Review on the influence of water quality on livestock production in the era of climate change: perspectives from dryland regions

Abstract

Freshwater availability is seriously threatened by expanding water demand and contamination concerns, particularly in dryland regions worldwide. Furthermore, global climate change is increasing water salinity by altering the global supply of groundwater and surface water. The quality of animal water has a significant impact on livestock production, influencing several processes such as growth, metabolism, reproduction, and body temperature. Although animals can tolerate bad water quality better than humans, livestock can be harmed if chemicals are added to the water. The poor quality of drinking water can have an impact on livestock productivity and welfare; however, tolerance to low water quality varies by species, race, and environmental conditions. As a result, this review examined the influences of poor-quality water on livestock production and productivity in arid and semi-arid areas in an era of changing climate. Despite variations in adapted physiological parameters, blood hematology, biochemical, food, and water consumption, camels and goats adapt to high salt levels in desert regions. Small ruminants’ nutritional intake and performance, as well as their breathing rate and blood biochemistry concentrations, all decrease when the salinity of their drinking water increases. While research on small and resilient ruminant breeds that can survive high salinity levels is underway around the world, further study is needed to understand the water-resistant features of adapted livestock species and breeds, particularly in dry and salty places impacted by changing climate.

Keywords:

• Climate
• response
• ruminants
• water

Review editor:

• Pedro González-Redondo [email protected] Senior Editor University of Seville, Spain

SUBJECT:

• Zoology
• Animal Ecology
• Animal Physiology
• Freshwater Biology

1. Introduction

The quantity and quality of freshwater in tropical regions, particularly deserts and dry areas, are uncertain due to the effects of climate change on rainfall patterns and temperature (Jiménez Cisneros et al., 2015; Konapala et al., 2020; Papa et al., 2023). Water quantity and quality are essential characteristics that affect feed intake and animal physiological welfare, which regulate performance and productivity. Quality depends on salinity (total dissolved solids (TDS)) contents, moisture, temperature, minerals, pH, hardness, and microbial load (Umar et al., 2014). The supply and salinization of soils are major issues around the world in the context of climate change, with major consequences for the welfare of animals and plants and production (Hamed et al., 2018; Urama & Ozor, 2010). As sea levels rise due to global warming, groundwater and surface water in many arid and semi-arid locations become polluted with higher salinity rates. Water quality is highly influenced by salinity, which poses considerable problems for livestock production and productivity, particularly in dry places where freshwater availability is affected by climate change (Chedid et al., 2014; Heinke et al., 2020; Nicholson, 2017; Zayed, 2022). As a result, it is critical to identify livestock species and breeds that produce exceptional productivity like milk and meat in stressful situations. This understanding has the potential to significantly improve the livelihoods of small-scale farmers (Sisay et al., 2020). Animals in dry regions are susceptible to stress due to a lack of water throughout the year. For most of the year, arid locations have a considerable impact on animals due to water-related stress (Sejian et al., 2015). Sheep, goats, and camels are highly recommended for small-scale farmers in Sub-Saharan Africa due to their outstanding disease resistance, efficient grazing habits, high feed conversion rates, and drought resistance (Ciliberti et al., 2022). Goats and sheep, due to their lower size and enhanced water usage mechanisms, can effectively consume water in semi-arid situations. These adaptive processes improve water absorption and metabolism throughout the gastrointestinal tract, ensuring efficient water usage during times of scarcity (Araújo et al., 2010). Environmental conditions, breeds, species, and diet all determine the extremely safe dose of salt that animals can endure (De et al., 2021; de Lima et al., 2023; Samuel, 2022). Animals develop salt sensitivity after prolonged exposure to saline water. Salt sensitivity responses differ depending on whether salt is ingested through food or drinking water (Masters et al., 2005). Sheep can tolerate high salt concentrations in their diet ranging from 5 to 20% (Digby et al., 2011), although deer can handle at least 6% (Ru et al., 2004). Therefore, identifying the biological and physiological response processes that drive livestock species to poor water quality is a key step toward creating enduring approaches to develop cutting-edge places with inadequate or poor water quality. As a result, this paper aims to critically review the implications of water quality on production and health, as well as the tolerance of farm animal species under climate change scenarios in the context of dryland regions.

