Artificial Insemination | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Introduction

The roots of artificial insemination trace back to 1322 when an Arab chief, by clandestinely collecting semen, mated a prized mare with a stallion of an enemy chieftain. Scientific research began in 1780 with Italian Physiologist L. Spallanzi's work on dogs, and in 1899, Russian investigator E.I. Iwanoff successfully undertook artificial insemination in cattle and sheep. In August 1939, Kumaran introduced this method in India at the Palace Dairy Farm in My me.

Significance and Applications of Artificial Insemination

• Artificial insemination, now commonly referred to as artificial breeding, is a widely employed technique by dairy farmers globally. 
• It efficiently utilizes superior sires, allowing a single bull to inseminate thousands of cows in a year, compared to the limited natural service. 
• The method permits the earlier and more rapid proving of young bulls under varied conditions, facilitating the assessment of their inheritance of economic traits. 
• This technique also reduces maintenance costs for small dairy farmers by enabling cooperative bull ownership.

Advantages and Innovations in Artificial Insemination

• Artificial insemination offers advantages such as disease control, improved record-keeping, and the ability to breed animals of unequal sizes or physically incapable sires. 
• The development of frozen semen technology allows the use of superior bull semen worldwide, even after the bull's death.

Limitations and Challenges in Artificial Insemination

• While artificial insemination provides numerous benefits, well-trained operators are crucial for its success. 
• Infections like brucellosis must be carefully checked to prevent spread, and improper selection may lead to the rapid spread of genetic defects. 
• Despite these limitations, the advantages of artificial insemination outweigh the drawbacks.

Processes in Artificial Insemination

• The various processes in artificial insemination include semen collection, evaluation, dilution, preservation and transport, and insemination. 
• Semen collection, a critical step, primarily utilizes the artificial vagina, which ensures quick and clean ejaculation. 
• Strict cleanliness measures are essential to avoid injury and bacterial contamination. The collected semen undergoes further processes to maintain its viability and facilitate widespread use.

Alternative Semen Collection Methods

Mechanical Manipulation

• In rare instances, alternative methods such as mechanical manipulation are employed for semen collection, particularly in cases involving disabled bulls or rams.

Vaginal Collection

• Another seldom-used technique is vaginal collection, usually reserved for extraordinary circumstances. 
• This method may be utilized for bulls or rams that face challenges with the conventional artificial vagina approach.

Electric Stimulus

• Electric stimulus represents an unconventional approach, typically applied in special cases where traditional methods are impractical. 
• This method may be employed for collecting semen from a disabled bull or ram.

Semen Collection from Different Livestock

Ram

• For rams, the artificial vagina follows a pattern similar to that designed for bulls, albeit with differences in size to accommodate the anatomical distinctions.

Boar

• In boars, the artificial vagina is approximately 35 cm long and 4 cm in diameter.
• The collection involves manipulation by the operator's hand, encouraging continued copulation and resulting in two or three successive ejaculates over a period of 6 to 20 minutes.

Fowl

• Semen collection in fowls involves a secured bird and a rapid abdominal massage. Ejaculatory response is induced by manipulating the genital region, and the collected semen is stored in a small test tube.

Semen Components and Characteristics

Semen Composition

• Semen is the complete discharge from the male genital tract during copulation, comprising spermatozoa suspended in seminal plasma. 
• The components vary in origin, composition, and function.

Spermatozoa Structure

• Spermatozoa have distinct structures with variations across species. The head, middle piece, and tail contribute to the typical flagellar spermatozoan structure. 
• The size and characteristics differ, such as the tadpole-like appearance in bulls and the elongated cylinder shape in fowls.

Detailed Analysis of Bull Spermatozoa

• In bulls, the spermatozoa exhibit specific characteristics, including a blunt ovoid head, an acrosome covering the anterior part of the nucleus, and a fragile neck piece. 
• The middle piece contains a medial axial filament and a helix surrounded by a mitochondrial sheath, while the tail consists of axial filaments encased in protoplasm. 
• The entire spermatozoa is covered by a single membranous lipid capsule.

