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Real-time ultrasonography of ovaries and breeding
ž
/
of the one-humped camel Camelus dromedarius
during the early postpartum period
Sumant Vyas
), M.S. Sahani
National Research Centre on Camel, Post box No. 07, Bikaner, Rajasthan 334 001, India
Received 1 February 1999; received in revised form 2 November 1999; accepted 16 February 2000
Abstract
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Ovaries of 17 adult, pleuriparous, and lactating one-humped she-camels Camelus
dromedar-. Ž
ius were examined per rectum for uterine involution and for presence of follicles G1.0 cm
.
diameter by real-time ultrasonography at the National Research Centre on Camel at Bikaner, India at 30, 45, 60, 75, and 90 days postpartum. Involution was completed from 25 to 30 days
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postpartum and follicles G1.0 cm diameter could be found in only nine camels 52.7% from 34
to 70 days postpartum. These nine camels were mated with virile studs. Four conceived and were
confirmed pregnant at 60 days.q2000 Elsevier Science B.V. All rights reserved.
Keywords: Ovary; Follicles; Postpartum period; Camel
1. Introduction
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The breeding season of camel in India extends from November to March Matharu,
. Ž .
1966 and females usually calve from December to April Khanna et al., 1990 . Short
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breeding seasons have also been reported in Somaliland Mares, 1954 , Pakistan Yasin
. Ž . Ž .
and Wahid, 1957 , Egypt Shalash, 1965 and Sudan Musa and Abusineina, 1978 .
Ž
Since the mean gestation period of the Indian camel is 390"0.99 days Sahani et al.,
.
1997 , the female camels are bred in one season, calve in the subsequent breeding season and then remain sexually quiescent until the following breeding season, leading
)Corresponding author. Tel.:q91-151-527-944; fax:q91-151-522-183.
Ž .
E-mail address: nrccamel@x400.nicgw.nic.in S. Vyas .
0378-4320r00r$ - see front matterq2000 Elsevier Science B.V. All rights reserved.
Ž .
Ž .
to long intercalving periods and significant economic losses Wilson, 1989 . Efforts have been made to breed camels during the nonbreeding season using hormonal therapy
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with a moderate success Elias et al., 1984, Agarwal et al., 1997 . The involution of
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uterus following parturition is reported to be complete by 21"0.5 days Musa and
. Ž .
Makawi, 1989 or 39 to 42 days Ahmed, 1990 postpartum.. Little information is found in the literature on the reinitiation of follicular activity after parturition in the camel
ŽElwishy, 1987 . Therefore, in this report, ovarian status was examined by real-time.
ultrasonography with an aim to exploring the possibility of breeding camels during the early postpartum period.
2. Materials and methods
2.1. Experimental animals
Ž .
Adult pleuriparous, lactating she-camels ns17 belonging to the herd of National
Research Centre on Camel, Bikaner, located in the Thar Desert, India and calved in the breeding season of 1997–1998 were included in the present study. Each she-camel had a suckling calf. The camels were maintained under a semi-intensive management system where camels were sent out grazing on rangeland from 9:00 a.m. to 4:00 p.m. They were offered dry fodder in the evening on their return from rangeland. The period of study was January to March 1998.
2.2. OÕarian examination
The camels were restrained in sternal recumbent posture with all the four legs
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correctly fastened with ropes. Inj. Xylazene 0.03 mgrkg b.wt. Xylaxene, Indian
.
Immunologicals, Hyderabad, India was administered intravenously for sedation. The
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endovaginal annular array probe 5 MHz of ultrasound scanner-200 Philips Medical
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System, Delhi, India was used for ovarian examination. The camels were examined at 30, 45, 60, 75, and 90 days postpartum. Due to the unavailability of a rectal probe, involution of the uterus was assessed by recto-genital manual palpation. All follicles were searched on both the ovaries and measured using the internal electronic calipers.
When a follicle of G0.5 cm diameter was observed on an ovary, the animal was
selected for frequent examination at a shorter duration of twice weekly to monitor the growth of the follicle. The observations were recorded by videocassette recorder, interfaced with a scanner. The video was then analyzed and selected frames were photographed using Sony Model UP 890 MD videographic printer.
The presence of a follicle G1.0 cm diameter in either of the ovaries was the criteria used to decide the mating of a camel with a virile stud. The mating was repeated at a
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3. Results
The involution of uterus as assessed by recto-genital palpation was completed in 25 to 30 days in every camel. Ovarian scanning up to 90 days postpartum revealed not a
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single follicle in either of the ovaries in five 29.4% of the camels. At least one follicle
of G0.5 cm diameter was found, between 30 and 60 days postpartum in the remaining
Ž . Ž .
12 70.6% camels. In three camels J 389, B 345 and B 102, Table 1 , a follicle G0.5
cm diameter was found by day 45 postpartum. However, no further increase in follicular size was observed on repeated ovarian examination in three cases. These three camels
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were not mated. In other nine 52.9% camels, further increases in follicular size were
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observed, and at least one follicle of G1.0 cm diameter Fig. 1. was found between 34
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and 70 days means56.6"3.4 days postpartum. No ovarian cysts 2.0 cm or more
were observed. The administration of hCG 5000 i.u. intramuscularly at the time of mating induced ovulation in 100% of cases between 72 and 96 h of the mating.
