Ž .
Ž the presence of 1–1.9 cm diameter growing follicles Musa et al., 1990; McKinnon
. and Tinson, 1992; Skidmore et al., 1996 . In lamoids, it was found that 750 IU hCG was
sufficient to induce ovulation in 100 of alpacas and 80–800 mg GnRH provoked ovulation in 80 of llamas and alpacas. In lamoids, the minimum ovulatory size follicle
has been determined as 7 mm and the follicles should be in growing phase. Ovulation cannot be induced in the presence of smaller follicles due to the lack of release of LH by
the pituitary gland and luteinization of the follicle occurs if female lamoids are bred in
Ž .
the presence of regressing follicles Bravo et al., 1991 . 4.3. Synchronisation of female camels
When preparing camels for AI, it is necessary to be able to control follicular growth and synchronise ovulation in groups of animals. This poses particular problems in the
camels due to the absence of a cyclical CL that would exist in spontaneously ovulating species such as the horse and cow, and would be lysable with PGF
or one of its
2 a
analogues. There are few published reports on the use of progestagens to control follicular growth in the camel. Treating them with PRIDS has been found to be
unreliable, because removal of the PRID may be followed very rapidly by spontaneous Ž
. ovulation in some animals Marie and Anouassi, 1987; Cooper et al., 1992 . Daily
intramuscular injections of 100 mg progesterone-in-oil for 10–15 days has been shown to limit follicular growth and is particularly effective at hastening the regression of large
Ž .
unovulated follicles McKinnon and Tinson, 1992; McKinnon et al., 1994 . However, as growth rates of individual follicles can be highly variable between different animals,
attempts to synchronise them with progesterone — so that they only have a few small follicles present at the end of treatment — is not always beneficial as it does not
necessarily mean that they will all have a mature ovulable follicle between 1 and 1.9 cm in their ovaries at the same time.
Synchronisation of female lamoids for AI has not been explored. Whenever insemina- tion was intended, sexually receptive females to vasectomised males andror intact males
have been used. Then, ovulation has been provoked by mating to a vasectomised male or administration of hCG, andror GnRH.
5. Methods of semen collection
Collection of semen from male camelids is complicated by the position during Ž
. mating, long duration of copulation 5–50 min , and intrauterine semen deposition.
Copulation takes place with the female in recumbent position, the male squatting behind and the male dictates the duration of copulation.
5.1. Collection of semen in lamoids In lamoids, several methods of semen collection have been devised such as intravagi-
nal condoms, vaginal sponges, fistulation of the urethra, electroejaculation, post-copula- tory vaginal aspiration and AV. A brief account of each method is given below.
A human condom, containing a small steel ball at its end, is inserted into the vagina of a sexually receptive female by the aid of a glass rod, then a small amount of air is
blown through a tube to adhere the condom to the vaginal wall and an adhesive tissue can be used to attach the outside of the condom to the vulva of the female. The
disadvantages of this method are that males do not copulate for the normal length of
Ž time and the females become uncooperative after a few attempts Mogrovejo, 1952;
. Johnson, 1989; Sucapuca, 1991 .
When a sterile sponge is used for semen collection, it is inserted into the cranial Ž
. vagina
San Martin et al., 1968 ; however, the samples collected from 39 males contained no spermatozoa in 20 of cases.
Collection of semen through a fistula in the penile urethra has the disadvantage of Ž
. post-operative care and impairment of the male von Kubiceck, 1974 .
For semen collection by electroejaculation, sedation or general anaesthesia of the Ž
. animal may be required Johnson, 1989; McEvoy et al., 1992 . The glans penis should
be exteriorized with the aid of gauze and the semen collected into a pre-warmed tube. After insertion of the probe into the rectum, electrical stimulation is initiated at the
lowest setting and gradually increased to 4–6 s of stimulation, followed by 4 s resting period. Several collection tubes should be at hand because of the possibility of urine
Ž .
contamination Fernandez-Baca and Calderon, 1963–1966 . Due to the short duration of ejaculation, the semen obtained is often of poor quality.
