Physiological and chemical responses in water-deprived Awassi ewes treated with vitamin C

The effect of water-restriction on various physiological variables in intensively reared Lacaune ewes

“…This promotes increased sodium retention and water adsorption at the kidney level, leading to a haemo-dilution in an attempt to restore the physiological values of sodium and chlorine. In similar previous studies on sheep, goats and cattle (Burgos et al 2001;Mengistu et al 2007;Casamassima et al 2008;Ghanem et al 2008) similar variations in sodium and chlorine in response to increased restrictions in water were reported. Other authors (Rawda 2003;Hanna 2006;Ghanem et al 2008) reported a strong influence of water intake on sodium ion concentrations in sheep plasma; the reduction of plasma volume in response to water restriction causes an increase in blood plasma osmolality, and leads to the concentration of electrolytes in plasma (Qinisa et al 2011), in particular, an increase in sodium and chlorine ions as has been reported by different authors for sheep and goats (Alamer 2005;Jacob et al 2006;Karnib 2009).…”

“…In water restriction experiments carried out on sheep, goats and cattle, low feed intake has been described to be partially offset by reduced intestinal peristalsis, which leads to an increased time of exposure of feed to the intestinal microflora with beneficial effects on digestibility and feed utilisation (Musimba et al 1987 Alamer (2010) also reported no change in rectal temperatures in water-restricted Aardi goat. However, Alamer and Al-Hozab (2004) described a significant increase in rectal temperature under conditions of water restriction during the spring and summer season in Awassi and Najdi rams; other authors (Ghanem et al 2008) made the same findings in Awassi sheep, which are due to the adaptive response of animals to the breeding environment that serve to reduce water loss through mechanisms of thermoregulation for the defence from heat.…”

“…During the summer dehydration almost always results in a reduction in plasma volume caused by a recall of water from tissues (Schaefer et al 1990). Although several authors (Laden et al 1987;Dahlborn et al 1988;Olsson and Dahlborn 1989;Abdelatif and Ahmed 1994;Ghanem 2005) agree that a reduction of corpuscular volume concentration and haemoglobin serve as good indicators of dehydration in plasma, other authors do not report these findings; in fact, the haematocrit concentration was higher in Awassi and Merinos sheep in conditions of water stress (Laden et al 1987;Ghanem 2005;Ghanem et al 2008). Moreover, under the same conditions other authors have failed to detect any significant variations in this as well as other breeds (Aganga et al 1989;Igbokwe 1993;Li et al 2000).…”

Effect of Pre-Mating Water Deprivation on Ovarian Activity and on Reproductive Traits of Mature Barbarine Ewes during Summer Season

“…In our work, rectal temperature value of the water-deprived ewes remained above that of the control ones. This is agree with previous works where temporary hyperthermia is often reported in dehydrated sheep [13]. Hyperthemia is one of mechanisms that allow animals to avoid excessive water expenditure during the hot part of the dayespecially as our study was conducted during the warmer months of the year.…”

“…Despite this result was not statistically significant, it should be taken into consideration. Further studies are needed to deepen this effect since some authors reported a variation of some metabolites in serum that could explain a difference like increase in serum protein [13] due to the decreased blood volume.…”