2. Methodology

The review study used a simple and systematic technique to study the impact of poor water quality on livestock productivity in dry areas under climate change (Palmatier et al., 2018; Patriotta, 2020; Paul & Barari, 2022). Key terms related to the topic were chosen, such as livestock, sheep, goats, salinity, dryland, arid and semi-arid regions, blood reaction, tropics, and climate change. Reputable databases and sources, including Scopus, Springer, Elsevier, and PubMed, were used in a thorough search, with the results being further refined using Boolean algorithms. To choose research on the effects of climate change, physiological reactions, and the impact of water quality on livestock productivity, inclusion criteria were developed. Only studies that met the criteria were selected for full-text evaluation after being filtered primarily on titles and abstracts. The study design, location, species of livestock, water quality indicators, factors related to climate change, and the effects on the physiological reactions and production of livestock were among the data that were extracted. To find recurring themes and patterns, the data were combined and examined, focusing on the relationships between livestock performance, physiological reactions, and water quality. The results were reviewed and analyzed and potential causes and pathways were investigated, along with implications for dryland areas under climate change. The review determined by brief the key findings, addressing research gaps and limits, and presenting recommendations for imminent lessons and methods to mitigate the impact of water quality on livestock productivity in dryland areas. The methodology employed ensured a systematic and comprehensive analysis of relevant studies, providing valuable insights into the relationship between water quality and livestock production in dryland areas of climate change.

3. Review results

3.1. Climate change and water quality in arid and semi-arid regions

Water is the most important constraining component of economic and environmental progress, but it is currently affected by climate change, mainly in Africa (Hamed et al., 2018; Hirwa et al., 2021). Furthermore, worldwide water demand has increased by an average of 6% in the last century and is continuing to rise at a continuous rate of 1% per year as a result of a growing population, economic expansion, and changing consumption habits (UNESCO & UN-Water, 2020). Climate change will have an impact on the availability, quality and amount of water required for basic human needs. This could jeopardize billions of people’s ability to enjoy their basic human rights to water and sanitation (Ma et al., 2022). Climate change and water quality are inextricably related because climate change affects water quality directly through changes in the hydrological cycle (Figure 1). More water evaporates from the surface as temperatures rise, resulting in more rainfall in some areas and dryness in others (Verweij et al., 2010). Furthermore, water quality is influenced by interactions among different environmental components like atmospheric, terrestrial, and aquatic processes in a watershed, as well as human resource use which result in direct and indirect changes in water quality (Mortsch et al., 2003). The consequences directly and indirectly affect water quality parameters including biological, physical, and chemical changes. Pathogenic bacteria in water bodies are an example of biotic change (Ganpat & Isaac, 2016).

Figure 1. An approach to assess the impact of climate change on water quantity and quality, as well as agricultural production systems (Cai et al., 2015; Hardelin & Lankoski, 2015).

Furthermore, the water cycle can have a wide range of effects on water quality. For example, runoff can transfer toxins into bodies of water like rivers and lakes (Assegide et al., 2022; Bhateria & Jain, 2016). As a result, these water sources may become contaminated with hazardous materials such as chemicals and heavy metals, posing major health risks to humans and aquatic creatures. Droughts, on the other hand, can produce reduced water flow in rivers and lakes, resulting in stagnant water. This promotes the development of potentially dangerous bacteria and algae that cause waterborne illness (Akhtar et al., 2021; Khatri & Tyagi, 2015). Changing the climate impacts the quality of water by increasing the temperature of water bodies. Water temperatures increase as global temperatures rise, causing dangerous bacteria and algae to proliferate in bodies of water. This can induce the formation of toxic algae blooms, which can cause waterborne sickness in humans and animals who come into contact with water (Marampouti et al., 2021; Tewari, 2022). Groundwater and surface water supplies are currently being strained in some areas due to increased use and decreased runoff and recharge. The quality of water is deteriorating in several regions, owing primarily to increased sediment and concentrations of pollutants following severe rainfall. Rising air and water temperatures, increased precipitation and runoff, and severe droughts all have a significant impact on water quality, particularly in lakes and rivers. Higher quantities of sediment, nitrogen, and other toxins are produced as a result of these environmental changes, thereby further worsening water quality (Melillo et al., 2014).

3.2. Quality of drinking water for livestock species

Water is widely documented as a vital nutrient that is consumed in greater quantity and more frequently than any other nutrient. It is fascinating to note that the human body consists of more than 50% water, although this percentage may vary depending on factors such as sex and body composition (Hossain, 2001). Individuals with higher levels of body fat, for example, have lower water content than those with a higher proportion of lean muscular mass (Hoffman, 1988; Hossain, 2001; Jéquier & Constant, 2010). Many factors influence livestock consumption of water, including size, productivity, food, and environmental circumstances; hence, good water quality and purity may increase the intake of water as well as enhance the profitability of livestock (Brown, 2006; Tobergte & Curtis, 2013; Ullah et al., 2021).

