A proposal of linear assessment scheme for the udder of dairy camels (Camelus dromedarius L.)

摘要

Digital images from the left side of the mammary gland of 146 multiparous lactating dromedary camels in mid lactation and managed under intensive conditions were obtained immediately before milking and used to build up a reference scheme for the morphological evaluation of camel mammary glands. A 5-point linear scoring scheme (with 0.5-point accuracy) was subsequently generated based on five mammary traits (udder, depth and floor inclination, teats, shape, length, and width). Results showed that Arabian dairy camels had voluminous udders with large-sized teats. Most common udder shape was globular (47.3 %), followed by the pear (34.3 %) and pendulous (18.4 %) shapes. Conical- or funnel-shaped teats (60.9 %) were the most frequent, followed by cylindrical- (29.5 %) and blew-up (9.6 %)-shaped teats. The observed variation in the udder and teat measurements, as well as in typology, attested that dromedary camels need especially large milking clusters to improve their machine milkability. Assessment of the previously indicated digital images according to the proposed linear scoring scheme, performed by 3 independent operators showed that the overall means were close to 3.00 points (values between 2.45 and 3.62), and the standard deviations were close to 0.76 points (values between 0.58 and 0.94). Moderate repeatability between operators (r > 0.69) was obtained for udder depth and floor inclination, indicating that training of operators, as well as improvements in the definition of traits should be considered in future studies. Further research is needed to validate the proposed linear scoring system in different stages of lactation and parities using a large number of camels.