POSTPARTUM UTERINE AND OVARIAN CHANGES AND THE EFFECT OF OESTRUS SYNCHRONIZATION ON REBREEDING IN THE SAVANNA BROWN GOAT
POSTPARTUM UTERINE AND OVARIAN CHANGES AND THE EFFECT OF OESTRUS SYNCHRONIZATION ON REBREEDING IN THE SAVANNA BROWN GOAT
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Date
2000-08
Authors
MOHAMMED, UMARU KAWU D.V.M.,
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Abstract
The study was designed to determine: (i) gross and
histological changes in the uterus and ovaries between d24
to d32 postpartum (pp); (ii) pp interval to resumption of
ovarian activities and conception (iii) and effect of time
of oestrus synchronization on rebreeding in the Savanna Brown
(SB) goat.
Eight multiparous SB goats (n=2 per group) were slaughtered
on d24, d26, d28 and d30 to 32 pp in order to determine gross
and histological changes in their genitalia between d24 to
32 pp. The uterine horns showed symmetry of shape and size
(length, diameter, and circumference)' during this period.
The caruncles were convex-shaped and light brown in colour.
A few caruncles were blood- tinged between d24 to 26 pp. The
mean (± SEM) weight of the entire uterus was 30.20 ± 9.93g
at d24 pp. A slight decrease in uterine weight was recorded
at d26 and d28 pp. This was followed by a an increase in the
uterine weight to 36.75 ± 7.73g at d30 to 32 pp. The mean
distance of the intercaruncular space in both uterine horns
at d30 to 32 pp was significantly longer (P < 0.05) than at
d24 pp. This distance in the left uterir.e horn
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was significantly shorter ( P < 0.05) on d24 pp than at d26
and d30 to 32 pp. The mean length of the left oviduct at d30
to 32 pp was significantly longer ( P < 0.05) than at d26 pp.
Except in a few instances, there was a slight increase in the
mean length, diameter and circumference of the uterine horns
from d24 to 32 pp. Re-epilialization of the caruncles,
intercaruncular space and maternal crypts was complete
between d24 and 32 pp.
In general, larger numbers of secondary and tertiary
follicles were recorded from both ovaries from d28 and 32 pp.
More primary follicles were observed from d24 to d26 pp . The
mean weight of the right ovary at d28 pp was
significantly greater (P < 0.05) than at d24 and d26 pp. The
diameter of the largest follicle in the right ovary at d28
pp was significantly wider (P < 0.05) than at d26 pp. The
number of tertiary and secondary follicles in the right ovary
at d30 to 32 pp were significantly more (P < 0.05) than at
d26 pp. The weight of fluid in all follicles of both ovaries
at d28 pp was significantly
heavier (P < 0..05) than in the other interval groups.
Too few corpora lutea were observed grossly and mainly at
d26pp. Histologically, large numbers of primary, growing
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and tertiary follicles were observed in ' all the pp
interval days studied. In contrast to the gross
observations, more growing and mature corpora lutea were
seen histologically between d.24 to 32 pp.
The first pp oestrus in the multiparous SB goat (n=5) occurred
at 19.5 ± 2.50 days pp, while the rebreeding
interval averaged 40.50 ± 1.50 days. Conception rate at the
first and second pp oestrus was 0. and 100%, respectively.
Based on progestrone (P4) profile. (n=20), resumption of
ovarian activity occurred around d5pp.
Following oestrus synchronization with Syncro-Mate-B (SMB)
at d21, d28 and d35pp (n=5 per group) , 14 out of the 15 animals
exhibited oestrus within 24.0 - 33.(3 hours
post-synchronization. The overall conception rates per group
were: 75%(d21), 80%(d28), and 100%(d35), respectively. The
mean (±SEM) rebreeding interval per group were: 48.33+0.33
, 47.27+5.12 and 53.80±5.53 days, respectively.
From the general and specific findings of this study the
following conclusions were drawn:
I. Uterine involution in the SB goat is complete by d24 pp.
Thereafter an increase in most uterine parameters
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occurred between d24 and 32 pp. Postpatum ovarian activity
occur more in the right than the left ovary
between d24 and 32 pp.
2. The first pp oestrus, in multiparous SB goats could occur
as early as 19.5 days pp, while the rebreeding interval
averages 40.5 days. Fertility at the first pp oestrus is
compromised, but improved at the second pp oestrus. Based on
P4 profile, resumption of ovarian activity in multiparous SB
goats could commence as early as d5 pp.
3. The rebreeding intervals of 47 to 53 days achievable with
SMB synchronization is capable of reducing the kidding
interval of 222 days to 200 days. Postpartum synchronization
with SMB is capable of achieving good oestrus and conception
rates. Fertility following SMB synchronization increases
with increasing pp interval from the commencement of the
synchronization.
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Description
A THESIS SUBMITTED TO THE
POSTGRADUATE SCHOOL IN PARTIAL
FULFILLMENT OF THE REQUIREMENTS FOR
THE AWARD OF THE DEGREE OF MASTER OF
SCIENCE
Keywords
POSTPARTUM UTERINE, OVARIAN CHANGES, EFFECT, OESTRUS SYNCHRONIZATION, REBREEDING, SAVANNA BROWN GOAT