The present study aimed at evaluating the general assessment of retained
placenta over 3 years in a dairy flock, belonging to Sakha Experimental Station,
Animal Production Research Institute, Agricultural Research Center, Ministry of
Agriculture. The study included a special assessment of incidence of retained
placenta (retention of fetal membranes for more than 12 hours post-partum) of 783
Friesian cows (350-650 kg and 1-11 parities) covering a period from 2001 to 2003.
Results revealed that Percentage of incidence of retained placenta was significantly
(P<0.05) the highest during August and September months (43.2 and 36.4%,
respectively) and the lowest in October and December (5.3 and 8.3%, respectively).
However, frequency distribution of retained placenta incidence was not affected
significantly by month of the year. Higher percentage and higher distribution of
retained placenta incidence occurred in February (32.1 and 17.7%, respectively),
however, the lowest corresponding values were observed in October (5.3 and 0.52%,
respectively). The highest incidence of retained placenta was significantly (P<0.05)
observed in the heaviest cows having body weight more than 550 Kg (34.25%) while
the lowest incidence (12.19%) was significantly (P<0.05) obtained from cows ranged
between 350 and 400 Kg LBW. The highest distribution was associated significantly
(P<0.05) with cows weighing between 450-500 Kg (41.6%), while cows having 350-
400 kg showed significantly (P<0.05) the lowest percentage and frequency distribution
of incidence of retained placenta, being 12.2 and 2.6%, respectively. The highest
percentage (65.6%) and the lowest frequency distribution (10.9%) of retained
placenta incidence were significantly (P<0.05) observed when the birth weight of calf
was more than 40 kg. Percentage of retained placenta incidence varied from 21.2 to
33.8% when the calf birth weight was less than 40 kg, however, the highest frequency
distribution (45.3%) was significantly (P<0.05) obtained for calves weighing 20-30 kg.
Percentage of incidence of retained placenta was 25.94 and 22.47% after male and
female calves calving, respectively. The distribution of retained placenta after male
calving was 53.64%, being comparatively more than frequent following the birth of
females (46.35%), but the difference was not significant. Percentage of retained
placenta incidence in calving multiparous was two folds of that in calving primiparous
cows (28.4 vs. 14.5%). The frequency distribution of retained placenta was 81.72%
being comparatively more frequent following calving multiparous than 18.27% in case
of primiparous cows. The percentage of incidence of retained placenta was 23.8% in
cows fed on green fodders (Trifolium alexanderenum), being lower than that in cows
fed on dry feeding 25.7%. Also frequency distribution of retained placenta incidence
was insignificantly higher during green feeding period than dry feeding period. From the obtained results, it could be concluded that month of year, weight
of dam and born had pronounced effects on incidence of retained placenta in Friesian
cows under Egyptian conditions.