Furthermore, water stress, including water quality issues, endangers cattle production in arid and semi-arid regions, especially during the dry seasons. Color, odor, taste, bacterial content, mineral content, salinity, and the presence of inorganic or organic substances are all characteristics that influence the appropriateness of water for various applications (Curran, 2014; Yıldırır, 2020). Drinking water quality is crucial for animals, and there are severe concerns about saltwater intake and the presence of toxins such as blue-green algae, organic compounds, heavy metals, and pesticides. The total amount of dissolved salt ions, including sodium, calcium, magnesium, chloride, sulfate, and carbonate, determines the salinity level of water. These variables have a direct impact on the quality of animal water (Ensley, 2013; Mostrom and Ensley, 2020). Salinity levels are an important consideration when evaluating water quality in livestock management. More than salty water can be hazardous to animals, resulting in decreased food intake, decreased productivity, and salt-related diseases. Water contamination can cause mineral imbalances, which can lead to less water consumption. When some salts and metals exceed allowed levels, they can affect animal growth and development, causing illness and even death (Sallenave, 2016). Improper levels of critical minerals, such as magnesium, calcium, sodium, and chloride, can cause the salinity to grow, which can endanger the health of cows. Sulfate ions, in particular, are commonly found at high salinity levels, and sulfate concentrations greater than 1500 mg per litre can harm animal copper status. Furthermore, too much alkaline water in animals can cause digestive difficulties, diarrhea, and decreased feed intake and conversion rates (Naqvi et al., 2013, 2015). Although animals may tolerate high-salinity water for a limited period, their tolerance levels vary based on factors such as age, species, season, and physiological parameters.

3.3. The influence of water quality on livestock species

Water quality is critical to the general health and performance of ruminant animals. The quality of water that they ingest can have a substantial impact on a variety of physiological processes, including growth rate, milk production, and reproduction. Several factors contribute to water quality, including its odor, taste, physical and chemical characteristics, presence of harmful chemicals, and levels of macro- and microminerals (Kurup et al., 2012; Meehan et al., 2021; Pfost et al., 2001). As a result, ensuring high-quality water is critical for animal health. High water demand is one major environmental hazard associated with animal water intake. This issue has far-reaching consequences, particularly during dry periods. Water scarcity can result in higher salt concentrations, lowering water quality. An excess of saline water in dry or semiarid environments might further deteriorate the quality of animal-derived goods (Hersom & Crawford, 2008; Tobergte & Curtis, 2013; Zayed, 2022). It is critical to solve these issues to protect both animal welfare and agricultural product quality

3.3.1. Intake and animal performance

The intake of animal feed is critical, especially for sheep in feedlots, as it has a significant impact on their overall efficiency. After all, their ability to absorb vital nutrients has a direct impact on their survival and productivity (Schütz et al., 2021). This intake is directly related to water consumption, which is affected by a variety of factors including age, weight, breed, species, ambient temperature, humidity, lactation status, nutrition, and production level (Morgan, 2011). Surprisingly, the quality of water, particularly its salt levels, influences animal feed consumption and nutritional absorption. High salinity might result in metabolic changes that affect performance and product quality. Furthermore, sheep have a rumination process that involves breaking down meal particles to facilitate smooth food transit through the gastrointestinal tract and regulate dry matter intake (Harini et al., 2022; Meehan et al., 2021; Thiet et al., 2022). Another important issue is the palatability of the water, and cattle prefer clean and contaminant-free water (Schütz et al., 2021). Excessive amounts of total dissolved solids, particularly sulfate salts, on the other hand, can harm animal performance (Makkar, 2018). This is especially true for pigs, especially neonates, where it can affect feed intake, body weight growth efficiency, and water utilization. Therefore, understanding and managing water intake and quality is essential for improving livestock productivity and ensuring animal welfare (Samuel, 2022). Numerous studies have been conducted to examine the effects of saltwater on the consumption and digestion of feed. According to Yousf and Ben Salem (2017), providing Barbarine sheep water containing NaCl at rates of 11 and 15 g/L resulted in a 4% and 14% decrease in feed consumption, respectively, compared to the group given tap water. Similarly, Katahdin sheep given brackish water (5596 mg TDS/L) and higher levels of TDS via NaCl experienced a decrease in feed intake and a change in organic matter intake as TDS levels increased, but overall digestibility of organic matter remained unchanged (Yirga et al., 2018). The different results could, however, be attributable to variances in the breeds employed in the studies as well as the environmental conditions. Unlike previous research, Moura et al. (2022) found no difference in dry matter consumption when sheep drank water with salinities ranging from 640 to 8326 mg TDS/L. Furthermore, raising water salinity to 8320 mg TDS/L did not affect dry matter and nutritional fraction consumption, nutrient digestibility, or water intake in Morada Nova or Santa Ines sheep (de Araújo et al., 2019). Furthermore, progressively introducing such water can enhance the tolerance of domestic animals to low-quality water.