Composition of Spermatozoa

Head Structure

• The lipid membrane enveloping the spermatozoa head comprises 19.3% nitrogen and is rich in cystine. 
• It exhibits Keratin-like characteristics, high histidine, arginine, and cystine content, while lacking lysine. The membrane is resistant to trypsin, pepsin, and dilute acids and alkalis.

Bull Sperm DNA Content

• The dry matter of bull sperm cell heads includes 19.6% lipoprotein, with the remaining being DNA.
• The DNA content of bull sperm heads is 3.38 x 10 milligrams per sperm, containing 2.07 x 10 milligrams of arginine in the nucleus.

Phosphorus and Sulphur Content

• Whole spermatozoa contain 2.3% phosphorus and 1.2% sulfur, while the head specifically contains 4.7% phosphorus and 1.7% sulfur.
• Lecithin constitutes half of the lipid in bull sperm, with B-II semen containing acetal phospholipid or plasmalogen.

Glycogen and Lipoid Mantle

• Glycogen is present in the midpiece of bull sperm, and a lipoid mantle surrounds the neck, midpiece, and tail.
• Bull spermatozoa contain 241 milligrams of potassium and 17 milligrams of calcium per 100 milliliters, with antigens serologically identical to red blood cells.

Lipoprotein Layer and Preservation

• A layer of labile lipoprotein surrounds the bull sperm cell, predominantly around the head and localized in the neck and midpiece. 
• Egg yolk stabilizes this lipoprotein, effectively preserving the life of spermatozoa.

Enzymes in Spermatozoa

Phosphatases and Cytochromes

• Spermatozoa contain both acid and alkaline phosphatases, along with cytochromes a, b, and cytochrome oxidase. 
• Various enzymes, such as succinic dehydrogenase, aconitase, and amino acid oxidases, are present in spermatozoa.

Acrosomal Enzymes

• Enzymes located on the acrosome of the sperm cell include hyaluronidase, neuraminidase, RN acetyl glutaminidase, acid phosphatase, phospholipase A, aryl sulfatase, aryl amidase, and several acrosomal proteinases.

Adenylpyrophosphatase and Metabolic Enzymes

• Adenylpyrophosphatase is distributed in the head, midpiece, and tail. 
• Succinic dehydrogenase is found in the midpiece and tail, while cytochrome oxidase exhibits activity in the head, midpiece, and tail. Enzymes involved in spermatogenesis metabolism primarily act in the midpiece and tail.

Acetylcholine-specific Enzyme

• The enzyme cholinesterase, specific to acetylcholine, is present in bull sperm, playing a significant role in coordinating the motility function of spermatozoa.

Seminal Plasma

The seminal plasma, primarily derived from accessory sex glands like seminal vesicles, prostate, and bulbo-urethral glands, constitutes a significant portion. This fluid provides an optimal medium for the viability, motility, and storage of male germ cells.

• Water: Forms the majority of seminal plasma, providing a fluid medium for various substances.
• Sugar (Fructose): Serves as an energy source, contributing to the metabolic needs of sperm.
• Cholesterol: Present in varying proportions, influencing the fluidity and stability of cell membranes.
• Protein: Essential for various physiological processes, contributing to the overall structure and function of seminal plasma.
• Non-Protein Nitrogen: Includes substances like urea and ammonia, providing additional nitrogen sources.
• Salts: Comprising essential ions, salts play a role in maintaining osmotic balance and cellular function.
• Phospholipids: Contribute to the structural integrity of cell membranes within the seminal fluid.
• Fatty Acids: Provide a source of energy and contribute to the lipid composition of seminal plasma.
• Enzymes (Phosphatase, Dehydrogenase, Hyaluronidase, etc.): Catalysts that facilitate various biochemical reactions, influencing sperm function.
• Vitamins (Ascorbic Acid): Essential for antioxidant protection and overall sperm health.
• Hormones (Androgen and Oestrogen): Play a role in regulating reproductive processes and influencing sperm production.
• Trace Minerals (Zinc, Iron, Copper, Calcium, Sodium, and Potassium): Essential for enzymatic activity, cellular function, and overall reproductive health.