Data quality assessment and preliminary investigations on fertility in the Italian Holstein Friesian

Data from insemination and calving events of Italian Holstein cows and heifers collected from January 1996 until December 2002 were used to assess the quality of the Italian fertility data set and to estimate the effects of some environmental factors on fertility measures of Italian Friesian. A validation procedure based on gestation length (GL) and information on service sire is presented. According to these procedure, in Italy 75.9 % of the calvings are associated to service or inseminations events, considering a GL within 240 and 300 days and with the sire equal to the SS. The traits considered in the subsequent analysis were: days to first service (DTFS), interval between two successive calving dates (CI), number of services per conception (NSC) and non-return rate at 56 days (NRR56). The effect of month and year of calving (or insemination), of sampling bull code and of the age of the cow were statistically significant as p<0.0001 for all the considered traits. Current findings are going to be used in a subsequent variance components and breeding value estimation.