The influence of use systems on the productivity of shrubephemeral desert pastures and the preservation of herbage

The article is devoted to the urgent problem of developing a scientifically based organization and use of distant pastures in the south of Kazakhstan. It has been found that the composition and diversity of pasture grasses have significant effect on the forage value of the grass stand and ultimately affect the forage capacity of desert pastures. Grazing of farm animals should be carried out with an optimal load on pastures, that is, no more than 70% of the productivity of the pasture mass should be exploited. Due to the better preservation of various types of forage plants and pasture herbage in general with systematic use, the yield of pastures in the summer season was 6.15 c/ha, in other words it was higher by almost 1.0 c/ha of dry forage mass compared to unsystematic grazing (5.20 c/ha). All pasture plants exploited in early spring produced aftermath in 10–15 days and were well preserved from overexploitation and trampling.

The Known Antimammalian and Insecticidal Alkaloids Are Not Responsible for the Antifungal Activity of Epichloë Endophytes

Asexual Epichloë sp. endophytes in association with pasture grasses produce agronomically important alkaloids (e.g., lolitrem B, epoxy-janthitrems, ergovaline, peramine, and lolines) that exhibit toxicity to grazing mammals and/or insect pests. Novel strains are primarily characterised for the presence of these compounds to ensure they are beneficial in an agronomical setting. Previous work identified endophyte strains that exhibit enhanced antifungal activity, which have the potential to improve pasture and turf quality as well as animal welfare through phytopathogen disease control. The contribution of endophyte-derived alkaloids to improving pasture and turf grass disease resistance has not been closely examined. To assess antifungal bioactivity, nine Epichloë related compounds, namely peramine hemisulfate, n-formylloline-d3, n-acetylloline hydrochloride, lolitrem B, janthitrem A, paxilline, terpendole E, terpendole C, and ergovaline, and four Claviceps purpurea ergot alkaloids, namely ergotamine, ergocornine, ergocryptine, and ergotaminine, were tested at concentrations higher than observed in planta in glasshouse and field settings using in vitro agar well diffusion assays against three common pasture and turf phytopathogens, namely Ceratobasidium sp., Drechslera sp., and Fusarium sp. Visual characterisation of bioactivity using pathogen growth area, mycelial density, and direction of growth indicated no inhibition of pathogen growth. This was confirmed by statistical analysis. The compounds responsible for antifungal bioactivity of Epichloë endophytes hence remain unknown and require further investigation.

336 Occurrence of Mycotoxins in 2020 US Pasture Grasses and Harvested Hay Feed Ingredients

Mycotoxins are harmful secondary fungal metabolites which limit animal health and performance through various negative effects such as reduced feed intake, diarrhea, and compromised immune and reproductive function. These metabolites are found in a variety of feedstuffs worldwide. This study monitored mycotoxin occurrence and contamination levels in fresh pasture grasses and harvested dry hay from across the US. Samples were screened for six major mycotoxin groups: aflatoxins, type A trichothecenes (A-Trich), type B trichothecenes (B-Trich), fumonisins (FUM), zearalenone (ZEN), and ochratoxin A via LC-MS/MS. Samples that were above the limit of detection for each mycotoxin group were analyzed using the GLIMMIX procedure of SAS (SAS 9.4, Cary, NC) to test the effect of harvest year on average contamination level. Results are presented in Table 1. Zearalenone and B-Trich contamination prevalence for fresh grass samples was lower in 2020 compared to the previous two years. A-Trich tested positive in 34% of samples which was greater in 2020 compared to 2018 and 2019. Mean concentration levels (parts per billion, ppb) for B-Trich, ZEN, A-Trich were not different in 2020 compared to the previous two years. Prevalence of mycotoxin contamination for dry harvested hay samples for B-Trich and ZEN decreased in 2020 compared to the previous two years, but 64 and 28% of samples tested positive, respectively. A-Trich prevalence was greater than the last two years and resulted in 17% of samples testing positive compared to 0 and 6% in 2018 and 2019, respectively. Mean B-Trich levels in 2020 were similar to levels seen in 2018 and lower than 2019 (P = 0.005). Mean ZEN and A-Trich concentration levels averaged 1,612 ppb and 796 ppb, respectively. Mycotoxin analysis of pasture grasses and harvested hay forages is warranted to identify potential sources of mycotoxin contamination in ruminant diets.

Novel real-time PCR based assays for differentiating fall armyworm strains using four single nucleotide polymorphisms

The fall armyworm, Spodoptera frugiperda, is a polyphagous global pest with a preference for gramineous crops such as corn, sorghum and pasture grasses. This species is comprised of two morphologically identical but genetically distinct host strains known as the corn and rice strains, which can complicate pest management approaches. Two molecular markers are commonly used to differentiate between strains, however, discordance between these markers can lead to inconclusive strain identification. Here, we used double digest restriction site associated DNA sequencing to identify diagnostic single nucleotide polymorphisms (SNPs) with alleles unique to each strain. We then used these strain-specific SNPs to develop four real-time PCR based TaqMan assays to rapidly and reliably differentiate between strains and interstrain hybrids. These assays provide a new tool for differentiating between strains in field-collected samples, facilitating future studies on strain population dynamics and interstrain hybridization rates. Understanding the basic ecology of S. frugiperda strains is necessary to inform future management strategies.

