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 viii 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 ix 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 x 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. xi .
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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
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