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.