Exam 3 Swine Production

Functions of the Male Repro system

production of spermatozoa

secretion of hormones (testosterone)

transportation, nourishment, & deposition of Semen into FRT

Function: Testes

spermatogenesis, Hormone production, temperature regulation

Spermatogenesis

production of sperm in the seminiferous tubules

Optimal sperm production

scrotum keeps temp 2-4oC cooler than body temp

What are the two compartments of the testes?

Parenchyma & Mediastinum

Parenchyma

Consists of two compartments: Interstitial Compartment (leydig cells → testosterone) & Tubule Compartment (seminiferous tubules & sertoli cells → germ cells and blood-testis barrier)

Mediastinum

central connective tissue core → houses rete testis 

Maintains integrity of rete tubules

What does the Excurrent Duct Systems consist of ?

efferent ducks, epididymis, vas deferens (ductus deferens)

Epididymis

Caput (head) → maturation & epididymal fluid is secreted to help with movement

Corpus (body) → morphological changes & motility expression (fertilization potential)

Cauda (tail) → sperm metabolic activity decreases & sperm eligible for ejaculation

What is the main function of the epididymis 

sperm maturation (gain motility & fertilizing ability) & storage of sperm (tail)

Vas Deferens

connect cauda to ampulla, transport sperm from epididymis to urethra

What are the 3 Accessory Sex Glands and their functions?

Seminal Vesicles (fluid and nutrients (fructose) for sperm survival)

Prostate Gland (buffer and enzymes to aid sperm motility)

Bulbourethral Glands (cowpers - gel fraction that forms a plug in the female tract to prevent semen backflow)

What is the shape of a boar’s penis?

corkscrew - shaped to match the sow’s cervix

Ejaculate Volume

150-300 mL → larger compared to cattle and sheep

Sperm concentration

30-60 billion sperm per ejaculate

Ejaculate Duration

5-10 minutes

how many turns does the penis make in the cervix ? flaccid and erect

Flaccid: one

Erect: six

what type of penile tissue does a boar have?

Fibroelastic penis: limited erectile tissue encase in a non-expandable, dense connective tissue

Has a Sigmoid Flexure → allows for retraction inside the body (retractor penis muscle maintains S-shape)

What type of penile tissue does a stallion an humans have?

Musculovascular penis: NO sigmoid flexure

Function of the LH in a male repro system

stimulates testosterone production in Leydig cells (which produce testosterone)

Function of the FSH in a male repro system

acts on Sertoli cells for sperm cell development, it also triggers Sertoli cells to release androgen-binding protein, which keeps T concentrated within the testes

Function of Testosterone

provides libido, spermatogenesis, and masculine traits (tusks, odor, aggression)

produced by Leydig cells under LH stimulation

and provides a negative feedback to hypothalamus & pituitary to regulate GnRH and LH secretion

Function of the Hypothalumus

releases GnRH in pulses (constant tonic flow) NO surge

GnRH stimulates the anterior pituitary gland to release LH & FSH

Anterior Pituitary Gland

responds to GnRH by secreting LH and FSH

Where are the Leydig cells located and what do they respond to?

located between seminiferous tubules, has receptors for LH, which produce testosterone

Where are the Sertoli cells located and what do they respond to?

located inside seminiferous tubules, has receptors for FSH and T, which support spermatogenesis and secrete inhibin

Function of Inhibin

secreted by Sertoli Cells

provides negative feedback to pituitary gland to reduce FSH secretion, maintaining hormonal balance

External Factors Affecting Hormonal Function

Photoperiod, nutrition, age, stress, boar pheromones

What are the goals of breeding programs?

max repro efficiency & genetic improvement, improve litter size, growth rate, feed efficiency, carcass quality, and maintain repro longevity in sows and high semen quality

Ideal boar Selection traits:

high libido and sound repro anatomy, good BCS, semen quality: motility > 70% & morphology > 80 % normal, pedigree and performance data, sound legs and feet

Ideal Gilt Selection traits:

Large litters with strong maternal lineage, puberty ~ 5-7 months, breed on 2nd or 3rd estrus for optimal fertility & litter size, Good BCS

Detection of estrus

standing reflux (reliable), red swollen vulva, restlessness, and decrease feed intake

Optimal breeding/AI time in gilts and sows

Gilts: 12 hours after standing heat detected

Sows: 24 hours after standing heat

How much is AI used in the breeding systems?

85-90%

Breeding Ratio: Boar to Sow

1 boar per 15-20 females, can service 1 female every other day or 4-5 a week

When does the embryo enter the uterus post-ovulation?

2-4 days

What is Transuterine Migration

occurs between 8-12 days of gestation

embryos migrate through uterine horns and distribute evenly

Equal Spacing: vital for uniform placental development and adequate nutrient supply

What do the embryos secrete around 12-14 days of gestation?

estrogen → signals the uterus to maintain CL and prevent luteolysis

Reason why pregnancy is not maintained?

if fewer than 4-5 embryos implant

Gestation Period

114 days (3m, 3w, 3d)

3 Trimesters

Day 0-35: implantation and early placental formation

Day 36-75: rapid organ development

Day 76-114: fetal growth and mammory development

Hormonal Triggers in Farrowing

P4 decreases, while E2, relaxin and PGF2a increase

PGF2a causes luteolysis = decrease in P4 = uterine contractions increase

oxytocin released during labor → uterine contractions and milk letdown

Stage of Farrowing

Stage 1: Preparatory Phase (2-12 hours)

