Calf Beef Heifer Requirements Calf Beef Heifer Nutrients

Basic Beef Cattle Diet

Agdex#:	420/x
Publication Engagement:	09/91
Order#:	91-066
Terminal Reviewed:	28 September 2015
History:	Not Available
Written by:	Tom Hamilton - Beef Cattle Specialist/OMAFRA

Tabular array of Contents

1. Introduction
2. Digestive System
3. Nutrients
4. Feedstuffs
5. Energy Digestion
6. Protein Digestion
7. Ration Formulation
8. Summary
9. References

Introduction

The proper nutrition of beefiness cattle is a key component of a successful production system. Feed usually accounts for the single largest input cost associated with beef cattle. An understanding of the ruminant digestive process and basic diet is required for effective feeding and management.

Digestive Organization

Cattle belong to a course of animals chosen ruminants. This group includes sheep, goats and deer. Ruminants have a digestive arrangement which allows them to utilize roughages (eastward.k. hay, grass) as a major source of nutrients. These animals have a large (capacity up to fifty gal.), fluid filled digestive organ at the beginning of the digestive tract chosen the rumen. The rumen contains a large population of microbes (bacteria and protozoa). Much of the initial digestion of feed is done by microbes in the rumen.

These microbes have the ability to suspension down cellulose and hemicellulose, which are main components of roughages. Rumen microbes as well suspension down other components of the animal's nutrition such every bit poly peptide and starch. The reticulum is a smaller organ which acts equally a holding area for feed later it passes down the esophagus. The omasum is an organ which absorbs h2o from the digesta (mixture of feed and fluid) earlier information technology flows into the abomasum (truthful stomach). The animal's ain digestive enzymes break downward food in the abomasum and minor intestine. Absorption of these nutrients occurs mainly through the minor intestine

Monogastric (not-ruminant) animals (e.g. pigs, dogs, man) are non able to efficiently digest cellulose.

When ruminants consume forages, they accept adequately large bites and swallow the cloth with a minimum of chewing. After eating, they stand or lie down to "chew their cud". This involves regurgitating boluses (masses) of forage up the esophagus and into the mouth, where it is re-chewed and then swallowed. This reduces the size of the forage particles and greatly increases the surface area available for microbial digestion.

Nutrients

Feed requirements are based on the need for specific amounts of various classes of nutrients. Each food fulfills specific roles in growth, product or metabolism. Nutrient classes are defined by their chemical construction or by their function in metabolism.

Energy

Energy provides the body with the ability to practise work. In beefiness cattle rations energy is usually expressed as % Total Digestible Nutrients (TDN). Piece of work includes growth, lactation, reproduction, movement and feed digestion. Energy is the food required past cattle in the greatest amount. It usually accounts for the largest proportion of feed costs. The primary sources of energy for cattle are cellulose and hemicellulose from roughages and starches from grains. Fats and oils have a high energy content but usually make up only a small part of the diet.

Protein

Protein is one of the chief building blocks of the body. It is usually measured equally %4 Rough Protein (CP). It is a major component of muscles, the nervous system and connective tissue. Protein is composed of chains of amino acids. Adequate dietary protein is essential for maintenance, growth, lactation and reproduction. Protein is composed of several fractions which vary in their solubility in the rumen. Rumen soluble protein is digested past microbes in the rumen. Rumen insoluble protein passes intact through the rumen to the lower digestive tract. A portion of this bypass (or escape) protein is digested in the pocket-sized intestine.

Minerals

Various minerals are required for growth, bone formation, reproduction and many other body functions. Those that are required in fairly large amounts are called macrominerals. They include sodium (salt), calcium, phosphorous, magnesium and potassium. Those that are required in very small-scale amounts (micro or trace minerals) include iodine, copper, zinc, sulphur and selenium. Mineral content is affected by the type and quality of the feedstuff. Calculation supplementary minerals to the ration is commonly required to ensure that the proper amounts of these elements are available to the animal. The blazon of supplementary mineral mix required is adamant by the feeds in the ration and the animal's requirements. Problems caused by deficiencies of some minerals are shown in Table ane.

