Animal Reproduction: Semen Quality, Preservation, and Artificial Insemination

Comprehensive vocabulary and concept flashcards covering animal reproduction, semen evaluation, cryopreservation, and artificial insemination based on the lecture notes.

Semen

The entire seminal discharge of the male during normal ejaculation, consisting of cellular spermatozoa ($10\%$) and liquid seminal plasma ($90\%$).

Spermatogenesis

A complex process of cell division and differentiation in the seminiferous tubules resulting in the formation of spermatozoa.

Spermatocytogenesis

The proliferative phase of spermatogenesis where primitive germ cells multiply by mitotic divisions and then undergo meiotic divisions to produce haploid spermatids.

Spermiogenesis

The differentiation phase involving the metamorphosis of a spermatid into a mature spermatozoa, including nuclear condensation and tail formation.

Acrosome

A membrane-bound structure on the anterior part of the sperm nucleus containing hydrolytic enzymes like acrosin and hyaluronidase to help penetrate the ovum.

Axoneme

The core structure of the sperm flagellum originating from the distal centriole, typically exhibiting a $9+2$ microtubule arrangement.

Mitochondrial Sheath

A helical arrangement of mitochondria in the middle piece of the sperm tail that provides $ATP$ energy for motility.

Spermiation

The final stage of spermatogenesis characterized by the release of formed germ cells from Sertoli cells into the lumen of the seminiferous tubules.

Fructose

The main energy source for spermatozoa in most species, synthesized from blood glucose in the seminal vesicles.

Ergothionine

A sulfur-containing antioxidant found in high concentrations in boar semen that protects sperm from oxidative damage.

Glyceryl Phosphorylcholine (GPC)

A molecule synthesized in the epididymis that acts as an aerobic energy source; it is found in particularly high concentrations in ram semen.

Seminal Plasmin

An antimicrobial agent present in seminal plasma.

Aspermia

A condition characterized by the complete absence of any seminal discharge.

Azoospermia

A condition where there is zero concentration of spermatozoa in the ejaculated semen.

Asthenozoospermia

A clinical term indicating a significant decrease in sperm motility.

Necrozoospermia

A condition where all spermatozoa in the ejaculate are dead.

Teratozoospermia

A condition characterized by a high percentage of morphologically abnormal spermatozoa.

Methylene Blue Reduction Test (MBRT)

A biochemical test where active sperm metabolism reduces blue methylene blue to colorless leucomethylene blue; faster decolorization indicates higher quality.

Hypoosmotic Swelling Test (HOST)

A test evaluating the functional integrity of the sperm plasma membrane by observing tail curling when sperm are placed in a hypoosmotic medium ($280-300\,mOsm/L$).

Fructolytic Index

The amount of fructose utilized by $10^9$ spermatozoa in one hour at $37^oC$, reflecting sperm viability and metabolic activity.

Cold Shock

Damage to the sperm membrane caused by rapid cooling; it is prevented in extenders by adding lipoproteins or lecithin from egg yolk or milk.

Cryoprotectant

A substance such as Glycerol ($7-10\%$) added to semen extenders to prevent intracellular ice crystal formation during deep freezing.

Pampiniform Plexus

A network of spermatic veins surrounding the coiled testicular artery that facilitates countercurrent heat exchange to keep testes $4-6^oC$ cooler than body temperature.

Direct Vagina Collection

The simplest and oldest method of semen collection, involving aspirating semen from the vagina after natural service, though it results in poor quality and contaminated samples.

Artificial Vagina (AV) Method

The most widely accepted method of semen collection that uses warmth, pressure, and friction ($42-45^oC$) to simulate natural service.

Gloved Hand Method

A common method for semen collection in boars where pressure is manually applied to the spiral penis after the boar mounts a dummy.

Fern Pattern

A branching crystallization pattern observed in dried cervical mucus under a microscope that indicates an animal is in estrus.

Gomer Bull

A teaser bull (often vasectomized or surgically altered) used to identify cows in estrus through mounting behavior.

Recto-vaginal Method

The most effective AI technique in cattle where the operator's hand in the rectum guides the AI gun through the cervix into the body of the uterus.

Repeat Breeding Syndrome

A condition where a cow fails to conceive after three or more services despite having normal estrus cycles and no palpable abnormalities.

Anestrus

A functional disorder of the reproductive cycle characterized by the absence of observable signs of estrus.

Silent Estrus

A condition common in buffaloes during summer where ovulation occurs normally without outward behavioral signs of heat.

Testicular Hypoplasia

A congenital defect characterized by incomplete development of the ovaries or testes, often resulting in sterility.

Diadem Defect

A hereditary sperm head defect appearing as a row of bead-like spots along the nuclear ring caused by nuclear pore formation defects.

Dag Defect

An abnormality where the sperm midpiece and tail are strongly coiled or folded, often associated with high zinc levels and reduced motility.

Knobbed Acrosome Defect

An autosomal recessive defect in bulls characterized by a thickened acrosomal cap that prevents the sperm from penetrating the ovum.

Alpha-Lecithin and Lipoproteins

Components found in egg yolk that form a protective layer over the sperm membrane to prevent damage from cold shock.

Ampulla

The terminal fusiform enlarged glandular portion of the vas deferens, which is absent in dogs and cats.

Bulbo-Urethral Gland (Cowper’s Gland)

Paired glands that provide pre-ejaculatory secretions to clean the urethra; they are responsible for the gel fraction in boar semen.

French Straw

A plastic (PVC) packaging system for frozen semen ($0.25\,ml$ or $0.5\,ml$) that is the most widely used method today due to its high fertility rates and ease of handling.