Studies on some factors influencing the shape of the lactation curve in Romanian Black and White cows

Abstract

The aim of this paper was to study the effects of farm and parity on the shape of the lactation curve for milk yield, milk fat percentage, milk protein percentage and milk lactose percentage. Researches were carried out on 421 lactations obtained from a population of 260 Romanian Black and White cows reared in the South-eastern Romania. Test day data was modelled using the incomplete gamma function, and then the lactation curves were drawn taking into consideration the effect of farm (farm 1 and farm 2) and parity (lactation 1, 2 and 3+). Both factors had a significant effect (p<0.05) on the shape of the lactation curve, affecting the initial production (parameter a), the rate of increase/decrease to the peak/nadir (parameter b), as well as the rate of decrease/increase of production until the end of lactation (parameter c).

Keywords

• cow
• farm management
• lactation curve
• parity
• romanian black and white