DS 825 Ruminant Nutrition Physiology DS 825 Ruminant Nutrition Physiology Glossary

Condition characterized by a low rumen pH (below 6). The normal rumen function are impeded usually because too much concentrates were fed.

A latin word that means "to one's pleasure." In nutrition, ad libitum (abbreviated "ad Lib") refers to feeding management in which animals are fed without restriction. Cows are usually considered fed ad libitum when the refusals (orts) amount to approximately 5 to 10% of what has been offered the day before.

Allometric equations take the general form Y = aM^b, where Y is some biological variable, M is a measure of body size, and b is some scaling exponent. See West et al. (2012) for more details.

One of the 20 building block units of protein. Amino acids contain both an amino group (NH₂) and an acid or carboxyl group (COOH).

A pungent gas. Ammonia is extensively used to manufacture fertilizers and nitrogen containing compounds. Also, ammonia is the end-product of protein degradation by ruminal bacteria.

The part of the metabolism in which metabolites are used in the growth and repair of body tissues.

A disease due to a deficiency in red blood cells or in hemoglobin that carries oxygen in the blood.

Protein released in the blood that is generated in reaction to a foreign protein (antigen) that has entered the body. Antibodies produce immunity against certain micro-organisms or their toxins.

Desire for food that can be quantify by measuring dry matter intake.

Reproductive procedure by which semen previously collected from sires, packaged in “straws” and frozen in liquid nitrogen is thawed and manually deposited in the uterus of a cow in estrus, in the hope of conception. Artificial insemination is a technology that allows for genetic improvement based on selection and use of superior sires.(see also Timed Artificial Insemination).

A method of expressing the concentration of a nutrient in a feed. For example, a feed containing 12% crude protein on a dry matter basis contains 12 g of protein for each 100 g of feed "as-is" (or "fresh"). When feed ingredients are added to a mixer, they are weighted on an "as-is" of "fresh" basis. See also "Dry Matter Basis.

Single-cell organisms living either independently or in close association with other living organisms. Often referred to as microbes or microorganisms because of their microscopic size. Some bacteria are beneficial, but others cause infectious diseases.

A liver secretion that is necessary for proper digestion of fats.

A measure of protein quality. The percentage of protein in a feed which is not lost in the urine or the feces of the animal. Biological value is a reflection of the balance of amino acids available to the animal after digestion and absorption.

A unit of heat that can be used to measure the amount of energy in a feed or a ration. A calorie is the amount heat required to raise the temperature of 1 gram of water from 14.5 ° centigrade to 15.5 ° centigrade.

A gas produced by combustion or oxidation of organic matter. Carbon dioxide is also produced in large quantities during ruminal fermentation.

The part of the metabolism in which metabolites are oxidized for the production of work and heat.

Involving or based on direct observation of the patient (a clinical diagnosis). A clinical disease is a disease that can be diagnosed by examination because of signs / symptoms of discomfort, anomalies of the normal state

A measure of the amount of protein in a feed determined as the amount of nitrogen multiplied by 6.25. The factor 6.25 is the average grams of protein that contains 1 gram of nitrogen. The word "crude" refers to the fact that not all nitrogen in most feed is exclusively in the form of protein. Because most feeds contain non-protein nitrogen (NPN), crude protein generally overestimates the actual protein content of a feed.

A measure of the concentration of matter per unit of volume (e.g., g/l or kg/m3)

Pathologically excessive evacuation of watery feces. Diarrhea may be due to an infectious agent (bacterial infection) or a dietary imbalance.

The mixture of digestive secretion, bacterial population and feeds undergoing digestion in the gastro-intestinal tract (such as rumen content).

A measure of the proportion of a feed that is digestible. The digestibility of a nutrient is often measured as the difference between the amount of nutrient ingested minus the amount of nutrient excreted in the feces, expressed as a percentage of the nutrient ingested: 100 x (intake - excreted)/intake.

A method of expressing the concentration of a nutrient in a feed. For example, a feed containing 12% crude protein on a dry matter basis contains 12 g of protein for each 100 g of feed dry matter

Quantity of dry matter ingested by a cow in a 24 h period. For example, a cow eating 18 kg of grass silage of 33% of dry matter ingest 18 x 0.33 = 6 kg of grass silage dry matter.

