The role of the ruminant’s digestive tract as a water reservoir

Shkolnik, Amiram; Maltz, E.; Choshniak, I.

doi:10.1007/978-94-011-8067-2_35

Cited by 36 publications

(33 citation statements)

References 13 publications

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“…The results show that 1) lactating camels drank in anticipation of coming water deficits when water was offered at 4-or 8-day intervals but not enough to compensate body weight losses after 16 days water deprivation; 2) dehydrated lactating camels actively searched shade despite rectal temperature below 35°C; 3) plasma sodium concentration and osmolality increased after 4 days and, after 8 days, total plasma protein and vasopressin concentrations also increased; and 4) it took a long time for the lactating 4 812 16 1 4 812 16 1 4 812 16 1 4 812 camels to restore body fluid homeostasis after 16 days of water deprivation. Drinking huge amounts of water to rapidly replenish body weight loss in the camel was described about 50 years ago (36), and later the black Bedouin goat was shown to immediately drink amounts of water compensating a 40% loss of its body weight (38). Storage of the consumed water in the forestomach and gut, saliva buffering the forestomach contents, and the continuous exchange of electrolytes and water between gastrointestinal tract and blood plasma are important factors that explain the exceptional tolerance to water deprivation in camels and ruminants (40,41).…”

Section: Discussionmentioning

confidence: 99%

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

Bekele¹,

Olsson²,

Olsson

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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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...

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Section: Discussionmentioning

confidence: 99%

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

Bekele¹,

Olsson²,

Olsson

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Several water restriction studies pointed out that the body mass loss in ruminants associated with a reduction in water and feed intake is considerably influenced by environmental temperatures and body water loss (Silanikove, 1992;Alamer, 2006 and2009). Shkolnik et al (1980) found that during 4 days of water deprivation, black Bedouin goats lost 25% to 30% of their body mass. The TBW was found to be reduced from 76% to 69%, whereas the animals continued to eat normally under arid desert conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, these animals have developed various behavioural, morphological and physiological adaptation mechanisms to enable them to survive, and in particular, to tolerate dehydration (Kay, 1997;Atti et al, 2000;Alamer and Al-hozab, 2004;Hamadeh et al, 2006). Compared with most other mammals, where losses of water over 15% of body mass can be fatal (Shkolnik et al, 1980), ruminants are able to tolerate water losses of up to 18%, 20%, 25% and more than 40% of their body mass as reported for cattle, sheep, camels and Bedouin goats, respectively (Shkolnik et al, 1980). This greater tolerance to water loss is mainly attributed to the rumen acting as a water reservoir (Silanikove, 2000).…”

Section: Introductionmentioning

confidence: 99%

Effect of water restriction on drinking behaviour and water intake in German black-head mutton sheep and Boer goats

Al-Ramamneh

Riek

Gerken

2012

Animal

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The present study was conducted to evaluate and compare the physiological responses of sheep and goats to water restriction using the deuterium dilution technique (D 2 O) to predict the total water intake (TWI) in both species. In two consecutive trials, 10 non-lactating Boer goats and 10 non-lactating German black-head mutton ewes were each randomly allocated into a treatment and a control group. In the control groups (n 5 5, for each species), water was offered ad libitum, whereas the treatment groups (n 5 5, for each species) received water 3 h/day on experimental days 8 to 14 and 6 h every 2 days on experimental days 15 to 22. The respiratory rate, rectal temperature, body mass and drinking behaviour were also recorded. The TWI was estimated by D 2 O for each animal. Water restriction for 21 h/day or 42 h/2 days had no significant (P . 0.05) effect on water intake (WI), feed intake, WI to dry matter intake ratio or body mass in both species. The absence of differences between species in their WIs was also confirmed using D 2 O. However, sheep had higher respiratory rates and rectal temperatures than goats in both control and treatment groups. Both species showed the ability to tolerate a moderate water shortage by activating several physiological mechanisms and behavioural strategies.

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“…Water ingestion during rehydration does not lead to an increased rumen fluid outflow, in contrast to the ingestion of isotonic fluid (Shkolnik et al, 1980). Particularly long fluid retention times in the rumen of desert ruminants may support the water reservoir function (Hummel et al, 2008a).…”

Section: Comparative Studies On Ruminantsmentioning

confidence: 98%

Evolutionary adaptations of ruminants and their potential relevance for modern production systems

Clauss

Hume

Hummel

2010

Animal

186

148

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Comparative physiology applies methods established in domestic animal science to a wider variety of species. This can lead to improved insight into evolutionary adaptations of domestic animals, by putting domestic species into a broader context. Examples include the variety of responses to seasonally fluctuating environments, different adaptations to heat and drought, and in particular adaptations to herbivory and various herbivore niches. Herbivores generally face the challenge that a high food intake compromises digestive efficiency (by reducing ingesta retention time and time available for selective feeding and for food comminution), and a variety of digestive strategies have evolved in response. Ruminants are very successful herbivores. They benefit from potential advantages of a forestomach without being constrained in their food intake as much as other foregut fermenters, because of their peculiar reticuloruminal sorting mechanism that retains food requiring further digestion but clears the forestomach of already digested material; the same mechanism also optimises food comminution. Wild ruminants vary widely in the degree to which their rumen contents 'stratify', with little stratification in 'moose-type' ruminants (which are mostly restricted to a browse niche) and a high degree of stratification into gas, particle and fluid layers in 'cattle-type' ruminants (which are more flexible as intermediate feeders and grazers). Yet all ruminants uniformly achieve efficient selective particle retention, suggesting that functions other than particle retention played an important role in the evolution of stratification-enhancing adaptations. One interesting emerging hypothesis is that the high fluid turnover observed in 'cattle-type' ruminants -which is a prerequisite for stratification -is an adaptation that not only leads to a shift of the sorting mechanism from the reticulum to the whole reticulorumen, but also optimises the harvest of microbial protein from the forestomach. Although potential benefits of this adaptation have not been quantified, the evidence for convergent evolution toward stratification suggests that they must be substantial. In modern production systems, the main way in which humans influence the efficiency of energy uptake is by manipulating diet quality. Selective breeding for conversion efficiency has resulted in notable differences between wild and domestic animals. With increased knowledge on the relevance of individual factors, that is fluid throughput through the reticulo-rumen, more specific selection parameters for breeding could be defined to increase productivity of domestic ruminants by continuing certain evolutionary trajectories.Keywords: herbivory, hindgut fermenter, foregut fermenter, browser, grazer ImplicationsUnderstanding evolutionary adaptations of ruminants will have an impact on (i) husbandry of captive wild ruminants, many of which cannot be kept or fed as domestic ruminants and (ii) research for continuous refinement of the production potential of domestic ruminants, ...

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The role of the ruminant’s digestive tract as a water reservoir

Cited by 36 publications

References 13 publications

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

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

Effect of water restriction on drinking behaviour and water intake in German black-head mutton sheep and Boer goats

Evolutionary adaptations of ruminants and their potential relevance for modern production systems

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