ISRAEL JOURNAL OF
VETERINARY MEDICINE
SUPEROVULATION RESPONSE TO A PROGESAGEN EAR IMPLANT,
PMSG AND HCG TREATMENT IN FEMALE CAMELS
Deen A.* and Sahani M.S.
National Research Centre on Camel P.B. No. 07 Bikaner 334001, INDIA
Introduction
Multiple ovulation and embryo transfer technology has been applied in cattle to
increase reproductive rates of genetically superior females. In cattle it may be possible
to raise an elite herd of genetically superior animals within a short period of time
using only a few females of superior genetics, and the genetics of the elite herd can be
spread through an entire nation through artificial insemination. The methods of
superovulation and embryo transfer have been well standardized in cattle, but because
of the physiological characteristics of the camel, i.e. seasonally breeding induced
ovulator type, which exhibits only a follicular phase when bred, no ovulation occurs
in non-mated female camels. Thus these methods need to be evaluated and suitably
modified to optimize the camel's response. Progestagen implants have been
successfully applied for superovulation in infertile cattle suffering with cystic ovaries,
a condition in which there in no spontaneous ovulation. As such, there is a valid
scientific background to adapt these implants for superovulation in non-spontaneously
ovulating camels.
Materials and Methods
The study was conducted on 8 female camels, which were inserted with a norgestomet
ear implant [Intervet, Boxmeer, Holland] for 7 days, to mimic the luteal phase, a prerequisite for superovulation treatment, followed by withdrawal, and i/m injection of
2000-4000 i.u. pregnant mare serum gonadotrophin(PMSG) [Intervet, Boxmeer,
Holland] to hasten multiple follicular growth for superovulation. And followed by
25mg i-m prostaglandin F2a [Intervet, Boxmeer, Holland] at appropriate stages at the
time of withdrawal of the Crestar implant to complete luteinization on day 7. The
female were naturally bred with a fertile male 6-7 days after PMSG administration..
Ovulations are expected around 36 hr after mating and flushing of the uterus was
attempted 7 days after mating, using a 2-way Foley catheter and Dulbecco's phosphate
buffered saline (PBS). Blood samples were collected at regular intervals from the day
of implant insertion to 6-7 days post-mating for peripheral plasma progesterone
profiles. These were monitored using an Elisa kit of Biochem Immuno system which
showed slightly lower values than expected but indicative of the follicular or luteal
phase.
Results
The ovarian response, performance of uterine flushing and recovery of embryos are
presented in Table 1. The peripheral plasma progesterone profiles are given in Figure
1.
Ovarian response
Of the 8 females, 4 did not ovulate and the numbers of ovulations in the other 4 were
inadequate to meet the objectives of multiple ovulation. Large unovulated follicles
were recorded in 2 females.
Performance of uterine flushing
To block the uterine horn before flushing to harvest camel embryos, 35ml and 50ml
air need to be pushed using the Foley catheter bulb into the right and left horn
respectively. The balloon was not fixed in the cervix or common body of uterus, as it
does not stay at these sites in camelidae. The balloon should be fixed in the horns of
the uterus, and this technique has been standardized to my complete satisfaction. We
had to put the balloon in individual horns, and if we attempted cervical fixation, it
failed, and we lost the entire infused fluid. The differences in the amount of air to be
pushed is due to asymmetry of the right and left horns. The results presented in Table
1 shows that in 2 of the 6 animals flushed, the loss of fluid into the vagina could not
be prevented. This happens because the bulb tends to slip back, and if the operator is
not careful, the catheter and its bulb may come out of vulva resulting in loss of fluid
into the vagina and hence loss of the embryos.
Embryo recovery
No embryo could be recovered from 6 of the 8 flushed females. I feel that the protocol
used for superovulation is not effective in inducing multiple ovulations.
Hormone Profiles
Peripheral plasma progesterone profile indicated that there was no ovulation in 4 of
the eight animals, and in the remaining four the rise in progesterone was too small,
indicating ovulation but non-fertile mating.
Discussion
The results indicated that the ovarian response to the treatment was very poor. Half
the animals did not ovulate.In the remainder, though ovulations were observed, the
numbers were too low to be of use for MOET programme in this species.
