor was two levels of water restriction regimes: one emulating typical field conditions of the rangeland, and the other simulating severe water restriction. The experimental design was a randomised complete block design (four defoliation heights x two water restriction regimes x five blocks). The experiment was conducted in a glasshouse, and the data were interpreted using accumulated growing degree days (GDD; base temperature of 0 °C). Defoliation at a height of 10 cm promoted lamina elongation and plant growth under both water restriction regimes, compared to treatments with a greater defoliation intensity. The phyllochron for the species was estimated to range between 262 and 286 GDD across all treatments, increasing up to 504 GDD under severe water restriction at the end of the experimental period. Soil water restriction delayed plant development (i.e., increased the phyllochron) and extended leaf lifespan. Festuca gracillima exhibits a conservative growth strategy (slow traits), which enables it to tolerate high levels of water restriction.

ASSESSMENT OF PLANT DENSITY AND INTERACTIONS WITH SOIL TYPES AND TRANSPLANTING METHODS IN RICE CULTIVATION

2025-02-24T14:15:52-05:00

Soil properties play a critical role in determining rice yield by influencing both belowground and aboveground parts of the plant, while also affecting optimal plant density. This study aimed to evaluate the effects of plant density and its interactions with two distinct soil types under manual and mechanical transplanting across two growing seasons of rice cultivation. A split-split plot arrangement was employed within a randomized complete block design with four replications. Two soil types with distinct properties (first soil type and second soil type) were considered as the main factor, planting methods (manual and mechanical transplanting) as the sub-factor, and plant densities (15.9, 20.8, and 27.8 plants m-2) as the sub-sub-factor. Phenological traits, root characteristics, yield, and yield components were assessed. In 2022, at panicle initiation, the longest root length (23.93 cm) was observed at a density of 27.8 plants m-2, while the highest root fresh weight (66.23 g) was recorded in the second soil type. At maturity, the second soil type at a density of 15.9 plants m-2 with manual transplanting recorded the longest root length (22.43 cm), and the highest root fresh weight (86.40 g). Regarding number of spikelets per panicle, in 2021, the highest values were observed in the first and second soil types at 27.8 and 15.9 plants m-2, reaching 122.7 and 122.1 spikelets, respectively; in 2022, the second soil type with 27.8 plants m-2 recorded the highest value of 122.4 spikelets. The second soil type with 27.8 plants m-2 achieved the highest number of panicles, with values of 554.6 and 547.4 under mechanical and manual transplanting, respectively. Grain yield was indirectly
influenced by yield components, being 8.7% higher in the second soil type compared to the first soil type (8048 kg ha-1), peaking at 8687 kg ha-1 at a density of 27.8 plants m-2. A density of 27.8 plants m-2 increased the number of spikelets per panicle in the first soil type, while it increased the number of
panicles per m-2 in the second soil type. Accordingly, a density of 27.8 plants m-2 is recommended for both soil types.

EFECTO DE DIFERENTES TIPOS DE MULCH SOBRE EL DESARROLLO AGRONÓMICO DEL CULTIVO DE PEPINO (Cucumis sativus L.), ECUADOR

2024-11-01T20:48:57-04:00

La mayoría de los cultivos son afectados por diversos factores, como la geotemperatura y microclima, los cuales impactan significativamente el desarrollo de las plantas. El uso de coberturas vegetales o mulch tiene un impacto positivo sobre la geotemperatura y microclima, la temperatura en la zona radicular, la vida microbiana y las propiedades físicas del suelo, contribuyendo al incremento en la productividad de los cultivos. El objetivo de esta investigación fue evaluar el desarrollo agronómico del cultivo de pepino (Cucumis sativus L.) bajo coberturas vegetales. Se analizaron parámetros de geotemperatura, humedad relativa, temperatura ambiental y propiedades físicas del suelo, así como variables morfológicas y de rendimiento. Se utilizó el diseño cuadrado latino, donde el factor de estudio fue diferentes tipos de mulch orgánico: suelo desnudo (control; T1), banano (T2), paja (T3) y cacao (T4). Los resultados mostraron que los tratamientos con mulch redujeron la temperatura del suelo hasta en 4,69 °C (T3) respecto al control, generando un microclima más estable. T3 y T4 presentaron los mejores valores en diámetro de tallo, biomasa y rendimiento (7,61 t ha?¹ y 6,39 t ha?¹, respectivamente). En conclusión, las coberturas vegetales evaluadas son una alternativa eficaz para aumentar la productividad y rendimiento del cultivo del pepino.

ENHANCEMENT OF GERMINATION IN SOYBEAN (Glycine max L. Merrill) SEEDS BY PRE-TREATMENT OF SEEDS WITH MAGNETIC FIELD

2025-01-23T13:10:19-05:00

The effects of magnetic field (MF) on the germination percentage of soybean seeds and the development of seedlings were investigated in this study. Static MFs of 0, 0.5, 1.0 and 5.0 mT, generated by a coil, were applied to seeds. Sterilized seeds in plastic bags were exposed to the MF flux densities for one hour per day over four days. After MF application, seedlings were potted in soil and germinated under greenhouse conditions. The germination experiment was conducted over a 72 hour-period. Germination percentages increased in the 0.5, 1.0, and 5.0 mT treatments, compared to the control group. The length and fresh weight of seedlings exposed to MF were greater than those of the control group (p<0.005), but there was no significant difference in mean dry weights between the experimental and control groups (p>0.005).

