Dairy cow nutrition Flashcards
how efficient are dairy cows
90% of the efficiency of pure corn/soy protein diet
when do you want heifers to calve
2 years
how often should cow have a calf
every 13-14 months
how long is dry period
2 months at end of pregnancy
how many calves do cows usually have before being replaced
3
how many times are cows milked/day
2-3
does reticulum have enzymes
no
rumen lining
papillae lining –> mucosa
what does rumen break feeds down into and synthesize
VFA, amino acids, protein, some vitamins
does omasum have enzymes
no
does abomasum have enzymes
yes –> glandular
what does abomasum secrete
HCl, mucin, pepsinogen, rennin (clots casein), lipase
how much of feed is digested in rumen
70%
what do microorganisms produce
VFAs –> primary energy source, protein
what happens to excess hydrogen in rumen
attached to carbon to produce methane (can’t make CO2, H2O because no O2)
what is fiber broken down into in rumen
acetate, butyrate (2c, 4c)
what are starches and sugars broken down into in rumen
propionate (3c)
what can cow convert into glucose
propionate (in the liver)
body condition during calving, peak, dry off
- calving: >3
- peak: >2.5
- dry off: >3.25
lactation stages and times
- early: 7-70d
- peak: 71-140d
- mid and late: 140-“305”
do different lactation stages need a different ration?
no - just different amounts
dietary changes dry cow –> transition
- different ration for dry cow than lactation
- transition from dry to lactation diet 3w prior to calving and 1 week after
early lactation
- rapid increase in milk production
- negative energy balance
- increasing dry matter intake
- requires high protein
peak production
- max dry matter intake
- highest milk production
- sets pattern for whole lactation
- limited by dry matter intake
- high energy density, protein, bypass protein
