Abstract: The potential fertility of a semen sample is evaluated using a kit comprising a collection tube with volume gradients on its side; a funnel which is fitted into the collection tube for guiding an ejaculate into the collection tube; a pipet containing a standard aqueous solution of the dye resazurin stored therein for metering a predetermined amount of the solution into the collection tube; and insulating sleeve for surrounding a glass containing hot water and the collection tube and for maintaining the water at an elevated temperature for a predetermined period of time, and a color chart ranging in color from the color of the semen sample and dye solution mixture immediately after mixing to the color of a corresponding mixture of the dye solution and a highly fertile semen sample, after being maintained at the same elevated temperature for the same period of time.

Abstract: Method of artificially inseminating a plurality of animals with aliquots of sperm obtained from a breeding stock individual of that species, obtained by fractionating the collected semen into first and second motile-sperm containing fractions, the first of which is free from immotile sperm and non-sperm components, both suspended in a liquid vehicle which is physiologically acceptable to the sperm and for artificial insemination; dividing the first and second fractions into a plurality of aliquots, each of which contain enough motile sperm to ensure a pregnancy when used for an artificial insemination; artificially inseminating a plurality of individuals of that species in which a predominance of male offspring is desired with the aliquots of the first fraction; and artificially inseminating a plurality of individuals of that species in which a predominance of male offspring is not a desired objective with the aliquots of the second fraction.

Abstract: The likelihood of conceiving a female fetus is substantially enhanced by promoting ovulation in a fertile female mammal with an ovulation-inducing agent and artificially inseminating the female mammal during the period of expected ovulation with a sperm fraction of enhanced sperm motility from which immotile sperm and non-sperm seminal components have been separated and which is suspended in serum albumin or like physiologically acceptable vehicle.

Abstract: Motile sperm are separated from immotile and abnormal sperm of mammalian semen by maintaining, at a temperature at which the motile sperm are motile, a layer of at least the sperm portion of the semen in interfacial contact with a discrete lower layer of an aqueous contacting medium physiologically acceptable to the sperm in which the motile sperm have a lower migration rate than in the upper layer, until the motile sperm of the semen have migrated at a preferential rate to the contacting medium, thereby providing a sperm fraction consisting essentially of normal motile sperm with enhanced Y-sperm content. Repeating the process with a second contacting medium physiologically acceptable to the sperm which further retards the migration rate of the motile sperm increases substantially the Y- to X-sperm ratio of the sperms which migrate thereto. The resulting sperm fraction, because of its enhanced Y-sperm content, can be used for artificial insemination to increase the incidence of male offspring.

Abstract: The percentage of the motile sperm of semen which survives frozen storage is increased by a process wherein the motile sperm is separated from the immotile sperm and the non-sperm components of the semen prior to storage. An insulated collection kit for collecting semen protects the semen from the adverse effects of handling and thermal shock.