Abstract:
The study was undertaken to evaluate the reproductive performance of imported Jersey
and Jersey x Holstein Friesian cattle over a period of 9 years (2015–2023) at the National
Livestock Development Board (NLDB) farm Ridiyagama, located in the dry zone of Sri
Lanka. The records on reproductive traits viz. age at first calving (AFC), gestation length
(GL), calving to service period (CSP), number of services per conception (SPC) and dry
period (DP) of 4806 records of 1356 cows were used. Data were analyzed using general
linear model with SAS online version. In addition to the above listed variables, year of
calving, season of calving, year of dry off and season of dry off were included in the
model. The overall least square means (±SEM) of studied reproductive traits were AFC:
28.83±0.003 months, GL: 275.56±0.003 days, CSP: 70.15±0.01 days, SPC: 4.28±0.002
and DP:144.84±0.04 days, respectively. The least square means (±SEM) of reproductive
traits for Jersey and Jersey x Holstein Friesian crosses were AFC: 29.04±0.15 months and
28.7±0.13 month; GL: 276.77±1.33 days and 275.91±1.31; CSP: 67.47±1.11 days and
70.81±0.93 days; SPC: 4.06±0.29 and 4.42±0.28; DP: 139.94±4.11 days and 144.49±3.39
days, respectively. Current study revealed that AFC for both breeds lie within the
optimum range of 24 to 30 months for cattle. The traits CSP, SPC, and DP exceeded
standard values of 45-50 days for CSP, ≤ 2 for SPC and 60 days for DP. However, for
these traits, Jersey showed lower values than Jersey x Holstein Friesian crosses indicating
the adaptive nature of Jersey to the tropical climatic condition.
