ANSC 4394 Exam 2 |Complete Q’s
and A’s
As fed (wet ; fresh) - --expression of nutrient concentration of a feedstuff in
the wet form of that feedstuff
- Dry Matter (moisture free) - --expression of nutrient concentration of a FS
in the dry form of that FS
*we prefer this*
- Air dry (approx 90% DM) - --expression of nutrient concentration in a FS in
a 90% DM basis
-For dry grains and air : air dry = as fed
- Conversion calculation - -%nutrient as fed/%feed dry matter=%nutrient
dry matter/100% dry matter
- Conversion - --changing nutrient concentration of all feedstuffs to be
compared to a dry matter basis allows accurate comparisons of nutrient
concentration of all various feedstuff
-differences in % moisture invalidates the comparison of feedstuffs on an as
fed basis
-the moisture effectively dilutes the concept of nutrients in the FS
- AF to DM - -nutrient content increases, weight decreases
- DM to AF - -nutrient content decreases and weight increases
- Digestion/metabolism trial - --differences between what went in and what
came out
1. analyze feed ingredients
2. feed animal a given amount
3. collect feces
4. analyze feces
- Determining a digestion coefficient for protein - -Assume: Step 1: calculate
weight of feed and feces collected (days X lbs collected per day)
- Determining a digestion coefficient for protein (con't) - -Analysis: Step 2:
calculate DM consumed= total lbs for feed X % DM feed
Step 3: DM consumed X %CP feed
Step 4:DM excreted= lbs for feces X feces % DM
Step5: DM excreted X %CP feces =CP excreted
, Step 6: %CP of feed consumed - %CP of feces excreted=answer/%CP of feed
consumed X 100=digestion coefficient
Step 7: %CP of feed X digestion coefficient
- Ruminants - -Digest in rumen
%CF digested=50-90% aka EXCELLENT
- Digestibility of CF by species - -Horse-cecum-13-40%(poor)
Pig-cecum-3-25% (poor)
Rabbit-cecum-65-78% (better)
rat-cecum-34-46%(poor)
dog-cecum-10-30% (poor)
Man-S&L Intestine-25-62(better)
Poultry-cecum-20-30% (poor)
- Feedstuff Energy Methods of Measuring - --Total digestible nutrients (tdn):
popular
-Calorie system:human measure this way
-roughage/concentration ratio (r/C) system
-Net energy:new
- TDN - --determination: use chemical analysis to determine nutrient
composition to get crude composition
-determine the digestibility of feed nutrients by a digestion trial to get
digestion coefficent
-calculates digestible nutrients (crude composition X digestion coefficient)
-calculate TDN (%dig pro + %dig fbr + %dig NFE + %dig fat X 2.25)
- TDN Advantages - --establish
-familiar
- TDN Disadvantages - --considers only digestive losses (feces ignores
energy losses via urine, gases, and heat production)
-not expressed in energy terminology
-% of weight vs calories
-overestimates energy value of forages, especially: poor quality forages
- Net Energy Methods - --energy balance trial: direct caloric measurement
of energy intakes and losses
-comparative slaughter technique: measure energy retention NE directly;
NEm=.77 mcal/mbs/day
- Gross potential energy (GE) - Fecal energy (FE)= - -Digestive energy (DE)
- DE- (UE: Urinary energy + GPD: gaseous production)= - -Metabolic energy
(ME)
and A’s
As fed (wet ; fresh) - --expression of nutrient concentration of a feedstuff in
the wet form of that feedstuff
- Dry Matter (moisture free) - --expression of nutrient concentration of a FS
in the dry form of that FS
*we prefer this*
- Air dry (approx 90% DM) - --expression of nutrient concentration in a FS in
a 90% DM basis
-For dry grains and air : air dry = as fed
- Conversion calculation - -%nutrient as fed/%feed dry matter=%nutrient
dry matter/100% dry matter
- Conversion - --changing nutrient concentration of all feedstuffs to be
compared to a dry matter basis allows accurate comparisons of nutrient
concentration of all various feedstuff
-differences in % moisture invalidates the comparison of feedstuffs on an as
fed basis
-the moisture effectively dilutes the concept of nutrients in the FS
- AF to DM - -nutrient content increases, weight decreases
- DM to AF - -nutrient content decreases and weight increases
- Digestion/metabolism trial - --differences between what went in and what
came out
1. analyze feed ingredients
2. feed animal a given amount
3. collect feces
4. analyze feces
- Determining a digestion coefficient for protein - -Assume: Step 1: calculate
weight of feed and feces collected (days X lbs collected per day)
- Determining a digestion coefficient for protein (con't) - -Analysis: Step 2:
calculate DM consumed= total lbs for feed X % DM feed
Step 3: DM consumed X %CP feed
Step 4:DM excreted= lbs for feces X feces % DM
Step5: DM excreted X %CP feces =CP excreted
, Step 6: %CP of feed consumed - %CP of feces excreted=answer/%CP of feed
consumed X 100=digestion coefficient
Step 7: %CP of feed X digestion coefficient
- Ruminants - -Digest in rumen
%CF digested=50-90% aka EXCELLENT
- Digestibility of CF by species - -Horse-cecum-13-40%(poor)
Pig-cecum-3-25% (poor)
Rabbit-cecum-65-78% (better)
rat-cecum-34-46%(poor)
dog-cecum-10-30% (poor)
Man-S&L Intestine-25-62(better)
Poultry-cecum-20-30% (poor)
- Feedstuff Energy Methods of Measuring - --Total digestible nutrients (tdn):
popular
-Calorie system:human measure this way
-roughage/concentration ratio (r/C) system
-Net energy:new
- TDN - --determination: use chemical analysis to determine nutrient
composition to get crude composition
-determine the digestibility of feed nutrients by a digestion trial to get
digestion coefficent
-calculates digestible nutrients (crude composition X digestion coefficient)
-calculate TDN (%dig pro + %dig fbr + %dig NFE + %dig fat X 2.25)
- TDN Advantages - --establish
-familiar
- TDN Disadvantages - --considers only digestive losses (feces ignores
energy losses via urine, gases, and heat production)
-not expressed in energy terminology
-% of weight vs calories
-overestimates energy value of forages, especially: poor quality forages
- Net Energy Methods - --energy balance trial: direct caloric measurement
of energy intakes and losses
-comparative slaughter technique: measure energy retention NE directly;
NEm=.77 mcal/mbs/day
- Gross potential energy (GE) - Fecal energy (FE)= - -Digestive energy (DE)
- DE- (UE: Urinary energy + GPD: gaseous production)= - -Metabolic energy
(ME)
