Feed sources and
Digestibility
Rations made up of 20-40% rice straw, 20 or 40% Alfa hay, 20% rice hulls, 40% dehydrated sudangrass pellets. The roughage source had more energy digestibility than roughage level. Increasing levels of rice straw from all of the above concentrates to 20-40% lowered in the digestible energy (DE) content of the rations from 3.065-2,832 to 2,613 kcal per kilogram of dry matter. (Hembry, 2015),
Silage and maize
Forages consist of nearly the same amount of gross energy as cereal grains per unit of dry matter, the energy value of forage grasses is lower and more varied, from 33% (wheat straw) to 70% (siledge maize) 80% (leafy ryegrass) of maize grain value. Energy values between grain and forage results from the high content of cell wall in forage plants and the limited digestion by herbivores animals of this fibre fraction by micro organisations in the digestive tract of the animals (Gallais, 2004).
Protein
Threonine and valine in protein have higher digestibility in corn and wheat. The microbial phosphate enzyme has improved the digestibility of proteins and amino acids.
Forages have high amounts of sugar. Mature grains not a lot of sugar. Sucrose and maltose fed in high amounts decreases ruminal fibre digestion. They travel through the small intestine undigested and are fermented via microbes in their colon to gases then are extracted and short chain fatty acids and lactase are created. These short chain fatty acids are absorbed via the intestinal wall by passive diffusion (Bryden, 2015).
Fibre
Roughages have high amounts of crude fibre content and low digestible energy content. Corn silage has high amounts of crude fibre and high levels of digestible energy. The fibre that is digested in the large intestine is low, however it ranges from 5- 30 percent of the total fibre digested. When fibre is digested via microorganisms some of the energy is kept in fatty acids created by microorganisms. When fibre is digested the creation of microbial cells will travel through the remaining pieces of the digestive tract and broken down for energy and protein. Without fibre in the animals’ diet they will become ill due to fibre contributing to allowing food to pass through the body with ease and if fibre is not in the diet then the animal will become constipated so the animal will not want to eat.
Cellulose
This requires mechanical digestion cellulose fibres are broken down mechanically. It is difficult to digest because they need a specialised enzyme (cellulases and hemicellulase) to break down the beta-glycosidic bonds and divide molecules up in to their sugars.
Digestibility of feed is the amount absorbed in the animal. Apparent digestibility is found by taking away nutrients kept in the faeces from nutrients kept in the dietary intake. True digestibility is found by correcting endogenous and microbial amount of nutrient lost in the faces.
DE = GE - energy lost in faeces
ME = DE - energy lost in urine and gases
NE = ME - heat loss (heat increment)
Wet and dry food
Carbohydrate and dietary fibre; digestibility of wet and dry does not change a lot. Both foods have digestibility of 80-90%. However, wet foods are more palatable than dry foods as they are moist contributing to easily being moved through the body.
How often fed effects digestibility
Dog food digestibility of protein, fat and carbohydrates are 81%, 85% and 79%. Nutrient digestibility is higher in premium brands and lower in economy products. Manufacturers will say that they are 80-90% digestible. Raw products put into dog food digestibility is 40-100%. Muscle, egg whites, dairy products and offal are highly digestible. Cereal grains, oats and corn have low digestibility until they are cooked. Digestibility is increased by heat. However, over cooking can deteriorate the digestibility of nutrients. Cereal products (wheat, barley, and oat meals) have a digestibility of 40-90%. Fibre decreases the apparent digestibility of dry matter, organic matter, the energy and crude protein is from 2-20% (Vets online, 2015). If the animal is fed once a day it is not going to be digested as fast as if they eat 2-3 times a day.
Different foods for different life stages
Nutrient digestibility is decreased in puppies. 5% protein and becomes higher with age. Geriatric animals require more palatable food than adult dogs, as do puppies due to not eating as well. Pancreatic amylase enzyme is low in puppies and increases as they get older (vets online, 2015).