Phosphorus Non-Point Pollution from Equestrian Wastes and the Need for Recycling

South Florida and much of the rest of the World suffers from harmful algal blooms (HABs) and controls of both nitrogen (N) and phosphorus (P) pollution are required to curtail the onset, spread and/or expansion of these blooms. This report covers our studies on several aspects of equestrian waste (viz. horse manure) aimed at yielding an overview of phosphorus and its pollution stemming from non-point horse manure sources in portions of Palm Beach County Florida. Methods included a modified Hedley extraction sequence, emphasizing ‘easily extractable phosphorus’ (EEP), and 31P nuclear magnetic resonance (NMR) spectroscopic identification of organic phosphorus (Po) species. Samples included fresh and aged horse manure, pasture soils, horse feed and pasture grasses, and canal waters adjacent to equestrian or agricultural fields. Easily extractable Phosphorus (EEP) averaged about 54-77% of the total horse manure phosphorus. Total phosphorus ranged from 13,020 – 22,300 mg per kilogram dry weight. (≈60-100 lbs. P2O5 / ton and on a wet weight basis, this equates to 4,000 to 14,818 grams-P/ U.S. ton or 8.8 to 32.6 pounds of phosphorus (≈ 20-75 lb. P2O5) per wet weight ton of horse manure. Considering the values of EEP in fresh samples from a single horse, we found a range of 8,000 – 17,000 mg-P/kg (8-17 g-P/kg) dry weight horse manure. Soil samples yielded the highest P in the NaOH extract of the Hedley sequence. This equates to the Al, Fe and ester forms. Phosphorus (viz. EEP) runoff is viewed here as a non-point P pollution source.

A comparison of shared patterns of differential gene expression and gene ontologies in response to water-stress in roots and leaves of four diverse genotypes of Lolium and Festuca spp. temperate pasture grasses

Ryegrasses (Lolium spp.) and fescues (Festuca spp.) are closely related and widely cultivated perennial forage grasses. As such, resilience in the face of abiotic stresses is an important component of their traits. We have compared patterns of differentially expressed genes (DEGs) in roots and leaves of two perennial ryegrass genotypes and a single genotype of each of a festulolium (predominantly Italian ryegrass) and meadow fescue with the onset of water stress, focussing on overall patterns of DEGs and gene ontology terms (GOs) shared by all four genotypes. Plants were established in a growing medium of vermiculite watered with nutrient solution. Leaf and root material were sampled at 35% (saturation) and, as the medium dried, at 15%, 5% and 1% estimated water contents (EWCs) and RNA extracted. Differential gene expression was evaluated comparing the EWC sampling points from RNAseq data using a combination of analysis methods. For all genotypes, the greatest numbers of DEGs were identified in the 35/1 and 5/1 comparisons in both leaves and roots. In total, 566 leaf and 643 root DEGs were common to all 4 genotypes, though a third of these leaf DEGs were not regulated in the same up/down direction in all 4 genotypes. For roots, the equivalent figure was 1% of the DEGs. GO terms shared by all four genotypes were often enriched by both up- and down-regulated DEGs in the leaf, whereas generally, only by either up- or down-regulated DEGs in the root. Overall, up-regulated leaf DEGs tended to be more genotype-specific than down-regulated leaf DEGs or root DEGs and were also associated with fewer GOs. On average, only 5–15% of the DEGs enriching common GO terms were shared by all 4 genotypes, suggesting considerable variation in DEGs between related genotypes in enacting similar biological processes.

THE EFFECT OF TIME OF INITIAL CUTTING ON FORAGE YIELD AND QUALITY OF THREE PASTURE GRASSES AT SHIKA, NIGERIA

The effect of time of cutting on yield and nutritive value of three year old pastures of signal (Brachiaria decumbens), green panic (Panicum maximum var. trichoglume) and buffel (Cenchrus ciliaris ev. Gayndah) grasses were studied. The pastures were harvested for hay yield on 5th November, 1977 and allowed to rest until subjection to initial cut in June, July, August or September, 1978. Immediately after the July cut, all the plots received 100kg N/ha and 40kg P205/ha. Regrowths from the initial cuts and the control (uninterrupted growth) were all cut on 16th November, 1978. The dry matter (DM) yields of the grasses increased with increasing stage of maturity. Signal grass was more productive (P < 0.05) (17.3t/ha) than the other grasses averaged over the cutting dates. The yields of green panic and buffel grasses were 8.3 and 11.0t/ha respectively. The regrowth DM yields declined with a delay in the initial cut. Except for the increases in CP (6.9%) and IVDMD (50.1%) contents of the primary growth in August, these parameters declined as the grasses aged. Deferring the initial cutting date resulted in significant (P < 0.05) increases in CP and IVDMD contents of the regrowths. Percent increases as a result of cutting at the different date over the control for DM and CP yield were 28 and 74, respectively. Further evaluation of the three species in grazing trial is suggested.