A/15. Nutrient Requirements and Feeding of Beef Cows. Flashcards
Describe the yearly cycle in beef cattle at calving?
- Spring calfing( around Feb)
- First time heifers calving at 2 years of age
- ovulation satrts around may( they have 5th of may!!)
- calf is suckling cow at this stage(period when cow needs most energy)
- give 150% energy and 160% protein and 100% maintenance
How much Ca and P needed after calving?
33g Ca
25g P
Describe the yearly cycle in beef cattle from mating onwards?
- start of mating around start of may, lasts for approximately 125 days and ends around sep-oct at weaning of first calf(when it is 7 months old)
- cow in calf and supporting the first calf
- give 120% energy and 130% proteins
How much Ca and P needed during mating period?
27g Ca
22g P
Describe the weaning period?
- Weaning of the calf occurs around oct
- lasts for approximately 110 days
- lasts around 110 days at start of jan just before calving of the second calve
- mid pregnancy
- 1st stage of dry period
- no suckling
- energy for pregnancy is low (maintenance period only give 100%)
how much Ca and P should be given during 3rd period(maintenance) (weaning period)?
17g Ca & P
Describe the dry period(period 4)?
- start of dry period around 1st of jan lasts for 50 days and ends at calfing!
- 2nd stage of dry period
- shorter
- extra energy needed opposite to dairy cow
- to prepare for calving because the cow is usually in a suboptimal state(since she has been lactating and been pregnant at the same time!
- critical period: give 120% energy and 115% proteins to reach optimal bcs
Dry period Ca and P requirement?
Ca 25g
P 20g
Energy for Maintenance?
0.322 x W0.75 NEm MJ
- Pregnancy(gestation needs)
- the transformation from ME⇒ NE(k value) is only 13%(bad) during pregnancy
- NEm depends on the birth weight and the time of pregnancy as the foetus growth is exponential in the end
Energy requirement for Milk production?
NEm = 4.184(0.1 fat% + 0.35) MJ/kg milk
Depend on the milk fat % ( great differences between genotypes)
Energy requirement for weight gain?
We also have use NEg, not only NEm, for breeding heifers, pregnant heifers and first lactation cows, because they all need a certain weight gain
What happens 2-3 weeks before breeding?
- We increase the energy and CP supply for flushing to increase the number of eggs ovulated
- For the protein requirements use MP
Name and describe the two systems for condition scoring in cattle?
Nebraska system: We have to touch the ribs and feel how they are covered with fat
- from 1-9 ( 5 is optimal, 6 in case of autumn calving)
Scottish system: used for dairy cows
- from 1-5
- back and tail region must be evaluated
- the condition at the time of calving strongly correlates with the next conception rate!
- 3-3.5 optimum in dairy cow
Feedstuffs for beef cattle?(Cheap!)
- Grazing & their hays
- straws (corn stalk)- dependent on the cutting time! if cut early they are similar to hays
- sorghum, green wheat, whole corn plant
- NPN sources cannot be used due to constant small energy deficiency( the microbes do not receive enough energy to build in urea)
- second growth ( after harvesting, cobs lying on the ground) cut stubble field(often the best)
- beet pulp
- silage with combination: corn stalk and diluted molasses(due to its DM content) it is cheap and good mix
are concentrates fed to beef cows?
Only in case of strong demand(expensive)
prior to calving and after calving!
