Recipient Organization
FORT VALLEY STATE UNIVERSITY
1005 STATE UNIVERSITY DRIVE
FORT VALLEY,GA 31030
Performing Department
Animal Science 0331
Non Technical Summary
This research project will be conducted to evaluate the effects of using mixtures of endemicforages and high-qualityforagesfor meat and dairy ruminants to increased animal production in tropical and subtropical areas of the United States. This research would contribute to developing efficient methods to increase animal production under tropical andsubtropical conditions andreduce groundwater contamination by ruminants. This project would help low-income farmers in Georgia to increase revenues from animal products (meat and milk) by using local forages and reduce the use of commercial forages. Additionally, this project would help to increase animal health by preventing parasitic infections. To accomplish these objectives the current project would use dairy and meat goats as a model of study, the animals will be fed with mixtures of the forages previously mentioned in the form of silage, simultaneously another group of animals will be fed with a typical silagewithout any mixture(control animals). At the end of the study, both milk and meat samples will be collected and compared between groups (mixtures vs control). Scientific information from this study will serve for training undergraduate students and graduate students in the areasof animal sciences and food science. The study will include an economic analysis to educate farmers in extension programs. Finally, this project would help toincrease Animal productionin Georgia but also indirectly reduce the importation of meat and dairy goat products in theUnited States.
Animal Health Component
70%
Research Effort Categories
Basic
20%
Applied
70%
Developmental
10%
Goals / Objectives
Thisproject will expand the current knowledge about the mode of action of silage additives applied to silage mixtures and its effects on the metabolome and microbial communities in silages. Likewise, this study will evaluate the subsequent effects of silage mixtures on microbial communities in the rumen and nitrogen balance in ruminants.The specific objectives of the project are:To evaluate the associative effects of homofermentative bacterial inoculants on fermentation, quality, microbial communities and metabolome of alfalfa-bermudagrasssilage mixturesTo evaluate the associative effects of homofermentative bacterial inoculants on fermentation, quality, microbial communities and metabolome of alfalfa-lespedeza silage mixturesTo measure the effects of alfalfa-bermudagrass silage mixtures on intake, microbial communities, milk yield and cheese quality of dairy goatsTo measure the effects of alfalfa-lespedeza silage mixtures on intake, digestibility, rumen microbiome and metabolome of meat goats infected withHaemonchus contortusRationale and significance of the projectIn the southeastern United States, warm-season forages are the major source of fiber for ruminants, however warm-season grasses are considered low-quality forages(Bernard et al., 2010). Biological and chemical treatments during ensiling have proven to be effective for increasing the quality and digestibility of warm-season grasses(Adesogan et al., 2004; Dean et al., 2005), however, their effects on animal performance have been inconsistent(Arriola et al., 2011; Bernard et al., 2010; Romero et al., 2016). Thus, ensiling mixtures of lower-quality and higher-quality forages could be an alternative to increase the use of warm-season grasses like bermudagrass and lespedeza but also reducing nitrogen losses in high-quality legumes like alfalfa(Wattiaux and Karg, 2004). Likewise, silage supplementation using mixtures of medium-quality forages like lespedeza and high-quality forages like alfalfa could be a valuable strategy to increase animal performance in subtropical areas because lespedeza and bermudagrass cannot fully meet the nutritional requirements for growing animals in tropical and subtropical areas (Turner et al., 2005; Animut et al., 2008) . Ensiling lespedeza-alfalfa mixtures could increase animal performance and meat quality in goats but could also serve as a nutraceutical by preventing parasitic infections. The effects of ensiling mixtures of forages on the dynamics of microbial communities and pathway regulation in the silage have not been evaluated. Therefore, this study will be evaluating the associative effects of inoculants on fermentation, quality, microbial communities and metabolome of alfalfa-bermudagrass mixtures and alfalfa- lespedeza silage mixtures.This study would evaluate for the first time the effects of silage mixtures of forages on nitrogen balance in dairy goats in the southeastern United States and its effects on microbial communities in the rumen, milk yield, meat quality and cheese quality.This study will expand the current knowledge about silage mixtures with nutraceutical properties and its effects on performance, health and meat quality in ruminants.