FOLIAR AND ROOT INOCULATION OF LETTUCE PLANTS WITH BACTERIA ISOLATED FROM MELIPONIDS IN COMBINATION WITH ARBUSCULAR MYCORRHIZAL FUNGI AND PHOSPHORUS APPLICATION

2024-07-22T23:44:56-04:00

This research evaluated the plant growth-promoting effects of the inoculation of bacterial strains isolated from meliponids (stingless bees) in lettuce. Two bioassays were performed under greenhouse conditions. In the first bioassay, eleven bacterial strains previously isolated from meliponids were inoculated through leaves or roots of lettuce seedlings; greenness index (SPAD units), leaf area, and dry weight (aerial, root and total) were evaluated using a completely randomized design, and the two bacteria with the highest plant- promoting capacity were selected. In the second bioassay, the selected strains were inoculated in combination with arbuscular mycorrhizal fungi (AMF; Claroideoglomus claroideum and Funneliformis mosseae) and three doses of phosphate fertilization (11, 22 and 44 ?g P mL-1); fresh weight, leaf area, dry weight (aerial, root and total), and mycorrhizal colonization were assessed using a 4x2x3 factorial design. In the first bioassay, the results showed that the evaluated bacteria had positive effects on all variables, with Pantoea anthophila and Serratia
nematodiphila being the most prominent strains as plant growth promoters. In the second bioassay, significant differences were observed between the inoculated plants and the control, particularly in dry weight and leaf area. AMF-inoculation did not show significant differences compared to the bacterial combination. In addition, the application of 22 ?g P mL-1 with the combined inoculation of Pantoea anthophila and Serratia nematodiphila had a significant impact on plant growth. Overall, the use of bacteria isolated from stingless bees enhances plant growth and, combined with AMF and/or low or medium doses of P- fertilization, constitutes a good strategy to produce lettuce plants.

POST-MOWING AND SEQUENTIAL HERBICIDE APPLICATION IN THE MANAGEMENT OF SOURGRASS (Digitaria insularis)

2025-03-25T09:59:28-04:00

The excessive use of glyphosate in crop production has led to the emergence of sourgrass (Digitaria insularis) populations resistant to this herbicide. The species has a high capacity for emergence and development throughout the year, making it difficult to control during the off-season. The objective of the this study was to evaluate the effectiveness of glyphosate application, alone or in mixture, integrated with post-mowing management or sequential herbicide application for the control of sourgrass in fallow areas in Paraná State, Brazil. The experiment was carried out in a 2 × 5 factorial scheme (with or without mowing × herbicides), under a complete block experimental design with randomized treatments, with four replications. Herbicide applications were made on the reshoots of the mowing management treatment when plants reached a height between 10 and 20 cm. In the unmowed plants, after the initial herbicide application (glyphosate + graminicides), a sequential application of paraquat was performed. Sourgrass control was determined at 7, 14, 21, 28 and 35 days
after application, DAA). The results revealed that mowing D. insularis followed by the combined application of glyphosate and other herbicides is a good strategy for the management of this weed. The combined application of glyphosate + clethodim (1480 + 248 g a.i. ha-1), followed by a sequential application of paraquat, was effective in controlling sourgrass and produced results comparable to mechanical management.

DIFFERENTIAL VARIATION IN THE MEAN ISOTOPIC SIGNATURES OF SPIDER HUNTING STRATEGIES INFLUENCED BY LANDSCAPE FEATURES

2025-02-28T08:38:35-05:00

Spiders may play a crucial role as versatile predators within agroecosystems. Their diverse behavioral patterns, organized into different guilds, can significantly impact multitrophic interactions. Natural vegetation cover surrounding orchards can influence this predatory behavior, which in turn can impact the feeding patterns of different spider predatory guilds. This study aims to examine the differences among spider guilds actively foraging on apple orchards with different levels of surrounding natural vegetation density (SNVD). To achieve this, natural carbon and nitrogen isotope enrichment was used to assess the variations in isotopic signatures among spider guilds across a gradient of surrounding natural vegetation cover, categorized into three levels (low, medium, and high density), as an indicator of landscape complexity. The mean carbon and nitrogen isotopic signatures exhibited greater variability in diurnal aerial ambushers and orb-weaving spiders, particularly in landscapes with high complexity. Interestingly, similar variability was observed in samples from orchards surrounded primarily by agricultural land (with low SNVD). No significant differences in spider abundance were found across guilds or SNVD categories in apple orchards, suggesting that the spiders guilds identified in these orchards are not influenced by landscape categories. We further describe the guilds identified, which could potentially contribute to the biological control of pests in apple orchards.

Colletotrichum sp. ASSOCIATED WITH SOYBEAN AND CORN ANTHRACNOSE IN THE PAMPAS REGION OF ARGENTINA

2025-04-12T16:20:48-04:00

Colletotrichum species (C.) exhibit considerable genetic variability, causing diseases in different hosts and showing physiological specificity between isolates that interact with different genotypes of the same crop. The objective of this study was to identify Colletotrichum isolates collected from symptomatic plants of various plant species and environments in the central region of Argentina. Isolates were obtained from symptomatic stems of soybean, corn, alfalfa, and citrus plants. Fungal identity was confirmed through macro- and micromorphological analysis, as well as molecular techniques including by RAPD and sequencing of ITS1 and ITS4 fragments amplified by PCR. The identified Colletotrichum species included: C. truncatum and C. gloeosporioides in soybean, C. graminicola in corn, C. gloeosporioides in tangerine, and C. truncatum in alfalfa. These results highlight the plasticity of this pathogenic complex and the epidemiological risk posed by corn-soybean crop rotation for the development and severity of anthracnose.