R

Ralgro® - Growth implant containing zeranol (a fermentation product exhibiting estrogenic activity).

random mating - System of mating whereby every female (cow and/or heifer) has an equal or random chance of being assigned to any bull used for breeding in a particular breeding season.  Random mating is required for accurate progeny tests.

ration - Feed fed to an animal during a 24-hour period.

REA - See rib-eye area (REA).

reach - See selection differential.

realizer - Feedlot animal that is removed before the end of the feeding program.  Only part of the animal's potential value is realized because of disease, injury, or the like.

recessive gene - A gene that has its phenotypic expression masked by its dominant allele when the two genes are present together in an individual.

rectal prolapse - Protrusion of part of the large intestine through the anus.

red meat - Meat from cattle, sheep, swine, and goats.  See also white meat.

reference sire - Bull designated to be used as a benchmark in progeny testing other bulls (young sires).  Progeny by reference sires in several herds enables comparisons to be made between bulls not producing progeny in the same herd(s).

registered - Recorded in the herdbook of a breed.

regurgitate - To cast up undigested food to the mouth as is done by ruminants.

replacement heifers - Heifers, usually between 6 months and 16 months of age that have been selected to replace cows in the breeding herd.

replacements - Cattle that are going into feedlots or breeding herds to replace those being sold or that have died.  See also replacement heifers.

reproductive tract score - Numerical score based on palpation of the heifer's reproductive tract (1 = not cycling; 5 = heifer cycling).

resource - Input or factor used in production, such as cattle, labor, or land.

retail cuts - Cuts of beef in sizes that are purchased by the consumer.

retained ownership - Usually refers to cow-calf producers maintaining ownership of their cattle through the feedlot.

retained placenta - Fetal membranes (afterbirth) are not expelled through the reproductive tract in the normal length of time following calving.

reticulum - One of the stomach components of cattle that is lined with small compartments giving a honeycomb appearance.

rib-eye area (REA) - Area of the longissimus dorsi muscle, measured in square inches, between the twelfth and thirteenth ribs.  Also referred to as the loin-eye area.

rib-eye area per cwt carcass wt - Rib-eye area divided by carcass weight.

risk - Possibility of suffering economic loss.  Sources of risk include climate, disease, and changes in the marketplace.

risk management - Managing risks in ways that allow a desired outcome to be achieved.

rotational crossbreeding - Systems of crossing two or more breeds whereby the crossbred females are bred to bulls of the breed contributing the least genes to the females' genotype.

roughage - Feed that is high in fiber, low in digestible nutrients, and low in energy (e.g., hay, straw, silage, and pasture).

rugged - Big and strong in appearance; usually heavy boned.

rumen - A compartment of the ruminant stomach that is similar to a large fermentation pouch where bacteria and protozoa break down fibrous plant material swallowed by the animal.  Sometimes referred to as the paunch.

ruminant - Mammal whose stomach has four parts--rumen, reticulum, omasum, and abomasum.  Cattle, sheep, goats, deer, and elk are ruminants.

rumination - Regurgitation of undigested food that is chewed and then swallowed again.