A measure of the concentration of energy in a feed or a ration usually expressed as a unit of energy (megacalorie or megajoule) per lb of dry matter or per kg of dry matter.

Membranous tissue, usually in a single layer, composed of closely arranged cells separated by very little intercellular substance. The epithelium forms the lining of the respiratory, intestinal, and urinary tracts and the outer surface of the body.

The removal of a material from an organism. Example of material excreted include tears, urine, feces, sweat and carbon dioxide. Examples of an organism's organs involved in excretion include eyes, bladder, rectum, skins and lungs.

An animal that tests as negative but who is actually positive. The percent of false negative for a test can be calculated as 100 – SENSITIVITY.

An animal that tests as positive but who is actually negative. The percent of false positive for a test can be calculated as 100 – SPECIFICITY.

A chain of carbon terminated by an acid (carboxyl) group (COOH). Fatty acids with less than 4 carbon units are volatile. Fatty acids with 5 to 20 carbon units are usually found as part of fats and oils.

The transformation of carbohydrates in absence of oxygen by rumen micro flora that produces volatile fatty acids such as acetic acid, propionic acid and butyric acid, and gases such as carbon dioxide (CO2) and methane (CH4).

Nutrient of low energy density present in large quantities in forages. Fiber is composed of structural carbohydrates (cellulose and hemicellulose) and phenolic compounds. Fiber is important for dairy cows because they stimulate rumination and promote a healthy rumen environment for bacterial growth. However, in large amounts in the diet, fiber may fill the rumen, limit intake of energy and constrain milk production.

Hemicellulose and cellulose that can be quantify by the neutral detergent fiber procedure.

Usually expressed as two percentages. The percentage of ration dry matter that is made up of forage and the percentage of ration dry matter that is composed of concentrates. The two total 100. For example a 50:50 forage to concentrate ratio means that a cow eating 20 kg of dry matter of that ration would eat 10 kg of concentrate dry matter and 10 kg of forage dry matter.

The stomach and the intestine as a functional unit.

To begin to or to cause to grow (syn to sprout.

An enlargement of the thyroid gland associated with iodine deficiency and visible as a swelling at the front of the neck.

Seed from cereal plants.

Family of plants including rye grass, fescue, brome, timothy and other herbaceous plants often referred to as grass. Cereals are gramineous plants but often, they are considered apart from the grass because they are cropped for the grain rather than the vegetative parts of the plant.

A period of 9 to 24 hours preceding the ovulation during which cows are receptive to bulls and exhibit a typical behavior of mounting other cows or standing when mounted by other cows (or a bull).

A young female cow that has not yet given birth to a calf.

A type of carbohydrate similar to cellulose except that it contain not only glucose but also other 6 carbon sugars and also 5 carbon sugars.

An iron rich protein found in the red blood cells which function as a carrier of oxygen and carbon dioxide.

Strong acid secreted by the abomasum that breaks down chemical bounds and thus contributes to the digestion of feeds.

Decomposition of a chemical compound by reaction with water.

The arrangement of flowers on a stalk that characterizes a plant species.

A unit of measurement of the amount of biologically active vitamin in a feed or required in a diet.

A condition characterized by a lack of appetite, especially for concentrates and an abnormally high concentration of ketone bodies (e.g., acetone, hydroxy-butyrate) in the blood. Ketosis or acetonemia occurs when the cow mobilizes large amounts of body reserves in early lactation.

One thousand calories.

Inflammation of the sensitive vascular tissue of the hoof.

A feed or drugs that will induce bowel movements (defecation) and relieve constipation.

Indigestible phenolic compound which, as the plant matures, is deposited in the cell wall and is responsible for the decrease in digestibility of the cell wall carbohydrates.

A sedimentary rock, chiefly calcium carbonate (CaCO3), containing variable amounts of magnesium. It is used as building stone, but also as a source of calcium in ration of animals.

An enzyme that breaks down fat.

Any of the numerous fat or fat-like materials that are generally insoluble in water, but soluble in common organic solvents. Nutritionally, lipids contain about 2.25 times more energy then carbohydrates.

