Rachel Doyle

Project Title: The effects of genetics and nutrition on fertility in lactating dairy cows

Overview: It is necessary to periodically verify that a particular breeding objective is truly delivering genetically superior animals. While phenotypic data is important (milk production, pregnancy rates etc.), it is beneficial to understand the long term effects of intensive selection on changes at tissue and cellular levels. Teagasc has established a Next Generation Herd of Holstein-Friesian dairy cows (within the top 1% of the national herd based on EBI; ELITE). These cows are being compared against national average cows (i.e., national average EBI; AVG). The ELITE cows have greater milk solids production and improved fertility performance compared with the AVG cows. This project will examine the detailed physiological differences between these two groups of cows. The aim is to identify the basic mechanisms responsible for observed differences in animal phenotypes. With new breeding tools on the horizon, it is important to identify the gene expression profile that supports improved phenotypic performance. This study will ensure that Ireland is well placed to exploit these new breeding tools when they become available.

Bachelor of Agricultural Science (Hons) UCD

Programme Area: PhD

Supervisors: Dr. Stephen Butler and Dr. Matthew Lucy

Location: Teagasc, Moorepark, Fermoy, Cork

Funding Source: Teagasc