SUGARCANE BAGASSE SILAGE TREATED WITH DIFFERENT LEVELS OF UREA FOR IMPROVING SHEEP PRODUCTION. II. BODY WEIGHT CHANGES AND EWES` REPRODUCTIVE PERFORMANCE

ABSTRACT
This study was carried out to investigate the influence of sugarcane bagasse silage treated
with different levels of urea on body weight and ewes reproductive performance. The study
included 179 3/4 Chios x 1/4 Ossimi sheep, 103 ewes and 76 newborn lambs. Animals were
divided into four treatment groups, a control group (26 animals) fed concentrates with wheat
straw, and three silage fed groups, T0 (25 animals), T1.5 (26 animals) and T3 (26 animals)
receiving silage containing 0, 1.5 and 3 % urea, respectively. The animals were fed 60 % of their
nutritional requirements from a concentrate mixture while the roughages, silage or wheat straw,
were given ad libitum. The experiment was lasted 10 months and consisted of 4 periods, premating
(1 month), mating (1 month), pregnancy (5 months) and lactation (3 months). Body
weight, incidence of estrus, number of service per conception and fertility rates were recorded.
During the pre-mating period, silage or urea had no significant effect on body weight or body
weight gain, whereas the increase in feed intake was significant (P<0.05). During pregnancy, T0,
T1.5 and T3 had higher body weight and body weight gain (P<0.05) and feed intake (P<0.01) as
compared to the control group, whereas during lactation, T1.5 and T3 groups had higher body
weight than that of T0 fed group.
Numbers of ewes that exhibited estrus or lambed were less in urea fed groups (T1.5 and
T3) than the control and T0 silage fed groups. Number of services per conception (S/C) was
adversely affected by urea treatment, particularly the 3% urea level. Silage fed groups had
higher body weight at lambing and their lambs had higher average and total birth weight and
weaning weight than the control group. Long term feeding of urea had adverse effect on fertility
of treated ewes as compared to fertility before treatment. About 18% (8 out of 45 ewes) of urea
fed-groups had estrus length more than 48 hours as compared to about 4% (2 out of 49 ewes) for
both control and silage (T0) fed groups. In conclusion, feeding sugarcane bagasse silage with or
without urea may improve growth performance, whereas feeding urea, particularly the combined
effect of long term feeding and high level (3%), have had a negative effect on reproductive
performance of ewes.