Nutrient requirement should meet maintenance needs first before taking care of other body functions. The livestock and poultry require half of all the feed to meet the maintenance requirements. The feedlot animals may use only 30 to 40% of nutrients from their full feed for maintenance purpose.
Young animals require sufficient nutrients to build up the growth. The requirement of nutrients to support the growth includes energy, protein, mineral and vitamins. Protein is required for the muscle building. Minerals like calcium and phosphorus help for the bone growth.
As the young grow into adults, the nutrient requirement changes due to increase in weight and growth rate. The TDN, protein intake and net energy intake requirements are also increased. Sufficient quantities of macro and micro elements and vitamins are supplied through the feed stuff to support the healthy growth in the animals.
Mature breeding animals require 90% of their feed for the maintenance purpose. Most efficient dairy cows that produce 100lb milk per day consume daily feed 4 or 5 times to meet the maintenance requirement.
To carry out normal function and maintenance in animals water availability and intake are very important. Water intake varies with the animal age, stage of production, level of feed intake and various other environmental factors. The water requirement for beef cattle is about 7 to 20 gallons per day. The dairy cattle require 10 to 29 gallons of water per day.
Chickens require 0.05 to 0.10 gal/day, horses need 8 to 12 gallons of water per day. Sheep and goats require 1 to 4 gallons per day, swine needs 3 to 5 gallons per day and turkeys require 0.10 to 0.15 gallons of water per day.
Nutritional requirements for reproduction include requirement for gamete production and fetal growth in the uterus. Healthy males and females produce gametes and the energy needs for germ cell production are similar to the energy required for the maintenance of healthy animals.
Ruminant animals graze upon pastures of mixed grass and legumes obtain sufficient amounts of phosphorus to keep them fertile. Lack of phosphorus in the feed may result in disturbances in estrous cycles and impaired breeding in females.
Animals may lose weight rapidly due to poor feed conditions or some animals are overly fat. These types of animals have low fertility. Optimum fertility can be maintained by moderately low to moderate body fat condition during the breeding season. It should be increasing or animal should gain weight 2 to 4 weeks prior to the breeding season.
The growing fetus requires nutrients in high amounts during the last trimester of the pregnancy. In the first two trimesters little fetal growth is observed. The growing fetus and young animal after birth both will have similar nutrient requirements for their growth.
Healthy females supply the nutrients to the growing fetus from their body when the feed quality is low. This may result in poor reproductive performance because of inadequate nutrition. Sufficient nutrition should be provided to the cattle for 2 to 3 months and for few weeks in swine and sheep.