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Identification of Dairy Associated QTL in a Cattle Resource Herd (RoBoGen) - LS3206

This programme of work builds on the unique opportunity presented by the Charolais x Holstein resource herd that has been established at Roslin Institute through MAFF/DEFRA, Industry and BBSRC funding to detect quantitative trait loci (QTL) controlling variation in health welfare and production traits in cattle. In this project, breeding of the second-generation crossbred heifers will be completed and measurements on milk production and quality traits and feed conversion efficiency will be carried out. In addition mastitis incidence, which is the cause of economic loss and is a major welfare problem, will be examined. The aspects of these traits that are functionally important will be studied and a genome mapping approach will be used to localise the QTL involved.
The ultimate objective of this study is to identify quantitative trait loci (QTL) involved in improving health and welfare of cattle, product quality and efficiency of production, and as far as possible to protect samples that will allow fertility to be examined at a later date. These traits are important for dairy producers and consumers.
A number of Objectives have to be completed to create the resources and generate the data necessary to achieve the goals of the project.

Breeding objectives:
1) It is necessary to bred the heifers that will be used in the study and raise them to breeding age. The second generation cross-bred heifers in the herd are in three, yearly, cohorts. The first cohort calved during autumn and winter 2001 and have started their first lactation.
2) To establish a lactation, the heifers in the second and third cohort of second generation cross bred heifer and two cohorts of third generation cross bred heifers will have to be mated, complete a successful pregnancy, then calve. The second group of “F2” was mated in January 2002 with the objective hat they will calve in autumn/winter 2002. The final second-generation crossbred and the third generation crossbred heifers will be mated in January 2003

1) DNA will be prepared from the final cohort of second generation crossbred heifers and the third generation heifers.
2) DNA will be provided to the sub-contractor “GeenSeek” that has undertaken the genotyping work for the panel of approximately 180 markers for the F0, F1 and F2 animals to date. An additional ~10 markers not typed by GeneSeek will be typed in Roslin.
3) As work progresses candidate loci identified from other studies will be typed on the heifers to examine whether these loci are involved in the traits being examined.

Trait measurements:
1) The measurement of juvenile traits in the last group of second generation cross bred heifers will be completed: a) Growth: to 6 months, b) Feed efficiency, c) onset of puberty and juvenile fertility traits
2) Lactation associated traits on all second and third generation crossbred heifers will be measured as they come into milk: a) yield and quality, b) management traits (weight, condition etc) c) feed efficiency, d) mastitis, and e) udder function
3) Steps will be taken to protect samples from traits that cannot be measured immediately, such as fertility, so that measurements can be made later.
Time-Scale and Cost
From: 2002

To: 2007

Cost: £1,484,530
Contractor / Funded Organisations
Roslin Institute, Edinburgh (BBSRC), Hannah Research Institute, University - Scottish Agricultural College
Climate Change              
Livestock Farming              
Sustainable Farming and Food              
Sustainable Production              
Fields of Study