Use of Supplements to Increase Liveweight Gain and Wool Growth of Sheep Mainly Dependent on Fibrous Feeds

The experiments reported in this thesis were conducted to study sources of protein, which are available in developing countries, as supplements for ruminants fed low quality fibrous diets. Supplementation with dietary protein or non-protein nitrogen (urea) is usually suggested as a means to increase production of animals fed a low quality diet. The provision of rumen undegradable protein is suggested to supply dietary amino acids to ruminant. In the study presented here, urea and by-pass protein sources (cottonseed meal, sunflower meal, palm kernel cake, and copra meal) were used in combination as supplements for sheep fed a low quality fibrous diet. In the first experiment, the efficiency of utilization of these protein-rich supplements was compared in sheep given a low quality fibrous diet. In the second experiment, the accuracy of a technique for estimation of intake of the supplements was determined using lithium chloride as a marker. Supplementary feeding of grazing sheep during winter/spring in The Northern Tablelands of New South Wales is necessary to maintain or to support animal production. A third experiment was carried out in grazing sheep to investigate the effect of supplementary feeding during a period of low pasture growth in winter/spring in The Northern Tablelands of New South Wales. The lithium chloride technique was used to measure the intake of supplements by grazing sheep

Meta-analysis quantifying the potential of dietary additives and rumen modifiers for methane mitigation in ruminant production systems

Increasingly countries are seeking to reduce emission of greenhouse gases from the agricultural industries, and livestock production in particular, as part of their climate change management. While many reviews update progress in mitigation research, a quantitative assessment of the efficacy and performance-consequences of nutritional strategies to mitigate enteric methane (CH4) emissions from ruminants has been lacking. A meta-analysis was conducted based on 108 refereed papers from recent animal studies (2000-2020) to report effects on CH4 production, CH4 yield and CH4 emission intensity from 8 dietary interventions. The interventions (oils, microalgae, nitrate, ionophores, protozoal control, phytochemicals, essential oils and 3-nitrooxypropanol). Of these, macroalgae and 3-nitrooxypropanol showed greatest efficacy in reducing CH4 yield (g CH4/kg of dry matter intake) at the doses trialled. The confidence intervals derived for the mitigation efficacies could be applied to estimate the potential to reduce national livestock emissions through the implementation of these dietary interventions

Quantifying daily methane production of beef cattle from multiple short-term measures using the GreenFeed system

On-farm CH₄ emissions have been identified as the largest contributors to the carbon footprint of livestock production systems. A requirement to quantify on-farm mitigation under commercial production conditions and a desire to establish the phenotype of thousands of ruminants for breeding programs, has fueled the development of techniques to estimate daily methane production (DMP) from short-term measures of methane concentration or methane flux.The accuracy, precision and applicability of these methods has been largely untested and forms the susbtance of this thesis. In assessing the accuracy of short-term emissions measures to estimate DMP, a high level of concordance was observed between DMP measured over 24h in a respiration chamber (RC) and estimated from multiple short-term measurement estimates using the GreenFeed Emission Monitoring system (GEM). Three independent experiments comparing DMP confirmed that estimates between methods differ by 5% to 8% (P>0.05). This implies that multiple short-term measures of emission rates are complementary to and consistent with respiration chamber-derived measures, providing capability to measure a greater number of animals, potentially in their production environment over extended periods of time. Methane yields (MY; g CH₄/kg DMI) were also derived based on multiple short-term emission measures, with results consistently within 10% of those calculated based on 24h RC data. The overall MY of animals consuming roughages was 21.8g CH₄/kg DMI using GEM data, in keeping with the 22.3g CH₄/kg DMI average in the literature. That implies that GEM units can not only accurately estimate DMP of cattle but also support accurate MY estimates that can be used in quantifying livestock emissions for national greenhouse inventory calculations

