Emma Pettigrew

Citation

Thesis Title
The effect of birth rank and age of dam on the reproductive performance of ewe replacements managed under New Zealand pastoral conditions

Read article at Massey Research Online:

For New Zealand farmers, the selection of replacement ewe lambs is an important decision. Lambs born to young dams are not commonly selected as replacements, however there is potential to increase the rate of genetic gain and efficiency of the flock by selecting them. Ms Pettigrew investigated the relative production from ewes born to young or older dams and investigated gene markers for ewe lamb live weight and puberty attainment. She found that replacements born to younger dams were lighter than those born to older dams, while they produced similar weights of lambs at weaning. She identified five gene regions associated with live weight of the ewe lambs, which will aid in identifying ewe lambs that have a greater chance of attaining breeding weight targets. The results suggested that farmers could select lambs born to younger dams as their replacements, if they meet selection criteria.

Supervisors
Professor Rebecca Hickson
Professor Stephen Morris
Professor Hugh Blair
Professor Paul Kenyon