| dc.description.abstract | Dairy cattle selection strategy in Kenya
prefers cows with good 305-day lactation milk yield
(TMY) in previous parity. This has improved milk
production although increased incidences of
physiological disorders and reduced fertility have been
reported in herds. Records on functional traits are
scarce. Properties of lactation curves could indirectly
explain reproductive efficiency in cows. This study
assesses relationship between lactation curve traits, to
evaluate effects of selection for TMY on lactation
curve properties, to explain reduced physiological
efficiency and fertility. Genetic correlations between
peak milk yield (MYmax) and persistency (S), MYmax
and Days in milk at peak (DIMP), TMY and DIMP
were negative. Genetic correlations were positive
between DIMP and S, TMY and MYmax implying that
selection for high TMY increases MYmax and reduces
DIMP. This shifts production pressure to early
lactation aggravating negative energy balance thus
compromising physiological integrity of cows | en_US |
