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Colostrum fed to newborn Scottish dairy calves is highly contaminated. Bacteria in colostrum have the potential to cause disease and prevent calves from absorbing antibodies from their gut after birth, so calves are more likely to get sick and to die. Bacterial contamination may come from a number of different sources including the: cow’s udder, collection bucket, storage bucket and calf feeder. It is important that buckets and feeders are scrupulously cleaned after every use, but many farmers fail to do this. The project aims to identify the main source of contamination for first milking colostrum to allow farmers to focus their attention on these ‘critical control points’ which will have implications for calf health and welfare. In addition, the prevalence of Mycoplasma which causes significant disease in newborn calves will be ascertained. Recent UK work has focussed on bulk milk samples and concluded that contamination is low, but prevalence in colostrum is unknown.

Intramammary infections of ruminant livestock impact animal health, welfare, and the economics of the dairy industry worldwide. A major hurdle to studying the ruminant mammary gland is the lack of in vitro tools to perform research on the mammary response to infection under laboratory conditions. Here, we propose to develop ruminant derived three-dimensional culture models (“organoids”) which represent the internal cellular structure of the mammary gland. Firstly, we will establish a tissue bank from non-lactating and lactating sheep and cow at different ages and various stages of the lactation cycle. Secondly, we will identify a panel of ruminant epithelial cell-type specific antibody markers using the tissue sections from lactating and non-lactating cows and sheep. Thirdly, we will use the panel of basal and luminal epithelium-specific antibody markers to define the structural and cellular organization in mammary epithelial organoids. We will induce lactation by hormonal stimulation of the organoids and characterize the response by gene expression and proteomic analysis. Finally, we will demonstrate the utility of ruminant mammary organoids as a model for intramammary bacterial infection. This will provide a well characterized laboratory tool in support of the development of new mastitis control measures.

The dairy-beef sector has increased markedly in the UK due to the use of sexed dairy semen as not all cows within the dairy herd will be needed to breed replacement dairy heifer calves. The majority of these dairy-bred calves will enter the dairy-beef production cycle by being sold onto calf rearing units at a young age. At such rearing units, these calves will enter an unfamiliar environment and potentially be mixed with other calves from other farms. These all present a challenge to such calves. The initial objectives of this study were to:

• assess the respiratory health of dairy-beef calves, sourced from a collection of dairy farms, on arrival at a commercial rearing unit
• assess the impact of different grouping strategies, based on health assessments or normal farm practice, on calf health and performance outcome

However, due to concerns regarding the physical movement between pens, combined with the handling of calves to allow measurements to occur and an extended period of extremely high environmental temperatures for the geographical location, all of which were stressors on the calves, it was decided that the calves would remain in the groups in which they arrived, and any assessment of grouping strategy would be done on reflection but no physical mixing of calves. Any grouping would still be based on the arrival clinical and respiratory health.

There have been a number of welfare concerns raised about the individual rearing of dairy calves in early life, such that the practice is now not allowed for many Scottish dairy farmers under a number of supermarket-aligned contracts. Using a non-randomised control trial, this project will examine the effects of individual versus pair-rearing of dairy calves on calf productivity (assessed via daily liveweight gain), health (morbidity and mortality) and welfare assessments (assessed using a number of behavioural measures including latency to feed, novel object test and Qualitative Behavioural Assessment (QBA) as well as salivary cortisol measurements). The hypothesis is that pair-rearing dairy heifer calves from birth to 2-3 weeks of age compared to individual rearing will provide long-term benefits in calf performance, health and welfare.

High-protein legume grain import dependency has placed Scottish organic producers in an unattractive position financially, and environmentally. High import prices and price-volatility can be avoided by producing legume grains ‘at home’. This approach also offers environmental benefits, as legume crop residues present a complex organic provision to help realise more holistic crop rotations. The potential is due to ‘biological nitrogen fixation’, a process whereby atmospheric nitrogen is ‘fixed’ into biologically useful forms. This is a function of the symbiosis between legumes and soil bacteria termed ‘rhizobia’. The benefits of high protein grain production are therefore allied to enriching crop residues which remain in-field. Here, protein yield, yield qualities, and soil-enrichment potential will be maximised using novel grain legume and cereal ‘crop mixtures’, i.e., cultivating multiple crop species in the same field at the same time. The project also tests the efficacy of elite-rhizobia to further optimise the protein yield potential

Animal welfare is an increasingly important subject gaining interest not only from veterinarians and scientists, but also from consumers. The public drive for higher welfare standards has increased the need for research to better understand the needs and nature of animals. Welfare assessment has typically focused on the elimination of negative welfare challenges (e.g. disease), whereas the recently established approach of Positive Animal Welfare (PAW) focuses on promoting positive experiences as an indicator of good welfare. Play behaviour is observed in the absence of environmental adversity, and as such reflects a good welfare state. Assessment of play behaviour can therefore provide veterinarians and livestock keepers an indicator of positive health, wellbeing and welfare. The introduction of motion sensor technology has allowed for detailed analysis of animal behaviours such as lying, playing, and feeding in a much less time-consuming manner. The impact of housing, socialisation, and play behaviour on future performance of dairy cattle has not been investigated. Therefore, this project aims to use accelerometers to investigate the impact of early life housing on calf play behaviour, and to assess the effect this may have on future health, performance and behaviour. The results will contribute evidence to the debate on calf housing systems and will aid veterinarians and animal health advisors when discussing housing and husbandry practices on farm.

Making better use of dietary protein would reduce the environmental impact of dairy farming and increase farm profitability. One way to do this is to target supplemental protein at specific periods of the cow’s lactation cycle. Specifically, providing extra protein just in diets provided during the first few weeks after a cow has calved may have longer term benefits for the efficiency of protein use and the production of milk protein. This has been demonstrated under controlled experimental conditions, and we now plan to test this idea using feedstuffs that could be used in practice on UK dairy farms.

The cost of helminth infections in dairy cattle in Europe and the UK was recently estimated at €941 million per annum, due to reduced productivity and the cost of anthelmintic treatment. The negative impact of helminth infections on the livestock industry is amplified by the global emergence of anthelmintic resistance to all three broad spectrum anthelmintic classes licensed for use in cattle against gastrointestinal and pulmonary nematodes and a widely used flukicide, triclabendazole, leaving farmers with reduced options once resistance arises. While resistance in gastrointestinal worms of cattle has received much less attention than in sheep, initial reports concerning reduced drug efficacy of pour-on products were published in 2009 and resistance to all classes is now thought to be widespread.

Coxiella burnetii is a zoonotic pathogen that can cause febrile illness in people and reproductive disease including abortion and stillbirth in livestock. In the UK, C. burnetii appears to be widespread in dairy cattle herds but the epidemiology and productivity impacts of infection remain poorly understood. Our study aimed to address this knowledge gap by generating data on C. burnetii infection patterns within dairy cattle herds, and to estimate production impacts of infection in these herds.

Funded by the Hannah Dairy Research Foundation and supported by the Journal of Dairy Research, Next Generation Dairying Workshops and Conferences stimulate dairy-related research in Scotland and connect researchers and industry globally.

The 6th HDRF Conference, Next Generation Data-Led Dairying will be held on the 18th and 19th November, 2024, in Edinburgh.

Abstract Submission is open (deadline November 4th) for sessions dedicated to short oral communications and poster presentations on any relevant dairying topic.