Hewa Ariyarathne

Citation

Thesis Title
Genetic and Genomic Studies of Animal Welfare and Environmental Traits in Dairy Cattle

Read article at Massey Research Online:

Dairying plays a vital role in the New Zealand economy, with cows predominantly pasture-grazed outdoors. Pasture-based milk production is cost-effective but raising cows outdoors may cause heat stress in summer which is an animal welfare issue. Expelled cow excreta also contribute to air and water pollution. Ms Ariyarathne’s study aimed to investigate whether between-cow genetic variation could contribute to improved animal welfare and environmental sustainability. She explored the genetic variance of rectal temperature as an indicator of heat stress and milk urea as an indicator of environmental pollution. The results of her study confirmed that dairy cows in the Manawatu region are less likely to be heat stressed for prolonged periods in summer. She investigated genetic variance and genes associated with milk urea. Her results suggest that genetic selection for less milk urea is an unlikely solution for reducing environmental pollution in the immediate future.

Supervisors
Professor Nicolas Lopez-Villalobos
Professor Hugh Blair
Professor Dorian Garrick