Project Methods
Methods for mini-silo experiments (objectives 1 and 2)This study will be conducted in collaboration with the department of Animal Sciences at University of Georgia- Tifton and Kentucky State University. Representative samples of alfalfa and bermudagrass will be harvested from 3-year plots previously established and evaluated (Hendricks et al., 2019). Plots will be harvested at early bloom following the procedure described by Hendricks et al. (2019) and Ogunade et al. (2018). Both forages will be chopped to a cut of 19 mm with ~ 50% DM content for alfalfa and ~25% DM bermudagrass. Alfalfa will be ensiled in 3 kg mini-silos in a 2 x 6 factorial arrangement with two treatmentsa)Control (distilled water only)b)1 × 106cfu/g ofLactobacillus plantarumR2014and six inclusion levels of bermudagrass forage0, 20, 40, 60, 80and100%. Similarly, representative samples of early regrowth lespedeza will be harvested (~ 40% DM) from experimental plots at Fort Valley State University and ensiled with Alfalfa in 3 kg mini-silos in a 2 x 6 factorial arrangement with two treatmentsa)Control (distilled water only)b)1 × 106cfu/g ofLactobacillus plantarumR2014and six inclusion levels of lespedeza forage at0, 20, 40, 60, 80and100%. All treatments will be ensiled in triplicate for 0, 3, 7, 16 and 100 days. After opening, 200 grams of fresh silage from each treatment will be immediately frozen (-20°C) for microbiome analysis (16s rRNA) and metabolomic profiles.Representative samples (100 grams) of each treatment will be oven-dried and ground at 1 ~mm for chemical composition, including DM, CP, NDF, ADF, and WSC. Additionally, the silage extract will be analyzed for pH, ammonia nitrogen, and organic acids (Lactic acid, Acetic acid, Propionic acid, and Butyric acid), as well as microbial counts (yeast and mold). Samples ensiled for 100 days will be analyzed for aerobic stability for 14 days.All treatments will be evaluated forin-vitrotrue DM digestibility. Samples will be incubated for 24 hours in quadruplicate. Individual samples will be incubated in 250 mL-glass vials sealed with a rubber cap and aluminum seals, and gas production will be measured at 0, 3, 6, 12, and 24 h andresidues will be analyzed forin vitroNDF and ADF digestibility.Silage samples will be suspended in deionized water, centrifuged (17,000 ×gfor 10 min), and the supernatant fluid will be stored at -20°C prior to determination of metabolites with global metabolomics profiling using gas chromatography-mass spectrometry (GC-MS). Similarly, functional diversity of the silage microbiome will be investigated by generating a metatranscriptomic profile of the diverse microbial community, with major focus on plant cell wall degrading enzymes. Polyadenylated RNA will be sequenced andcontigs will be assembled and specific plant degrading enzymes will be identified from the assembled contigs.Methods for in vivo evaluation of silage mixtures using dairy and meat goats (objectives 3 and 4)Dairy goats studyFor experiment 3, 30 early lactation (~20 days in milk) multiparous Alpine dairy goats will be used.The goats will be stratified by body weight (BW), milk yield, and parity into three treatment groups;a) Alfalfa silage, b) Bermudagrass silage and c) Alfalfa: Bermudagrass silage mixture.The optimum ratio between alfalfa and bermudagrass will be estimated based on the results of objective 1. The experimental diets will be fed for 10 weeks with the initial 10 days used as covariate. The diets will be formulated following the dairy NCR (2001), and the total mixed ration (TMR) will include concentrate, vitamins, minerals and the silage treatments. The TMR will be fedad libitum, estimating ~10% refusal per day.Fresh forages will be chopped (~19 mm), packed to a density of 210 kg/m3and ensiled for 180 days before initiation of the feeding experiment. Silage treatments will be prepared in bunker silos (500 kg each) and sprayed with1 × 106cfu/g ofLactobacillus plantarumR2014. Representative samples of the silage will be taken before and after ensiling to estimate quality and chemical composition.Dry matter intake will be recorded daily (Calan-systems). Orts will be collected and weighed individually every day at 07:30 h, additionally, blood samples will be collected weekly for analysis of glucose, blood urea nitrogen (BUN), Non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHBA). Once a week, rumen contents from 15 animals (5 per treatment) will be sampled using the stomach tube method before feeding and a subset of strained rumen fluid samples will be used to estimate fermentation parameters (VFA and Ammonia nitrogen concentrations). Another subset of strained rumen fluid samples will be centrifuged (17,000 ×gfor 10 min) and the supernatant fluid will be stored at -20°C prior to determination of metabolites. Functional diversity of the ruminal microbiome will be investigated by generating a metatranscriptomic profile of the diverse microbial community.Milk yield will be recorded daily, and milk samples will be collected twice a week for milk protein, fat and fatty acid profiles analyses. Representative samples of milk (100 ml/animal/treatment) from each treatment will be collected once a week, pooled, and stored to manufacture cheese. Cheese preparation will be conducted following the procedure reported by Siddique and Park, (2019). Cheeses will be manufactured in triplicate and chemical analysis and cheese fatty acid composition will be analyzed per treatment. Additionally, samples of whey will be collected and analyzed for metabolites and global metabolomics profiling using GC-MS.Meat goats studyFor experiment 4, 30 growing Spanish kids (21 kg) will be used.The goats will be naturally infected withHaemonchus contortus. Before starting the experiment, animals will be placed in individual cages and fed three treatmentsa) Alfalfa hay, b) Lespedeza hay c) Alfalfa: lespedeza silage mixture.The optimum ratio between alfalfa and lespedeza will be estimated based on objective 3 results. The experimental diets will be fed for 8 weeks. The diets will be formulated following NCR recommendations, and the total mixed ration (TMR) will include concentrate, vitamins, minerals and the silage treatments. The TMR will be fedad libitum, estimating ~10% refusal per day.For the alfalfa:lespedeza mixture, forages will be chopped at (~19 mm) and ensiled with a density of 210 kg/m3and ensiled for 180 days before starting the feeding trial. Silage will be prepared in a bunker silo and sprayed with1 × 106cfu/g ofLactobacillus plantarumR2014. Representative samples of the silage will be taken before and after ensiling to estimatechemical composition.Dry matter intake will be recorded daily. Orts will be collected and weighed for individually every day at 07:30 h. Feed samples will be taken every week to adjust intake and analyzed for chemical composition (CP, NDF, ADF, and Organic Matter).The goats will be weighed once a week, blood and fecal samples will be collected weekly. Blood samples will be analyzed for glucose, blood urea nitrogen and non-esterified fatty acid concentration, as well as for packed cellular volume (PCV). Fecal samples will be analyzed for gastrointestinal nematodes (eggs per gram) and coccidial oocysts to estimate the parasitic burden. At the end of the experiment, the animals will be slaughtered and a subset of strained rumen fluid samples will be used to estimate fermentation parameters (VFA and Ammonia nitrogen concentrations).Another subset of strained rumen fluid samples will be centrifuged (17,000 ×gfor 10 min) and the supernatant fluid will be stored at -20°C prior to determination of metabolites. Functional diversity of the ruminal microbiome will be investigated by generating metatranscriptomic profile of diverse microbial community .Representative samples of muscle will be collected and analyzed for meat quality and fatty acid profiles.