Research Information System
Tarim Bilimleri Dergisi-Journal Of Agricultural Sciences, vol.26, no.3, pp.324-330, 2020 (Journal Indexed in SCI)
Purpose of this study
was to investigate the relations of dry period lengths (DPL) with subsequent
lactation (305-d) milk yield (MY) and reproductive performance of Holstein
cattle. Data were obtained from 800
Holstein cows raised in a private dairy operation and which were in different
parity (2nd, 3rd and ≥4th). DPL was classified in 5 categories as; ≤40, 41-50,
51-60, 61-70 and ≥71 days. The differences in lactation milk yields of
experimental DPL groups were not significant. The highest MY (7808.6±135.1 lt)
was obtained from ≥71 days DPL group and the lowest MY (7529.4±159.8 lt) was
obtained from ≤40 days DPL group. DPL had significant effect on the number of
inseminations resulted in pregnancy (P<0.01). The greatest pregnancy ratio
(53.0%) in the first insemination was obtained from ≤40 days DPL group and the
lowest pregnancy ratio (30.8%) was obtained from 61-70 days dry period group.
There was a positive correlation (0.056) between DPL and 305-d MY and a highly
significant positive correlation (0.141) between DPL and the number of insemination
resulted in pregnancy. Present findings revealed that longer DPL might have
positive effects on lactation MY, but shorter DPL practices might have better
outcomes for pregnancy ratios of the first insemination for this farm.