Animal Reproduction - Booklert B.docx

**Animal Reproduction  - Booklet B** Chromosomes 23 pairs 1. **Sexual Determination ** Each human cell contains 46 chromosomes. Each human gamete contains:  1. 22 Autosomes  1. 1 Sex chromosome  Chromosomes contain genetic material  The Y chromosome is the sex chromosome and determines ma...

**Animal Reproduction  - Booklet B** Chromosomes 23 pairs 1. **Sexual Determination ** Each human cell contains 46 chromosomes. Each human gamete contains:  1. 22 Autosomes  1. 1 Sex chromosome  Chromosomes contain genetic material  The Y chromosome is the sex chromosome and determines maleness.  XX = Female  XY = Male  SRY gene - (Sex Determining Region) is found on the Y chromosome. This gene leads to the formation of the testis.  The SRY gene determines if the gonads and ducts form into the Wolffian duct (male) or Müllerian duct (female) **Male Reproductive Physiology:** 1. Functions of the male reproductive system: 1. **Spermatogenesis** b. **Delivery of spermatozoa to female** c. **Production of male sex hormones** 1. **Development of secondary male characteristics** 1. **Development of sex drive (libido)** ----------------------------  ---------------------------- **[Sperm]** +-----------------------------------+-----------------------------------+ | - **Head** | Diagram of a sperm cell | | | Description automatically | | - Acrosome - Fertilisation | generated | | | | | | | | | | | - Haploid Nucleus - | | | Condensed DNA | | | | | | | | | | | | - **Midpiece** | | | | | | - Centrioles | | | | | | | | | | | | - Mitochondria- Energy | | | Production (ATP for | | | locomotion) | | | | | | | | | | | | - **Tail: Flagellum** | | | | | | - Microtubules - | | | Structure/Movement | | +-----------------------------------+-----------------------------------+ 5. Male Hormones  -------------- --------------- **Hormone:** **Function**: -------------- --------------- Follicle Stimulating Hormone (FSH) Responsible for stimulating synthesis of sperm cells in the testicle  --------------------------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------------- Luteinising Hormone  Responsible for stimulating testosterone production in the testicle  Gonadotropin Releasing Hormone (GnRH) Produced by the hypothalamus in the brain. Function is to stimulate synthesis of LH and FSH by the pituitary gland which is location in the brain also.  Testosterone  Responsible for sexual development and sex characteristics in males, required for synthesis of sperm cells and bull sex drive (libido)  **Female Reproductive Physiology: ** 1. **Oestrous Cycle - Cow:** 1. 21 day cycle 1. polyestrous 1. oestrus typically lasts 14 to 24 hours 1. Gestation -- 283 days   2. **Oestrous Cycle - Ewe:** 1. 17 day cycle 1. seasonally polyestrous 1. oestrus lasts 24 to 36 hours 1. Gestation -- 147 days **Oestrous Cycle - Sow:** e. 21 day cycle e. seasonally polyestrous e. oestrus lasts 2 to 3 days e. Gestation -- 3 months, 3 weeks & 3 days    **Cow reproductive tract:** --------------------------------------------------------------------------------  -------------------------------------------------------------------------------- +-----------------------------------+-----------------------------------+ | Ovaries | Produce ova and steroid sex | | | hormones | +===================================+===================================+ | Oviducts | Site of fertilisation | +-----------------------------------+-----------------------------------+ | Uterus  | Nourishes and protects embryo and | | | foetus | +-----------------------------------+-----------------------------------+ | Cervix  | Prevents infection | +-----------------------------------+-----------------------------------+ | Vagina  | Site of sperm deposition  | | | | | | Birth canal | +-----------------------------------+-----------------------------------+ **Bovine Oestrous Cycle:** **Hormone ** **Function** ---------------------------------------- --------------------------------------- **Follicle stimulating hormone (FSH)** **Follicular development** **Luteinizing hormone (LH)** **Causes ovulation** **Progesterone (P4)** **Promotes maintenance of pregnancy** A blue background with black text Description automatically generated **Methods of Fertilisation: ** 1. **Artificial Insemination:** Artificial insemination (AI) in bovine animals is a reproductive technology where semen is collected from a selected bull and manually introduced into the reproductive tract of a cow or heifer to achieve fertilisation. This method allows for controlled breeding, enabling farmers to use genetics from high-quality bulls