Physiological and behavioral responses to different watering intervals in lactating camels (Camelus dromedarius)

Abstract

Bekele T, Olsson K, Olsson U, Dahlborn K. Physiological and behavioral responses to different watering intervals in lactating camels (Camelus dromedarius). Am J Physiol Regul Integr Comp Physiol 305: R639-R646, 2013. First published July 10, 2013 doi:10.1152/ajpregu.00015.2013.-During drought periods camels are watered at long intervals, but effects on body fluid homeostasis of lactating camels are not known. It was hypothesized that camels store water after drinking and minimize water losses by diurnal variation in body temperature, changes in behavior, and release of vasopressin. The aim was to find a sustainable watering interval for lactating camels. Seven lactating camels were studied in a cross-over trial in which they were watered once daily (W1), every fourth day (W4), every eighth day (W8), or after 16 days (W16) with a 5-day interval between treatments. When offered water every fourth or eighth days, the camels drank sufficient amounts to cover their needs for subsequent days, but after 16 days of dehydration they did not drink enough to compensate the body weight loss. Rectal temperature fell at night and the camels searched shade during daytime minimizing evaporative fluid losses. Plasma osmolality and sodium concentration were elevated after 4 days of water deprivation and plasma protein and vasopressin concentrations after 8 days. Milk production decreased during the last week of W16. Plasma aldosterone concentration was elevated upon rehydration after W16, indicating sodium deficiency. In conclusion, lactating camels stored water after drinking and reduced water losses by staying in shade, keeping body temperature low, and releasing plasma vasopressin. However, serious dehydration was observed during W8, and after 16 days of water deprivation recovery took a long time. A watering interval between 4 and 7 days seems advisable under similar environmental conditions. aldosterone; body weight; dehydration; osmolality; vasopressin IN ARID AND SEMI-ARID REGIONS recurrent droughts often decimate livestock but camels survive and continue to produce milk (22). Nomadic camel pastoralism is therefore a rational human adaptation to a severe and adverse environment, but it has a great potential for improvement (34).In the dry season it is customary to water camels every 7-15 days, but the interval can be up to 30 days if the water source is far away (2). Water is often collected manually from deep wells making watering the most laborious activity for camel herders during drought periods (8).Studies on fluid and temperature regulation in males and nonpregnant, nonlactating females have given basic understanding of the adaptive mechanisms by which camels cope with their hostile environment, e.g., diurnal variation in core body temperature, low water turnover in the body, maintained plasma volume, and behavioral adjustments (35-37, 39, 40, 45). Camels show salt appetite as do some other mammals (16,22) and are regularly given salt or taken to salt-rich places (10, 44).Camel milk contains 15-20 mmol/l of sodiu...

Daily rhythms of physiological parameters in the dromedary camel under natural and laboratory conditions

“…This proportion is similar to the proportions previously found in sheep and horses (Piccione et al, 2005). The mean level of the measured variables was generally within the range of values reported in previous studies in camels (Aichouni et al, 2010;Ayoub and Saleh, 1998;Bekele et a., 2013;Eltahir et al, 2010;Hussein et al, 1992) with, notably, lower plasma concentrations of sodium, creatinine, ALP, ALT, AST, and LDH but higher concentrations of cholesterol, globulin, and total protein in our study.…”

“…The dromedary camel (Camelus dromedarius) is an important livestock species uniquely adapted to hot arid environments by its ability to reduce water loss through feces, urine, and evaporation (Bekele et al, 2013;Ben Goumi et al, 1993;Robertshaw and Zine-Filali, 1995;Schmidt-Nielsen et al, 1956). With increasing human population and inadequate food production in Africa and parts of Asia, it is important to develop semi-arid and arid rangelands through appropriate livestock production systems, and the camel is a natural choice (Schwartz and Dioli, 1992).…”

Daily regulation of body temperature rhythm in the camel (Camelus dromedarius) exposed to experimental desert conditions

“…), (Zine‐Filali ), (Bengoumi and Faye ), (Bekele et al. ) and is in contrast to the findings of (Al‐Haidary ). The use of small temperature‐sensitive data loggers continuously recording Tb without any manipulation of the animals, as well as the use of rooms with controlled conditions, has permitted long‐term detailed study in adaptive heterothermy and the description of novel aspects of its regulation.…”

When less means more: dehydration improves innate immunity in rattlesnakes

“…1). Their tolerance of hyperosmolality (277-436 mOsm kg −1 ) is greater than most other species known to use this strategy [camel: 310-352 mOsm kg −1 (Bekele et al, 2013); Gila monster: 280-350 mOsm kg −1 (Davis and DeNardo, 2009)], but not as high as has been documented for tortoises (up to 562 mOsm kg −1 ; Peterson, 1996). During periods of elevated plasma osmolality, whether naturally in the wild or via manipulation in the laboratory, rattlesnakes had enhanced innate immune function.…”