Poultry and Livestock Examination Review

All in/all out
Definition: A production system where all animals go through all stages of production without additions during the cycle.
Purpose: Preserves biosecurity.
Vertical integration
Definition: A structure in which multiple phases of production, processing, and distribution are owned by a single entity.
Economy of scale
Definition: A cost advantage that arises with increased output, where fixed costs are spread over a greater number of units of production leading to higher profit margins.

Time from ovulation to egg being laid: Approximately 24-27 hours.
Time until another yolk is ovulated after laying: 30 minutes.
Anatomy:
The left ovary and oviduct are present in birds, consisting of a long oviduct divided into several sections.
Incubation Period of Chickens: The time from egg laying to hatching is 21 days.

Definition: A process where farmers induce birds to stop egg production, molt, regrow feathers, and regenerate their reproductive tract.
Method: Often achieved by withdrawing nutrition.
Benefit: Extends hens' egg production abilities for up to 2 years.
Observation: Hens typically produce 20-25% fewer eggs in the second year, with a decrease in egg quality as they age.

Farrow to Wean: Yes, incorporates breeding and semen; piglets are produced and weaned.
Finishing operation: No.
Farrow-to-Finish Operation:
A business model where a breeding herd produces piglets that are raised until they reach market weight.
Purebred/Seedstock Operation: Similar to farrow-to-finish operations but focuses on foundation purebred pigs for showing or cross-breeding systems.

Type: Monogastric omnivores, similar to humans.
Diet: Fed high-energy feeds/concentrates, primarily sourced from the Midwest, which is a hub for swine production.

Evolution from a focus on fatty meat to leaner cuts.
Increase in litter sizes alongside longer bodies means more meat per animal.
Housing has moved indoors for more concentrated and aggressive swine production.
Crossbreeding majorly used for hybrid vigor, which improves productivity.
Weaning ages have decreased while litter sizes have increased.

### Reproduction
- Gilts reach puberty: 5-8 months of age.
- Breeding: On the 2nd or 3rd heat cycle at 7-9 months.
- Estrus cycle: Occurs every 21 days year-round.
- Processing Age: Pigs are typically sent to processing at 6-7 months, weighing between 250-300 lbs.

Sheep: Graze, preferring grass and ground vegetation.
Goats: Browse, consuming a variety of vegetation including bark, twigs, and leaves.
Note: Goats are more susceptible to parasites.

Factors:
Lower demand for wool.
Lack of infrastructure for slaughter and marketing.
Competition for land.
Difficulty in hiring and maintaining reliable herders.
Seasonal breeding causing production peaks and valleys rather than consistent output.
High susceptibility to parasites.

Causes: Pox virus.
Transmission: Direct contact.
Common Clinical Signs: Sores, crusting, blisters on the lips, muzzle, udders, feet.
Treatment: Supportive care; allow time for healing.
Note: This condition is zoonotic; humans can contract it.

### Length of Pregnancy
- Cattle: 9 months.
- Sheep and Goats: 5 months.
- Pigs: 3 months + 3 weeks + 3 days.
- Dogs: 2 months.

Length of Estrous Cycle: 21 days.
Breeding Age for Beef Heifers: Typically bred at 13-15 months, aiming for 65% of projected mature weight.
First Calving Age: Heifers will typically calve for the first time at around 24 months.

Cow/Calf Farms:
Output: 400-750 lbs weanlings, 6-10 months old.
Stocker Operations:
Buys weanlings, feeds them, sells at 600-850 lbs approximately 12-16 months of age.
Feed Lot:
Cattle reach market weights of 1000-1450+ lbs in about 18-24 months.

Type: Horizontal, highly segmented with different stages of production managed by distinct entities.
Health Implications: Constant movement can predispose cattle to shipping fever due to transportation stress leading to lowered immune defenses.
Disease Risk: Cattle in transit may become susceptible to Bovine Respiratory Disease Complex.

Cause: Pathogenic form of a normally occurring protein (PrP) caused by misfolded proteins.
Incubation Period: Ranges from 2 to 8 years.
Common Clinical Signs: Ataxia, down cow syndrome, depression, weight loss, acute death, aggression, and muscle twitching.
Treatment: No viable treatment available; euthanasia is the only option.

### Phases of Beef Production and Feed
- Cow/Calf Farms: Primarily feed forage (grass) and roughage, utilizing pasture or hay.
- Stockers: Diet includes forage and roughage.
- Feed Lot: Introduces concentrate feeds with some forage to maintain rumen health.