Effect of milking interval on secretion rate and composition of camel milk in late lactation

SUMMARY. The effect of milking interval on secretion rates of milk and milk constituents was studied in four milking camels during late lactation. An interval of 4 h produced the highest milk secretion rate compared with 8, 12 and 16 h intervals, and rates tended to decline with increasing milking intervals. Secretion rates of organic (lactose, SNF, fat and protein) and inorganic milk constituents (sodium, potassium, calcium and magnesium) generally followed similar patterns of decreasing secretion with increasing milking intervals. Many of the values for different intervals were significantly different. Previous studies with cows have suggested that the secretion rates of milk and some milk constituents are adversely affected by prolonged milking intervals of > 12 h, perhaps as a result of increased intramammary pressure (Schmidt, 1960; Tucker et al. 1961). On the other hand, increases in milk secretion of up to 40% as a result of thrice daily milking in cows were reported more than 30 years ago (Elliott, 1959). More recently, less dramatic effects of shortening the milking intervals have been reported in both cows (Pearson et al. 1979; Rao & Ludri, 1984; Amos et al. 1985; Van der lest & Hillerton, 1989; Hillerton et al. 1990; Alshaikh, 1991) and goats (Linzell & Peaker, 1971; Henderson et al. 1983, 1985; Knight et al. 1990; Alshaikh, 1991). Camel milk is an important component of the human diet in many countries and there is sufficient evidence to indicate that the dromedary (Camelus dromedarius) possesses practical and unique attributes for high milk production (Knoess, 1980; Yagil & Etzion, 1980). Under intensive management, these animals can produce relatively large amounts of milk, with average yields of 10-15 kg/ d (Rao et al. 1970; Knoess, 1980). With good feeding their milk production can even exceed 2000 I per lactation (Knoess, 1980; Yagil, 1982). In most camel breeding countries, the length of the lactation period is reported to be in the range 9-18 months, with considerably higher yields during the second than the first lactation (Yagil, 1982). In Saudi Arabia, the camel population is ~ 400000 (Ministry of Agriculture and Water, 1990), and they are regarded as an important source of meat and milk. Several modern farms have recently been established for commercial milk production. The objective of the present study was to investigate the effect of milking interval on secretory rates of milk and its organic and inorganic components in milking camels