3.4. Effects of saline drinking water on various types of livestock

It’s a well-known fact that every animal, regardless of its specific species, needs a daily intake of pure and refreshing water. This essential element plays a crucial role in maintaining the overall welfare and productivity of animals. From regulating body temperature and aiding digestion to lubricating joints and promoting muscle growth, water is the cornerstone of almost all essential biological processes in animals (Wright, 2007). Contaminants such as salts, excess nutrients, or bacteria may deteriorate water quality and become increasingly concentrated during droughts as sources of water dry off (Emon, 2018). High dissolved solids in animal water used for drinking inhibit feed proficiency and growth, induce health issues (e.g. scours, tooth decay) and are potentially lethal (Costa et al., 2021; Gaughan & Mader, 2009; Jaster et al., 1978; Kronberg & Schauer, 2013; López et al., 2014, 2021; Valtorta et al., 2008). Recommended values for dissolved solids are undetermined. Several studies (Berger & Rasby, 2011) indicate the upper limits; however, investigations frequently exceed the prescribed limits with no obvious consequences. The suggested maximum intake of total dissolved solids (TDS) for cattle is 3000 ppm (Tobergte & Curtis, 2013). Furthermore, a majority of the publications indicate the maximum limits for farm animal species (Table 1) without proof based on actual trials (Bagley et al., 1997; Brown, 2006; Dyer et al., 2017; Emon, 2018; Hersom & Crawford, 2008; Higgins & Gumbert, 2008; Pfost et al., 2001; Sallenave, 2016). Surprisingly, Africa does not have a water quality standard for farm animal species, although water quality is severely affected by climate change and variability (Brouillet & Sultan, 2023; Isaacman & Musemwa, 2021; Rahimi et al., 2021). As a result, water resources for livestock species should be monitored and maintained sustainably to ensure long-term economic development in regions that depend on the livestock sector.

Table 1. Effects of saline drinking water on various types of livestock.

Livestock	No adverse effects on animals expected	Animals may have initial reluctance to drink or there may be some diarrhea, but the stock should adapt without loss of production	Loss of production and a decline in animal condition and health would be expected. Stock may tolerate these levels for short periods if introduced gradually
species	EC in μS/cm	EC in μS/cm	EC in μS/cm
Poultry	0–3100	3100–4700	4700–6300
Dairy cattle	0–3900	3900–6300	6300–10,900
Beef cattle	0–6300	6300–7800	7800–15,600
Horses	0–6300	6300–9400	9400–10,900
Pigs	0–6300	6300–9400	9400–12,500
Sheep	0–7800	7000–15,600	15,600–20,300

Adapted from Curran (2014).

3.5. Water salinity effects on animal productivity

In animal farms, enough water for drinking is needed to sustain appropriate production levels. Water shortages are a growing concern in the context of the changing climate globally, and they will lead to a rise in the use of inadequate-quality water by the agricultural industry in numerous regions of the globe (López et al., 2021). The quality of water can have an impact on a wide range of physiological states in ruminant animals, including the rate of growth, milk production, and the reproduction process (Giri et al., 2020; Kurup et al., 2012). The excessive use of animal water is a significant economic disadvantage. Furthermore, the reality that harsh or semiarid locations contain high salt water can decrease the overall value of products produced by those livestock (Costa et al., 2021).