Protein coated packages that transport fats in the bloodstream

Any compound that helps to prevent the accumulation of abnormal or excessive amounts of fat in the liver, control blood sugar levels, and enhance fat and carbohydrate metabolism.

A large gland that has multiple functions, one of which is to secrete bile and digestive enzymes that are mixed with the digesta entering the duodenum.

One of the 20 amino acids constituting the building blocks of proteins. Animals have a high requirement for lysine, and it is often deficient in proteins of plants.

A diet that supplies the nutrients required to maintain vital functions (heart beat, respiration) and assure a constant body temperature.

A physiological state in which the animal is neither gaining nor losing weight, performing work or expending nutrients for any type of production.

To grind or crush (food) with or as if with the teeth to prepare it for swallowing and digestion (Syn: Chew).

An infammation of the udder (often caused by a microbial infection) resulting in pain and the secretion of milk with a high count of white blood cells (referred to as somatic cell count).

The mean of a normal distribution is the most likely value (the value that has the lowest probability of being "wrong"). The mean is the best measure of central tendency of a normal distribution. With a normal distribution, approximately one-half of the samples have values lower than the mean and one-half have values higher than the mean.

One million calories.

Refers to all of the changes that nutrients undergo after they are absorbed from the digestive tract. Metabolism is divided into anabolism and catabolism.

A product of metabolism of nutrients.

In ruminant nutrion, metabolizable protein, often abbreviated MP, is the amount of digestible protein that reach the small intestine, which is the source of amino acids absorbed into the blood. The three main sources of MP include rumen undegraded protein (the dietary protein fraction that has not been degraded in the rumen), the microbial (bacterial) protein synthesized in the rumen from the fermentation process, and the endogenous protein (intestinal digestive enzymes and sloughed cells from the gastro-intestinal tract). The latter source is minimal.

Inflammation of the uterus.

Animal or vegetal organism of microscopic dimension (syn Microorganism).

(see Microbe).

Condition that occurs immediately or within the first day after calving. The cow has cold ears and a dry muzzle. This condition is due to a calcium imbalance. As opposed to what the name implies, there is no "fever", but rather a paralysis of the limbs.

1. A building equipped with the machinery for grinding grain into flour or meal. 2. A device or mechanism such as rotating millstones, that grinds grain.

To grind, pulverize or break down into smaller particle size in a mill.

1. The inorganic chemical elements (e.g., calcium phosphorus magnesium) determined by combusting a sample in a furnace and weighing the mineral residue. 2. Minerals play major roles in numerous metabolic processes. (syn Ash).

Having one digestive cavity (i.e., one stomach).

Morbidity is an incidence of ill health. It is measured in various ways, often by the probability that a randomly selected individual in a population at some date and location would become seriously ill in some period of time. Contrast to mortality.

is incidence of death in a population. It is measured in various ways, often by the probability that a randomly selected individual in a population at some date and location would die in some period of time. Contrast to morbidity.

A cow that has given birth more than once.

The amount of energy in a feed which is available for milk production and body maintenance. Feeds generally are similar in total energy content but vary widely in the proportion of the total energy which is available for maintenance and milk production. The remainder of the energy in the feed is lost in the feces urine, gas belched form the rumen and excess heat production by the cow. In the cow, it takes 0.74 Mcal NEl to produce 1 kg of milk containing 4% fat and the net energy content of most feed range from 0.9 to 2.2 Mcal NEl per kg dry matter.

A measure of the amount of cell wall in a feed determined by a laboratory procedure. Neutral detergent fiber includes cellulose, hemicellulose and lignin.

Carbohydrates that are not part of the neutral detergent fiber, but generally accumulate in the plant as energy reserve (e.g., starch). These carbohydrates usually are more rapidly and more completely digested than the fibrous carbohydrates (syn Non-structural carbohydrate).

Nitrogen that comes from a source other than protein but may be used by a ruminant in the building of protein. NPN sources include compounds such as urea and anhydrous ammonia, which are used in feed formulations for ruminant only.

The chemical substances found in feeds that can be used, and are necessary, for the maintenance, production and health of the animal. The main classes of nutrients are carbohydrates, fats, proteins, minerals, vitamins and water.