The post-copulatory vaginal aspiration is easily applicable and is a non-invasive method, but the semen samples obtained usually are incomplete and often contaminated
with blood. Collection of semen by an AV mounted inside a dummy is more natural and reliable
Ž .
than the other methods Sumar and Leyva, 1981; Moscoso, 1996; Bravo et al., 1997a . The difficulty is that male llamas and alpacas have to be trained to the dummy, but after
acceptance, they keep the normal ejaculation time and the ejaculates are similar to those deposited into the female reproductive tract. The characteristics of lamoid semen
collected by the various methods are shown in Table 2.
5.2. Collection of semen in camels The accepted methods of semen collection in camels are by AV and by electroejacu-
Ž lation. For collection by AV, a modified bull vagina 30 cm long, 5 cm internal
. diameter has given the best results. However, care must be taken to avoid the ejaculate
making contact with the rubber liner of the AV, since this has been shown to adversely affect sperm motility. Hence, a shortened AV may be used, allowing the semen to pass
directly into the collection flask. Alternatively, an additional disposable plastic inner liner may be inserted to avoid contact with the rubber material. The AV is filled with
water at 55–608C to give an internal temperature of 38–408C and a clear glass
Ž .
water-jacketed 35–378C semen vessel is attached to the apex of the cone-shaped internal latex rubber liner to enable visualization of ejaculation. Observation of natural
matings suggested that the highly mobile urethral process of the camel penis may need to gain entry to the cervix to stimulate ejaculation during the extended copulatory
Table 2 Mean characteristics of lamoid semen collected by different methods
Method of Volume
pH Motility
Concentration Normal
Reference Ž
. Ž .
Ž .
collection ml
ml spermatozoa
Ž . Condom
1.9 8.3
low 33,320
41 Mogroveja, 1952
Condom 0.7
7.3 slow
83,750 –
Sucapuca, 1991 Electroejaculation
1.4 7.0
low 31,688
– Fernandez-Baca and
Calderon, 1963–1966 Electroejaculation
1.0 7.1
48.2 38,705
Cardenas et al., 1987 Urethral fistula
6.6 7.5
– 600,000
– von Kubiceck, 1974
Vaginal sampling 1.2
7.4 slow
– 10–78
Neely, 1993 AV
2.8 –
fair 192,000
– Sumar and Leyva, 1981
AV 0.5
– low
145,000 –
Quispe, 1987 AV
2.3 7.1
30.6 339,040
– Cardenas et al., 1987
AV 1.7
– slow
150,000 –
Garnica et al., 1993
a
AV 3.0
8.1 23.7
100,000 39.7
Lichtenwalner et al., 1996b AV
1.9 7.8
85 147,500
75.9 Bravo et al., 1997a
a
Values for llama.
process. For this reason, a foam imitation cervix of about 8 cm in length is placed inside Ž
. the AV Fig. 1 . A sexually receptive female is first teased by the male in order to make
Fig. 1. Diagram of an artificial vagina used in dromedary camels.
olfactory contact. The male is then led up from behind to the sitting female with the operator sitting on the left side of the female. As soon as the male has sat down on the
female and makes a few thrusts, the operator grasps the male’s sheath and directs his penis into the AV, and holds it there by manual pressure at the base of the scrotum. The
male will make several thrusts, interspersed by periods of rest, until ejaculation is completed. The ejaculate usually occurs in fractions and this whole process can take
between 5 and 10 min, although it may occasionally last for 20 min or even longer.
Electroejaculation may be employed if collection by AV cannot be achieved, using a Ž
. standard bovine ejaculator Standard Precision Electronics, Denver . The male is secured
Ž .
in sternal recumbency and then turned on his side as described by Tingari et al. 1986 . Depending on the temperament of the individual male, the collection can be done with
Ž or without the use of sedative and analgesic Domosedan Detomidine hydrochloride,
Ž .
. 30–35 mgrkg body weight bwt , i.v., or 70–80 mgrkg bwt, i.m. , which is superior to
other sedatives such as xylazine and acepromazine for obtaining semen by electroejacu- Ž
. lation Jochle et al., 1990 . Ejaculation can be achieved by using the rectal probe
lubricated with a copious amount of jelly to ensure good contact with the mucosa and giving two sets of stimulation, each of 10–15 pulses of 3–4 s duration at 12 V and 180
mA with a rest of 2–3 min between the two series of impulses. The semen is collected into a flask held at the prepucial orifice with occasional milking of the prepuce to expel
all the semen. The volume of semen recovered by electroejaculation is usually less than that obtained by AV, but the other semen parameters are similar.
6. Characteristics of semen