3.5.1. Water salinity effects on meat production

According to the previous results, water is the most plentiful nutrient in beef cattle, accounting for approximately 98% of all molecules in the body of an animal (Arispe, 2015). Despite this fact, water is often overlooked as a nutrient, which can have detrimental effects on the performance and health of the animals, as well as the economic viability of producers. As the availability and quality of water might vary drastically depending on the season, ensuring that they have constant access to fresh, high-quality water is critical for their welfare. Producers that prioritize the provision of clean water not only improve the health of their cattle but also save money in the long run by reducing the likelihood of disease outbreaks (Ahlberg et al., 2019; Wagner & Engle, 2021). Choosing poor water quality, on the other hand, may appear to be a cost-cutting solution initially, but it ultimately jeopardizes the herd’s health and productivity. Notwithstanding this, it is also the most ignored substance at the expense of livestock productivity and health, as well as producer profitability (Gerbens-Leenes et al., 2013; Umar et al., 2014). High-salt water has a deleterious effect on animal water intake, dry matter, and performance. When animals consume high-sulfate water, the impacts are more harmful than when they consume high-chloride water (López et al., 2014). In a study conducted by Yousfi et al. (2016), it was determined that the consumption of saline water with a NaCl concentration of 7 g/l had no impact on the body weight at slaughter, hot carcass weight, or chilled carcass weight in Barbarine lambs. These findings were further supported by the findings of Castro et al. (2017), who discovered that various levels of salinity in water (ranging from 640 to 8326 mg TDS/l) did not affect lamb slaughter weight, cold carcass weight, or hot carcass weight. However, the findings of Zayed (2022) disputed these conclusions, demonstrating that drinking water with varying salinities had a good influence on carcass features and non-carcass edible sections in Barki lambs. This suggests that decreased salt levels in drinking water may help enhance lamb carcass features. However, while saltbush (Atriplex) feeding was found to decrease the dressing percentage in Barki lambs, it did not have any significant effect on their slaughter weight or carcass weight, according to a study by Ahmed et al. (2015). It should be noted that there is currently limited knowledge about how drinking water salinity affects carcass characteristics in sheep or goats, especially in dryland conditions. Nevertheless, research has shown that incorporating saltbush into diets has no impact on key carcass attributes, such as edible and non-edible offal, indicating that it is a viable substitute for nutrient-rich concentrates in sheep diets up to a 20% inclusion rate without compromising carcass characteristics, cuts, or non-edible components, as hinted by Hintsa et al. (2018).

Moreover, the meat quality may be impacted by the water quality, due to the complex interaction of various interconnected factors, both environmental and biological, as noted by Li et al. (2023). As such, understanding the multitude of variables affecting sheep meat quality is crucial for small ruminant meat industry profitability. According to Cymru (2021), both genetic and non-genetic elements in sheep production under extensive systems, as well as post-slaughter processing processes, play a considerable impact in determining the quality of sheep meat. Furthermore, water, which accounts for approximately 74% of meat tissues, plays an important effect in the physical properties of meat, such as water-holding capacity, drip loss, tenderness, and color, as highlighted by Ponnampalam et al. (2015). It is also critical to note that water consumption in animals is not only a physiological requirement but also a key contributor to overall sheep quality. Meat quality is determined by factors such as pH, color, water-holding capacity, shrinkage, and tenderness. Many studies have discovered that these parameters can be utilized to evaluate the quality of animal meat (Orzuna-Orzuna et al., 2021; Yagoubi et al., 2021). A multitude of factors determines meat color, including nutrition, myoglobin content, muscle type, pH levels, and intramuscular fat (Jacob & Pethick, 2014). Furthermore, water salinity has a substantial impact on meat quality, impacting color, cooking and drip loss, and tenderness. Different levels of salt have been found in various studies to have variable effects on meat (Pearce et al., 2008; Ruedt et al., 2022; Zayed, 2022). Furthermore, Moreno et al. (2015) discovered that Santa Inês lambs fed a diet containing 30% saltbush hay had an excellent 60.99% water retention rate in their longissimus lumborum muscle. As noted by Cheng and Sun (2008), the diet an animal consumes plays a significant role in its meat’s ability to retain water. Additionally, the consumption of water with a high salt content can also affect the drip and cooking loss of sheep meat. Generally, the concentration of salts in water, known as salinity, can have a significant impact on beef cattle. When salinity is too high, it can interfere with their capacity to convert feed, resulting in decreased weight gain, similar to other water quality problems. As a result, it is critical to carefully examine the optimal salt levels (Table 2) for beef cattle to enhance their overall health and welfare.

Table 2. Total soluble salts in water for beef cattle.

Quality	Total dissolved solids (ppm)
Excellent	0–1000
Good	1000–2,000
Fair	2000–4,000
Poor	4000–6000
Limit	10,000

Adapted from Boyles et al. (1988).

3.5.2. Water salinity on milk production and quality

Water is an essential component in the diets of lactating animals because it supports the transfer of nutrients and elimination of waste products that occur during the processes of metabolism, digestion, and thermoregulation in all living creatures. Water makes up a significant portion of the body, accounting for 56% to 81% of the body weight of a dairy cow (Dagar et al., 2016). Water quality is an important aspect that influences its intake and is a major problem for both the cattle and dairy industries (Singh et al., 2022). The presence of salts and hazardous chemicals, such as biological or chemical agents, can have an impact on this property. In general, groundwater is thought to be a safer option for herds than surface water.

