Breeding for improved calving performance in Piemontese cattle - economic value

Economic values for calving performance in first and later parities were estimated for the Piemontese cattle. Calving performance is a threshold trait usually recorded using a scoring system with categories corresponding to the rate of difficulty. In the Piemontese breed five categories were adopted (from unassisted to foetotomy). A normal underlying distribution with thresholds corresponding to used categories was assumed. A cost function, expressing the extracosts of difficult calvings and Caesarean sections with respect to normal calvings, was defined. Costs included veterinary fees, additional labour, increased stillbirth rates, reduced fertility and involuntary culling of cows as a consequence of a difficult calving. The cost of an average case of dystocia in first parity was 61.8 € and 22.1 € for male and female calves respectively. Corresponding costs in later parities were 34.2 € and 11.4 €. Dystocia showed a great economic incidence mostly when male calves were born from first calving cows. Economic values were computed as marginal increase of the cost function for a marginal increase in the normal underlying distribution. Economic values for calving performance were -1.02 € in first parity and -0.42 € in later parities per a 1% increase of dystocia. In first parity the economic value of calving performance was two times greater than in subsequent parities suggesting that, also from an economic standpoint, calving performance in the first and later parities should be considered as different traits.