Water in Animal Nutrition

Water Restriction

• Moderate water restriction can lead to a loss in body weight, increased pulse and rectal temperature, increased respiration rate, reduced productivity, and haemo-concentration.
• Animals become irritable and bad tempered.
• Severe water restriction can lead to difficulty in muscular movements, a marked drop in urine and faecal water excretion, prostration, and death if deprivation persists.

Water Quality

• Poor water quality can affect consumption, productivity, and animal health.
• Common issues include salt poisoning, refusal to drink, diarrhoea, and reduced production.
• Substances such as salts, pathogenic organisms, algae, and pesticides can pollute water supplies and affect palatability.

Water in Animal Nutrition

• Water is an essential chemical for life.
• All species need an ad-libitum supply of clean drinking water.
• Water constitutes about 60-70% of the animal body.

Sources of Water

• Animals obtain water from drinking, free-water in feed, and metabolic water.

Metabolic Water

• Metabolic water is produced as a byproduct of the oxidation of carbohydrates, fats, and proteins.
• It represents a small portion of total water intake compared to drinking water and water content in feed.
• The body produces approximately 110g of water per 100g of fat, 40g of water per 100g of protein, and 60g of water per 100g of carbohydrate.

Functions of Water

• Water is essential for metabolism, acting as a universal solvent to facilitate biochemical reactions involved in digestion, absorption, and transportation of nutrients.
• It aids in the excretion of waste products through urine, feces, and sweat.
• Water plays a role in regulating body temperature.
• It is essential for milk and egg production.
• Water and minerals work together to regulate body fluids.
• Water is a transport medium within the body, carrying nutrients and oxygen to cells and removing waste products.

Water Requirements and Consumption

• Animals typically consume 3-4g of water per gram of dry matter consumed.
• This amount can increase during heat stress.

Water Losses

• Water is lost from the body through urine, feces, lungs, skin surface, milk, and egg production.

Water Turnover

• Water turnover refers to the rate at which body water is excreted and replenished in the tissues.
• Turnover in cattle is approximately 3.5 days.
• Non-ruminant species may have a faster turnover rate due to lower water content in the gastrointestinal tract.
• Species that tolerate greater water restriction, such as camels and some sheep breeds, have lower turnover rates compared to species like horses and European cattle.
• Water turnover is influenced by species, climatic factors (temperature and humidity), and ingestion of compounds like NaCl, which can increase urinary or fecal excretion.

Factors Affecting Water Requirements

Animal Factors

• Age
• Species
• Breeds
• Body size
• Growth rate
• Salt level
• Pregnancy
• Lactation
• Activity Level

Dietary Factors

• Type of diet (green or dry)
• Dry matter intake
• Composition of the diet

Distribution of Water in the Body

• Intracellular water: Located inside cells, constituting approximately 65% of total body water.
• Extracellular water: Encompasses interstitial fluids (between cells or body parts), blood plasma, lymph, synovial, and cerebrospinal fluids. It represents about 35% of total body water.