A nutritionist considers multiple factors when determining forage and grain ratios for livestock. These include the animal’s species, age, and purpose (growth, maintenance, reproduction), the availability and cost of different feedstuffs, and the nutritional content of both forage and grain. The goal is to create a balanced diet that meets the animal’s needs efficiently and economically.
What Factors Influence Forage and Grain Ratios?
What are the animal’s nutritional needs?
Different animals and different stages of life require different levels of nutrients.
- Maintenance, Growth, and Reproduction The basic nutrients that animals require include carbohydrates, protein, fat, minerals, vitamins, and water. The energy needed for growth and activity is derived primarily from carbohydrates and fats. Protein will also supply energy, particularly if carbohydrate and fat intake is inadequate or if protein intake exceeds the needs of the body. For immature animals, protein is also needed for the growth of the muscles and other parts of the body.
- Vitamins Vitamin A is required for growth, reproduction, milk production, and the maintenance of normal resistance to respiratory infections. Vitamin D enables animals to use calcium and phosphorus; a deficiency causes rickets in young growing animals. The vitamin B group is not important in the feeding of cattle, sheep, and other ruminants, because the bacteria in their rumen synthesize these vitamins. Vitamin E is necessary for normal hatching of eggs.
What feedstuffs are available?
Geographic location, climate, and agricultural practices affect what feedstuffs are accessible.
- Concentrates Grains and their by-products (barley, corn, oats, rye, wheat), high-protein oil meals or cakes (soybean, canola, cottonseed, peanut), and by-products from processing of sugar beets, sugarcane, animals and fish are high in energy value.
- Roughages Pasture grasses, hays, silage, root crops, straw, and stover (cornstalks) are important for animal feed. Beef cattle can utilize roughages of both low and high quality, including pasture forage, hay, silage, corn fodder, straw, and grain by-products.
What are the cost considerations?
Balancing nutritional needs with economic realities is crucial for farmers.
- Nonprotein Nitrogen Cattle utilize nonprotein nitrogen in the form of urea and biuret feed supplements, which can supply from one-third to one-half of all the protein needs of beef animals. Nonprotein nitrogen is relatively cheap and abundant and is usually fed in a grain ration or in liquid supplements with molasses and phosphoric acid or is mixed with silage at ensiling time; it also may be used in supplement blocks for range cattle or as part of range pellets.
- Vitamin A Synthetic vitamin A sources have become so cheap as to permit the use of 10,000 to 30,000 International Units per day for cattle being fattened for market in enclosures bare of vegetation used for this purpose.
How does the digestive system of the animal impact feed ratios?
Different animals process feeds differently, affecting nutrient absorption.
- Monogastric Digestion Animals with a simple single stomach (monogastric), including humans, monkeys, swine, poultry, rabbits, and mink, require correct amounts of the 10 essential amino acids daily: arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. High-quality protein, such as that supplied by eggs, milk, fish meal, meat by-products, and soybean meal, contains high concentrations of the essential amino acids in the proper balance for their full utilization.
- Ruminant Digestion A protein source’s amino acid profile is of secondary importance to ruminants, such as cattle, sheep, goats, and the other animals that have four stomachs, because the bacteria that aid in the digestion of food in the rumen (first stomach) use simple nitrogen compounds to build proteins in their cells. By this indirect means, ruminants produce high-quality protein from a food that might originally have contained poor protein or from urea (a nitrogen compound).
People Also Ask
What is the role of roughage in animal diets?
Roughage, such as pasture grasses, hays, and silage, provides essential fiber for proper digestion in livestock. Fiber helps maintain gut health, promotes chewing and salivation, and aids in nutrient absorption. For ruminants like cattle and sheep, roughage is particularly important as it supports the microbial activity in their rumen, which is necessary for breaking down plant matter.
How do feedlots maximize weight gain in cattle?
Feedlots maximize weight gain through high-energy diets of grains and legumes like corn and soy. These feeds are easily digestible and nutrient-dense, promoting rapid growth. The feedlot environment also reduces the animal’s energy expenditure by limiting movement and foraging activity. This combination of high-calorie intake and reduced energy output leads to efficient weight gain.
What are the potential health problems associated with high-grain diets in cattle?
High-grain diets can cause digestive issues in cattle because they evolved to primarily eat grass. The rapid fermentation of grains in the gut can lead to acidosis, bloat, and liver abscesses. These conditions can reduce weight gain, cause discomfort, and even lead to death. Therefore, careful management and monitoring of cattle on high-grain diets are essential.
How do nutrient requirements change as animals grow?
Young, growing animals require more protein to support muscle and tissue development. As animals mature, their protein needs decrease, while their energy requirements remain high to maintain body condition and activity levels. Pregnant or lactating animals also have increased nutrient demands to support fetal development and milk production.
What is the impact of feed additives on animal nutrition?
Feed additives, such as vitamins, minerals, and nonprotein nitrogen, can supplement deficiencies in the base diet and improve animal health and productivity. Vitamin and mineral supplements ensure animals receive adequate micronutrients, while nonprotein nitrogen sources like urea can provide a cost-effective way to meet protein requirements, particularly for ruminants.
Understanding these factors allows nutritionists to create effective feeding strategies.
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