to improve herd characteristics such as milk production, growth rates, or disease resistance. AI also helps to reduce the spread of sexually transmitted diseases and increases the efficiency of breeding programs by allowing one bull to sire a large number of offspring across a wide geographic area. +-----------------------------------+-----------------------------------+ | **Advantages of AI ** | **Disadvantages of AI ** | +===================================+===================================+ | **- \*\*Genetic Improvement:\*\* | **- \*\*Requires Specialized | | Allows the use of superior | Training\*\*: AI requires skilled | | genetics from top bulls, | personnel to correctly perform | | enhancing desirable traits like | the procedure, which may not be | | milk production, growth rates, | readily available in all areas.** | | and disease resistance in the | | | herd.** | **- \*\*Higher Initial Costs\*\*: | | | The equipment, semen storage | | **- \*\*Disease Control:\*\* | facilities, and training involved | | Reduces the risk of transmitting | in AI can be expensive to set | | sexually transmitted diseases | up.** | | compared to natural mating, | | | promoting healthier herds.** | **- \*\*Reduced Genetic | | | Diversity\*\*: Relying heavily on | | **- \*\*Cost-Effective:\*\* | a few selected bulls can decrease | | Eliminates the need to keep and | genetic diversity within a herd, | | maintain a bull, reducing costs | potentially leading to inbreeding | | associated with feeding, housing, | issues.** | | and veterinary care for male | | | animals.** | **- \*\*Lower Conception | | | Rates\*\*: If not performed | | **- \*\*Wide Accessibility:\*\* | correctly, AI can result in lower | | Semen from a single bull can be | conception rates compared to | | used to inseminate cows across | natural breeding.** | | different locations, making elite | | | genetics available to a broader | **- \*\*Logistical | | range of farms.** | Challenges\*\*: Proper timing is | | | crucial for AI to be successful, | | **- \*\*Controlled Breeding:\*\* | requiring accurate detection of | | Provides precise control over the | estrus (heat) in cows, which can | | timing of insemination, improving | be labor-intensive.** | | the chances of successful | | | conception and allowing for | **- \*\*Potential for Disease | | better management of breeding | Transmission\*\*: Although AI | | cycles.** | reduces the spread of sexually | | | transmitted diseases, poor | | **- \*\*Record Keeping:\*\* | hygiene or improper handling of | | Facilitates accurate | semen can still lead to the | | documentation of breeding and | transmission of other diseases.** | | genetic lineage, aiding in the | | | management of breeding programs | | | and the tracking of offspring | | | performance.** | | +-----------------------------------+-----------------------------------+ 2. **Sexed Semen:** **\*\*Sexed semen\*\* in bovine animals is a reproductive technology used to predetermine the sex of offspring before conception. This process involves sorting sperm cells into those carrying X chromosomes (which produce female calves) and those carrying Y chromosomes (which produce male calves). The sorted semen is then used for artificial insemination, typically to increase the likelihood of producing female calves, which are often preferred in dairy farming due to their milk production potential. Sexed semen technology enhances herd management and can improve economic outcomes by aligning the offspring\'s gender with the farmer\'s specific needs.** **Heat Detection:** **1. \*\*Tail Paint/Chalk\*\*:** **   - A simple and cost-effective method where paint or chalk is applied to the tailhead of cows. The paint or chalk is rubbed off when another cow mounts the animal in heat, indicating that the cow is in estrus.** **2. \*\*Activity Monitors\*\*:** **   - These are electronic devices, such as pedometers or accelerometers, attached to the cow\'s leg or neck. They measure increased activity, which is a common sign of heat, and often sync data to a central system for monitoring.** **3. \*\*Heat Detection Patches\*\*:** **   - These adhesive patches are placed on the cow\'s tailhead. When a cow is mounted by another, the pressure causes a colour change or a rupture in the patch, indicating heat. Example: Kamar Heatmount Detector** **4. \*\*Heat Detection Software/Apps\*\*:** **   - These digital tools integrate data from various sources (e.g., activity monitors, milk production data) to analyze and predict the onset of heat. They often use algorithms and provide alerts to farmers via smartphones or computers.**