S 

SNF Solids-not-fat of milk; proteins, lactose, minerals, and other water-soluble constituents. This is the same as NFS and NMS.
Sanitize To kill or remove injurious, microorganisms but not necessarily to sterilize. Dairy equipment is commonly sanitized with heat or chemicals.
Scale The overall size of an animal. 
Scours A persistent diarrhea in animals. 
Scrub An animal from nonpurebred parents not showing the predominant characteristics of any breed. 
Scurs Regrowth of horn tissue after dehorning. 
Secondary waste treatment Usually, a second treatment of waste water to reduce pollution potential or health hazard. With animal manure an example would be storage in an anaerobic treatment lagoon and sprinkler field application.
Selection The causing or allowing of certain individuals in a population to produce the next generation. Artificial selection is that practiced by man; natural selection is that practiced by nature.
Selection intensity The margin of true genetic superiority of those animals selected in comparison to all those from which the choices were made.
Self-feeder A feeding system that allows animals to eat at will. See ad libitum. 
Septicemia The presence of microorganisms and their associated poisons in blood (commonly called blood poisoning). If the microorganisms are bacteria, the condition is bacteremia.
Serotype The type of microorganism as determined by the kind and combination of constituent antigens associated with the cell.
Service A term commonly used in animal breeding, denoting the mating of male to female. Also called serving or covering. 
Service sire The sire to which a female currently is bred. Service sire information should be reported on DHI barnsheets.
Settled A term commonly used to indicate that an animal has become pregnant. 
Settling basin Any area that reduces flow velocity and allows particulates to settle from a liquid suspension. With manure suspensions, usually built to allow solids removal on a regular basis.
Shelf life The time after processing during which a product remains suitable for human consumption, especially the time a food remains palatable.
Shrinkage A term used to indicate the amount of loss in body weight, as in dairy steers, when exposed to various conditions and/or slaughter. Also, the decrease in volume of dairy products during storage, and the loss of milk or milk solids in processing.
Shy breeder A male or female of any domesticated livestock that has a low reproductive efficiency. 
Sib (sibling) In genetics, a brother or sister. 
Sickle-hocked Describes an animal having a crooked hock, which causes the lower part of the leg to be bent forward out of a normal perpendicular straight line.
Silage (ensilage) Green forage, such as grass or clover, or fodder, such as field corn or sorghum, that is chopped into a silo, where it is packed or compressed to exclude air and undergoes an acid fermentation (lactic and acetic acids) that retards spoilage.
Silo A vertical cylindrical structure, pit, trench, or other relatively airtight chamber in which chopped green crops, such as corn, grass, legumes, or small grain and other livestock feeds are fermented and stored. See silage.
Sire The male parent. The verb means to father or beget. 
Sire selection Process of identifying bulls to be used as service sires with the goal of increasing the genetic potential of the herd.
Sire summary See USDA sire summary. 
Sketch (photo) A method of permanent identification to be cross-referenced with visible identification. Accurate sketches or photographs of Holsteins, Ayrshires and Guernseys provide unique identification.
Skim milk Milk from which sufficient cream has been removed to reduce its milk fat content to less than 0.5 percent (usually less than 0.1 percent). Skim milk contains as much protein, lactose, minerals, and water-soluble vitamins and only half as many calories as whole milk. Skim milk is
practically cholesterol-free.
Slip To abort. 
Soilage Freshly cut green forage often fed to animals in drylot. Also called green chop. 
Solids-not-fat (SNF) See milk solids-not-fat. 
Solvent-extracted Fat or oil removed from materials (such as soybean seeds) by organic solvents. 
Somatic cell count A measurement of the number of somatic cells present in a sample of milk. A high concentration of more than 500,000 somatic cells per milliliter of milk indicates an abnormal condition in the udder.
Somatic cells The cell content of milk is composed of approximately 95 percent leukocytes (white blood cells) from the blood and 5 percent epithelial cells from the secretory tissue of the udder. Leukocytes are present in response to infection or injury, and epithelial cells are present as a result of infection or injury. Collectively, these cells are called somatic cells.
Somatotropin A protein hormone produced by the pituitary gland, which stimulates growth of muscle, bone and mammary development in young animals and increases milk production in lactating animals by making available nutrients for milk synthesis and secretion.
Spayed To have surgically removed the ovaries of a female. 
Sphincter A ring-shaped muscle that closes an opening, such as the sphincter muscles in the lower end of a cow's teat. 
Springer A term commonly associated with female cattle showing signs of advanced pregnancy. Often used to refer to heifers close to term with their first calf.
Stablemate See herdmate. 
Stage of lactation Period of milk production during a lactation determined by the length of time since parturition. 
Stale A period when an animal does not work or lactate at the normal standards, as opposed to bloom. Also refers to milk products that have deteriorated in storage.
Stanchion A specially designed headgate to hold an animal in place while allowing feeding and resting. 
Standardization The process of adjusting the milkfat and solids-non-fat content of milk to meet a required standard. 
Standby pool An arrangement between cooperatives in markets that have periods of milk shortages and cooperatives in areas of surplus milk production. Cooperatives in the deficit market make monthly payments to certain cooperatives in the surplus regions to assure that they have sources of
milk available at reasonable prices when local milk does not supply their Class I needs.
Statistically significant It usually refers in research to tests for differences resulting from treatments. The reliability of such differences is expressed as degree of probability or the percentage of time an observation would be expected to fall outside a certain range of variation
from normal observation.
Steer A male bovine castrated before development of secondary sex characteristics. 
Sterilize To remove or kill all living organisms. Also, to make barren or unproductive, as a vasectomy in bulls. 
Stillborn Born lifeless; dead at birth. 
Stover Fodder; mature cured stalks of grain from which seeds have been removed, such as stalks of corn without ears. 
Streak canal See teat meatus. 
String A group of animals within a larger group, or herd. 
Strip cup A small cup or device to collect forestrippings which makes abnormal milk easier to observe. 
Stud A unit of selected animals kept for breeding purposes (e.g., bulls). 
Subclinical A disease condition without clinical manifestations. 
Subcutaneous Situated or occurring beneath the skin. 
Succulence A condition of plants characterized by juiciness, freshness, and tenderness, making them appetizing to animals.
Supplement To add minerals, vitamins, or other minor ingredients (volumewise) to a ration. 
Support Price The equivalent price of milk as set by prices of NDM, cheese, and butter offered by the Commodity Credit Corporation of USDA. These prices effectively set a minimum price for milk and intermitantly provide milk producers an indirect government subsidy.
Surplus milk The quantity of grade A fluid milk in excess of that needed for Class I purposes. 
Surprise tests These are tests for verification performed on cows whose projected 2X (twice daily milking), 305D (305-day lactation), ME (mature equivalency) records exceed certain levels of milk and/or fat as established by breed associations.
Sweet butter Unsalted butter. 
Sweetened condensed milk The food obtained by partially removing water from a mixture of milk and a safe and suitable nutritive sweetener.
Switch The brush of hair on the end of a bovine's tail.