Investigation of the effect of genetic base and lactation number on persistency of lactation in a population of Black Pied cattle. [A short version of master thesis]
1996
Stojic, P. ("Agroekonomik - PKB", Belgrade - Padinska Skela (Yugoslavia))
The study was carried out with 370 cows, daughters of 14 bull-sires. The average milk yield of 6695 kg, with 3.96 of milk fat, was obtained for 305-day lactation. The maximum milk yield was 29.2 kg of milk with 3.93 of milk fat (second measurement). Milk persistency was very good (P2:1 = 0.8101). Daily decrease in milk yield was in the range from 0.0602 kg (0.2772), calculated by exponential regression, to 0.0651 kg (0.3002), calculated by cubic regression. The influence of bull-sires was highly significant for all persistency indicators (P0.01), except for P2:1 coefficient (P0.05). The best persistency was with first-calving cows, and worst with third-time calving cows (P0.01). The portion of Holstein genes had positive, but insignificant (P0.05), effect on milk persistency.
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