Primary supervisor: Dr Emma Bleach, [Email Address Removed], Agriculture and Environment Department
Second supervisors: Dr James McCaughern and Dr Joe Roberts
Project title: Feeding strategies to enhance early life and long-term productivity and wellbeing of dairy-bred calves.
Please note this project is only open to applicants who qualify for Home student fees.
Background to the project
The calf is born a functional monogastric utilising nutrients from milk feeds to support early growth and development. Typically, in the UK milk feeds will cease by 6 to 12 weeks of life, so with in this very short period, rumen development must be sufficient to support target growth and development across the weaning transition and into ruminant life. There has been much research into the type and level of milk feed offered to calves , which has generally led to increases in the milk allowances. However, there has been less focus on the supplementary feeds offered alongside milk, which are crucial to easing the weaning transition. The dairy calf will typically be offered a supplementary concentrate starter feed, with or without forage to effectively support rumen development. They are considered ready for weaning once they are consuming 1 to 1.5 kg of concentrate feed  in the days before weaning. However, research suggests that intakes of individuals will vary greatly . Indeed, research undertaken at Harper Adams Dairy Calf rearing unit shows that calf concentrate intakes may be as low as 200 g/d, despite a step-down milk weaning schedule in the weeks before expected weaning. This maybe a consequence of high rates of milk feeding and / or because sub-optimal supplementary feeds are offered.
An alternative to concentrate feed may be to offer a total mixed ration (TMR). TMRs are often fed to adult dairy cows creating a more stable rumen environment and enhancing intakes . TMR formulated from concentrates and longer chop hay enhanced body weight and rumination times  when compared to concentrate mixed with ground hay. Our preliminary studies at Harper Adams suggest that calves offered a maize silage-based TMR will grow to greater weaning weights and have an easier weaning transition than those receiving concentrate and straw alongside their milk feeds. Anecdotally these calves also appeared more sated, an observation supported by the longer lying times reported by . Thus, this alternative feeding strategy may be used to overcome hunger in milk-fed dairy calves reported recently .
Metabolomics has been used to demonstrate metabolic differences between animals using a variety biological samples, including readily available materials such as faecal or hair samples. Serum metabolomic profiling demonstrated changes in energy, protein and liver metabolism of calves on enhanced milk feeding regimes . Further, faecal profiling has been used to show the benefits of faecal microbiota transplantation in diarrheic calves . As far as we are aware, temporal changes in the calf metabolome in relation to feed intake, growth and development of milk-fed calves from birth and across the weaning transition have yet to be explored.
· To investigate the effects of alternative forms of supplementary feed on calf growth, development and satiety from birth to 4 months.
· To determine with-in and between calf variation in faecal and hair metabolome of calves during the first 4 months of life, in relation to feed intake, growth and development.
· To determine whether metabolomic profiling can be used to indicate rumen development sufficient for a smooth weaning transition, indicating readiness for weaning.
· To investigate whether the impacts of supplementary diets fed in early life continue long-term, influencing heifer growth, reproductive performance and subsequent milk production.
The stipend for this studentship is £16,062 at the 2022/23 UKRI rate. The expected start date will be 27th September 2022, although a later start date will be considered for the best applicant. The student will be registered for a PhD at Harper Adams University and based at Harper Adams University, Edgmond, Shropshire, UK.
It is expected that the student will have a good understanding of UK dairy calf rearing practices and be able to demonstrate a passion for improving calf wellbeing. The student will have the opportunity to develop research that includes both applied animal aspects and novel laboratory analyses.