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Financial pressures associated with high pre-weaning rearing costs, result in dairy calves (Boulton et al., 2017) being weaned from milk much earlier than would occur naturally. This limits the time available for the digestive system to develop from a milk-fed pseudo-monogastric system to a functional ruminant system able to digest complex, fibre-based diets. Calves weaned with a poorly functioning digestive system may have lower growth rates post-weaning (Steele et al., 2017) and consequently may be older at first calving (Heinrichs et al., 2005). Strategies to predict sufficient digestive development for weaning to occur have been developed (e.g. concentrate intake or weaning weight); however, these are often impractical commercially. Identifying the precise point at which a calf is ready to be weaned is therefore challenging (Welk et al., 2024).This project will use already obtained gut tissue, content, and faecal samples from a time-series study on calves to identify molecules in the faeces that have potential to act as markers of digestive tract maturity.

Bovine mastitis represents a major economic and welfare problem to the dairy industry worldwide, estimated to result in annual costs of €20 billion. Streptococcus uberis is a leading cause of bovine mastitis and the second most common cause in Scotland. Treatment often relies on antimicrobials, but with growing concerns over antibiotic resistance across all of human and veterinary medicine, there is a need to develop alternative treatments to preserve conventional antimicrobials. One promising approach to new antimicrobial drugs is phage therapy. Bacteriophages (phages) are naturally-occurring, free-living viruses that infect and kill bacteria. Despite promising results in human medicine, phage therapy has received limited attention for the treatment of veterinary infections. This proposal aims to identify and characterise phages active against S. uberis mastitis isolates from Scotland as validating the potential to develop phage therapy against this important dairy cow pathogen and as a route to preserving effective therapies.

Traditional dairy systems remove calves from their mothers soon after birth. Some Scottish dairy farms have explored ‘cow with calf’ (CwC) systems whereby calves are left with their mothers for up to six months, during which time the cow is also milked for human consumption. There may be health and welfare advantages to CwC systems; internationally, work has begun to study these, but no UK work has compared disease incidence and transfer of passive immunity (TPI). Calves must ingest adequate quantities of quality colostrum soon after birth to confer immunity from their dam; failure to do so (FTPI) increases disease susceptibility. Calf colostrum ingestion may differ in CwC systems, thus altering calfhood morbidity and mortality and cow disease risk (e.g. mastitis). This project will compare traditionally reared calves with CwC calves; investigating the incidence of FTPI and of disease in calves and cows in the first three months after calving.

Agricultural technologies have been commended for their potential to increase farm productivity, but there is limited knowledge about their social impact. This research will investigate the impact of one technology – wearable biosensors for cows – on dairy farmers’ work and wellbeing. Qualitative interviews will be conducted with dairy farmers who have adopted wearables to understand their experiences of using the technology, focusing particularly on how it has influenced their work (i.e. labour processes) and wellbeing (i.e. occupational stress). Additionally, a focus-group will be held with adopters and non-adopters of wearables to further explore perceptions and experiences of the technology. Fieldwork will take place primarily in Scotland, with a small number of interviews in Ireland and southwest England to provide a wider geographical perspective. Outputs will be of interest to a range of agricultural, technology, policy and academic audiences and will inform the development of a larger funding application.

Two groups of cows will be grazed for 1-month long periods in paddocks of two different sward types: perennial ryegrass monoculture (PRG) and a multi-species sward (MSS) comprising of PRG, timothy, white and red clovers, chicory, and plantain. The Grass Is Greener project will assess cow behaviour on these different sward types and evaluate any impacts on cow welfare via leg mounted accelerometers, fitted on all cows as standard farm practice.

Between these month-long grazing periods, all cows will be given the choice of both sward types (MIX), with their behaviour and welfare being assessed again, as well as their location recorded (PRG or MSS) to assess preference.

The Grass Is Greener project would collect additional data from an existing European funded grazing project, Re-Livestock, taking place at SRUC’s Barony campus.

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Bovine viral diarrhoea (BVD) is a major cattle disease caused in the UK by BVD virus type 1 (BVDV1). Other livestock pestiviruses (BVDV type 2 and Border Disease Virus) can also infect cattle. BVDV1 generally causes mild clinical signs, however abortion, stillbirth and birth of persistently infected (PI) calves can also occur. BVDV2 outbreaks in BVD-free herds carry more severe consequences. Scotland’s BVDV eradication programme, started in 2012, has reduced the number of infected animals significantly, but dairy herds remain particularly affected by BVDV. BVDV2 infections must be reported ‘as soon as possible’ to APHA, however current large scale diagnostic tests do not distinguish between these pestiviruses. A Moredun in-house test can differentiate the three viruses, however validation is required for use with eartags. We intend to validate this and other PCR-based assays and produce a report to allow informed policy decisions on BVDV testing in Scotland.

Parasitic worm infections in dairy cattle is often considered a first grazing season problem, however sub-clinical infections in lactating animals can negatively impact milk production. Currently parasitic nematodes in dairy cattle are controlled using drugs, however long-term use of these drugs has resulted in worm resistance, making the treatments less-effective. Long-term, vaccination against these parasites will provide a means of effective and sustainable parasite control. This project will use high-throughput screening of parasitic worm proteins to identify potential vaccine candidates. The screen will identify worm proteins that are recognised by dairy cattle that show resistance to parasite challenge and assess their potential for incorporation into a vaccine. This work will lead the way to the development of a worm-vaccine to protect dairy cattle against parasitic worm challenge.

Bovine mastitis persists as one of the most important challenges to the dairy industry, estimated to result in annual costs of €20 billion. Streptococcus uberis is a leading cause of bovine mastitis worldwide and in Scotland it is the second most common cause of both clinical and subclinical cases (1). Traditionally, S. uberis has been classified as an ‘environmental’ mastitis pathogen, primarily spreading through indirect means via environmental contamination. However, emerging evidence challenges this model, suggesting that certain strains exhibit contagious transmission characteristics and may be adapted for cow-to-cow transmission. Despite this recognition of contagious spread, there remains a gap in our understanding of the genetic and mechanistic basis of this distinct transmission, and the lack of reliable diagnostic tools for identifying such strains. Addressing these knowledge gaps holds promise for new interventions in bovine mastitis management, potentially reducing the impact of S. uberis on food production, enhancing animal welfare, and reducing the use of antimicrobials.

Fungi are a known cause of mastitis in cattle. Despite this, fungal milk communities associated with development of intramammary infections are under researched. Mastitis is one of the most common and costly diseases in dairying, particularly due to decreased production in subclinical cases. Commonly, broad-spectrum antibiotics are used in treatment and may lead to an unbalanced milk microbial community (microbiome), potentially allowing for overgrowth of mastitis-causing fungi. This research aims to explore the microbiome associated with healthy and mastitic (clinical and subclinical) milk, with a focus on fungi and bacterial-fungi interactions, and implications of repeated antibiotic usage. This work will contribute to a knowledge gap in dairying, by i) identifying potential milk microbiome biomarkers relating to health status, ii) providing evidence for pre/probiotic development, iii) exploring whether repeated antibiotic usage impacts upon microbiome communities and reoccurrence of mastitis. This knowledge could help farmers and industry in tackling a global issue.