Jeremy Bryant

Citation

Thesis Title
Quantifying genetic variation in environmental sensitivity of New Zealand dairy cattle to apply in the development of a dairy cattle simulation model for pastoral systems

Read article at Massey Research Online:

Mr Bryant’s thesis aimed to determine if dairy cattle sires genetically re-rank in different nutritional and climatic environments in New Zealand. The environmental sensitivity data was then used to construct a dairy cattle simulation model for pastoral systems. Analyses identified that sire re-ranking in different environments throughout New Zealand is not a major problem. However, Jersey cattle were better suited to grassland systems and were less susceptible to hot conditions than New Zealand or Overseas Friesian cattle that performed best in systems expected to use moderate levels of supplements. Results were then used to construct a simulation model called MOOSIM, which incorporates the effects of age, genotype, body fatness and feeding level on mammary gland cellular dynamics. MOOSIM can be used by farmers, researchers and consultants to predict dairy cattle daily feed intake, live weight changes, milk solids production and responses to supplements based on genotype and environmental sensitivity data.

Supervisors
Professor Nicolas Lopez-Villalobos
Professor Colin Holmes