Rations made up of 20-40% rice straw, 20 or 40% Alfa hay, 20% rice hulls, 40% dehydrated sudangrass pellets. The roughage source had more energy digestibility than roughage level. Increasing levels of rice straw from all of the above concentrates to 20-40% lowered in the digestible energy (DE) content of the rations from 3.065-2,832 to 2,613 kcal per kilogram of dry matter. (Hembry, 2015),
Silage and maize
Forages consist of nearly the same amount of gross energy as cereal grains per unit of dry matter, the energy value of forage grasses is lower and more varied, from 33% (wheat straw) to 70% (siledge maize) 80% (leafy ryegrass) of maize grain value. Energy values between grain and forage results from the high content of cell wall in forage plants and the limited digestion by herbivores animals of this fibre fraction by micro organisations in the digestive tract of the animals (Gallais, 2004).
Protein
Threonine and valine in protein have higher digestibility in corn and wheat. The microbial phosphate enzyme has improved the digestibility of proteins and amino acids.
Forages have high amounts of sugar. Mature grains not a lot of sugar. Sucrose and maltose fed in high amounts decreases ruminal fibre digestion. They travel through the small intestine undigested and are fermented via microbes in their colon to gases then are extracted and short chain fatty acids and lactase are created. These short chain fatty acids are absorbed via the intestinal wall by passive diffusion (Bryden, 2015).
Fibre
Roughages have high amounts of crude fibre content and low digestible energy content. Corn silage has high amounts of crude fibre and high levels of digestible energy. The fibre that is digested in the large intestine is low, however it ranges from 5- 30 percent of the total fibre digested. When fibre is digested via microorganisms some of the energy is kept in fatty acids created by microorganisms. When fibre is digested the creation of microbial cells will travel through the remaining pieces of the digestive tract and broken down for energy and protein. Without fibre in the animals’ diet they will become ill due to fibre contributing to allowing food to pass through the body with ease and if fibre is not in the diet then the animal will become constipated so the animal will not want to eat.
Cellulose
This requires mechanical digestion cellulose fibres are broken down mechanically. It is difficult to digest because they need a specialised enzyme (cellulases and hemicellulase) to break down the beta-glycosidic bonds and divide molecules up in to their sugars.
Digestibility of feed is the amount absorbed in the animal. Apparent digestibility is found by taking away nutrients kept in the faeces from nutrients kept in the dietary intake. True digestibility is found by correcting endogenous and microbial amount of nutrient lost in the faces.
DE = GE - energy lost in faeces
ME = DE - energy lost in urine and gases
NE = ME - heat loss (heat increment)
Wet and dry food
Carbohydrate and dietary fibre; digestibility of wet and dry does not change a lot. Both foods have digestibility of 80-90%. However, wet foods are more palatable than dry foods as they are moist contributing to easily being moved through the body.
How often fed effects digestibility
Dog food digestibility of protein, fat and carbohydrates are 81%, 85% and 79%. Nutrient digestibility is higher in premium brands and lower in economy products. Manufacturers will say that they are 80-90% digestible. Raw products put into dog food digestibility is 40-100%. Muscle, egg whites, dairy products and offal are highly digestible. Cereal grains, oats and corn have low digestibility until they are cooked. Digestibility is increased by heat. However, over cooking can deteriorate the digestibility of nutrients. Cereal products (wheat, barley, and oat meals) have a digestibility of 40-90%. Fibre decreases the apparent digestibility of dry matter, organic matter, the energy and crude protein is from 2-20% (Vets online, 2015). If the animal is fed once a day it is not going to be digested as fast as if they eat 2-3 times a day.
Different foods for different life stages
Nutrient digestibility is decreased in puppies. 5% protein and becomes higher with age. Geriatric animals require more palatable food than adult dogs, as do puppies due to not eating as well. Pancreatic amylase enzyme is low in puppies and increases as they get older (vets online, 2015).