About the Project
A unique population of dairy cattle raised at the SRUC Crichton farm in Scotland will be studied to test the hypothesis. These cattle are closely monitored and densely phenotyped as part of a long-running feed and genetic selection study. Cows are split in two distinct diet groups characterised by high and low forage ration concentrations, respectively. Cows are further divided into two genetic lines of high and average genetic merit for productivity.
Individual cow records include daily/weekly milk yield and composition (protein, fat, lactose), feed intake, live body weight, and body condition score. Data on the nutrient composition of feed consumed by the cows are also available on monthly samples; there is both random and systematic variation in feed nutrient composition. The database comprises several hundreds of dairy cows with detailed data spanning more than 20 years.
The successful student will analyse individual cow records to derive metabolic profile traits including, but not being limited to different measures of body energy level, energy balance, cumulative energy and milk component concentration. These data will then be matched with nutrient composition and intake data, and jointly analysed with random regression models to derive novel phenotypes reflecting the response of animal milk production and metabolic function to variation in nutrient composition and supply. The magnitude of this response will determine the animal’s resilience to external challenge, exemplified here by variability in nutrient intake.
Three studies are envisaged: (i) a retrospective study using all available historic data; (ii) a prospective study on the current animal population based on new weekly monitoring of feed nutrient quality; (iii) a prospective study on cows of high and average genetic merit, where different degrees of nutritional challenge will be imposed and their impact on metabolic and production efficiency will be assessed.
In all studies, novel resilience phenotypes derived will be examined and characterised for variation among individual animals. Differences in animal resilience between cows in the two diet groups and the two genetic lines will be assessed. Genetic analyses will be conducted using extensive animal pedigree data to estimate the heritability of resilience and the genetic correlation with other animal traits. Cow genotypes are also available and will be used in genome-wide association studies and regional heritability mapping to identify genomic markers and regions affecting animal resilience to nutrient variation, thereby shedding a first light into the genomic architecture of the new traits.
The project will require advanced statistical, computational and genetic analysis skills, and good knowledge of ruminant nutrition. Relevant specialised training will be available as needed.
Applicants should download the required forms from http://www.eastscotbiodtp.ac.uk/how-apply-0 and send the following documents to email@example.com:
a. EASTBIO Application Form
b. EASTBIO DTP Equality Form
d. Academic transcripts (a minimum of an upper second class or first class honours degree or equivalent is required for PhD study
e. Two references should be provided by the deadline using the EASTBIO reference form (http://www.eastscotbiodtp.ac.uk/how-apply-0). Please advise your referees to return the reference form to firstname.lastname@example.org.
f. If you are nominated by the supervisor(s) of the EASTBIO PhD project you wish to apply for, they will provide a Supervisor Support Statement.
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