Moreover, the quality of water influences both the productivity and health of milk as well as its quality, as it induces the bioaccumulation of water solutes in dairy and tissues within the body (Giri et al., 2020). Inadequate or poor-quality water for dairy animals can reduce the production of milk and development and pose health complications (ILRI, 2015; Valtorta et al., 2008). The primary quality of water concerns influencing the farming of livestock includes excessive mineral concentrations (excess salinity), high levels of nitrogen (nitrates and nitrites), contamination by bacteria, high growth of blue-green algae, and unintentional contamination by petroleum, pesticides, or fertilizer products (Alkire, 2008; Bagley et al., 1997; Dyer et al., 2017). The effect of drinking water salinity levels varies according to species, breed, age, nutrition, physiological status, and environmental factors (Ibidhi & Ben Salem, 2019; Runa et al., 2020). Animals can also withstand a certain amount of salinity in their water intake (Tables 3 and 4). The scholars observed that salinity had no significant effect on the intake of nutrients, digestibility and milk production and quality in trials with lactating goats drinking water with varying degrees of salinity (640, 3188, 5740, and 8326 mg L⁻¹ total dissolved solids (TDS)) (Paiva et al., 2017). Furthermore, a recently published study found that giving water with various total dissolved solids (640, 3188, 5740, and 8326 mg L⁻¹) for a short period does not influence goat milk production, physicochemical factors, or organoleptic characteristics (Costa et al., 2021). Similarly, Elgharbi et al. (2015) found that saltwater (10 g L⁻¹) did not influence the production of milk or composition in sheep. However, available information on the effect of water salinity on milk production and lactating ruminant composition is scant and, at times, contradictory (Thomas et al., 2007). According to some studies, drinking water with high salinity levels has an important effect on dairy cattle milk yield and quality. Evidence suggests that elevated salt levels in drinking water combined with greater ambient temperatures reduce milk production in dairy cattle (Schroeder, 2015; Vinet & Zhedanov, 2011). Similarly, Jaster et al. (1978) discovered a milk yield decrease of approximately 2 kg for cows on salt water, and while the difference was slight, it suggested a tendency that, if followed throughout lactation, might be serious. According to Solomon et al. (1995), the quality of the water did not affect cow production of milk or quality. In these investigations, changes in milk yield could indicate differences in water consumption or differences in mineral content in milk yield. Sanchez et al. (1994) discovered that feeding high levels of sodium did not affect the yield of milk or lactating efficiency under nongrazing situations. Milk protein and urea nitrogen levels in the blood of sheep who drank saline water were high (Elgharbi et al., 2015), whereas water salinity did not affect milk quality in dairy cows (Valtorta et al., 2008).

Table 3. Tolerance of different livestock species to salty drinking water.

Species	Total salt in drinking water (%)
Camel	5.5
Goat	1.5
Sheep	1.3–2.0
Cow	1.0–1.5
Donkey	1.0
Horse	0.9
Pig	0.9

Adapted from Golher et al. (2021).

Table 4. Guidelines for the use of saline water in dairy livestock.

Total dissolved solids (ppm)	Suggestion effects
Less than 1000	There is no significant impact on livestock
1000–2999	Although it should not affect health or performance, it may induce brief mild diarrhea
3000–4999	Generally, usually pleasant, it may produce diarrhea, especially when first consumed
5000–6999	Adult ruminants can be employed with moderate safety; pregnant animals and calves should be avoided
7000–10,000	Pregnant, nursing, stressed, or young animals should be avoided if at all possible.
More than 10,000	Not safe; should not be used under any circumstances.

Source: Schroeder (2015).

3.6. Tolerance of livestock species to drinking water salinity

A sufficient quantity and quality of water are required for successful cattle production. As a result, maintaining the appropriate amount and quality of water is critical for maintaining livestock health and productivity (Bagley et al., 1997; Çapar et al., 2020; Chapagain, Fukushi, et al., 2022; Chapagain, Mohan, et al., 2022). This is especially important in areas with high temperatures and low rainfall, where factors like water salinity and the presence of pollutants have a substantial impact on cattle water quality. Blue-green algae, organic matter, heavy metals, and chemicals are examples of pollutants that can harm not just the health of animals but also their productivity (Smith, 2021). Defending the right to supply enough water for cattle can have significant consequences for animal welfare. Tolerance for pollutants in water varies by animal type and species, with sheep, cattle, horses, pigs, and poultry showing the lowest levels of tolerance (ANZG, 2023). According to Lefebvre et al. (2008), animals have an exceptional ability to tolerate varied quantities of salt in their drinking water, which may be related to renal performance. The kidneys play an important part in regulating the balance and composition of physiological fluids, and studies have shown that sheep fed 1.3% NaCl water can build a salt tolerance without experiencing any harmful consequences. According to McGregor (2004), this adjustment is made possible by the kidneys’ unique adjustments, specifically in filtration and salt elimination. Ruminant breeds that live in dry environments have developed a variety of adaptations to deal with the problems of heat and drought. As part of their water preservation strategies, these unique breeds exhibit a significant decrease in urine production and fecal moisture. Analyzing their overall performance is crucial in comprehending their physiological reactions to their surroundings (Eigenberg, et al., 2013). Dry ruminants with exceptional digestive abilities, such as goats and desert sheep, exhibit distinct physiological traits, including well-developed salivary glands, a vast absorbing surface in their rumen tissue, and the ability to quickly modify the size of their foregut to respond to environmental changes.

