Elsevier

Theriogenology

Volume 80, Issue 6, 1 October 2013, Pages 609-618
Theriogenology

Research article
Ultrasonographic fetometry and prenatal fetal sex assessment in camels (Camelus dromedarius)

https://doi.org/10.1016/j.theriogenology.2013.05.028Get rights and content

Abstract

The aims of this study were to determine the developmental patterns of some fetal parts to achieve a high accuracy level in the assessment of gestational age and to assess the feasibility and accuracy of ultrasonic prenatal fetal sex assessment in camels. Serial ultrasonographic examinations were carried out on seven pregnant dromedary camels. A total of 329 ultrasonographic examinations were conducted between the second and the 54th weeks of pregnancy. Intrauterine fluid accumulation was detected between the second and third weeks of pregnancy. The embryo proper was noticed between the third and fourth weeks. Organization of the embryo was first observed between the sixth and seventh weeks. Ossification was first detected between the seventh and ninth weeks. The accessibility during the total gestational period was 35/329 (10.6%) for crown-rump length, 35/329 (10.6%) for biparietal diameter, 42/329 (12.8%) for abdominal diameter, 42/329 (12.8%) for ruminal length, and 126/329 (38.3%) for eyeball diameter. A high correlation was found between gestational age and each of the studied parameters (P < 0.0001). The highest correlation was found with the crown-rump length and the biparietal diameter during the first trimester and with the eyeball diameter during the third trimester of pregnancy. The overall accuracy of the ultrasonic prenatal fetal sex assessment was 91.7%. The best window was found during the 11th week of pregnancy. It was concluded that sonographic fetometry can be useful for the evaluation of fetal development, the estimation of gestational age, and the prediction of prenatal fetal sex in camels.

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.

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