CONTRIBUTIONS TO THE STUDY OF REARING DAIRY COWS FROM ROMANIAN BLACK PIED BREED IN DOBROGEA
V. Ujică, I. Nistor, S. Bulancea, D. Cozma, C.E. Nistor, Gh. Neaga, Ioana Raluca Pāntia, Ancuţa Elena Coşuleanu
The study was conducted on a population of 1575 BNR cows exploited in 6 representative farms with private capital from Dobrogea. The mean phenotype values of the milk production indexes on successive lactations (1st-7th) enlightened, in assembly, a certain low productive level, ranged between 4342.03 kg of milk in 1st lactation and 4463.45 kg of milk in 3rd lactation, but with great differences from one farm to another. The best performances were obtained at Dairy Farm, which realised in the first three lactations over 5000 kg of milk on normal lactation and individual performances of 9728 kg of milk in 1st lactation, respectively 10113 kg of milk in 2nd lactation. Milk content in fat and proteins, on the whole population from the six farms in Dobrogea, was placed between 3.73% and 3.80% for fat, respectively 3.18% and 3.27%, for proteins. In the studied population were identified 92 genetic families of paternal half-sisters, from which 53 families had an average milk production superior to mean of population, which was of 4342.03 kg of milk at first lactation, from which 20 genetic families with a mean of over 5000 kg of milk. These genetic structures constitute a valuable genetic-fund, based on which could be conceive a programme for genetic breeding of productive performances for these population. Analysing the age of first calving for the 1611 cows from the studied farms resulted a mean value of 967.15 days (32 months and 7 days), with limits between 442 days (14 months and 22 days) and 2002 days (66 months and 22 days). These extreme limits prove that the management of reproduction function was poor and with exploitation mistakes. Must be mention the fact that for the feature of reproductive precocity the best one was the genetic family of the indigenous bull code 16866, of which the four daughters had the age of first calving at 808.83 days (26 months and 28 days) and for the exploitation period, genetic family code 11014 with a mean of 4430.71 days (14.5 normal lactations).
Key words: milk production, Romanian black pied cows (BNR), genetic families