GATT (General Agreement on Tariffs and Trade) - An agreement originally negotiated in Geneva, Switzerland in 1947 among 23 countries, including the U.S., to increase international trade by reducing tariffs and other trade barriers. The agreement provides a code of conduct for international commerce and a framework for periodic multilateral negotiations on trade liberalization and expansion.
gene - Segment of DNA in the chromosome that codes for a trait and determines how a trait will develop.
gene map - A blueprint of the chromosomes of a species, indicating the relative order of location of genes and DNA markers.
generation interval - Average age of the parents when the offspring are born.
generation turnover - Length of time from one generation of animals to the next generation.
genetic correlation - Correlation between two traits that arises because some of the same genes affect both traits. See correlation coefficient.
genetic engineering - Changing the characteristics of an animal by altering or rearranging its DNA. It is an all-embracing term for several techniques: (1) manipulations at a cellular level (cloning); (2) manipulation of the DNA itself (gene manipulation); (3) changing the DNA sequence through the selection and mating of cattle.
genome - Total number of genes in a species.
genotype - Genetic constitution or makeup of an individual. For any pair of alleles, three genotypes (e.g., AA, Aa, and aa) are possible.
genotype--environmental interaction - Variation in the relative performance of different genotypes from one environment to another. For example, the superior cattle (genotypes) for one environment may not be superior for another environment.
gestation - Time from conception until the female gives birth, an average of 285 days in cattle.
goal - Target or desired condition that motivates the decision maker.
gonad - Testis of the male; ovary of the female.
gonadotrophin - Hormone that stimulates the gonads.
grade augmentation - Supplementation of traditional USDA visual carcass grading using objective instrumentation.
grade and yield - Marketing transaction whereby payment is made on the basis of carcass weight and quality grade.
grading up - Continued use of purebred sires of the same breed in a grade herd.
grass tetany - Disease of cattle marked by staggering, convulsions, coma, and frequently death that is caused by a mineral imbalance (magnesium) while grazing lush pasture.
grazier - A person who manages grazing livestock.
grazing cell - A parcel of land subdivided into paddocks and grazed rotationally.
grazing cycle - The length or passage of time between 2 grazing periods in a particular paddock of a grazing unit. One grazing cycle includes 1 grazing period and 1 rest period.
gross margin - Difference between the revenue and variable production cost for one unit (one acre or one animal) of an enterprise.
growing ration - Usually a high-roughage ration whereby gains of 0.25-2 lb per day are anticipated.
growth - Increase in protein over its loss in the animal body. Growth occurs by increases in cell numbers, cell size, or both.
grubs - Larvae of the heel fly found on the backs of cattle under the hide.