This refers to meeting the animal's need of the various classes of nutrients for maintenance, growth, reproduction, lactation and physical work.

Lipid, usually of vegetal origin, which is liquid at room temperature (as opposed to fats).

Compounds composed of carbon oxygen hydrogen and nitrogen. All living organisms are composed primarily of organic matter. Fats, carbohydrates and proteins are examples of organic compounds.

Release of an oocyte (i.e., egg) from a mature follicle. In dairy cows, ovulation occurs 24 to 32 hours after the first standing event of behavioral estrous. Similarly, ovulation occurs 24 to 32 hours after an injection of Gonadotropin Releasing Hormone; (Gn-RH) administered in the presence of a dominant follicle.

The taste and flavor property of a feedstuffs that make them more or less acceptable to be eaten.

1. Small projections on the inner surface of the rumen and the reticulum wall that increase the surface area of absorption of volatile fatty acids and other end-products of bacterial fermentation.

Protuberances at the surface of the tongue that detect the taste of a feed.

The act of giving birth (Syn Calving).

A digestive enzyme found in the gastric juice that breaks down proteins into peptides.

1. At least 2 but not more that 100 amino acids linked together by a peptic bound. 2. Product of pepsin digestion of proteins.

Organic substance in which the carbon atoms are linked together in a ring structure (also called aromatic structure). Lignin is an example of phenolic compound.

The process by which the chlorophyll of plants converts carbon dioxide and water into simple sugars with the simultaneous release of oxygen.

To free from coarseness; to refine.

Having more than one digestive cavity; Having a stomach divided into different chambers (e.g., ruminants).

The set of individuals, items, or data from which a statistical sample is taken. In statistical terms, a population is defined as a larger set from which samples are obtained.

1. The degree with which a measurement is reproducible, that is, yielding similar results when repeated (see also Accuracy).
2. the number of significant digits to which a value has been reliably measured.

1. A young cow that is pregnant for the first time. 2. A cow that has given birth once.

A chain or multiple chains of amino acids (more than 100). Proteins are composed of carbon, oxygen, hydrogen nitrogen (16% on average,found in the form of amino acids) and often sulfur. Proteins have important functions in the body. They are present in all plants and animals and they are essential in the ration of animals. See also Crude Protein.

The part of a plant embryo that develops into the primary root.

Reversal of the natural direction in which contents flow through a tube or a cavity in the body. During rumination, rumen contents are regurgitated through the esophagus in the mouth for further mastication.

The first two stomachs of a ruminant comprised of the reticulum and the rumen. A microbial population lives in the rumen and enable the cow to digest dietary fiber. The digesta in the rumen and the reticulum is being exchanged once about every 50 to 60 seconds under the influence of a rhythmic cycle of contraction which also results in passage of some digesta from the reticulum into the omasum through the reticulo-omasal orifice.

The second stomach of a ruminant in which folds of the mucous membrane form hexagonal cells. Also called honeycomb stomach. The reticulum is joined to the omasum by the reticulo-omasal orifice.

A type of bacteria that live in association with the roots of legume plants and make the nitrogen of the air available to the plants.

A root-like usually horizontal stem growing under or along the ground that sends out roots from its lower surfaces and leaves or shoots from its upper surface.

A deficiency disease resulting from a lack of vitamin D or lack of sunshine exposure, characterized by defective bone growth.

The movement of a material from one place to another. Secretion is often required to move a material to the place where it can be excreted. Examples of materials secreted include all materials excreted (see Excretion above), plus enzymes, hormones and saliva. The organs that play a role in secretion include all those involved in excretion, plus the digestive glands like salivary glands, pancreas, liver and gallbladder and endocrine glands like the thyroid gland, pituitary gland, and ovaries and testes.

The probability that a test is positive, given that the animal has the disease (See also specificity).

Method of preservation of fresh forages based on the partial fermentation of the sugars in absence of oxygen. Silage can be made in various silos.

Structure constructed to help preserving forages as silage. Different types of silos includes: Tower silo, oxygen limiting silo, trench silo, etc.

A cavity formed by a bending or curving; a dilated passage.

