Erastus Ngaruka 

Many farmers seem to focus more on forage or feed intake as the factor that contributes to livestock performance, however, all physiological processes responsible for intake, reproduction, growth, milk and meat production, amongst others, depend on water. For example, milk and meat production are a function of water because the composition of milk contains about 88% water, and meat contains about 75% water.
It is estimated that water makes up about 75% or more of an animal’s body. Different animal species have different daily water requirements. These daily water needs are influenced by factors such as the environmental temperature, the animal’s physical activity, age, production stage (e.g. lactating cow or dry cow), and the moisture and fibre content of the feed, amongst others. For example, a mature beef cow will require about 45 litres of water per day, and a sheep ewe about 8 litres per day.

Water is an essential multifunctional nutrient in animal production. Its functions are needed in the process of feed digestion such as the production of saliva and other fluids or juices needed to digest the feed.
Firstly, the animal’s feed intake and digestion are greatly influenced by the moisture content of the feed and the quantity and quality of the accessible drinking water. Animals would prefer to eat soft or fresh nutritious feeds or forages that are easily digestible with their moisture content also contributing to their daily water requirements. This is evident, for example, during summer grazing where the animals’ feed intake and digestion are higher or faster, but the daily water intake is lower. 

During the dry season, it is the opposite, the feed intake and digestion are lower or slower, and the daily water intake or requirement is higher. This is because the grazing materials (e.g. grass) are dry and harder, making it difficult for animals to bite, chew and digest, thus, their body will require more water to enhance the process. 

Water is also a medium through which the blood and the nutrients are transported throughout the body to all organs and tissues, and through which the waste substances such as urine and faeces are removed from the body (excretion).
Water also plays a crucial role in regulating the internal body temperature of an animal as a response to influences from the environmental temperature and other activities such as draft work by oxen. The maintenance of this temperature is needed for optimal physiological functioning and overall performance of the animal. For example, when the environmental temperature is high or during the hot season, an animal will have to cool its body. 
One of the cooling mechanisms is sweating where the body will release moisture (sweat) onto the skin surface to allow cooling as the air is blowing. For that, the animal will need to replenish the water lost from the body through sweating, by having to drink water. When animals have limited access to water, their feed intake and performance are compromised.

Other functions of water include the lubrication of joints so that they are also able to absorb shock and for the animal to walk with ease. Moreover, water also lubricates the membranes of the mouth, eyes, nose and all the other internal organs such as lungs, amongst others.
Water is an essential nutrient that contributes greatly to livestock survival and performance. The quality of water should also be considered as it also affects water intake. For example, water intake will be low if the water is contaminated by toxic substances or contains higher mineral content and has a salty or bitter taste. 

It is advisable that farmers take water samples to laboratories for testing and advice about the water quality, usage and remedial options if the quality is poor. To conclude, water is life, thus, animals should have unlimited access to clean water and enough to meet their daily requirements for their optimal productivity.

*Erastus Ngaruka is Agribank’s Technical Advisor: Livestock & Rangeland