3.5 Feeding GF pigs pt 1 - T3 Flashcards
What is the main objective when feeding GF pigs? What decisions have to be made?
Optimize profit
- maximize income over feed cost
- not the same as “least cost diet”
- not the same as maximizing performance
Decisions
- optimize profit per pig?
- optimize profit per pig place?
- maximize performance?
What is gain:feed?
How much they gain compared to how much they eat
- better managed = grow more with the same amount of feed
How to go from good performance to best performance?
Higher daily gain = less days in barn
- also better carcass index
How is carcass index calculated?
With carcass grading grid
Carcass wt vs. live wt? Which dietary factor mostly affects dressing percentage?
- viscera wt is what makes the difference btw the two
- fiber bc it causes a thickening of viscera and reduces carcass wt and negatively affects dressing percentage
How do producers minimize variation? Would we minimize variation?
- Could minimize variation by selling pigs over a period from 1 room
- Producers are more likely to keep the all-in-all-out system and take the hit for lack of uniformity (in order to prevent disease)
How can feed cost be minimized?
Meet requirements
- excess nutrients = waste of resources and money
- insufficient nutrients = reduce performance, extra das in barn, maintenance costs
Knowledge
- actual and potential performance of pigs
- FI
- marginal effects of nutrients on performance
Does an incremental intake of lysine result in an incremental increase of growth?
NO! There is a limit
What is performance potential vs. actual performance? Can we change performance potential?
- performance potential occurs under ideal conditions to grow and ideal diets; may not be feasible in production
- as a producer cannot change it but genetic companies can
What factors affect performance?
- Genotype, sex
- lean genotypes
- gilts > barrows - Environment
- Health status
What does an ideal nutrition program match?
Matches nutrient supply for maintenance + growth to actual performance on farm
Stress is…
ADDITIVE
- high temperature, high density, re-grouping
- if you add more stressors you get a greater reduction in feed intake
What do we commonly use as an indicator of stress in pigs? Why?
Cortisol = stress hormone
- plasma or saliva
- amygdala (stress signalling)
- hypothalamus (activation of hypothalamic pituitary adrenal axis)
- adrenal (cortisol)
What does an increase in cortisol do to pigs?
- Increases blood glucose concentration
- Decrease insulin sensitivity
- Acute: lipolysis; chronic: lipogenesis and proteolysis
- Immunosuppression: inhibition of pro-inflammatory cytokines
Diet nutrient concentration
Req of pigs
- g/day or MJ/day
Diet formulation
- %, MJ/kg
How can diets be optimize?
- Need to know feed intake on a daily basis (g/day, MJ/day)
- Need to know performance (drives requirements)
- pigs that grow at higher rates have higher requirements
Is a diet higher in lysine a better diet?
NO, depend on context
What happens if feed intake is underestimated?
- Diet is formulated to contain more AA (more nutrient dense)
- Excess nutrients, but no impact on lean growth
- Wastes $$$
What happens if feed intake is overestimated?
- Diet formulated to contain less AA
- Lower nutrient intake = lower lean gain
- Pigs need more days in barn to finish = higher maintenance costs
What happens when health status is reduced?
- Eat less = grow slower
- lower protein deposition -> lower AA req (g/day) - Shift in protein deposition
- muscle (fast twitch fibers) -> less protein deposition
- liver, lung and heart -> increased protein syn
- greater Phe, Tyr, Trp content in liver than muscle - Reduced FI -> compensates for lower daily req
- req (%) of diet not affected - Shift in AA req patterns during immune challenge
- tryp will have higher req
How do we change health status?
several ways
- biosecurity
- vaccination
- cleaning and disinfection
- optimizing enviro
What data can be used to access performance?
- Initial wt
- Mkt wt
- Growth rate
- ADG or days to mkt - Lean growth rate
- carcass data or real-time ultrasound - Feed intake (or F/G)
How is feed intake on the farm measured and utilized?
- Measure disappearance
- regular intervals (every wk)
- based on delivery slip - Relate to body wt
- weigh pigs at regular intervals - Establishes growth performance and feed intake curves
Feed intake vs disappearance, what is the difference?
Difference is WASTAGE
- hard to compute
- but want a good estimate bc bad data = bad decisions
- Well adjusted feeders will reduce wastage