It is difficult to explain the exact cause of the poor response of superovulation.
Gordon et al., (1) reported that attempts of superovulation in the Camelid species have
generally yielded poor and inconclusive results because of their ill-defined oestrus
cycle. Superovulation treatment in cattle, buffalo, sheep and goat is usually
undertaken during mid-luteal phase when large number of FSH-responsive ovarian
follicles are present, and these get support from exogenous gonadotrophines for
growth and ovulation in large numbers. Absence of cyclical corpora lutea in unmated
camels is a bit troublesome for superovulatory procedures The only practical
alternative is the administration of progesterone for 7-10 days to suppress further
growth of follicles already present in the ovaries, and to suppress the release of
pituitary gonadotrophines. Results obtained with progesterone supplementation in this
study and many others are not encouraging. Skidmore et al. (2) observed that although
the application of PRID in camels released adequate amount of progesterone, it failed
to produce the desirable suppressive and priming action on the ovaries as it does in
sheep and horses. Failure to produce desirable results was evident as a high proportion
of females ovulated while carrying PRIDs in situ, while another significant proportion
failed to ovulate at all after a further injection of hCG or GnRH analogue. Cooper et
al. (3) also reported that PRID alone did not seem to be a satisfactory method of
controlling ovarian function in the dromedary camel, premature ovulations induced by
PRID prevented the occurrence of well synchronized superovulation. Anouassi and
Ali (4) were of the opinion that progestational priming is not necessary to achieve
adequate ovarian response to exogenous gonadotrophic stimulation in the camel .
Contrary to the above reports of poor performance with progestagens, Tinson et al. (5)
reported very good results using i/m injection of progesterone for 14 days. As
suggested by Cooper et al (3) the premature ovulations associated with PRIDs in situ
are due to the mechanical action of intravaginally placed progestagens devices.
Moreover, the poor response obtained with progestagen ear implant in this study
cannot be explained. Further studies are therefore required to understand the follicular
dynamics and to devise a protocol which will yield a consistent multiple ovulation
response.
Failure to recover embryos might have been due to a poor ovulatory response and
fertilization failure in the ovulated animals. Non-surgical flushing of the uterine horns
to collect camel embryo has revealed the tendency of the catheter bulb to slip back,
which can result in a significant loss of fluid and embryos. Several workers have
advised to hold the bulb in place with the hand of the operator inserted transvaginally
(6). In our experience, holding the bulb firmly by making a noose of the operator's
thumb and finger around the uterine horn caudal to the fixed bulb might be helpful in
preventing fluid and embryo losses. Based on the present study, it can be concluded
that progestagen ear implant- PMSG treatment did not yield a meaningful
superovulation response in camels. Further studies are required to evaluate the
efficiency of progestagen to suppress follicular growth and pituitary gonadotrophin
release for developing a protocol that yields a consistent superovulatory response.
References
1. Gordon, I., Controlled reproduction in Horses, Deer and Camelids. CAB
International, Wallingford, Oxon. U.K, 1997.
2. Skidmore, J., Allen, W.R., Cooper, M.J., Chaudhary, M.A., Billah, M., Billah,
A.M., The recovery and transfer of embryos in dromedary camel: results of
preliminary experiment. Proceedings of the 1st International Camel Conference,
Dubai, UAE. 137-142, 1992.
3. Cooper, M.J., Skidmore, J.A., Allen, W.R., Wensvoort, S., Billah, M.A.,
Chaudhary, M.A., Billah, A.M., Attempts to stimulate and synchronize ovulation and
superovulation in dromedary camels for embryo transfer. Proceedings of the 1st Int.
Camel Conference, Dubai, UAE. 187-191, 1992.
4. Anouassi, A. Ali, A., Embryo transfer in camel (Camelus dromedarius).
Proceedings of the workshop "Is it possible to improve the reproductive performance
of the camel"? Paris 327-332 1990.
5. Tinson, A.H., Singh, K., Kuhad, K.S., Large scale management of camels for
embryo transfer. J. Camel Practice and Research. 143-147, 2000.
6. Tibary, A., Anouassi, A., Theriogenology in camelidae, 1st Edition, Ministry of
Agriculture and Information, UAE, 1997.