Ultrasonographic assessment of follicular size to reduce the age of first service in the dromedary heifers

In the present study we attempted to breed dromedary camel heifers (n= 68) at a younger age compared to the common practice of breeding camel heifers at 4 years of age. In the first experiment, heifers (n=15) were maintained on different nutritional groups viz. intensive system with fodder (ISF; n=5), intensive system with extra protein (ISP; n=5) and semi-intensive system with fodder (SIF; n=5) starting from 2.5 years of age. In experiment II, heifers (n=18) were maintained under SIF (n=12) and ISF (n=6) and in experiment III, heifers (n=35) were maintained under SIF. The heifers in all experiments were evaluated every 10^th day during the breeding season by transrectal ultrasonography and those evidencing a follicle (diameter ≥ 9 mm) were mated with virile stud camels. Ultrasound examination revealed follicular growth diameter ≥ 9 mm in 14/15 (93.3%), 18/18 (100%) and 31/35 (88.5%) of the camel heifers in Experiments I, II, III, respectively, at 3 yr ± 2 months of age and weighed at least 360 kg; these were successfully mated and 28 out of 68 heifers conceived at approximately 3 yr and delivered calf at around 4 yr age. The age of first service was positively correlated with body weight, heart girth and body girth. It was concluded that supplementary feeding of camel heifers had positive effects on the body weight and reduced the age at first service. Camel heifers attained puberty at 3 yr of age and >360 kg body weight and were successfully bred through ultrasonographic monitoring of follicle.