Institute of Animal Science and Pastures

This study evaluated combinations of defoliation frequencies and intensities to identify grazing strategies that optimize forage accumulation and morphological composition in mixed pastures of Marandu palisadegrass (Urochloa brizantha cv. Marandu) with the legume Macrotyloma axillare. Treatments consisted of pre-grazing heights of 30 and 40 cm (defining defoliation frequency) combined with post-grazing heights of 15 and 20 cm (defoliation intensity), in a 2 × 2 factorial randomized block design with four repetitions. Forage accumulation rate, morphological component mass, and leaf area index (LAI) were evaluated under rotational stocking. The highest forage accumulation rates of grass and its stems occurred at a pre-grazing height of 30 cm. A taller pre-grazing height (40 cm) resulted in greater pre-grazing forage mass, leaf and stem mass of Marandu palisadegrass and LAI, but it also increased the amount of dead material and post-grazing stem mass. The greatest Macrotyloma forage accumulation occurred under grazing strategies of 30–20 cm and 40–15 cm. Lenient defoliation (20 cm post-grazing height) favored post-grazing leaf mass, whereas severe defoliation (15 cm) favored stem mass. Marandu palisadegrass showed higher LAI at 40 cm pre-grazing height (4.7) than at 30 cm (3.6), with slightly greater values under 20 cm (4.3) than 15 cm (4.1) post-grazing height, while Macrotyloma axillare exhibited low LAI. Across all grazing strategies, the legume mass decreased over time. Therefore, future studies should explore alternative grazing strategies and periodic reseeding of Macrotyloma axillare to maintain its presence in mixed tropical pastures.

The Montana Tropical cattle, a Taurine and Indicine composite, were developed in Brazil since 1994 and were based on crossing four biological types of cattle: zebu (mainly Nelore), tropical adapted taurine (mainly Senepol and Romosinuano), British taurine (mainly Angus) and continental taurine (as Charolais, Simental and Limousin). This study aimed to characterise the genetic ancestry of this composite breed at the genomic level. Principal component analysis revealed the composite in intermediate space between indicine and taurine but closer to the Taurine cluster, which is consistent with its multi-breed origin. The ADMIXTURE analysis indicated the Montana Tropical to be composed of several progenitor breeds without an indication of a dominant breed. Local ancestry analysis showed the Montana animals to have an average of 24% (standard deviation of ±5.41) Zebu ancestry. The total taurine ancestry was 62%, consisting of 19.6% (±6.96) from tropical adapted taurine, 20.1% (±5.99) from British taurine, 21.92% (±7.79) from continental taurine and 14% (±5.26) of the genome was undetermined. Based on the pedigree, these animals would have 20.8% ± 8.5% Zebu, 50.5% ± 14.4% tropical adapted taurine, 21.1% ± 13.5% British taurine and 7.6% ± 5.1% of continental European taurine in their composition. The genomic regions in the composite originating from each biological type highlight the trait complementarity each genetic group contributes. For example, the genomic region of high tropical adapted taurine ancestry was shown to harbour the slick hair locus, and the regions of high indicine ancestry are associated with high length of productive life. This study unravels the complex genetic ancestry of the Montana Tropical composite, highlighting the effective blend of ancestral gene pools that enhance key production and adaptation traits.

Neem cake (Azadirachta indica) is a versatile plant with potential benefits for ruminant animals due to its effects on rumen modulation. This study aimed to evaluate the effects of increasing levels of neem cake and monensin on in vitro ruminal fermentation in cattle diets. Six treatments were tested: neem cake at 0, 240, 480, 720, and 960 mg/kg dry matter (DM) and monensin at 30 mg/kg DM. The basal diet consisted of a diet with a 15:85 roughage-to-concentrate ratio. Parameters evaluated included gas production kinetics, CH4 and CO2 emissions, pH, volatile fatty acids (VFAs), ammonia-N (NH3-N), and organic matter digestibility. Neem cake increased ruminal pH compared to monensin (p < 0.01). The total VFAs increased linearly with neem cake inclusion (p < 0.01). The acetate proportion increased quadratically (p = 0.06). Propionate decreased linearly (p = 0.02), while branched-chain VFAs (BCVFAs) increased linearly (p = 0.09). The neem cake addition increased the NH3-N concentration quadratically (p < 0.01). CH4 and CO2 concentrations were higher with neem cake compared to monensin (p < 0.05). Neem cake shows potential to reduce rumen acidosis and enhance fiber digestion, making it useful during the adaptation period for finishing diets in feedlots and for grazing animals. However, it was not effective in reducing greenhouse gas emissions in this in vitro system.