Monitoring temperature-related factors, such as rectal temperature, respiration and pulse rates, and thyroid function, is crucial in assessing an animal’s stress tolerance. Sheep, as homeotherms, strive to maintain a consistent internal temperature even in harsh weather conditions. In ideal conditions, sheep have a normal rectal temperature range of 38.3–39.98 °C. However, when faced with heat stress (33–38.58° C), your rectal temperature increases significantly. If the surrounding temperature goes above 42.8 °C, it can put the sheep’s survival at risk (Marai et al., 2006). While numerous studies have examined the link between water salinity and rectal temperature in sheep and goats, the findings have not been conclusive. One study, conducted by Hekal (2015), found that consumption of saline water with 2886 ppm total dissolved solids (TDS) led to higher rectal temperatures in Barki ram lambs compared to the control group that received water with 275 ppm TDS. However, other studies have shown that water salinity does not affect rectal temperature. Mdletshe et al. (2017) discovered that drinking saline water did not affect goat rectal temperature. More evidence may be found in a study conducted by Vosooghi-Postindoz et al. (2018), which showed that raising the TDS concentration in drinking water did not affect the rectal temperature of Baluchi lambs. Recent research has found a correlation between drinking saline water and an increase in respiratory rate. Hekal (2015), for example, reported that Barki ram lambs given water with a salinity of 2886 ppm TDS had a higher respiratory rate (55.34 breaths/min) than those given water with a lower TDS level of 275 ppm (48.8 breaths/min). Similarly, Eltayeb (2006) discovered that Nubian female goats fed saline water with different amounts of 0.8% to 2.0% NaCl at 2:30 pm for four consecutive 10-day periods had considerably higher respiration rates than those given tap water. However, Mdletshe et al. (2017) found that saline water with TDS levels of 0, 5.5, or 11 g/l did not affect respiratory rate in goats. The salinity of water is an important component in determining animal pulse rate. Mdletshe et al. (2017) discovered that when goats were exposed to water with a total dissolved solids (TDS) level of 11 g/l, their pulse rate rose considerably when compared to water with TDS levels of 0.0 g/l and 5.5 g/l. Similarly, Leite et al. (2018) discovered that a greater salinity level of 9.0 dS/m resulted in a 12.2% drop in the pulse rate of Morada Nova female sheep when compared to a lower salinity level of 6.0 dS/m. This implies that when exposed to increasing salinity levels, animals must use more energy on heart function to clear excess salt from their bodies. Yirga (2019) discovered that water salinity levels as high as 17 g of TDS/l did not affect major thermoregulatory indicators in blackhead Ogaden sheep and Somali goats at various stages of maturity. Furthermore, Tulu et al. (2022) validated these findings by noticing that sheep that sipped lake water with varied salinity levels had no deleterious effects. These findings show that small ruminants, regardless of environmental conditions or management practices, can adapt and maintain appropriate thermoregulation despite changing levels of water salinity.

Interestingly, research has shown that goats have the astonishing ability to consume excessively saline water with a TDS concentration of up to 11,000 mg/L and a salt content of 470 mg/L without having any harmful effects (Mcgregor, 2004). Goats have been found to prefer fresh water with salinity levels of up to 12,500 mg/L, albeit they must gradually adjust to such high-salt conditions. Although there is some evidence that goats can thrive in seawater, it should be noted that these goats were already adapted to such conditions and had access to shade and moist vegetation. During droughts, goat farmers regularly monitor the salinity levels of their water sources, especially when adopting new sources. Furthermore, more research is needed to assess the long-term implications of increasing saline water consumption and trace element exposure in acclimated goats. Young male goats can withstand high saline levels in their drinking water for at least two weeks, according to Zoidis and Hadjigeorgiou (2018). The tolerance of small ruminants to salt varies and is determined by factors such as species, age, and physiological status. Previous studies have demonstrated that animals under physical stress due to pregnancy, lactation, or rapid growth are more vulnerable to the effects of salt, including studies by Araújo et al. (2010) and Gerard (2016). Furthermore, it has been revealed that age and sex have a role in goat susceptibility and resilience to high salt levels, with younger animals being more vulnerable and less resistant than older animals (Runa et al., 2019).