(a) Any of the cells of a plant or animal except the reproductive cells. (b) Milk somatic cells are primarily leukocytes (white blood cells) and some epithelial cells shed from the lining of the mammary gland. The leukocytes are derived from blood and consist of macrophages, lymphocytes, and polymorphonuclear cells, primarily neutrophils (PMN). Normal milk does contain somatic cells, and the concentration of these cells is almost always less than 100,000 cells/ml in milk from uninfected/uninflamed mammary quarters.

The probability that a test is negative, given that the animal does not have the disease (see also sensitivity).

A ring-like muscle that maintains constriction of a bodily passage or orifice and opens upon relaxation.

Standard deviation (SD) is a measure of the dispersion of a set of data from its mean. If the data points are further from the mean, there is higher deviation within the data set. The SD shares the same unit as the mean. The SD is calculated as the square root of variance by determining the variation between each data point relative to the mean. The symbol for standard deviation is σ (the Greek letter sigma). Approximately, in a normal distribution,
38% of all observations are within ± 0.5 SD units of the mean;
68% of all observations are within ± 1 SD units of the mean;
95% of all observations are within ± 2 SD units of the mean;
99% of all observations are within ± 3 SDunits of the mean.

A calf born dead or that dies within 48 hours of birth.

Without clinical manifestations; said of the early stages or a very mild form of a disease, e.g. subclinical disease, infection, parasitism, or when a disease is detectable by biological tests but not by a clinical examination.

Narrowly defined, SI refers to increase food production from existing farmland in ways that place far less pressure on the environment and that do not undermine our capacity to continue producing food in the future. However, Garnett et al. (2013) added the following four premises underlying SI: (a) The need to increase production; (b) Increase production must be met through higher yields because increasing the area of land in agriculture carries major environmental costs; (c) Food security requires as much attention to increasing environmental sustainability as to raising productivity; and (d) SI denotes a goal but does not specify a priori how it should be attained or which agricultural techniques to deploy.

The intimate living together of two dissimilar organism in any of various mutually beneficial relationships.

Highly complex phenolic compounds in plants that may play a role of defense again microorganisms and possible predators (the herbivores). Tannin binds and reduces the availability of proteins and carbohydrates to ruminal microbes.

A two-lobed gland located in the throat and secreting the hormone thyroxin, which regulates the iodine metabolism in the body.

Method of AI breeding in which the timing of artificial insemination (AI) is based on a hormonal protocol that synchronizes the timing of ovulation. This is in contrast to timing insemination based on direct or indirect detection of estrous behavior. Hormonal protocols for Timed AI were developed in 1995 and have been widely adopted by dairy producers for reproductive management.

Mixture of the forages, concentrates, minerals and vitamin supplements of a ration. The total mixed ration has the advantage of offering a balanced ration at each meal rather than on a 24 h basis.

A fat composed of three fatty acids and glycerol.

Digestive enzyme secreted by the pancreas and responsible for the break down of peptide bonds of proteins. Some plants contain a trypsin inhibitor that prevent trypsin from functioning properly.

Ray in sunlight which enables vitamin D to be synthesized under the skin.

Usually refers to feeding insufficient energy.

The parts of plants that are involved in the growth as opposed to the parts of plants involved in reproduction.

Particles that carry cholesterol and fat throughout the bloodstream. These particles are released from the liver into the bloodstream. They are similar to chylomicrons which originate from the gut because they both carry cholesterol and triglycerides which are gradually released in the bloodstream to be absorbed by body cells along the way. In the process of losing triglycerides, the VLDLs grow smaller and turn into LDLs (Low Density Lipoprotein) which have lost all their triglycerides.

Complex organic substances occurring naturally in plants and animal tissue and essential in small amounts for the proper functioning of numerous metabolic processes.

Evaporating readily at normal temperature and pressure.

Products of fermentation of carbohydrates (and some amino acids) by the rumen microorganisms. Acetic acid, propionic acid and butyric acid are the primary volatile fatty acids which are absorbed through the rumen wall and used as an energy source by the cow.

The number of days between calving and first attempt to breed a cow. A typical voluntary waiting period is 45 days. However, it may varies from less than 40 to 80 days depending on farmer’s preference and reproductive protocol in place on the farm.