The use of processing techniques to increase the rumen-undegradable protein (RUP) content of protein meals aims to enhance the nutritional performance of high-performance animals. This study evaluated the effects of various processing techniques applied to peanut and cottonseed meals on ruminal parameters using a dual-flow continuous culture system. These two feeds were individually analyzed in two experiments, each one using five fermenters (1297 ± 33 mL) in a 5 × 5 Latin square arrangement with five periods of 10 d each, with 7 d for diet adaptation and 3 d for sample collections. Five treatments were evaluated in each experiment: no processed meal (control); meal thermally treated in an autoclave with xylose (autoclave); meal thermally treated in a conventional oven with xylose (oven); meal thermally treated in a microwave with xylose (microwave); and meal treated with tannin (tannin). All diets contained 60% concentrate (corn, minerals, and processed meal). Fermenters were fed 55 g of dry matter per day, divided equally into two meals at 06:00 and 18:00 h. The solid and liquid dilution rates were adjusted daily to 5.5% and 11% per hour, respectively. On days 8, 9, and 10, 500 mL samples of solid and liquid digesta effluent were collected, mixed, homogenized, and stored at −20 °C. Subsamples of 10 mL were preserved with 0.2 mL of a 50% H2SO4 solution for later determination of NH3-N and volatile fatty acids. Microbial biomass was isolated from the fermenters for chemical analysis at the end of each experimental period. Data were analyzed using the MIXED procedure in SAS with a significance level of α = 0.05. Regarding cottonseed meal, the tannin treatment tended to have a lower true digestibility of DM compared to the control, autoclave, and oven treatments (p = 0.09). Additionally, tannin fermenters exhibited a lower apparent digestibility of CP compared to all other treatments (p = 0.04). The tannin and microwave treatments resulted in the highest flow of dietary nitrogen and the lowest supply of RDP-N (p < 0.01). The control treatment had a greater flow of NH3-N compared to other treatments (p < 0.01). Regarding peanut meal, the autoclave and tannin treatments exhibited the highest acetate concentration (p = 0.03) and the lowest apparent digestibility of CP (p < 0.01). The tannin treatment increased the RUP content without impairing ruminal fermentation and exhibited a greater supply of RDP-N compared to all other treatments (p = 0.02). No significant differences were observed for the other digestibility and fermentation parameters (p > 0.20). Our results indicate that tannin inclusion and microwave processing were the most effective methods for reducing the protein fraction available in the rumen for cottonseed meal. Additionally, tannin inclusion increased the RUP in peanut meal without negatively affecting ruminal fermentation.

ABSTRACT The objective was to evaluate the influence of nonsteroidal anti-inflammatory drugs on the duration of the luteal phase, progesterone concentrations and pregnancy rates in buffaloes undergoing embryo transfer. Twenty-nine buffaloes were synchronized. After estrus detection, the recipients were divided into three groups: Control (uterine manipulation), Flunixum Meglumine (manipulation + administration) and Firocoxib (manipulation + administration). Ultrasound evaluations and hormonal dosages were performed on days 6, 12 and 18 to determine the plasma concentration of P4 and the functional duration of the corpus luteum. The control group presented a larger CL area on day 0 than the FM group, there was a significant increase in plasma progesterone concentration between D6 and D12 (P < 0.05), and a significant decrease between D6-D18 and D12-D18. Additionally, 8 buffalo cows underwent in vitro embryo transfer and were divided into three groups: CONT (manipulation of the reproductive tract), FM group (manipulation + administration) and FIRO group (manipulation + administration). Pregnancy diagnosis was performed at 30 and 60 days. No statistically significant differences in pregnancy rates were observed between groups. It was concluded that a single application of FM and FIRO at the time of embryo transfer did not significantly increase conception rates.