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Pregnancy diagnosis at 60 days postmating showed that four J 370, B 353, B 294, J
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344 of these nine mated camels conceived for an overall conception rate of 44.44%. In this study, it was impossible to relate estrous behaviour shown by the female camels to follicular activity in their ovaries. The presence of a dominant growing follicle was not always associated with clinical evidence of estrus or sexual receptive behaviour
in camels. More often than not, camels having a follicle of G1.0 cm diameter were
mated when they appeared to resent mating. Conversely, females with no follicular activity in their ovaries were showing clear signs of estrus, like frequent urination,
Table 1
Postpartum ovarian status in one-humped camel
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S.N. Camel No. Age year Duration between parturition Conception
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Fig. 1. Graffian follicle in ovary of post parturient 34 days she camel.
stradling of the hind leg, mounting other females, and submissive behaviour towards an approaching male. However, they were ignored by the male.
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Follicular growth was observed more commonly in young camels below 11 years of
. Ž .
age; Table 1 . Follicles of G0.5 cm diameter were found in eight out of nine 88.9%
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camels and follicles of G1.0 cm were observed in six of nine 66.7% camels in this
age group. The four camels that conceived were from this age group. In an older age
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group 11–20 years , a follicle of G0.5 cm diameter was found in 50% of the animals,
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and a follicle of G1.0 cm diameter could be observed only in three of eight 37.5%
camels.
4. Discussion
Uterine involution is considered to be rapid in Camelidae as the microcotyledonary and diffuse nature of the placentation in these species does not cause a great loss of
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uterine tissue Tibary and Anouassi, 1997 . In dromedary, the involution of uterus is
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reported to be complete as early as 21.0"0.5 days Musa and Makawi, 1989 to 39–42
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days Ahmed, 1990 . The present findings are slightly lower than a period of 40"2.1
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days reported by Sharma and Vyas 1972 under similar agro-climatic conditions. These workers have also mentioned that primiparous animals have a more rapid involution than multiparous animals.
Postpartum resumption of ovarian function and follicular activity is highly variable in
Ž .
Ž
delayed for 1 year Yasin and Wahid, 1957; Matharu, 1966; Williamson and Payne,
.
1978; Wilson, 1989 and irrespective of date of birth, until the next breeding season
ŽMusa and Makawi, 1989 . In another study, a variable number of mature follicles on.
the left ovary of nonsuckled animals was observed at 39–42 days postpartum; three
Ž .
camels were mated but none conceived Elias, 1990 . No growth of mature follicles
ŽAhmed, 1990 and an interval of 4.5–10 months for first postpartum estrus Evans and. Ž .
Powys, 1979 was reported in lactating dromedaries. In the present study, 52.9% of the
lactating and suckled animals were observed to have a follicle of G1.0 cm diameter. It
would appear that lactation may not have a negative effect on folliculogenesis in the camel. However, the hormonal mechanisms that drive the development of follicles, and the reason why they occur in only a proportion of postpartum camels, have yet to be elucidated. A shorter duration of 45 and 25 days to first postpartum estrus is reported in
Ž .
a small study on stall-fed lactating camels Yagil and Etzion, 1984 indicating a possible influence of improved feeding and management on the postpartum estrus.
Ž . Ž .
In the Bactrian camel Camelus bactrianus , Barminstev 1951 reported estrus in 10
Ž .
of 33 30.3% females within 2 months of parturition but only three had mature follicles
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in their ovaries and conceived after mating. Chen and Yuen 1979 described only
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follicular 1.0–1.4 cm growth in 33% animals and no conceptions. The percentage of animals having follicular growth and conception rate in the present study was higher than the results in bactrian camels reported by previous workers.
Ž .
Skidmore et al. 1996 reported that natural mating could induce ovulation in only 70% to 85% of camels. In the present study, administration of hCG 5000 i.u. at the time of mating, facilitated ovulation in every animal.
In the present study, it was observed that the resumption of follicular activity after
Ž . Ž .
parturition was better 88.9% in younger camels 8–11 years , than older camels
Ž11–20 years, 50% . The conception was also better in younger camels. The involution.
of uterus as assessed by size and shape was complete in both age groups but insufficient hormonal and endometrial milieu could be the probable reason for lower rate of follicular activity and conception in older camels.
Ž .
An estrous period of 3–6 days Joshi et al., 1978; Elias et al., 1984 to 21 days
ŽYasin and Wahid, 1957 with definite signs of estrus has been reported. However, signs.
of estrus in this study were observed to be highly variable and had a poor relationship with postpartum follicular activity. The estrus signs like stradling of the hind legs, raising the tail, frequent urination and submissive behaviour towards an approaching male were shown by animals, when there was little or no follicular activity in their
Ž
ovaries. These findings confirm the earlier reports in one-humped camel Skidmore et
. Ž .
al., 1996 and llama England et al., 1971 that signs of estrus bear little relationship to follicle maturity. Similarly, first estrus was reported to be silent and therefore not
Ž .
considered a reliable method for evaluation of postpartum activity Elias, 1990 .
Ž .
In summary, postpartum follicular G1.0 cm diameter activity is observed in some
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