Impact of gut kinetics on methane production within the sheep

Methane emissions from ruminant livestock is a major source of greenhouse gases, accounting for approximately two-thirds of anthropogenic methane sources. Methane yield from ruminants (MY; g/kg DM intake) is known to be positively correlated with the mean retention time (MRT) of rumen contents, and MRT in the rumen is largely controlled by the contractile forces of the reticulo-rumen and the relaxing of the reticulo-omasal orifice. The discovery of immuno-reactive endocrine and neural cells distributed throughout the epithelia and glands of the digestive tract suggest that the endocrine system may play a key role in regulating digesta MRT and MY in ruminants. The thyroid hormone triiodothyronine (T₃), known to influence digesta kinetics, was used to initiate our studies to modify digesta MRT and determine the impact that digesta MRT has on the production of enteric methane and MY. To investigate the influence digesta kinetics had on ruminant MY, it was necessary to develop a kinetic model capable of accurately estimating the rate of flow of digesta through the digestive tract. An extensive review of existing published mathematical models for ruminant digesta kinetics was conducted and a model developed by Aharoni et al. (1999) for the estimation of cattle digesta kinetics was selected and modified to produce a new multicompartmental double-marker digestive tract model for use in sheep

Sequence Variation in Multidrug-Ressitant Plasmid pLUH01, Isolated from Human Nasopharyngeal Swabs

Three variants of the multidrug-resistant plasmid pLUH01 were assembled by deep sequencing from nasopharyngeal swabs. All have a 21-bp deletion in the RS14515 hypothetical gene. Variants 1 through 3 have 2, 6, and 3 nucleotide substitutions, respectively, compared to the pLUH01 reference genome. We named the new plasmid variants pLUH01/Lancaster/2015/1 to pLUH01/Lancaster/2015/3

Genome Sequence of Human Rhinovirus A22, Strain Lancaster/2015

The genome of human rhinovirus A22 (HRV-A22) was assembled by deep sequencing RNA samples from nasopharyngeal swabs. The assembled genome is 8.7% divergent from the HRV-A22 reference strain over its full length, and it is only the second full-length genome sequence for HRV-A22. The new strain is designated strain HRV-A22/Lancaster/2015

Genome Sequence of Human Papillomavirus 23 Strain HPV-23/Lancaster/2015

The genome of human papillomavirus type 23 (HPV-23; family Papillomaviridae, genus Betapapillomavirus, species Betapapillomavirus 2, type 23) was assembled by deep sequencing from nasopharyngeal swabs. The assembled genome is 2.7% divergent over its full length from the single complete genome of HPV-23 in GenBank (accession no. U31781). We named the strain HPV-23/Lancaster/201

Nasopharyngeal metagenomic deep sequencing data, Lancaster, UK, 2014-2015

Nasopharyngeal swabs were taken from volunteers attending a general medical practice and a general hospital in Lancaster, UK, and at Lancaster University, in the winter of 2014–2015. 51 swabs were selected based on high RNA yield and allocated to deep sequencing pools as follows: patients with chronic obstructive pulmonary disease; asthmatics; adults with no respiratory symptoms; adults with feverish respiratory symptoms; adults with respiratory symptoms and presence of antibodies against influenza C; paediatric patients with respiratory symptoms (2 pools); adults with influenza C infection (2 pools), giving a total of 9 pools. Illumina sequencing was performed, with data yields per pool in the range of 345.6 megabases to 14 gigabases after removal of reads aligning to the human genome. The data were deposited in the Sequence Read Archive at NCBI, and constitute a resource for study of the viral, bacterial and fungal metagenome of the human nasopharynx in healthy and diseased states and comparison with other metagenomic studies on the human respiratory tract

Genome sequence of human papillomavirus type 20, strain HPV-20/Lancaster/2015

The genome sequence of human papillomavirus type 20 (HPV-20; family Papillomaviridae, genus Betapapillomavirus, species Betapapillomavirus 1, type 20) was assembled by deep sequencing from nasopharyngeal swabs. The assembled genome is 0.37% divergent over its full length from the single complete genome of HPV-20 in GenBank (U31778). We named the strain HPV-20/Lancaster/2015

An evaluation of emerging feed additives to reduce methane emissions from livestock

The inclusion of feed additives in livestock diets or supplements is a routine global nutritional management practice. Consequently, the existing commercial feed additive marketing and delivery pathways will be able to deliver rapid market penetration of feed additives specifically developed to reduce enteric methane emissions. So, the delivery path is clear, but are the methane mitigating additives available, effective, and are there any constraints or risks associated with their use? To answer these questions an assessment of the ten leading classes of compounds being studied for methane mitigation efficacy in ruminants was made. The assessment is provided as a concise resource that can serve as an evidence base to guide investment and management decisions by all actors in the livestock additive supply chain