Stage 2: Delivery of Piglets (2-4 hours)

Stage 3: Expulsion of Placenta

Stages of Farrowing: Step 1

Preparatory Phase (2-12 hours)

nesting behavior, restlessness, increase respiration and cervical dilation

Stages of Farrowing: Step 2

Delivery of Piglets (2-4 hours)

each delivered every 15-20 min

uterine contraction aided by Oxytocin

piglets alternate between horns

Stages of Farrowing: Step 3 

Expulsion of Placenta

delivered within 4 hours after last pig

Ideal temperature for Sows during farrowing

70 oF

Ideal temperature for piglets

90-95 oF

What are some investment considerations?

facilities & equipment, breeding stocks, feed & nutrition, health & biosecurity, labor & management

Coporate

large agribusiness company that owns multiple stages of production

Corporate-Private

corporate provides capital, genetics, feed

Private provides land, facilities, and labor

Private

managed by individuals, family, small group of investors

Investment Scheme - Corporate

high level of capital investment, vertical integration, focus on mass production

allows for consistent product quality and biosecurity

Challenges: high initial investment cost, complex management structure, environmental regulation and community scrutiny

Investment Scheme - Corporate-Private

operates under contract growing arrangements, shared risk and profits, common in integrator-grower systems

Advantages: decrease investment burden for individuals, farmers, access to corporate expertise, genetics, feed supply, and stable market

Challenges: limited independence for private partners, profit margins may be smaller due to contract terms, requires strong legal & management agreements

Investment Scheme - Private

Investment capital comes from personal funds, loans, management decisions made by owner, production focus on local or niche market, more flexible but more risk

Advantages: full ownership and control, specialized in local market demands, easier to adapt to changes

Challenges: limited capital and technology access, and increase unit production cost, vulnerable to market and disease shocks

Factors Favorable for Swine production

Biologically efficient → prolifacy, early maturity, and high feed conversion

Nutritional flexibility

Product Versatility → pork an by-products

Economical'

Adaptability of production systems

Site Considerations in Swine Production

Site should: support efficient production and animal welfare, minimize environmental pollution and odor, comply with zoning, environmental and public health regulations, and provide economic advantages

Key Factors in Site Selection

Topography & drainage

Soil type and Load-bearing capacity

water supply

climate and orientation

accessibility and transportation

proximity to feed and markets

biosecurity and disease control

regulatory compliance

Odor control

space regulation

future growth

What should be considered in topography and drainage?

select elevated sloping land to prevent flooding, avoid low-lying or waterlogged areas with runoff or ponding can occur, proper drainage prevents disease spread and structural damage, slop should be 2-5% to allow runoff without erosion

What should be considered in soil type and load-bearing capacity?

soils should be firm, well-drained, and non-clayey, sandy loam or loamy soils are Ideal, avoid high groundwater tables

What should be considered in water supply?

reliable, potable water source is essential → sow and litter need 15-25 liters a day

grower/finishing pigs need 8-12 L/day

What should be considered for climate and orientation?

moderate temp & humidity reduce stress and improve feed efficiency, building orientation should max natural ventilation and minimize heat stress

Hot climates→ building E to W (provide shade and cooling)

Cold regions→ wind breaks and good insulation

If you have a pig operation in warm to hot climates, how should you orient your building?

Building should be East to West to provide some shade and cooling

If you have a pig operation in cold climates, how should you orient your building?

Build windbreaks (hills, vegetation, trees) and have good insulation in the building

What should be considered in accessibility and transportation?

proximity to main roads for transport of feed, pigs, and supply. Allow easy access for feed delivery trucks and trailers. also maintain sufficient distance from highways to minimize noise and biosecurity risk

What should be considered in proximity to feed and markets?

sites closer to feed sources decrease transportation cost, near slaughterhouse or processors decrease marketing cost. Balance with biosecurity 

What should be considered in biosecurity and disease control?

isolation distance from nearest pig unit, have fencing and controlled entry, have buffer zones (barriers) to limit odor. Keep in mind of wind direction.

What should be considered in regulatory compliance?

meet local environment and zoning laws → distance from water sources, schools, and residential areas

What should be considered in Odor control?

Use vegetation screens, covered waste pits, proper ventilation

What should be considered in space requirements?

housing, waste management, feed storage and future expansion

What should be considered in future growth?

allows scaling up operations without violating zoning rules

What are some Site Layout Considerations?

Separate clean & dirty zones, facilitate 1-way animal flow from farrowing→nursery→grower/finisher.

easy cleaning and disinfection, include buffer areas and windbreaks, position office and storage away from pigs

Farrowing frequency

time from one group farrowing to the next

If you only have 1 farrowing facility then what would the farrowing frequency be?

the frequency and the facility schedule would be equal

If you have 2 or more farrowing facilities, then what would the farrowing frequency be?

facility schedule divided by # of facilities

number of litters depend on what?

number of days between farrowing (interval), average weaning to breeding interval, length of gestation, weaning age, farrowing rate

How do you determine farrowing interval?

average weaning to breeding interval + gestation + weaning age

What is the farrowing interval?

number of days between farrowing

how do you determine number of litters per year?

(days per year/farrowing interval) * farrowing rate %

EX: farrowing rate → 90% & farrowing interval is 140 days. What is the number of litters per year?

(365/140)*.90 = 2.34 litters