PARAMETRI GENETICI DELLA MUNGIBILITÀ RILEVATA CON LATTOFLUSSOMETRI NELLE DUE RAZZE BOVINE: BRUNA E FRISONA

Objective of the thesis was the investigation of genetic parameters of milkability in Italian Holstein Friesian and Italian Brown Swiss. A total of 2,886 records of Italian Holstein Friesian and 37,511 records of Italian Brown Swiss were collected using a milkometer. All records included milk yield, SCS, and measures of milk flow as: ascending time, time of plateau, decreasing time, total milking time, and main milking time. To estimate variance components, different multiple trait animal models were used specifically for each breed data. Heritabilities ranged between 0.06 and 0.41 for the Italian Holstein Friesian, and between 0.05 and 0.40 for the Italian Brown Swiss. Heritability and genetic correlation values showed that flow traits collected with milkometers can be genetically selected and that they would contribute to the genetic selection of milkability through the definition of the desired shape of milk flow specific for each one of the two breeds.