Age dynamics of milk productivity of the Bulgarian rhodopa cattle
2008
Nikolov, V. | Gadzhev, D.
The age dynamics of the milk production traits of the Bulgarian Rhodopa cattle BRC was studied for 1032 cows with 4615 complete and 3658 normal lactations for the period 1977-2002. It was found that the cows could be utilized maximum to their 15th lactation 41% of the cows produced up to their 5th lactation and 8.8 % of the cows – up to the 10th lactation. Life time curves of the milk productivity were with a slight dynamics. The most considerable were the changes in the level of the traits from the 1st to the 3rd and after the 11th lactation. The milk yield of cows increased steady to the 6th lactation the fat content – to the 3rd lactation and of the protein – up to the 5th lactation. The milk yield and butterfat from the 3rd to the 11th lactation exceeded the average lifetime productivity and the maximum differences between the lactations were 8.0 and 7.7% respectively. In conclusion it was shown that the BRC cows could be utilized effectively up to their 11th lactation and it could be recommended for increasing the lactation period to carry out selection at all stages during the multistage dam selection. The basic selection criteria for the BRC breed should be the lifetime yield of butterfat plus protein.
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