3.7. The significance of saltwater consumption and poisoning

Most macronutrients are nutrients that organisms require in sufficient quantities throughout their existence to regulate various types of physiological activities, growth and development. Salt is a prominent element in fluid blood that comprises approximately 0.17% salt and chloride and plays an important role in animal growth, efficiency, and reproduction (Lata & Mondal, 2021). Minerals are essential nutrients that must be supplied in a regulated, regular, and cautious manner. The mineral requirements differ depending on the species of animal, breed, diet, location, and kind of production (Johansson, 2008). The number of salts in drinking water is important for estimating sodium requirements in a meal plan. The amount of salt in drinking water is determined by the total dissolved salt content of the water. Control variables such as a high salt concentration in meals or a lack of water are commonly responsible for salt poisoning. Animals can adapt to rising salt levels in their diets if given enough time and access to clean drinking water (FAO, 2018). Inadequate water consumption or deprivation reduces salt excretion in the urine, leading to buildup in the animal’s central nervous system (CNS). Mineral poisoning induced by overabsorption (direct salt poisoning) or dehydration (indirect salt poisoning) is common (Gupta, 2012). In livestock, severe salt poisoning causes gastrointestinal and central nervous system symptoms such as diarrhea, depression, blindness, aggression, hyperexcitability, ataxia, head pressing, acute thirst, and constant chewing motions. Advanced symptoms include seizures, coma, and death (Ben Meir et al., 2023; Johansson, 2008; Schwennesen, 1994). Small-scale farmers with limited resources can use a variety of ways to assess and combat the detrimental effects of salty drinking water on their livestock. These strategies involve closely monitoring and observing their animals, as well as testing the quality of water sources. Additionally, managing water sources, providing dietary supplements, selectively breeding for resilience, and collaborating with other farmers through knowledge sharing can all play a vital role in addressing this issue. While these methods may not completely eradicate these challenges, they can empower farmers to make informed decisions and lessen the effects of salty water on their livestock (Atube et al., 2021; Ogunyiolaa et al., 2022).

4. Conclusions and suggestions for future research

Fresh and clean water is crucial for improving animal performance and production, as well as health; nevertheless, the current serious and accelerating climate change is harming worldwide drinking water quality. One of the most critical elements in water quality, particularly in drought-prone areas, is salinity. Although salt is required for regulating body water content, muscle and nerve function, and nutrient absorption, excessive salt consumption over time can interfere with feed and water intake and even pose major health problems. The findings of regional, national and international investigations on the effects of water quality on farm animal productivity provide scientifically grounded knowledge to cope with the hazards of water scarcity and food insecurity. Although uncertainty in warming estimates remains a major issue for policymakers, global and regional climate models, downscaling methodologies, and impact assessment methods are being developed to address uncertainty more positively.

Future research should prioritize the development of a comprehensive consideration of climate change, including its effects, response mechanisms, and adaption approaches for water and livestock management. Given the increasing frequency and severity of extreme weather events, it is critical to improve the forecast of these occurrences and their consequences. Furthermore, improving the forecast of microclimate changes caused by climate change is critical to assess their effects on crop and livestock production systems. This enables adaptation measures to be developed at the community level. Additionally, further investigation is needed to know the ideal drinking water salinity for different animal classes and age groups without affecting their performance. Additionally, studies should be conducted to examine the relationship among water stress, feed deficiency, and high ambient temperatures. To effectively address these difficulties, it is important to evaluate innovative methods and substances for managing stress, taking into account both animal welfare and practical impacts.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Diriba Tulu

Diriba Tulu is a lecturer and researcher at the School of Animal and Range Sciences, Haramaya University, and specializes in a M.Sc. degree in Climate-smart Agriculture. His research interest is on climate-smart agriculture focusing on resilient livestock production, and forage and pasture production and management.

Feyisa Hundessa

Feyisa Hundessa is a senior lecturer and researcher at the School of Animal and Range Sciences, at Haramaya University. His research interests are animal production and nutrition, feed production, and forage management. Currently, Feyisa serves as the Research Extension Coordinator at Haramaya University.

Sileshi Gadissa

Sileshi Gadissa (PhD) is an assistant professor of animal production, who is currently the head of the School of Animal and Range Sciences at Haramaya University. His research interests include animal production, animal nutrition and feed production.

Tasisa Temesgen

Tasisa Temesgen is an assistant professor of irrigation agronomy at the School of Natural Resources Management, Haramaya University. His research focuses on water and soil conservation, contributing to the sustainable management of natural resources.