Abstract:
The objectives of this study were to investigate whether the use
of intravaginal sponge for estrous synchronization of goats causes
oxidative stress, and to examine the effect of administering vitamin
E during preovulatory period on reproductive performance of
estrous synchronized goats. Estrus was synchronized in 36 nonlactating
adult does using intravaginal sponges containing 30mg
of fluorogestane acetate (FGA) for 14 days. All females received
500 IU of eCG at the sponge withdrawal. The goats were allocated
at random to two groups balanced for breed, age and body
weight. Treatment group (n = 18) received 200mg of vitamin E i.m.
at the time of sponge removal and again at the time of second
artificial insemination. The other 18 goats (control) were administered
1 ml of physiological saline instead of vitamin E on each of
these two occasions. All does in estrus was intracervically inseminated
at 12 and 24 h after the onset of estrus. Blood samples
were collected every 72 h during the experimental period for evaluation
of malondialdehyde (MDA) and vitamin E concentrations.
Serum MDA level increased and vitamin E concentration decreased
during the period of vaginal sponge application. Following the
sponge removal, MDA level declined rapidly to below basal level
in the treatment group but remained high in the control group. Conversely, vitamin E concentration increased in the treatment
group after the sponge withdrawal and remained at a low level in
the control group. No statistically significant differences (P > 0.05)
were observed between groups in terms of estrous response,
conception rate, gestation length or kidding rate.However, thenumber
of multiple births (70.0% versus 50.0%) and prolificacy rate
(2.40±0.37 versus 1.63±0.26 kids per kidding) were significantly
higher (P < 0.05) for the treatment group than those of the control
group. The results indicate that the use of intravaginal sponges for
estrous synchronization of goats causes an increase in level of oxidative
stress. However, the vitamin E treatment during preovulatory
period can prevent the overproduction of reactive oxygen species
(ROS), and it may improve the multiple birth rates and the number
of kids born in estrous synchronized goats.
