Animal Production

1
Animal Production
2
Forage/Plant Factors

• AP Fn FQl FQn
• Animal productivity in a forage based system is a
  function of forage quality (FQl) and forage
  quantity (FQn). The amount of forage available
  to the animal is also known as forage
  availability.

3
Forage Quality

• FQl fn FDg FCm)
• Forage quality is a function of forage
  digestibility, the amount of material that may be
  digested and utilized by the animal, and forage
  composition, what nutrients in both polymolecular
  (amino acids, vitamins, etc.) and molecular
  (minerals) forms.

4
Digestibility

• The amount of material broken down and absorbed
  by the animal
• increasing digestibility of the plant increases
  productivity per unit intake (efficiency) or
  decreases the intake per unit performance
  (productivity)
• increasing digestibility increases forage intake
  (when forage availability is not limited) because
  food material moves through the animal faster,
  allowing the animal to refill the gut.

5
Digestibility

• FDg fn Cp Pm
• Forage digestibility is a function of
  chemical/nutrient composition and plant maturity
• Nutrient Compositions
• Primary Components listed in least to most
  digestible
• Lignin
• Tannin
• Cellulose
• Hemicellulose
• Total nonstructural carbohydrates
• Secondary Components
• N, P, K
• Must balance animal/microbe needs to have optimal
  digestibility

6
Plant maturity

• As the plant ages
• It decreases in digestibility
• Physiological age
• Seedling
• Vegetative
• Reproductive
• Nutrient Composition
• increased cell wall thickness
• increased lignin, tannin, etc. content
• decreased TNC and hemicellulose
• Leaf content
• leaf is more digestible than stem
• leafstem ratio decreased

7
Plant Species

• C3 vs. C4
• C4 have addition CO2 pathway
• increased yield
• increased cell wall contents
• increased vascular bundle content
• NET
• increased drought tolerance
• increased risk
• increased cost
• Annual vs. Perennial
• less lignin, tannin and cellulose
• greater leaf content
• total yield is similar
• less TNC storage in the plant roots.

• Legumes vs. Grasses
• Legumes compared to grasses
• produce nitrogen
• higher CP content
• more digestible stem
• more TNC
• less structured carbohydrates
• NE Texas
• lower yield potential
• reduced drought tolerance
• tolerate a smaller range of soil conditions
• soil pH
• soil type
• P hogs.

8
Forage Intake

• FI fn RD FA
• Forage intake is a function of the rate of
  digestibility and forage availability
• Increased intake is associated with increased
  animal productivity
• Rate of digestibility
• A has higher total intake
• Increased intake due to reduced gut fill time.
• Forage A digests quicker, allowing the animal the
  room for more feed sooner.
• Gut fill regulated by
• metabolic rare in grazing
• physical often in grazing

9
Forage Availability

• Grazing Systems
• Continuous grazing
• FA fluctuates constantly due to animal intake and
  plant growth
• increase FA
• increase selectivity (increase leaf intake)
• decrease travel (decrease energy loss)
• Rotational grazing
• Flexible system that allows rationing of forage
• Herbage allowance the amount of forage available
  within a certain unit of time. Usually expressed
  as lb/head/day
• Grazing pressure Reciprecal of herbage allowance
  (head/unit forage weight)

• The amount of forage available for immediate
  animal consumption usually expressed in
  weight/area.
• FA fn PD PH
• forage availability is a function of plant
  density and plant height
• Plant structure changes both.
• Animal species difference
• sheep nibblers
• get closer to the ground
• cattle tongue adhesion
• require more leaf separation

10
Forage Acceptability

• Fac fn FPl FM)
• Forage acceptability is a function of forage
  palatability and forage morphology.
• Palatability Usually a chemical function.
  Reflects a preference of the animal based on
  inherent forage traits.
• Sugars increased palatability
• Alkaloids decreased palatability
• Morphology Plant structure that inhibits or
  enables animal consumption
• Large leaves high animal preference
• Thorns greatly reduced animal preference

11
Summary

• Forage management combines both crop and animal
  production techniques. Rules and laws are
  difficult to establish. Exceptions are easy to
  find. To truly understand forage management an
  ecological point of view (big picture) is
  required.