BackgroundThe selection of individuals based on their predicted breeding values and mating of related individuals can increase the proportion of identical-by-descent alleles. In this context, the objectives of this study were to estimate inbreeding coefficients based on alternative metrics and data sources such as pedigree (FPED), hybrid genomic relationship matrix H (FH), and ROH of different length (FROH); and calculate Pearson correlations between the different metrics in a closed Nellore cattle population selected for body weight adjusted to 378 days of age (W378). In addition to total FROH (all classes) coefficients were also estimated based on the size class of the ROH segments: FROH1 (1–2 Mb), FROH2 (2–4 Mb), FROH3 (4–8 Mb), FROH4 (8–16 Mb), and FROH5 (> 16 Mb), and for each chromosome (FROH_CHR). Furthermore, we assessed the effect of each inbreeding metric on birth weight (BW), body weights adjusted to 210 (W210) and W378, scrotal circumference (SC), and residual feed intake (RFI). We also evaluated the chromosome-specific effects of inbreeding on growth traits.ResultsThe correlation between FPED and FROH was 0.60 while between FH and FROH and FH and FPED were 0.69 and 0.61, respectively. The annual rate of inbreeding was 0.16% for FPED, 0.02% for FH, and 0.16% for FROH. A 1% increase in FROH5 resulted in a reduction of up to -1.327 ± 0.495 kg in W210 and W378. Four inbreeding coefficients (FPED, FH, FROH2, and FROH5) had a significant effect on W378, with reductions of up to -3.810 ± 1.753 kg per 1% increase in FROH2. There was an unfavorable effect of FPED on RFI (0.01 ± 0.0002 kg dry matter/day) and of FROH on SC (-0.056 ± 0.022 cm). The FROH_CHR coefficients calculated for BTA3, BTA5, and BTA8 significantly affected the growth traits.ConclusionsInbreeding depression was observed for all traits evaluated. However, these effects were greater for the criterion used for selection of the animals (i.e., W378). The increase in the genomic inbreeding was associated with a higher inbreeding depression on the traits evaluated when compared to pedigree-based inbreeding. Genomic information should be used as a tool during mating to optimize control of inbreeding and, consequently, minimize inbreeding depression in Nellore cattle.

Abstract Soil organic carbon (SOC) sequestration promotes several ecological, economic, and social co-benefits. However, most SOC studies rely on topsoil evaluations (0–30 cm), disregarding a significant fraction of the SOC that is stored in deep layers. Understanding the relationship between deep soil carbon and climate change is imperative in guiding sustainable land management practices, informing climate change mitigation strategies, and preserving the crucial role of deep soil carbon in regulating atmospheric CO 2 levels. We conducted a comprehensive literature review to discuss the origins of deep soil carbon, the globally standardized methodology recommended for measuring SOC stocks, the mechanisms controlling SOC sequestration (physical, chemical, and biochemical) in deep layers, the significance of microbial community in deep soil layers, advancements in radiocarbon studies, the impact of management practices on deep SOC, and the influence of climate change on deep SOC stocks. Overall, more empirical data and long-term studies are needed to address the knowledge gaps in terms of deep SOC and advance our understanding of the role of deep soil carbon in shaping global carbon cycles and climate resilience. The main challenges for accurate SOC estimations and global carbon budgets are the high spatial variability, the relative lack of deep soil measurements, and the need for reliable reference data for modeling improvements. A practical and accurate soil bulk density (BD) estimation in deep layers (i.e., 30–100 cm) is crucial to improve the accuracy of global C stock estimations and should be addressed in further studies. Modeling approaches based on sensors and machine learning techniques are promising tools to overcome this challenge. However, there is still a large variability in methods to measure and report soil BD and SOC stocks worldwide, preventing further advances.