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).

BIOLOGICAL VALUE (of a protein)

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 chemical substances, such as sodium bicarbonate, that can maintain the pH of the rumen content around neutrality (pH = 6 to 7). The pH is maintained by neutralizing the volatile fatty acids and other organic acids produced by ruminal fermentation.


Glumes, husk, or other seed coverings, together with the plant parts, separated from seeds in threshing or processing.

DIGESTIBILITY (Coefficient of)

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.

EAR (of corn)

The seed-bearing part of a cereal plant. An ear of corn is composed of the grains, the cob, but not the husk, which are removed during harvesting.


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.


1. Ester of glycerol and fatty acids. 2. Organic compound containing carbon, hydrogen and oxygen, but as opposed to the carbohydrates, fats have a ratio of hydrogen to oxygen well above 2:1. Fats, as opposed to oils, are solids at room temperature and usually are of animal origin.


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.

FERMENTATION (in the rumen)

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).


The unborn young.

FIBER (dietary)

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.


Coarse feeds, such as straw, corn or sorghum stalks.


Feed that stimulate rumination due to their long particle size and their high content in fiber. Generally, forages are composed of the leaves and stems (stalk of plants. The bacterial population of the rumen allows the ruminant to digest forages.


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.


Is a polymer of fructose molecules generally, but not always, found as "carbohydrate storage in cool season grasses (C3 plants). Tall fescue and perennial ryegrass tend to have the highest levels of fructans when compared to other grasses under the same conditions. Fructan is stored in vacuoles inside cells throughout the plant where it is readily available as needed. In some species of grass the lower part of the stem is a carbohydrate storage organ.


A sweet sugar occurring in many fruits and honey.


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


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


Structure, usually flat and green that grows from a stem or stalk of a plant and is responsible for photosynthesis.


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.


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).


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


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


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.


Usually refers to feeding insufficient energy.

Unit of Mass in Metric System

1,000,000,000,000,000  1x1015 petagram (Pg) quadrillion  
1,000,000,000,000  (Million Metric Tons or Megatonnes)1x1012 teragram (Tg) trillion
 1,000,000,000  (Thousand Metric Tons) 1x109 gigagram (Gg) billion
 1,000,000  (Metric Ton) 1x106 megagram (Mg) million
 1,000   1x103 kilogram (Kg) thousand  
 100   1x102 hectogram (Hg) hundred  
 10   1x101 decagram (Dg) ten  
 1    gram    
   0.1 10-1 decigram (dg) tenth   
   0.01 10-2 centigram (cg) hundredth  
   0.001 10-3 milligram (mg) thousandth  
   0.000,001 10-6 microgram (µg) millionth  
   0.000,000,001 10-9 nanogram (ng) billionth  
   0.000,000,000,001 10-12 picogram (pg) trillionth  
   0.000,000,000,000,001 10-15 femtogram (fp) quadrillionth  


Fat containing fatty acids that can accept hydrogen atoms to saturate their structure (e.g., oleic, linoleic, linolenic and arachidonic acids).


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.