Research articleUltrasonographic fetometry and prenatal fetal sex assessment in camels (Camelus dromedarius)
Introduction
Pregnancy diagnosis and the estimation of gestational age are considered to be essential for maintaining a high level of reproductive efficiency in camels [1], [2]. Such information would allow producers to group animals based on their nutritional needs so that they are fed appropriate rations [3]. Additionally, most camel farms still adopt uncontrolled natural mating as a breeding strategy, with the subsequent lack of information about service date and gestational ages [4], [5]. This hinders the correct management of pregnant camels at the appropriate times.
Prenatal ultrasound investigations have been used to measure some fetal parameters and to predict the gestational age in several animal species including cattle [6], [7], buffaloes [8], horses [9], [10], [11], sheep [12], [13], [14], [15], [16], [17], [18], goats [19], [20], and llamas and alpacas [21], [22], [23], [24]. In dromedary camels, however, the fetuses have only been studied after being removed from dams at slaughter [25], [26], [27], [28], [29]. Therefore, further investigations on conceptuses of known breeding dates are needed to give more exact data on the development of the camel conceptus and to enable the accurate estimation of gestational age [27]. In contrast to slaughterhouse studies, prenatal ultrasonography can provide sequential measurements of the same conceptus throughout different developmental stages.
The assessment of prenatal fetal sex might be important in camel reproductive management because it could allow marketing of male and female fetuses still in utero. The ultrasonographic appearance of the genital tubercle (GT) has been used to assess prenatal fetal sex in cattle [30], [31], [32], [33], [34], [35], buffaloes [8], equines [36], sheep [37], and goats [19], [38]. Ultrasonographic visualization of the scrotum and mammary glands has also been used to diagnose prenatal fetal sex in different animal species [18], [19], [30], [34], [37]. The best windows for prenatal fetal sex identification have been found between Days 55 and 120 in cattle [31], [32], [34], between Days 70 and 126 in buffaloes [8], between Days 100 and 220 in equines [36], [39], beginning from Day 50 in sheep [37], and from Day 40 onward in goats [19], [38]. No literature has been available to date regarding the application of ultrasound to assess prenatal fetal sex in camels.
Specific fetal parameters have been used to determine the gestational age in different animal species. For example, thoracic, abdominal, and umbilical diameters have been used in cattle [7], aortic systolic and biparietal diameters, eye volume, femur length, and kidney cross-sectional area in equines [39], crown-rump length (CRL), amniotic vesicle, biparietal, and eyeball diameter (EBD) in buffaloes [8], CRL, chest depth, abdominal, biparietal, and EBDs, and ruminal length (RUL) in sheep and goats [18], [38], and gestational sac diameter, biparietal diameter, thorax height, femoral, tarsus-hoof, tibial, and fronto-occipital lengths in llamas and alpacas [21], [22], [23], [24]. The choice of these parameters depended on their feasibility in ultrasound examinations at different gestational periods. The aim of this study was to set up the biometric threshold of different fetal parts and organs (CRL, biparietal and abdominal diameter [ABD], RUL, and EBD) at which a high accuracy level in the estimation of gestational age using ultrasonography is realizable in camels, in addition to the assessment of the feasibility and accuracy of ultrasonic prenatal fetal sexing.
Section snippets
Animals and management
A group of 12 pluriparous, nonlactating female camels (Camelus dromedarius) aged 10 to 14 years and weighing between 380 and 440 kg were synchronized for estrus during the traditional breeding season for the Qassim territory in the Kingdom of Saudi Arabia (September to May, 2010–2011) with controlled internal drug release (Eazi-Breed CIDR; Pfizer, Auckland, New Zealand), containing 1.9 g progesterone, vaginally inserted and allowed to remain for 14 days. After CIDR removal, the camels in estrus
Results
A total of 329 ultrasonographic examinations were obtained from the seven camels between the second and 54th weeks of pregnancy. The mean duration of pregnancy was 57 ± 1.2 weeks (range, 55–58 weeks). All pregnancies but one were located in the left uterine horn. The corresponding corpora lutea were found in the left (N = 3) and right (N = 4) ovaries. All calves were born alive and survived postnatally. Pregnancy could be anticipated on observation of anechogenic fluid in the uterine horn (
Discussion
This study used ultrasonography to describe the growth pattern of camel fetuses in vivo. It focused on measuring a number of specific body parts and on assessing prenatal fetal sex between 7 and 16 weeks of gestation.
In this study, intrauterine fluid accumulation was observed between the second and third weeks of pregnancy. Skidmore et al. [43] and Tibary and Anouassi [44] reported that in the early stages of pregnancy, the embryonic vesicle is relatively difficult to visualize because it is
Acknowledgments
This work was performed at: Veterinary Teaching Hospital, Department of Veterinary Medicine, Faculty of Agriculture and Veterinary Medicine, Qassim University, Saudi Arabia.
References (50)
- et al.
Artificial insemination in dromedary camels
Anim Reprod Sci
(2013) - et al.
Ultrasonographic screening of embryo development in cattle (Bos indicus) between days 20 and 40 of pregnancy
Anim Reprod Sci
(2005) - et al.
Ultrasonographic fetometry and determination of fetal sex in buffaloes (Bubalus bubalis)
Anim Reprod Sci
(2008) - et al.
Real-time ultrasound measure of the fetal eye (vitreous body) for prediction of parturition date in small ponies
Theriogenology
(2006) - et al.
Real-time ultrasound imaging for predicting ovine fetal age
Theriogenology
(1990) - et al.
Determination of early pregnancy in ewes utilizing transrectal ultrasonography
Theriogenology
(1993) - et al.
Ultrasonographic assessment of fetal growth: comparison between human and ovine fetus
Am J Obstet Gynecol
(1995) - et al.
Ultrasonographic assessment of embryonic, fetal and placental development in Ossimi sheep
Small Rum Res
(2007) - et al.
Estimation of gestational age in Egyptian native goats by ultrasonographic fetometry
Anim Reprod Sci
(2009) - et al.
Early pregnancy diagnosis in alpaca (Lama pacos) and llama (Lama glama) by ultrasound
Anim Reprod Sci
(1997)