Table 1. Some Symptoms of Mineral Deficiencies

Mineral	Deficiency Symptons
Calcium	poor growth bowed leg basic brittle basic
Phosphorous	poor growth craving for wood, hair, soil poor conception rates
Magnesium	muscle tremours staggering, convulsions (grass tetany)
Sodium (table salt)	poor growth chewing or licking of wood
Selenium	weakness, inability to stand up

Vitamins

Vitamins are biological compounds which are active in extremely pocket-sized amounts. Vitamins of business in beefiness cattle nutrition include Vitamin A, Vitamin D and Vitamin E. They are ordinarily reported in International Units (IU's). Fresh provender is a good source of Vitamins A, D and E. Vitamin content of well preserved hay is initially high, just declines over time. Silages ordinarily comprise depression amounts since the fermentation procedure destroys most of the vitamins. Grains normally contain relatively depression amounts of these vitamins.

Vitamin A is essential for normal growth, reproduction and maintenance. Insufficient Vitamin A is associated with lowered fertility in both bulls and cows. Vitamin D is required for proper development of bone. Vitamin D deficiency in calves results in bowing of the leg bones (rickets). In older animals bones go weak and easily fractured. Vitamin E, along with selenium, is required for proper development of musculus tissue. Lack of Vitamin E and/or selenium causes nutritional muscular dystrophy, commonly called white muscle affliction. It is well-nigh common in immature calves. Prevention of white muscle illness may be achieved past injecting calves with Vitamin E/selenium at birth, injecting pregnant cows with Vitamin East/selenium, or feeding cows supplementary Vitamin Eastward and selenium.

The level of B vitamins in beefiness cattle diets is not usually of concern, although some special situations exist. The rumen microbes manufacture big amounts of these vitamins, which are then available for assimilation by the animal. The B vitamins are of importance in the young calf which has non all the same developed a functional rumen. Cattle which take been severely stressed take a depleted rumen microbe population and may benefit from supplemental B vitamins.

Feedstuffs

Beef cattle tin can utilize a broad diverseness of feedstuffs. Feeds are classified into groups based on their food content and physical form. Nearly common feeds can be placed in one of the following groups:

1. Roughages
   • high in fibre (cellulose and hemicellulose) and unremarkably low to intermediate in energy
   • protein content varies widely, depending on the plant species and stage of maturity
   • examples are hay, grass, grain hulls, oilseed hulls
2. Grains
   • high in energy and relatively depression in fibre
   • most have a moderate protein content
   • examples are corn, barley, oats
3. Oilseeds
   • high in protein, usually high in energy
   • variable fibre content
   • examples are soybeans, canola meal
4. Byproducts
   • variable food content
   • may incorporate a loftier level of wet
   • examples are distillers grains, sweet corn cannery waste product, bakery waste material, grain screenings, apple pomace

A listing of the energy and protein content of some mutual feeds is independent in Table ii.

Table 2. Energy and Protein Content of Some Common Ontario Feeds*

Feed	% Dry Matter	% Rough Protein (dry matter basis)	% Estimated TDN (dry matter basis)
1st cut legume hay	86.seven	15.viii	58
1st cut grass hay	87.7	9.7	55
1st cut mixed hay	87.vii	12.ii	56
2nd cut hay	86.8	17.7	59
legume hay silage	46.nine	17.half-dozen	59
grass hay silage	38.8	xiii.0	57
mixed hay silage	49.4	fifteen.8	58
corn silage	36.five	eight.0	66
oats	88.5	12.1	74
barley	88.half dozen	12.2	82
wheat	89.9	13.2	88
mixed grain	88.4	12.iii	77
grain corn	86.6	nine.half-dozen	xc
soybean meal 44%	89.0	47.8	81

*Source: OMAFRA Feed Informational Plan

Energy Digestion

In the rumen, microbial digestion of cellulose and hemicellulose (from roughages) and starch (from grains) results in the production of free energy rich byproducts called volatile fatty acids (VFA'due south) which are absorbed by the beast through the rumen wall. This is the major source of energy for the animal. Some starch is not digested in the rumen and is passed on to the truthful tummy (abomasum) and small-scale intestine where information technology is cleaved down past the animal's enzymes and absorbed.

