Measurements of Milk Flow and Udder Morphology and Their Impact on Milkability and Selecting of Dairy Camels (Camelus dromedarius) Under Intensive System

Abstract

This study is composed of two experiments the first experiment aims to study milking traits and milk flow parameters during lactation and their relationship with milk yield in 22 multiparous dromedary camels machine milked twice a day. A total of 921 milk curves were recorded throughout the lactation period using a two electronic milk flow meters (Lactocorder©). Results revealed that within 43 weeks of lactation average daily milk yield was 5.57 ±2.6 l. The peak milk yield was reached at the 26th week of lactation with 8.66 l and decreased thereafter with high lactation persistency (90.7%). Machine Milk (MM), machine stripping milk (MSM), average milk flow rate (AFR) and peak milk flow rate (PFR) were 3±1.67 kg /milking, 0.136±0.01 kg, 1.11 kg/min and 1.99 kg/ min respectively. Average durations of main milking phase, ascending phase, plateau phase, descending phase and total milking were 2.79 ± 0.05 min, 1.92 ± 0.05 min, 0.39 ± 0.02 min, 0.93 ± 0.63 min, 6.59 ± 0.09 min respectively. Stage of lactation affected positively peak and average milk flow rate and milking yield per milking. Lowest milk yield per milking, stripping milk, peak and average milk flow were detected at early stage of lactation. Significant(P<0.0001) longest duration of total milking was observed at late stage of lactation. Milk yield, duration of total milk yield per milking and duration of main phase for 14 hours milking interval “morning milking” was significantly (P<0.0001) higher comparing with 10 hours milking interval “evening milking”. Bimodality represented 29.3% of the total curves but this type was more common at mid stage of lactation (33%). Also, a higher total milk yield with the increasing of main and descending phase of milking were observed in this milk flow curve. Negative correlation occurred between average and peak milk flow and the duration of certain (main, plateau XII and ascending) milking phase. Milk yield positively related to peak milk flow, average milk flow rate and duration of total milking time. Bimodality was positively correlated with milk yield, duration of main phase and descending phase. The second experiment aims to study the change of udder morphology traits after a machine milking and the change of udder traits during stage of lactation. Moreover, to evaluate udder and teat shape in relation with milk yield. To determine udder and teats measurements which were taken directly before and after milking a total of 77 multiparous dromedary camels were used. On average the length, height, depth and circumference of the udder were 43.6±4.9, 106.9±7.7, 43.8±4.6, 97.1±6.3 cm respectively. The teat length front and rear, diameter and distance between teats were 4.85±1.85, 5.09±1.85, 3.43±1.05, 8.92±1.92 cm respectively before milking. Udder length and height did not change before and after milking while udder depth and circumference showed significant(p˂ 0.00l) decrease after milking. Front teat length significantly increased after milking while, teat diameter and distance between teats showed significantly decreased. Udder depth, udder circumference and distance between teats positively correlated with milk yield and affected significantly (p˂0.05) by stage of lactation and showed highest value at mid stage of lactation: 46.1±4.2, 99.9±5.3, 9.6±1.8 respectively. Total milk yield reaches the highest value at mid stage of lactation. Seventy two lactating camels from experimental camels were classified for udder and teat shape. Udders were classified to: pear, globular and pendulous. While, teat were classified to: funnel, cylindrical and bottle shape. Globular shape at first and late stage was very common followed by pendulous and pear shapes. Cylindrical teats were more frequent followed by funnel and bottle shaped at XIII the first and late stages. A significant (p≤ 0.05) difference was observed in total milk yield according to udder shape at first stage of lactation. Highest milk yield of 5.64 kg was obtained from pear udder shaped followed by globular 4.7±0.28kg and pendulous 4.41±0.036 kg. Significant difference in length observed between pear against globular and pendulous. Teat length of front and rear, diameter and distance between teats were significantly (p≤ 0.05) lower in globular shaped from other shapes at first stage. We can conclude that stage of lactation, milking intervals and bimodality influence milking traits and milk flow parameters in dairy camels. Udder and teats measurement changes during milking and stage of lactation increase understanding for selecting lactating camels and improving camel machine milking efficiency. The study showed clear variation in the udder and teat shapes and dimensions and their relationship with milk yield in lactating camels