Rumen microbe species are specialized in their ability to pause down either starch or cellulose. When the diet is high in roughages, the cellulose (fibre) digesting microbes multiply and dominate. With a high grain diet the number of starch digesting microbes increases. Changes in the composition of a ration should exist made gradually to allow time for the rumen microbe population to adapt. Well-nigh 2 weeks is necessary for making major changes in ration ingredients.

Grains vary in their rate of breakdown in the rumen. This is due to the chemical nature of the starch and the physical structure of the grain. For example, dry out corn is degraded in the rumen much more slowly than high moisture corn or dry wheat. This has important implications for the maintenance of rumen health when feeding high grain feedlot rations.

Protein Digestion

Crude poly peptide includes both true protein and non-protein nitrogen (NPN). The digestion of a item protein depends to a large extent on how easily it dissolves in rumen fluid. Highly soluble protein is more probable to be broken down by rumen microbes than is insoluble protein. Nonprotein nitrogen sources (e.chiliad. urea, ammonia) are 100% soluble in the rumen. The rumen microbes use the nitrogen released in the rumen to form their own microbial protein. Microbes are continually existence moved with digesta into the lower digestive tract, where they are digested and absorbed by the animal. Near of the protein which is not soluble in the rumen (featherbed or escape protein) passes unchanged to the lower digestive tract. A portion of this protein is cleaved downwardly by the beast's enzymes and absorbed. Digestible featherbed protein is efficiently utilized and is an important component in rations for fast growing beef cattle.

The activity of the rumen microbes in breaking downward and reforming dietary protein has important implications for the ruminant:

1. ruminants can thrive on diets containing depression quality, low cost protein (relative to monogastrics) since rumen microbes upgrade the protein quality by manufacturing limiting amino acids
2. ruminants tin can utilize some inexpensive non-poly peptide nitrogen (such as urea) in their nutrition as a protein substitute.

For optimum operation, a remainder of rumen soluble protein (and NPN) and bypass protein is required. Diets with loftier levels of soluble poly peptide and/or NPN may not supply acceptable amounts of poly peptide to the small intestine. Diets with high levels of bypass poly peptide may not supply adequate amounts of nitrogen to rumen microbes for efficient microbial growth and feed digestion. Optimum diets unremarkably contain 30-40% available bypass protein and lx-seventy% rumen soluble poly peptide. Less than 30% of total poly peptide should be in the grade of NPN.

In lodge for rumen microbes to utilize NPN, sufficient soluble carbohydrates (e.g. starch) must included in the diet. Without adequate bachelor free energy in the diet, the capacity of the microbes to apply NPN would be overloaded. Excess NPN volition be absorbed past the animal as ammonia, and excreted. If NPN levels are loftier, toxicity will occur (urea poisoning).

Ration Formulation

A properly formulated ration supplies acceptable amounts of all nutrients to allow cattle to accomplish a desired level of production. Authentic ration formulation requires

1. precise description of the class of cattle (sex, weight, frame size, torso condition, desired rate of gain, stage of production)
2. knowledge of management practices utilized (implant usage, feed additives)
3. accurate description of the food content of the available feeds

Laboratory analyses of forages is essential for accurate ration formulation. The nutrient content of forages varies greatly depending on the type, phase of maturity at cut and how well it is preserved. For more information on lab analysis run into OMAF Factsheet, "Feed Sampling and Analysis" Agdex 400/60. Nutrient content of grains is not as variable as forages, but lab analysis is recommended. Help in formulating rations is available from your OMAF canton office, feed industry representatives and consultants.

Summary

A knowledge of the basic digestive system of cattle and the role of diverse nutrients is important to beef producers. Combined with authentic feed analysis, information technology allows the formulation of balanced rations which will run across production goals in an economic manner. Information technology as well enhances the management of the feeding programme by providing the background information necessary to prevent or resolve problem situations.

References

Church, D.C. 1977. Livestock Feeds and Feeding. 0 & B Books, Corvallis, Oregon

Byers F. 1990. Beef Production and the Greenhouse Effect. Texas A & Chiliad University.

NRC. 1984. Nutrient Requirements of Beef Cattle. National Academy of Sciences, Washington, D.C.

McBride, G. 1988. NRC Poly peptide System. Ontario Ministry building of Agriculture and Food, Guelph, Ontario.

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Source: http://www.omafra.gov.on.ca/english/livestock/beef/facts/91-066.htm

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